It’s much easier to design a system where you can swap engines when you don’t need to care about the size, weight, or dimensions of the final product. Which is kinda the opposite of vehicles in general and aircraft in particular.
Nonsense. Its super easy. Just ask anyone whos ever done a Auto to Manual Trans swap. Piece of cake... Just like that LS swapped Honda Accord that was made rear wheel drive. Did it by myself over a weekend with simple tools i got at walmart. Id show you pictures but ummmmm my uhhhh camera broke. They really dont. The amount of work involved is staggering. All those little details and things that come up when you actually sit down and start the work. Every problem you fix potentially creates another. Wtih something like a combat aircraft, you also have logistics and manufacturing to consider and that's its own world of complexity. With something like the P38, the war would be over by the time you were done and you would have been further ahead if you simply built a new aircraft from the ground up.
My son wants to modify his Chevy Avalanche's suspension. He stated he knew what to do and I told him He is not an engineer and modifying even small things can have dire results. I know what u mean, but you can't argue with a someone the already Knows it all.
P-38, my favorite WW II fighter/attack airplane. Long range, fast, highly armed and beautiful. American design at its best, Kelly Johnson strikes again.
P-38 / K. Johnson - "Skunk Works" close-collaboration project model scores again!! Read up on this - it WORKS IRL; few mgmt "cults" do. !!NO NECKTIES!!
@@mrcat5508 >>Mach limits, airframe dive limits, etc. Thing was too slick for it's own good. Stall recovery was non-standard, too: standard recovery put you into another stall/spin, usually the other way!! The dive brakes must have been kinda a hoot: DIVEspeedDIVESPEEDSPEEDDIVEyokebackNUTHINomgomgohyeahleverpullomgomGoMGOMGPULEEASE nose up "I watched some of the P-47 guys go flying straight on past to make smoking holes in the ground and I wondered what that was." - B-17 pilot (some documentary I saw)
My all time favourite piston engined aeroplane is the Mosquito - known as the Timber Terror or the Wooden Wonder by pilots in different places. But then I'm on the other side of the Pond to you guys. Because it was mainly built from plywood it was quite stealthy for its time; hard to spot with German Radar. It also had a very good reputation for getting the crew back home, even if badly damaged. I also like the P-38, which was definitely an effective aircraft, but it had a poor reputation if it lost an engine or went into a stall or spin.
I wonder if another factor against using Merlins in a P-38 might be better utilization of total US mfg capacity. Adding P-38 2x per air-frame engine requirements would drive a big increase in Packard Merlin production demand vs leaving the total P-51/P-38 engine requirements split between Allison and Packard.
It would have been a problem for sure, but given time, Allison production could have been switched over the Merlins. They did that sort of thing all the time during WW2.
If there HAD been a compelling reason for such a switch, what would have prevented Allison from simply switching some V-1710 production capability to build the Merlin copy V-1650's along with Packard? Or Allison not growing as fast, while Packard grew faster? You seem to think labor is locked into working for one specific company, that the company is of a fixed given size that doesn't respond to market needs, and that this company can only produce a certain product even if customers demand something else. None of this is true. As Greg makes crystal clear, there's utterly no reason to put a dual-supercharged Merlin (X and later) into the P-38. It's not as if there is some nagging doubt remaining to be quashed by questions of engine availability.
@@lqr824 In order to produce more of the other engine by switching over production capacity, you also need to change tooling and that both takes time and introduces a slump in production where overall engine availability goes down because the tooling is being modified/replaced and workers are being retrained to switch over to a different engine production - that also comes with potential production quality issues that may take some time to resolve. In a scenario where the weapon system you're using is "good enough", there is almost never a valid reason to change it unless the change directly increases the speed of producing or performance of said weapon without incurring major logistical drawbacks. So the reason for something major like switching to a completely different engine type doesn't only need to be compelling, it would have to be compelling enough to be worth the temporarily reduced production output which is a very high bar to meet. The saying goes that perfection is the enemy of good enough.
@@lqr824 because you were trying to make switching engine production between types sound a lot more trivial than it is. The person you're replying to originally is pointing out a fairly major logistical consideration that played a role in what kind of motor was chosen for various planes in practice.
Greg, running out of superlatives for your videos. They just keep getting better and better...and they have been the best on YT for some time. Great work. It reveals so much about the issues that faced designers and engineers in the period. Some really amazing folks did some amazing things. Have to feel for the Allison team...with the proper boosting their engine was a beast. By the time they got it right with the King Cobra it was too late. Kudos for such great work.
Greg, this is your best video yet. I can't thank you enough for addressing the Merlin swap issue. At least your viewers will be better informed than the droves of internet fanboys that don't understand the airplane and think the V-1710 was the problem and that the Merlin would have worked magic on the airplane. I especially appreciated the detail on the paddle blade props. I love the P-38, but agree that further development would have been a misapplication of resources by that time. Plus, spending a huge amount of money on making an airplane with compressibility issues go really fast at altitude was not the best option in light of the available alternatives. None of this takes away from the original brilliance of the P-38 when one considers the circumstances behind its design.
Kelly Johnson was involved in the design... second project I think. No wonder it was such a good aircraft. Charles Lindbergh showed how to operate the engine in the high boost low rpm area for extended range.... and Anton Dr sanzuperey died in one over the med
"brilliance of the P-38" Why do people like this plane so much? A genuine question. From my point of view, this airplane was heavy, hard to maneuver, difficult to bail out from and had those compressibility issues. All of that on top of what I consider to be the main problem, that is the high cost of production. In the times when the Brits counted how many flush rivets the Spit actually needs to remain fast, P-38 was trying to do the same job, but with two engines instead of one, and two turbos on top of that. Stainless steel too, in case those difficulties could be powered through somehow. I mean, it was a good airplane. Good enough to justify all of the above? I feel like it wasn't, but feels are nothing when confronted with facts, so hit me with those.
@@bakters lighting was an early design and the pace of aeronautical knowledge increased as never before so Lockheed were pushing the envelope with all these ground breaking features.... that's what Kelly does. The only way to find out is to do it but as the war progressed they learnt a lot very fast. A Merlin engine lightning would probably look like a mosquito....no need for tailbooms and stainless steel to accommodate a few the enormous turbocharger so it's a fusilage with enginese on the wing. As for the Brits they always develop a design. It's what they are good at. The later spitfires were roughly twice as heavy twice as powerful and had almost no parts in common with the early ones... only the name.
Quality video. The new tech in the Allison's turbo superchargers, was complex and buggy at Northern Europe's cold high-altitude missions and gave newly trained pilots a helluva lot to deal with and almost always during combat when it was least appreciated. It's why they were reconsidered for 8th AAF Bomber escort duty and put to a much more advantageous environment in the Pacific and why their legacy in the Mediterranean was more fortunate as well.
The problem of icing induction systems persists today (nearly). I had an 900cc Yamaha bike (omg a bike isn’t an aircraft). It made 90 bhp at 8500rpm. Twin cams eight valves one carburettor per cylinder. It was great with smooth usable power. But wet misty weather would ice up the carbs. It was hard to clear because closing throttle increased the chilling effect. Not a good experience on a fast motorway. Absolutely terrifying when there’s an FW190 on your tail.
@@richardbriscoe8563 >>mismatch turbo yes - I'd read this, too. Is there also something in the manufacturing / metallurgy that caused problems in the high-RPM turbo disks? Or have I got that part wrong. I believe the problem was disintegrating disks spitting shrapnel thru the rest of the engine. Can you confirm or set me right?Thanks. I also understand that the fuel in the field was way flaky (wet, god-knows-what-infused, maybe 80+ octane at best) which also goofed up the turbo system. Any info there?
Having watched your earlier videos, I immediately knew the P-38's supercharging system would be at the heart of your answer regarding the suggested Merlin swap. I am in awe at your ability to explain complex technical issues to a lay (but inquisitive) audience of non-engineers.
>>your ability to explain complex technical VERY big agreement with this compliment from a 40-year high-tech/aerospace technical writer and professional geek. It is hard to make it seem as simple as you do. VERY hard.
Fitting two stage Merlins in a P-38 means a major redesign of the whole engine nacelle if not the whole airplane. The two stage supercharger is attached directly to the Merlin's back side, making it quite long. It gets even longer because the two supercharger stages are on the same shaft and between the stages there is the intercooler. Does that fit in front of the P-38's firewall without shifting the center of gravity forward? I don't think so. The big turbos are behind the CG. When they are not installed the CG of the airplane shifts forward. So, there are two things shifting the CG forward. That is not a good idea because there barely is enough equipment inside the booms that could be repositioned further back to compensate for the CG shift. An important reason for not switching to paddle blades on the P-38 is, when the paddle blade prop became available there was not that desperate need for more performance anymore. The Japanese were already getting weaker and were already outnumbered by Allied fighters. In Europe the P-51 already had started to replace the P-38. The expensive and time consuming conversion of production lines, time consuming field conversions of existing aircraft and difficult conversion of the supply system for replacement parts simply was not worth it. The P-38 was an expensive airplane. Its main advantage over other fighters was its range. New versions of the P-51 and P-47 already were in developement in 1944 and they were designed to overcome their previous disadvantage in range without getting as expensive as the P-38. No doubt the Air Force already was thinking about phasing out the P-38 in mid 1944.
Some Mosquitoes had 5 exhaust stacks and some 6. The 5s were on shorter nacelle single stage supercharger Mosquitoes with the last exhaust port directed forward and twinned so as to clear the inboard leading edge radiator intake.
I entirely agree with your above statement. They had quite similar issues with the thoughts of modifying the Westland Whirlwind, an aircraft not unlike the P38. To fit Merlins in place of the Peregrine was a major problem, not only in C of G but other complicated factors too.
The Merlin/P-38 debate has been a long discussed topic, with some revisionist theories constantly polluting the facts. As detailed in Warren Bodie’s excellent tome on the P-38, Lockheed, specifically Kelly Johnson, early after production worked up drawings using Merlins 2stages on P-38s. As explained by Greg’s excellent explanation the greater power ratio would have been offset by the reduced weight of the removed Turbo Super, but not to the extent that the War Production Board (WPB) would allow a delay in the line at Lockheed. Additionally; the Paddle bladed P-38’s were to be used on the P-38K, however using those props created a change in the thrust line, which again the WPB would not allow Lockheed delay production for an aircraft that was in much needed demand. Even a supreme version like the P-38K, the WPB wasn’t going to halt production for one month, much less than 6 months than what Lockheed estimated for modifications on the line. Hindsight is always 20/20, but the real disappointment should be placed on Material Command not introducing a second production until 1945 with Vultee. Had a second line started in early 1943, say with Bell instead of building P-39/63s for lend lease, or Curtiss with the P-40 variants (while useful, but obsolete) and the Helldiver (forced onto the Navy), possibly the shortfall of the aircraft in the PTO could have been avoided and actually hasten the island hopping campaign through the Philippines.
@@ikekelly3157 I doubt that Bell would ever have been asked to stop production of P-39s and P-63s. The Allies were very keen on keeping Stalin friendly to a) avoid a separate peace between the USSR and Germany and b) secure Soviet assistance against Japan once Germany was taken care of. The Cobras were a prominent part of the carrot that was Lend-Lease. I also doubt that Curtiss would have stopped making P-40s. It was no world-beater in terms of raw performance, but then neither was the Hurricane or Hellcat, and they still did fantastic service. Besides, war is a numbers game, and the P-40 was one of the most produced American planes. Vultee being contracted to set up another production line might have worked. That, or perhaps Lockheed could have set up an additional line of their own, similar to North American and Republic.
@@Beowulf_DW Yeah, but the difference between the P-40 and the Hurricane is that it was modified for other missions like CAS with the Mk. IId and Mk. IV. And the Hurricane did well in those missions. And the Hellcat was still competitive in it's operational enviroment, as well as sturdy and easy to fly, with good handling around the boat. The latter of which is something of a rarity in Warbirds. Also the Hellcat's Performance is decidedly superior to the P-40. Edit: However, the P-40 is a severely underapreciated plane, just as the Hurricane is in public perception.
Greg, as usual an excellent video. Thanks for straightening out the what ifs on the Merlin powered P-38. One thing I remember reading in Daniel D. Whitney's "Vees for Victory, The Story of the Allison V-1710 Aircraft Engine 1929-1948" was that the Army Air Corps was insisting the Allison use the new GE turbocharger instead of a two stage supercharger. As I remember, this was well before the U.S. entered WWII and may have even been before the 1939 start of the war in Europe. The book also notes, that while the proposed Merlin powered P-38 would have been faster than the Allison powered version, it would also have had shorter range, which was one of the P-38's great advantages. Thanks again for a great video.
That's true, I cover that aspect in other videos. Yes, the USAAF was married to the idea of using the exhaust driven turbosupercharger, thus Allison didn't bother with a mechanical second stage until very late in the war.
@@GregsAirplanesandAutomobiles I gather that the turbo is a more economical way to get more power as the compression is gained from otherwise wasted exhaust gas pressure whereas a mechanical supercharger has a substantial and continuing cost in power to drive the turbo disc from the crank or an accessory shaft with that power requiring fuel burn. That is why a Merlin P38 would have suffered significant range loss. Its takes a lot of power to achieve more power - the Wasp Major as fitted to the B36 achieved a gain of about 2000 HP at 30,000 feet by supercharging at a cost of 500HP so a useful net gain but not cheap. This is figure is my recollection from the great book "Magnesium Overcast".
@@terrybrown8539 Also, V for Victory made an interesting point about the Allison's needed to pass a rigorous 100 hour test stand run before type acceptance by the Army, which I found very interesting.
@@terrybrown8539 the numbers all point to the turbocharger as the way to go but it was a big step technologically to actually make one back then. Very high speed shafts and discs to balance. The early ones were huge and heavy...cast iron etc. Halfway to a turbojet really
@@johnp3937 It's an odd detail, but ME262s had a much lower production cost then often thought because of this. A high power engine like this is very hard to make, and very expensive, and while jet power was of course very new and revolutionary, requiring massive engineering and physics work to be done, mechanically they're a lot simpler to make.
Greg, you're incredible with your explanations. One thing I have to confess, I was always taken by the beauty of the P-38 and the P-51-D, but after watching al your videos, I'm all in for the P-47-D, H and J! I always thought of them as big, lumbering slowpokes. Was I EVER wrong! Thanks for helping us get better informed.
Another excellent video! I'd like to point out that the P-38 had only one production facility which was in Burbank. Another production facility didn't open until very late in the war. A Consolidation-Vultee IIRC. Working up various experimental a/c along with ramping up the P-80 in only one plant probably forestalled any major modifications to the already quite capable P-38J/L as Greg points out. Meanwhile the P-47D and P-51D were being produced in two facilities respectively, allowing modifications to be introduced without completely shutting down production. I have to say as a fan of the P-38 the "K" would have been a winner with climb and acceleration outweighing compressablity issues IMO.
So in demand was the P-38K that Material Command requested it again in April/June 1944, because they needed *more* fighters. It was the War Production Board that forestalled nearly every single advance in the P-38, either slowing or preventing them completely. Consider that half the plant capacity where the P-38 was built was utterly *wasted* building B-17 bombers. If you have fighters preventing your bombers from being shot down, you don't need to build as many replacement bombers or train as many replacement crews. Using 100% of Lockheed Burbank to build the highest demand fighter only made good common sense. Consider that you'd have nearly twice as many P-38's available. That's advantage one. But then consider you'd have skipped the J, and gone to the K, and it would have been 2-3 months ahead of schedule. Now, you have the K built, and you build on that, not the J. So you have even more HP, and you quickly move to a *four* blade Hamilton Standard High Activity paddle prop. Next, with double capacity, you phase in improvements one line at a time, allowing the updates to the center wing and nacelle, including the new radii fillets to improve dive performance, and moving the inlets and outlets for radiators and oil coolers. If you do away with the arrogance, stupidity, and politics of the War Production Board, you change everything.
Yes, even with all the valid arguments, I just cannot see that it would not have been worthwhile to put the "K" into production...and I'll never understand, given all the problems with the R-3350 at it's introduction and deployment in the B-29, they didn't switch over to the Allison V-3420 on at least one production line, considering the performance improvements(and reliability improvements also no doubt)....@@AlanRoehrich9651
Lockheed, Love Field handled much more types of modifications than P-38 mission specific mods. The B-17 & P-51 were Love products too just to name two others. Very many B-17G-VE were H2X mods. That BTO capability had great effect on the CBO strategy of 1944.
Thanks for pointing out how incredibly complicated this whole issue was. Even with these problems the P38 was a great warplane. I heard once it had the highest kill ration of the American aircraft which, of course included the Pacific theater.
@@georgesheffield1580 Pfui - ask about Richard Bong. BOOM AND ZOOM; drop the flaps and out-turn them till they stall; rake things with multiple MGs (and a few cannon just for fun) all with ZERO CONVERGENCE. Pfui.
Concerning the paddle props-the 3 bladed paddle props fitted on the "K" prototypes not only was wider, but longer (bigger diameter). The extra diameter was the issue-to keep the tip speed subsonic the prop had to turn slower. To turn slower meant different reduction gearing (2.35 vs 2.0 IIRC). The different reduction gearing meant a different distance between the crankshaft and the prop centerline-which was the real issue. That meant structural changes to keep the thrust axis located properly and new sheet metal to make that all work. So-the issue was the bigger diameter, 3 bladed (paddle) props. The question I've never seen answered is why didn't it get 4 bladed props, with the same OD as the standard, 3 bladed one, like virtually every other fighter did? The extra blade lets the high activity paddle "work" at the same RPM as the standard, 3-bladed one, eliminating the need for different reduction gearing and revising the thrust axis. Seems like it would have been a much simpler way to go. The other issue, why not a liquid to air intercooler like the Merlin got? Much more streamlined to put a small liquid cooled heat exchanger in the intake air stream, rather than duct all the intake air out to and back from to the air to air one. The original design with the wing leading edge intercoolers was a great concept-intercooling with no added drag. Unfortunately it ran out of cooling capacity at much over 1200hp. The big, chin-mounted intercoolers did the job properly, but added drag-even though they made a lot more power, J & L models were only marginally faster than the G. A liquid cooled intercooler offered more packaging options for the secondary side, potentially utilizing the Meredith effect like the Mustang did to reduce drag. It would also eliminate all that duct work in a crowded engine compartment. Big issue was still compressibility. At high altitudes the standard P-38s weren't far from compressibility speed even in level flight-more power would have got them there quicker. Granted, the huge boost in clime rate alone would have justified it. The other big question-why were no other plants built to produce the P-38? Every other fighter was built in multiple facilities, meaning that new designs could be cut in at one plant, without impacting production at the others. The '38 was only built at Lockheed's Burbank plant until very late in the war, when Vultee built ~100, none of which made it into combat IIRC. Until the P-51-B finally saw combat in December 1943, the Lightning was our only high performance, long range, high altitude fighter. Seems like it would have been obvious that more plants needed to be building them.
This one is for Greg. Your videos always discuss very complex technical issues, but even I, complete noob, understand what you are talking about. Great job. It also shows how complex designing an aeroplane had become by then.
Great Video! I didn't think, that there were people actually thinking that an engine replacement in the P-38 was needed and possible, even less - beneficial. Ultimately, this question is resolved by this video. This has already been resolved in advance, within the video about superchargers, where Turbo- and Mechanical Superchargers were compared with their pro-s and con-s.
There have been several just on Gregs vids, tons upon ton on other 38 vids on YT. Its very much the pop culture view that the Merlin is always better than the Allison when in fact the 51 was more of a special case than most realize
*in Sept 1943 Lockheed delivered to the AAF at Eglin field, a P-38 fitted with 1,875 bhp Allisons and Paddle-Bladed Propellers.* *it had a Top Speed of 432 mph on Military Power, and >450 mph on War Emergency Power. 4,800 ft/min climb rate and 5 mins to 20,000 ft*
Yup, and Lockheed estimated they would have to stop production for at least 6 weeks to update the lines to implement the modifications IF Allison could even mass produce the engines needed. A loss of 6 weeks of production was considered unacceptable, so the "K" was relegated to a historical footnote of P-38 "could-have-been."
@@everking3767 *- it wasn't that Lockheed didn't have the Knowledge or the Expertise to Engineer a Superior Aircraft, but the Decision not to go forward was strictly political.*
@@gerardlabelle9626 *- if in the middle of a WW your Bombers are Suffering Heavy Losses, and a company like Lockheed upgrades their Lightning to the next level. Superior in Speed and Climb, with additional Range and Payload, to anything the Allies had at that time, and you're going to reject it because you don't want to interrupt production for 2-3 weeks.* *What would you call that?*
It would have required 2-4 weeks of production halt. Of course, it would also require the props to be produced. Allison was more than ready to produce the engines. Unfortunately, half of the production capacity of the plant that produced the P-38, Lockheed Burbank, was being used to produce B-17 bombers, the U.S. was desperately trying to keep up with losses due to unescorted bombing. There were also multiple theaters literally begging for the P-38, remember that there were no P-51's at the time. Had the War Production Board chosen wisely, and moved the B-17 production out of Lockheed Burbank, the P-38 improvement curve would have been radically accelerated. Every theater would have been flooded with the P-38K by August or September 1943. Flooded as in the 20th and 55th would have been able to put up at least double what they did, maybe 3-4 times as many aircraft. The dive flaps, boosted ailerons, and flat armor glass would have been there in late 1943, not early to mid 1944. The P-38L could then have been equipped with an even more improved four blade prop, and the G series Allison V-1710 would have been available. So would the unified power control for the throttles, props, and mixture. Would the P-38 have still been limited in dive speed and top speed? Yes, of course. However, the dramatic improvement in rate of climb, acceleration rate, and combat radius would more than make up for the dive limits. The P-38 would have been able to sustain climb and turn rates far superior to most anything except jets. Combat radius allows you to be nearly everywhere. Being able to out climb, out turn, out roll, and out accelerate your enemy means more than dive speed.
Excellent! You have covered this well here and previously. I believe we have all viewed "P-38 A Personal Story". The second quote in the beginning "Once the P-38 received the aileron boost and dive brakes... ". Also, General Kenney made it abundantly clear, he wanted all available P-38s in the Pacific theater. This was for obvious reasons. The P-38 did better in warmer climates and did not handle the high altitude low temperature in the European theater as well as the P-47 and P-51. Lastly, I believe we all want 2 engines over water with very little landing choices available.
Actually, it was the PILOTS flying out of England, that didn't handle high altitude low temperatures well. Not surprising, in a non-pressurized, poorly-heated cockpit. Plus, the compressibility dive danger before the -J-25 models hit the squadrons just destroyed the P-38 in 8th Fighter Command. Of course, the idiot RAF pilot who mistook a C-54 for an FW-200 and Shot Down a plane load of dive flap refit kits for ALL the P-38's then in England, didn't help matters either. I hate rookies...
I think Kenney was less concerned about Cold Weather performance as much as he was with viable and effective range. Especially over open ocean. While the P-47 wasn’t that far behind the lightning in terms of it’s textbook combat range, the Lightning’s 3000+ mile Ferry range was an often unheralded key feature in the Pacific. They could move the planes where they needed them quickly and without a ton of complex logistics or borrowing a Carrier for ferry duty.
@@jameskratzer4538 I'm glad you brought that point up about that C-47 getting shot out of the air. Tragic really. I'm not as well read as some of you are on this, but I think that the P-38 at cold, high altitudes in Europe with the turbocharger and gasoline octane issues may have contributed to a significant amount of detonation. BTW, Greg did a great study/dissertation on the P-47 with the proper external fuel tanks what it could have really done at altitude escorting bombers deeper into Europe.
@@jameskratzer4538 not really. the P-38's early GE turbochargers were not well designed and insulated for VERY low temperatures at high altitudes, and the condensing water in the exhaust gases froze up the turbos just where they were vital for horsepower at altitudes where the B-17s flew. Without boost the P-38 had about 200kt speed.
Peter Snell from what I've been able to find, purely in published documents, the turbochargers weren't so much the problem as the poorly heated cockpits and the gasoline separating the lead out at altitude (yes, probably, but not definitely, because of the turbochargers). This separation caused extreme octane loss, with resulting engine detonation. The biggest turbocharger malfunction problem at altitude over Northern Europe was the controls freezing up; I'm not sure whether this was a runway water-spray issue, or cable and linkage lubricant icing. The end result, however, was a turbo power setting that was either too low to sustain flight, or too high to maintain the engine and turbocharger as a serviceable unit. For a more in-depth explanation of the "teething troubles" of the P-38, I recommend Martin Caidin's book, "Fork-Tailed Devil: The P-38." It's a head first, no holds barred dive into the history of one of the greatest propeller driven fighters ever built.
I've gained respect for the Alison engine now. I thought it was sub-par but with turbocharging, it produces a power level at altitude that surprised me.
@@JohnRodriguesPhotographer wait the king cobra didn't have turbo supercharger most of them have superchargers optimizes low and mid level altitude due to the frequent air combat in that level in the eastern front.
@@aker1993 the king cobra used to totally different system for boost then the p38. It had a turbocharger with a secondary supercharger that was mechanically driven. This gave the aircraft a service selling your 40,000 ft. An altitude that cannot be attained by a single turbocharger.
I really enjoy these videos you are doing. The depth and detail is quite good. It's a huge step up from the very basic summaries that are more common. I'd really enjoy a series on early war developments in planes like the P-40, F4F, Dauntless, etc, or even some Pacific theater content.
@@GregsAirplanesandAutomobiles That’s a shame it was the F4F was the plane that won the critical battles in the Pacific. Like the P 47 in in the ETO it did the heavy lifting before the P 51 and F4U showed up.
At 15:37, that's a shot of a P-38 flying west -- going "feet wet" just south of Ventura, CA. Great country for motorcycling, which I used to do in the 1970's and 1980's.
Thank you for the latest P-38 video Greg and I thoroughly enjoyed every minute of it. I'm an admin to a Lockheed P-38 Lightning Facebook group and like you said I see a lot of posts/questions as to why the P-38 wasn't fitted with Merlin engines like the P-51 Mustang did. So I'll share this video to my group and this should help to explain to everyone why the swap from an Allison to Merlin engine wasn't as simple straight swap. Thanks again Greg and I'm looking forward to the next Lightning video.
P-38 is and always will be my favorite WW II fighter, even as I learn more about its problems. But as others have said, every design is full of compromises (or something like that) And look at the list of top American aces, you'll see the P-38 is very well represented there, 3 of the top 10 flew P-38s Hard to argue with success.
*in Sept 1943 Lockheed delivered to the AAF at Eglin field, a P38 with 1,875 hp Allison's fitted with Paddle-Blade Propellers,* *but the U.S. War Board didn't want to pause production for 2-3 weeks for Retooling.*
@@kenneth9874 No, the actyally did well, I think. The planners and tacticians had good data: that they already had the P-52 and P-47 for escort AND ground attack (and the P-47 had more flak/small-arms survivable radial engines). US industrial production was HUGE but not LIMITless, and they had to use it wisely. If nothing else, you wind up choking the rail lines with airplanes you DON'T need but are on the rails instead of the ones you just made that you DO need. Not simple, war. P-47 and P-51 show up for long range escort; P-38 struggles at altitude. P-38 winds up all over the Pacific and at low altitude in Europe. Go find P-38 specific gun cam footage from 43 - 44. >> CRY HAVOC AND LOOSE THE DOGS OF WAR
Warren M Bode wrote a secondary source book on the P-38. In summary, the Merlin engine had a higher fuel consumption per brake horsepower than the turbo charged Allison. His point is the Merlin P-38 would have reduced range compared to the Allison. He does not address the possibility of converting the space from the turbocharger system into additional fuel supply. He also addresses the possibility of the paddle blade propellers. He agrees this would have increased the performance of the P-38. However at this point the US was already winning the war and the current production P-38 were doing a great job in the Pacific. Upgrading to the paddle propellers would have required Lockheed to shut down production to make the conversion to paddle blade propellers. His position is the military wanted more P-38s not a better one. Another great video Greg.
You have a knack for turning nuanced, complex topics into easily digestible videos for the interested laymen, without dumbing it down too much. I really appreciate your work.
Thank you for the very logical and concise explanation that I have been been wanting to hear for 55 years, from the first time my father (a WWII Pacific theater veteran) and I made a model of a P-38 for my 7th B-Day. I remember my dad showing me the turbo chargers on top of each engine boom, and explaining that this was what made the P-38 a superior high altitude fighter. I also remember him saying the P-38 pilots knew never to get into a turning dogfight with a Zero. Hit & run the best tactic even for this mighty plane. He got me a Zero, and a Hellcat too, all 1/48 scale, and I still have these planes today.
That was early on. Later models of P-38's had Fowler flaps installed that tightened up their turning radius. Some German airplanes also had Fowler flaps. Lightnings that were so equipped could turn with the Japanese 'Zero', but by that stage of the war it didn't matter. The handwriting was already on the wall.
@@juanordonezgalban2278 Now, yes, but Saab was the company that took turbos from being only on high-performance aircraft and racing cars, and some dieasel trucks, to making them common in ordinary cars back in the 70s.
Standard atmospheric pressure is 29.92 inches. So at 56.8 inches manifold pressure, we have 26.88 inches of boost. Since boost pressure typically these days is measured in pounds, and atmospheric pressure is about 14.7 pounds per square inch at sea level, or 0.4913 pounds per inch of mercury, we can calculate an approximate boost pressure of 13.2 psi. Really, if you subtract 30 from the inches of manifold pressure and divide that by half, you get an idea of how much boost these old engines actually ran. This 13.2 pounds of boost was on an Allison V-1710 48 valve SOHC V12 engine with 1710 cubic inches/28.0 liters of displacement. Granted, these engines only ran about 6.65:1 compression, and operated at a maximum speed of 3200 rpm, so you can see why these produced "only" about 1450 hp~ Great video!
@@Flies2FLL These aircraft engines back then were very modern and complex , if you look at car engines today . A DB 605 for example , there are components in that only hyper cars today have . Aluminum engine with steel cylinder liner's , SOHC driven by a mechanical master shaft (Königswelle , I hope the english translation is right ), direct fuel injection , 2 sodium cooled exhaust valves . For an 80 year old engine this is astonishing in my opinion . 😉
Wonderful job explaining why the Allison v-1710 engine remained in the Lightning. The British, who received P-38's, were pissed off as they got them without the then, "highly classified" proprietary turbo superchargers that the U.S. withheld for itself, and they called them, "castrated Lightnings." I have Flying Iron's P-38L for Microsoft Flight Sim 2020 and it's become my favorite warbird to fly. It's just a dream machine to fly. I have a P-51D, a FG-1D Corsair, A BF-109 G6, a Spitfire Mk IXc and a Grumman F6F Hellcat...all fantastic computer sim recreations of the real aircraft, but the P-38L is BY FAR my favorite warbird aircraft to fly. It's simply superb. Good ol Kelly Johnson sure knew what he was doing. I totally understand why Richard Bong loved it so much. It's nickname of, "Cadillac of the skies" was well earned. For any interested, here's a short video I filmed of the ending to a flight I made from San Diego to Burbank CA, in the Flying Iron P-38L on my computer for those not familiar with how accurate and well done modern flight sim aircraft are recreated digitally. ua-cam.com/video/2lh7mnvi46U/v-deo.html Excellent video sir. You answered the question I had about why the P-38 never switched to Merlins. Thank you!
GM owned Allison. Also, a new Allison plant had been financed by USAAC and built in 1941. It's all about $ and influence. Lockheed engineers were upset with the lack of development on the Allison and the problems with the Allison and GE turbos, etc... They wanted Merlins; ie reliable engines at altitude.
One point you didn't bring up was that the Allison was designed from the ground up for opposite rotation with the exchange of a minimal number of components. An opposite rotating Merlin would have been more of problem.
@@givenfirstnamefamilyfirstn3935 It is reasonable, according to the WW2 time frame, to deduct these Merlin counter rotating 130/131 engines were much too late to see any action in WW2, thereby making them useless to P38s or any other aircraft to see WW2 service.
@@stanhathcoat920 Just the wiki page for the Mossie. Wiki says its from Janes. Data from Jane's Fighting Aircraft of World War II,[205] World War II Warbirds[206].
Damnit Gregg! You did it again! A question that I've pondered for 25 years, you put to rest in 25 minutes! There is a lot of aviation history buffs out there that are WAY gooder stuff - knowers thanks to you and these videos. I think you may be the "Ken Burns" of airplane videos! Thank you for all you do for us.
Always great info and love your videos. An interesting side note, an early photo shows the P-38 over a city by the ocean. The city is Ventura,CA, Very interesting to see it in the 1940's without the harbor that I am living in now.
Mostly the cost I would have thought... A Merlin P-51 was SO much cheaper than a P-38, and it was "good enough". Why spend any time or effort on P-38 upgrades after mid/late 1943. The P-38 carried the US through the first couple of years of the war when it was most needed, and did a great job. But then after that, there were just other more cost effective solutions for the high altitude roles over Germany. And the P-38's could then be transferred to a few select specialty roles, where its other qualities were very useful - and re-engining wasn't necessary.
You got it Greg did address this in another video the P-51 was almost half as costly as a P-38 and about 2/3 the cost of a P-47 I seem to recall something like 55 k for a P-51 vs over 90 K for a P-38 and something in the 70's or 80's for a P-47 ( sorry I m not exact I'm too lazy today and the internet is at your fingertips if you care to look)
Actually, the P-38 was the preferred aircraft in the PTO since the start of the war. General Kenney constantly begged General Marshall for P-38s throughout Pacific campaign. Long range and the safety of two engines were paramount in that theater. Once Iwo Jima and Okinawa were captured the range issue was eliminated for the planning of Operation Olympic. However because, “Europe First” was the hierarchy of defeating the Axis, Material Command prioritized aircraft to the ETO and MTO over the PTO. Only after D-Day, and then the breakout across France in late summer 44, did P-38 priority was shifted to the PTO.
I do think they should have let Lockheed make a “kit” for adding new propellers to late model Lightnings. I feel that would have been a small enough delay to be offset by the improved Thrust
@@spindash64 a “kit” would have been considered a maintenance depot assignment. Just switching props wouldn’t be the process. The gearing and cowling changes for the new propellers themselves and possibly a new prop center wouldn’t have been possible for change in the field.
Another great presentation Greg. I thing a subject for you to speak about is the actual power at the prop vs the drain by the engine accessories. This I think would be a natural progression of your talks so far. Once again thanks for all your efforts with quality vids.
Fantastic video. This guy has a great ability to explain and teach. That's undervalued and rare. I studied philosophy in college and was watching Monday Night Football. Ended up muting it and being fully wrapped up in this. Thanks internet guy Greg. Really good work. Really good.
Great analysis as usual. The advertisement at 11:00 is from Fafnir Bearing, a factory in nearby New Britain CT. They made high quality bearings for airplanes in to 30's and 40's , then space in the 60's. Now part of Timken.
Perhaps it should be pointed out that in addition to paddle blades, both the P-47 and P-51 were fitted with propeller cuffs from the base of the blade extending about two feet towards the tip. They squeezed a bit more thrust out of the blades at their hubs, and may have helped cool the R-2800 in the P-47 a bit.
@@georgettewolf6743 Well, I recall the P-51 blades look very thin and elongated compared to the prop blades of the Thunderbolt, that look way beefier ...
This is an EXCELLENT discussion Greg!! VERY nicely done! One other aspect of the difficulty of switching to the Merlin from the Allison (that you actually briefly touched upon, when you briefly mentioned weight) is that the Merlins are typically 300 pounds heavier each than the Allisons, so changing over would have required a DRASTIC redesign of the booms! If you look at the installation of the Allisons in the '38, as you very correctly point out, the ENTIRE DESIGN of the nacelles/booms was around the engine and the necessary ducting for the turbosuperchargers, AND the main landing gear. Adding 300 pounds at the very front of each boom would have required either the powerplant to be mounted further back into the nacelle or ballast being added to the tail. The way the Allisons are mounted, IRRESPECTIVE of the turbocharging ducting, the engine mounts not only carry the engine itself, but they also carry the hydraulic actuators for the main landing gear BETWEEN the engine and the firewall RIGHT WHERE the lower-slung Merlin updraft carburetor would be, so THAT actuator and ITS plumbing would have to be redesigned into an otherwise ALREADY space-starved area around the gear well somewhere, so there's just ONE major redesign problem. Also, they wouldn't JUST be ADDING 300 pounds out front, but they would ALSO be DELEATING the ENTIRE aft-of-CG turbosupercharger units, which would FURTHER complicate the weight and balance issues...another MAJOR redesign issue. AND by repositioning the engine placement, necessitated as already mentioned, it is VERY likely that the propeller discs would be in a different fore-aft position and/or up-down position relative to the wings and central gondola. As EVERYONE knows (or should know), the P-38 was plagued from very early on with SERIOUS AERODYNAMIC issues of tail buffeting and compressibility. By the time the P-38F was fielded, the tail buffeting had largely been eliminated through VERY CAREFUL filleting of the wing root/center gondola junction and the addition of external counterweights to the elevator (when you look at these weight closely, they are TOTAL "AFTER-THOUGHTS"!! ....the streamlined tube that holds the weight in position is simply welded to a flat plate and BUTT-JOINT SCREWED to the surfaces of the elevator structure, and the weights themselves are nothing more than BIG CHUNKS OF LEAD, JUST LIKE BIG FISHING LINE WEIGHTS, BOLTED to a plate welded to the end of the streamlined tubing!!). And, of course, the compressibility "tuck" issue was alleviated with the addition of the underwing "dive flaps." These "fixes" for these issues were very SPECIFICALLY sorted out for the existing layout and orientations of the various elements causing the various pesky airflow perturbations that precipitated them. If the props started getting moved around in this "equation," as they most likely would have HAD to have been with Merlins, that ENTIRE airflow environment gets altered, and the engineers likely would have had to go through the ENTIRE mitigation process ALL OVER AGAIN. The North American guys made the transition to the Merlin LOOK EASY, because, as you correctly point out, Ed Schmued's boys were ALREADY looking toward that eventuality very early on with the Mustang. Over at Lockheed, on the other hand, they were ALREADY looking at "improved" P-38 alternatives, in the form of the XP-49 and XP-58, along with development of the XP-80, so it wouldn't surprise me one bit if Lockheed had the LOUDEST VOICE AGAINST P-38s switching over to Merlins!!
GREG! Thank you. I simply feel smarter listening to you content, despite barely understanding it! P-38 note: At the Sacramento Capital Airshow, (in 2013 maybe) I had the pleasure of witnessing Four (4) P-38's fly in formation over the city of Rancho Cordova out of Mather Field. Quite the treat I must say! (And a rare one at that!) Thanks for being who you are!!! duhGlez
FOUR airworthy P-38s in one place in the air at one time?! What dreamland fantasy was this?! I don't think I would have been able to control myself... amazing. That sound...
Look at the propellers at 13:45. You can see they are counter-rotating, but they rotate the wrong way. This reduces drag since the descending propellor blade always produces more thrust than the ascending blade, and the proximity of the fuselage would cause interference. This of course produces atrocious engine out characteristics, since this effectively shifts the live engine farther out on the wing, requiring more rudder to compensate. I talked to a WWII pilot who flew P-38's and he said that often times if you lost an engine in one of these you would eventually reach Vmc with enough thrust to keep it in the air so you flew it to a place with less than full throttle in a slow descent to a place where you could bail out safely. Pretty crazy what these guys were up against back then~
What you're describing with descending and ascending blades delivering differential thrust is known as 'P-factor' and manifests only with aircraft flying through a high angle of attack (such as takeoff or landing). Loss of engine at takeoff was manageable (ie survivable) if you knew well enough to throttle back on the live engine to mitigate the asymmetric thrust that was worsened by the P-factor. It's the reason the prescribed takeoff procedure called for a takeoff with no flaps-- it was a precautionary move to ensure you reached safe single-engine speed as soon as you can during takeoff. A P-38 can climb and cruise on one engine. The only conditions a P-38 cannot maintain altitude on one engine is when _both_ the flaps and gear are down.
@@BogeyTheBear We are saying the same thing. What the man who flew the plane told me was different from what you are saying. He did not specify that this was the case in an effects of configuration scenario as you have posited; He simply said you flew the plane at lower power to a point where you could land it or bail out safely. It makes sense when you see how small those rudders are.
Why would they not keep full power and descend _if necessary_ to maintain the best single engine climb speed. That would surely give better performance than creeping down to the more draggy minimum control speed? Current multi engine training is superior to what was taught back then.
I'd imagine that there were more than enough customers for the Merlin's as it was too. It would make sense to have several engines being built and developed.
Thats another worth while point to make. The list of aircraft being built in large numbers using the Merlins was... extensive. Hell its why when they started designing the Typhoon it was planned to use either the Napier Sabre or the Rolls Royce Vulture specifically to avoid yet more stress on the supply of Merlins elsewhere, and the Typhoon was not the only mid to late war aircraft designed with other engines in mind specifically for that reason. And its not only complete engines, but also a ready supply of spares, which means a constant production of those as well.
Great job Greg. As usual another unbiased, truth based video. While the 38 is not my favorite {P-47} I do rate this AC above the 51. {IMO} She really showed her metal in the PTO. Hub Zemke {in his bio} mentioned this was a very difficult AC for the novice to fly into battle, to many things to accomplish in a very short time if bounced. That being said, afterall the top two USAAF Aces did fly her. Great job, Thanks!
What people fail to understand is that engines iterate endlessly. An Allison early or mid-war is nothing compared to a late war Allison, same as any other engine that was used throughout the whole war.
Great explanation. I always assumed it had to do with the large turbo superchargers, but I've never heard it explained before (or at all) in such detail. Thanks! Also, the graphs were great and made the choice very clear. Since the last video on the P38, I've been wondering what could have been done with this aircraft had they cleaned up the aerodynamics mid war. For example: lose the exposed turbo, clean up the collection of assorted scoops, and finally, get rid of the ridiculous double cruciform tail. It could have been replaced with something like the F82 tail . Getting the stabilizer up higher might have helped with the compressibility issues as well.
I can understand why later in the war, like the decision concerning paddle props, they opted not to invest further in the design since the aircraft was effective enough at its job and with the wars end in sight was becoming less relevant. But what I never got was some of Greg's earlier points about parasitic drag, not just from the scoops (which might require some redesigned engine support systems) but things like gun ports which NACA testing clearly showed to be a major source of drag. Sure, they didn't know about this until further along its evolution but it seems to be such a simple retrofit to resolve on the production line. Why wasn't some of the low hanging fruit addressed to further improve the type?
Finally, a definitive well researched and presented answer to a question I have had for a very long time. Thank you for all your hard work, you now have a new subscriber!
Great video. Reinforces my view of the P-38- a great design that pushed performance into uncharted territory, but necessarily committed to production because of the war and thus less able to exploit the principles that it itself had uncovered.
I'm a mechanical engineer specialising in automotive performance improvements, so when I make the following statements, keep that in mind. (1) while superchargers have a fixed relationship to the crankshaft, turbochargers do not. If you have a turbo on your car (likely) the position will be literally anywhere the manufacturer can find the room for the turbo whorl and the rather blocky intercooler of course. (2) turbos have lag, but this is not a negative on planes, which do not have to race quarter mile drags. (3) in wartime, secrecy and time pressures negatively affect engineerring idealism. Then you separate Kelly's skunkworks and RR's secret rural Coventry 'guerilla garages' by a big submarine-filled pond called the north atlantic, and you have a recipe for NOT using the (bird) engine in the bush for the (bird) engine in hand. I could crap on about RR's better sodium-filled valves (friction welding was pioneered) etc etc ,but tthough true, its not the reason for the actual choice. Blame Tojo/Adolf if you really want to allocate brickbats.
The best design is a compromise of many good designs. This I learned after 13 years employment working as a Detail Drafter in airframe design at McDonnell Douglas.
A superb explanation of what was a very complex decision on the part of Lockheed, and making clear just how vital an aspect of warfare are considerations of manufacture and production logistics (a point frequently overlooked even by military professionals!). Cheers, Greg!
Looking forward to the video on the GE turbos, and their charge air cooling ductwork, etc. I've always been fascinated by them. I've only seen Max Millar's drawings of them.
This video explains quite well that a extremely important factor of engines is packaging. Planes are often built around their engines, the P38 especially so.
I’ve got to thank you for a great video on why not Merlin engines. Now I can only hope to get into a heated discussion at a bar someday where I can debate the efficacy of turbocharging versus supercharging on world war two piston driven aircraft engines with special emphasis on second-stage turbo versus supercharging. Awesome information to have at one’s fingertips and I owe it to you for putting it together and putting it out so clearly, and understandably.
HA! But I have had that heated discussion with some jetski mechanics at their shop over some cylinder head and turbo swaps. Their collective lack of understanding of the very technology they were turning wrenches on was so profoundly disturbing I sent them Greg's two videos on the topic before meeting with next to explain my concerns. That led to much more productive follow-on conversations. The scary thing is the most mechanics today don't even know what the HEAT RANGE of a spark plug really is so they just open the gap instaed... Priceless. I do prefer teaching them to fish instead...
Great video. For WWII aircraft engines the super/turbo charging system was key. Allison did have the V1710-119 with more advanced mech supercharger but that was later and never fully developed. The place where Allison did make more advanced 1710's (the only place I know of) was in the P82 Twin mustang. Here you had no room for turbo system. Supposedly Rolls Royce wanted large royalty per engine for Packard-Merlins so NA went with Allison. According wikipedia "The G-series V-1710s installed on the F-82 E/F/G models had only anti-detonation injection (ADI) to deal with these problems, and not surprisingly had severe reliability and maintenance problems. In one record, it was stated that the F-82 required 33 hours of maintenance for each hour of flight. Supposedly these could make > 2000 HP? The Allison-equipped Twin Mustangs are under appreciated they filled the gap when US got caught off guard in Korean War. They were not most advanced in 1950 but they may have saved the day.
Well, wikipedia is garbage. The G series Allison is a much improved V-1710, capable of higher RPM, with better superchargers, better intake manifolds, and a host of other improvements. It was tested at 70+ inches of boost, at 3400RPM, for hours on end. It didn't require excessive maintenance.
They would have been better off to figure out how to put a turbo on the mustang than to put the Merlin in the p38. Only takes a quick glance at the speed and altitude charts to know the swap would be pointless. Greg has put the information out there in his videos and gives us the knowledge to have a decent understanding of what he's talking about. Even a casual fan such as myself should be able to answer this question with no trouble at all. You're doing great work Greg, thank you.
People say this about the Westland Whirlwind as well, not knowing that to accommodate the Merlin's, the Whirlwind would have needed a complete re-design. New wing, fuselage, possibly a new tail...
To my eye that is one dead sexy warbird. Both it and the men that flew it into combat don't get the credit they deserve. Shame it was forced to the wayside basically due to stretched resources not allowing the redesign that could have made it a war winner. At least it was able to acquit itself well unlike so many other aircraft that ended up in the what if category of history.
@@indydurtdigger2867 All the Merlin's under production at the time were earmarked for Spitfire's & Hurricanes, then later, the Mosquito. By the time we had the Mosquito, there was no need for the Whirlwind so it was withdrawn from service. That aside, the Whirlwind used the R/R Kestrel engine, hence the reason why it would have been such a pain to fit Merlin's to her.
@@navnig We had numerous aircraft over here that the same fate befell them. Several that like the Whirlwind the designers couldn't get the engine they wanted and had to make do with what was made available often with less than desirable results. Some that just weren't feasible to sink the resources into a redesign. And several that the leg work was done on but the result was either not enough improvement or by the time they were ready something else had been introduced that rendered all the work moot. I just did a bunch of reading on derivative aircraft of the Republic P-47. The amount of time and resources sunk into putting a liquid cooled engine on the airframe is astonishing and not a one of them went on to be a production machine. Just one of many what could have been scenarios from countries across the globe.
@@indydurtdigger2867 There's a book called 'Tumult in the clouds' by (I think) James W Goodson, it covers his time at the start of the war flying spitfires in the RAF's eagle squadrons, then on to the USAF in the P-47 and then Mustang....Its an amazing read, I could hardly put it down after I began reading it! That double wasp was a true giant of its time....In the book I mentioned, it tells a story of how one American p-47 had either 6 or 8 of the cylinders smashed in a dogfight over France and it still got home....Incredibly tough engines, paired with that 'Thud' airframe.....It was a flying tank! 🙂
@@navnig I will most certainly check that out and add it to my collection. Thank you Got a used very good condition hard back on the way. And holy krupp new uncirculated copies of that are over 500 US dollars!?
in the UK we have an enduring love affair with the Merlin. Every year the Battle of Britain flight makes appearances around the country, sowing nostalgia & reinforcing the hyperbole of how Merlin's won the war..... more recently, I was reading how Handley Page had to upgrade from Merlin's to radials for their Halifax bombers, since the merlin's at the time weren't powerful enough. & taking stock, the amount of high performance radial powered aircraft on both sides puts things into perspective. UK also had the Napier H engine used in Typhoons & Tempest which are worth mentioning. Many thanks for the vid.
this is my new favorite video! so many people dog on the allison v1710 so much, personally its my favorite engine of the war, was an absolute work horse on the eastern front and pacific!
Additional comment based on additional personal research is that the type 61 did not apparently have counter rotating version (wasn't used in the mossie) and both Tony Lavier and Robin Olds both attested to the advantage that was in combat. I also worked for a gentleman in Sante Fe NM in the late '80's who was an instructor on P38's in Washington State during the war.
Another great video! Thank you, your research is impeccable as always. I’ve read about ww2 aircraft since the 70’s and thanks to you I’m still learning a few things.
From when I was a kid, looking at WWII figher planes, I always thought the P-38 and P-51 were of similar design. The P-38 being something like two P-51's put together (in design). Your explanation of engine swapping shows just how much they're two separate and different planes, in their designs.
Apparently you’ve never heard of the Allison 3420, two V-12 Allison’s siamesed together. That engine sits in the “Superprop” section of fighters at Wright Patterson Air Force museum. Would you giggle at 3500 h.p.?
Excellent video and right on. Similar is mentioned in Bodie, and back in the late 70s at Planes of Fame Kelly Johnson noted much the same, as did Tony LaVier. And spot on, in 1943, Lockheed couldn't keep up production for demand, much less a 6-10 month delay or stoppage of production. Note, Merlin install planning in the P-51 started in the UK and NAA in the summer of 1942, and the first Merlin aircraft didn't come off the line until early 1943, and get into combat until December 43. P-51A production of 1200 aircraft was halted at 350 or so. The P-38 would have undoubtedly taken longer, and that year to re-engine, in a 42 to 43 time frame when you all ready had a decent high altitude fighter, would indeed have been a waste, and unacceptable given very small if any gain in horsepower or overall performance. Big gains in the P-51, small gains in the 38.
Thank you Greg for answering a question I have had for years, Why Allison engine worked on the P38 but not on the P40/P51. Now I know that is was all about the super charging system. Correct me if I am wrong but it appears to me that if the P40 and P51 had been designed and built with the same engine and super charger system as the P38 both the P40 and P51A would have performed much better. This video reveals the rapid pace of aircraft engine (really all aspects of aircraft design) development during WWII.
The P40 and P51 could not easily contain the turbocharger system such as was used by the P-38. Their Fusilages would have required extensive redesign. The designers have to pick the engine systems which POSSIBLY would be used and then do the designs, not afterward.
The American P-40s that were first deployed in North Africa, also were powered by Merlin Engines. I recall seeing photos of those P-40s on the deck of the WASP, headed for their destination.
Are you sure it was the USS Wasp (CV-7) and not the USS Ranger (CV-4) that transported the planes? USS Wasp (CV-7) was sunk on September 15, 1942 by a Japanese submarine south of Guadalcanal in the South Pacific.
Also, counterrotating engines would have been a problem with the Merlin engine. The counterrotating props made the thing much more forgiving in low speed flight. Yeah, the Brits called theirs "Casterated Lightnings.
Actually the XP38 had the correct counterrotating engines. After the XP38 crashed Lockheed erred and reversed the engine rotation thus creating "2" critical engines. By the time this was discovered it was decided not to switch back as too much redesign work was needed and the updates were coming so fast it was put on the back burner. The critical engine issue is covered in many P38 books.
@@michaelwillette5738 There would have been zero redesign work to swap the rotation of each engine. A small kit for each engine, and mounting the correct propeller to each side. As a matter of fact, one of the things that made the P-38 so popular is that there was one engine for the aircraft, with only a small kit installed in an engine to reverse its running rotation, and installation of the proper propeller.
@@immikeurnot This may be true of the Allison engines, but what works for one brand/model of engine won't always work for others. Also remember the Merlin was developed by Rolls-Royce, and had a tendency to be considered somewhat of a finicky thoroughbred. The Allison was on the other hand considered to be more utilitarian and versatile, as it was also used as the engines that equipped the PT boats of the U.S. Navy.
I enjoyed this presentation very much. Never gave much thought to put a Merlin in a P-38. But you are correct in your opinion, that it would have taken a massive redesign of both nacelles, plus the assorted plumbing. And during this time of the war priority was given for a certain plane certain engine. Production lines were stretched to the limits with the orders they already had. Along with continuing improvements and the next model.
Hi Brian, you're not the first to comment on that. I just might cover them. I'll put up a poll tomorrow to see what you folks think the next video release should be.
Was curious about that as well- the P-40 was supposed to be a very responsive craft- was wondering if it would have the high speed control issues that the Mustang was reported to have with the more powerful engine.
Good video. I had no idea that anyone outside of UA-cam wanted to try out the Merlin on the P-38. I'll stand correction, but as I understand it, by mid-1944 Lockheed and the USAAF were backing off on P-38 production. As Greg notes, the jet was the future. In addition, the P-38 - an innovative design and very good fighter in the right arena - was in essence two airplanes stuck together, almost doubling the maintenance routine - no small thing in an air force already sporting Jugs and Mustangs. All P38 fans should check the memoirs of Gen Ben Kelsey "The Dragon's Teeth?" Kelsey was the head of the USAAF fighter project and was deeply involved with the P38. He also gives an insider's view on how insiders viewed aircraft - they weren't thinking of creating machines for a joust.
Swapping the engine would also have impact on ballance. C.G. would move quite a bit forward, so it would require a whole lot of redesing, so it made no sense.
I was always under the impression that as phenomenal as the P-38 was, it was somewhat hobbled by a less than an ideal engine - boy did you just school me! Fantastic work!
That's why they used 2 of them. And the Allison can be easily configured to turn in either direction, making it particularly well suited to a twin engine plane. And we had shitloads of them.
One P-38 pilot said that when the later models added power assisted controls(from 1:1 to 1:12) they could roll & turn with anything. A shame they & the 'dive flaps' weren't added sooner. Great plane though.
It's great to see this questions addressed properly as it comes up almost as often as, "Why dont they just build more A-10's or restart production of them".
@@Hornet135 Well, actually really. The A-10 is obsolete. It the history, not the future, of close air support. Don't take it from me , take it from the commander of Air Combat Command: "China is our…pacing threat. If we’re going to keep pace with what they’re doing … you’re not going to do it by refurbishing a fleet of 40-year-old, single-mission, 210-knot airplanes. You’re just not, regardless of how much they’re loved and the great performance they’ve done." Gen. Mark D. Kelly, commander, Air Combat Command, offering his view of the long-term effectiveness of keeping the A-10 in the combat air forces, Air Force Life Cycle Management Center Life Cycle Industry Days streaming seminar, Aug. 3.
@@gort8203 Why are you taking to me? I only implied that just because someone mentions the A-10 doesn’t mean they know nothing, as the previous commenter suggested. It’s kinda weird he calls it a 210 knot aircraft though.
@@Hornet135 You're right, I actually shouldn't have replied at all. It seems I misinterpreted your comment as being in support of the idea of building more A-10s. I now see my first error was in misinterpreting the original comment. I jumped to the wrong conclusion after reading too many "brrrt boy" comments in other places lately. My apologies.
@Greg's Airplanes and Automobiles Greg, I am a Riddle grad, life long WWII aviation guy, you are the only channel where I am stumped by what you can document, explain. Please, Please, Please, in your next P 38 video, compare the Grumman Skyrocket to the Lighting and Mossie. If the Navy/FDR had the smallest amount of foresight, the Skyrocket would have shorten the war by a year. The tech to build the Skyrocket was proven/available in 37, the F7 could have been built in '40. Imagine the US mass producing a twin navy fighter in 1940. The F7 would have dominated the skies in every theater Instead we built the P 39.
Non engineers don't understand how hard it is to make design changes in complex systems. You did a very good job identifying the difficulty.
It’s much easier to design a system where you can swap engines when you don’t need to care about the size, weight, or dimensions of the final product. Which is kinda the opposite of vehicles in general and aircraft in particular.
Just maintenance on a twin is at least 3 times the work.
Nonsense. Its super easy. Just ask anyone whos ever done a Auto to Manual Trans swap. Piece of cake... Just like that LS swapped Honda Accord that was made rear wheel drive. Did it by myself over a weekend with simple tools i got at walmart. Id show you pictures but ummmmm my uhhhh camera broke.
They really dont. The amount of work involved is staggering. All those little details and things that come up when you actually sit down and start the work. Every problem you fix potentially creates another. Wtih something like a combat aircraft, you also have logistics and manufacturing to consider and that's its own world of complexity. With something like the P38, the war would be over by the time you were done and you would have been further ahead if you simply built a new aircraft from the ground up.
My son wants to modify his Chevy Avalanche's suspension. He stated he knew what to do and I told him He is not an engineer and modifying even small things can have dire results. I know what u mean, but you can't argue with a someone the already Knows it all.
@@johngilbert6036 How old is he?
P-38, my favorite WW II fighter/attack airplane. Long range, fast, highly armed and beautiful. American design at its best, Kelly Johnson strikes again.
The Mach limits were bad tho
P-38 / K. Johnson -
"Skunk Works" close-collaboration project model scores again!! Read up on this - it WORKS IRL; few mgmt "cults" do.
!!NO NECKTIES!!
@@mrcat5508 >>Mach limits, airframe dive limits, etc.
Thing was too slick for it's own good. Stall recovery was non-standard, too: standard recovery put you into another stall/spin, usually the other way!!
The dive brakes must have been kinda a hoot:
DIVEspeedDIVESPEEDSPEEDDIVEyokebackNUTHINomgomgohyeahleverpullomgomGoMGOMGPULEEASE nose up
"I watched some of the P-47 guys go flying straight on past to make smoking holes in the ground and I wondered what that was." - B-17 pilot (some documentary I saw)
@@michaelmcgovern8110 actually it was relatively high drag
My all time favourite piston engined aeroplane is the Mosquito - known as the Timber Terror or the Wooden Wonder by pilots in different places. But then I'm on the other side of the Pond to you guys. Because it was mainly built from plywood it was quite stealthy for its time; hard to spot with German Radar. It also had a very good reputation for getting the crew back home, even if badly damaged.
I also like the P-38, which was definitely an effective aircraft, but it had a poor reputation if it lost an engine or went into a stall or spin.
I wonder if another factor against using Merlins in a P-38 might be better utilization of total US mfg capacity. Adding P-38 2x per air-frame engine requirements would drive a big increase in Packard Merlin production demand vs leaving the total P-51/P-38 engine requirements split between Allison and Packard.
It would have been a problem for sure, but given time, Allison production could have been switched over the Merlins. They did that sort of thing all the time during WW2.
If there HAD been a compelling reason for such a switch, what would have prevented Allison from simply switching some V-1710 production capability to build the Merlin copy V-1650's along with Packard? Or Allison not growing as fast, while Packard grew faster? You seem to think labor is locked into working for one specific company, that the company is of a fixed given size that doesn't respond to market needs, and that this company can only produce a certain product even if customers demand something else. None of this is true.
As Greg makes crystal clear, there's utterly no reason to put a dual-supercharged Merlin (X and later) into the P-38. It's not as if there is some nagging doubt remaining to be quashed by questions of engine availability.
@@lqr824 In order to produce more of the other engine by switching over production capacity, you also need to change tooling and that both takes time and introduces a slump in production where overall engine availability goes down because the tooling is being modified/replaced and workers are being retrained to switch over to a different engine production - that also comes with potential production quality issues that may take some time to resolve. In a scenario where the weapon system you're using is "good enough", there is almost never a valid reason to change it unless the change directly increases the speed of producing or performance of said weapon without incurring major logistical drawbacks. So the reason for something major like switching to a completely different engine type doesn't only need to be compelling, it would have to be compelling enough to be worth the temporarily reduced production output which is a very high bar to meet.
The saying goes that perfection is the enemy of good enough.
@@tiikerihai duh. Why are you explaining the obvious to me?
@@lqr824 because you were trying to make switching engine production between types sound a lot more trivial than it is. The person you're replying to originally is pointing out a fairly major logistical consideration that played a role in what kind of motor was chosen for various planes in practice.
Greg, running out of superlatives for your videos. They just keep getting better and better...and they have been the best on YT for some time. Great work. It reveals so much about the issues that faced designers and engineers in the period. Some really amazing folks did some amazing things. Have to feel for the Allison team...with the proper boosting their engine was a beast. By the time they got it right with the King Cobra it was too late. Kudos for such great work.
I always like to listen Greg's explanation about the planes. Geetings from Germany Stuttgart
Superlaxarives perhaps the 😂
Cobra= helicopter
Always have an affection for the P38. That was my first plastic model. Dad helped me put it together.
Heinkel he-111 my first model dad helped me with
Mine was a Hubley metal toy P-38 -- a beauty with chromed props and rubber tires. (Almost bought a replacement once at an antique store.)
Greg, this is your best video yet. I can't thank you enough for addressing the Merlin swap issue. At least your viewers will be better informed than the droves of internet fanboys that don't understand the airplane and think the V-1710 was the problem and that the Merlin would have worked magic on the airplane.
I especially appreciated the detail on the paddle blade props. I love the P-38, but agree that further development would have been a misapplication of resources by that time. Plus, spending a huge amount of money on making an airplane with compressibility issues go really fast at altitude was not the best option in light of the available alternatives. None of this takes away from the original brilliance of the P-38 when one considers the circumstances behind its design.
Thanks Gort.
Kelly Johnson was involved in the design... second project I think. No wonder it was such a good aircraft. Charles Lindbergh showed how to operate the engine in the high boost low rpm area for extended range.... and Anton Dr sanzuperey died in one over the med
"brilliance of the P-38"
Why do people like this plane so much? A genuine question. From my point of view, this airplane was heavy, hard to maneuver, difficult to bail out from and had those compressibility issues. All of that on top of what I consider to be the main problem, that is the high cost of production. In the times when the Brits counted how many flush rivets the Spit actually needs to remain fast, P-38 was trying to do the same job, but with two engines instead of one, and two turbos on top of that. Stainless steel too, in case those difficulties could be powered through somehow.
I mean, it was a good airplane. Good enough to justify all of the above? I feel like it wasn't, but feels are nothing when confronted with facts, so hit me with those.
@@bakters lighting was an early design and the pace of aeronautical knowledge increased as never before so Lockheed were pushing the envelope with all these ground breaking features.... that's what Kelly does. The only way to find out is to do it but as the war progressed they learnt a lot very fast. A Merlin engine lightning would probably look like a mosquito....no need for tailbooms and stainless steel to accommodate a few the enormous turbocharger so it's a fusilage with enginese on the wing. As for the Brits they always develop a design. It's what they are good at. The later spitfires were roughly twice as heavy twice as powerful and had almost no parts in common with the early ones... only the name.
I sometimes wonder if the internet fanboys know or understand anything.
Quality video. The new tech in the Allison's turbo superchargers, was complex and buggy at Northern Europe's cold high-altitude missions and gave newly trained pilots a helluva lot to deal with and almost always during combat when it was least appreciated. It's why they were reconsidered for 8th AAF Bomber escort duty and put to a much more advantageous environment in the Pacific and why their legacy in the Mediterranean was more fortunate as well.
The problem was because of a mismatch between the Government furnished turbocharger and the engines.
The problem of icing induction systems persists today (nearly). I had an 900cc Yamaha bike (omg a bike isn’t an aircraft). It made 90 bhp at 8500rpm. Twin cams eight valves one carburettor per cylinder. It was great with smooth usable power. But wet misty weather would ice up the carbs. It was hard to clear because closing throttle increased the chilling effect.
Not a good experience on a fast motorway. Absolutely terrifying when there’s an FW190 on your tail.
@@richardbriscoe8563 >>mismatch turbo
yes - I'd read this, too. Is there also something in the manufacturing / metallurgy that caused problems in the high-RPM turbo disks? Or have I got that part wrong. I believe the problem was disintegrating disks spitting shrapnel thru the rest of the engine. Can you confirm or set me right?Thanks.
I also understand that the fuel in the field was way flaky (wet, god-knows-what-infused, maybe 80+ octane at best) which also goofed up the turbo system. Any info there?
@@Dave5843-d9m >>Absolutely terrifying when there’s an FW190 on your tail.
Nah: press Escape twice and re-start the mission.
Having watched your earlier videos, I immediately knew the P-38's supercharging system would be at the heart of your answer regarding the suggested Merlin swap. I am in awe at your ability to explain complex technical issues to a lay (but inquisitive) audience of non-engineers.
>>your ability to explain complex technical
VERY big agreement with this compliment from a 40-year high-tech/aerospace technical writer and professional geek. It is hard to make it seem as simple as you do.
VERY hard.
Fitting two stage Merlins in a P-38 means a major redesign of the whole engine nacelle if not the whole airplane.
The two stage supercharger is attached directly to the Merlin's back side, making it quite long. It gets even longer because the two supercharger stages are on the same shaft and between the stages there is the intercooler.
Does that fit in front of the P-38's firewall without shifting the center of gravity forward? I don't think so. The big turbos are behind the CG. When they are not installed the CG of the airplane shifts forward.
So, there are two things shifting the CG forward. That is not a good idea because there barely is enough equipment inside the booms that could be repositioned further back to compensate for the CG shift.
An important reason for not switching to paddle blades on the P-38 is, when the paddle blade prop became available there was not that desperate need for more performance anymore. The Japanese were already getting weaker and were already outnumbered by Allied fighters. In Europe the P-51 already had started to replace the P-38. The expensive and time consuming conversion of production lines, time consuming field conversions of existing aircraft and difficult conversion of the supply system for replacement parts simply was not worth it. The P-38 was an expensive airplane. Its main advantage over other fighters was its range. New versions of the P-51 and P-47 already were in developement in 1944 and they were designed to overcome their previous disadvantage in range without getting as expensive as the P-38. No doubt the Air Force already was thinking about phasing out the P-38 in mid 1944.
Some Mosquitoes had 5 exhaust stacks and some 6. The 5s were on shorter nacelle single stage supercharger Mosquitoes with the last exhaust port directed forward and twinned so as to clear the inboard leading edge radiator intake.
I entirely agree with your above statement. They had quite similar issues with the thoughts of modifying the Westland Whirlwind, an aircraft not unlike the P38. To fit Merlins in place of the Peregrine was a major problem, not only in C of G but other complicated factors too.
The Merlin/P-38 debate has been a long discussed topic, with some revisionist theories constantly polluting the facts. As detailed in Warren Bodie’s excellent tome on the P-38, Lockheed, specifically Kelly Johnson, early after production worked up drawings using Merlins 2stages on P-38s. As explained by Greg’s excellent explanation the greater power ratio would have been offset by the reduced weight of the removed Turbo Super, but not to the extent that the War Production Board (WPB) would allow a delay in the line at Lockheed. Additionally; the Paddle bladed P-38’s were to be used on the P-38K, however using those props created a change in the thrust line, which again the WPB would not allow Lockheed delay production for an aircraft that was in much needed demand. Even a supreme version like the P-38K, the WPB wasn’t going to halt production for one month, much less than 6 months than what Lockheed estimated for modifications on the line. Hindsight is always 20/20, but the real disappointment should be placed on Material Command not introducing a second production until 1945 with Vultee. Had a second line started in early 1943, say with Bell instead of building P-39/63s for lend lease, or Curtiss with the P-40 variants (while useful, but obsolete) and the Helldiver (forced onto the Navy), possibly the shortfall of the aircraft in the PTO could have been avoided and actually hasten the island hopping campaign through the Philippines.
@@ikekelly3157 I doubt that Bell would ever have been asked to stop production of P-39s and P-63s. The Allies were very keen on keeping Stalin friendly to a) avoid a separate peace between the USSR and Germany and b) secure Soviet assistance against Japan once Germany was taken care of. The Cobras were a prominent part of the carrot that was Lend-Lease.
I also doubt that Curtiss would have stopped making P-40s. It was no world-beater in terms of raw performance, but then neither was the Hurricane or Hellcat, and they still did fantastic service. Besides, war is a numbers game, and the P-40 was one of the most produced American planes.
Vultee being contracted to set up another production line might have worked. That, or perhaps Lockheed could have set up an additional line of their own, similar to North American and Republic.
@@Beowulf_DW Yeah, but the difference between the P-40 and the Hurricane is that it was modified for other missions like CAS with the Mk. IId and Mk. IV.
And the Hurricane did well in those missions.
And the Hellcat was still competitive in it's operational enviroment, as well as sturdy and easy to fly, with good handling around the boat.
The latter of which is something of a rarity in Warbirds.
Also the Hellcat's Performance is decidedly superior to the P-40.
Edit: However, the P-40 is a severely underapreciated plane, just as the Hurricane is in public perception.
Greg, as usual an excellent video. Thanks for straightening out the what ifs on the Merlin powered P-38. One thing I remember reading in Daniel D. Whitney's "Vees for Victory, The Story of the Allison V-1710 Aircraft Engine 1929-1948" was that the Army Air Corps was insisting the Allison use the new GE turbocharger instead of a two stage supercharger. As I remember, this was well before the U.S. entered WWII and may have even been before the 1939 start of the war in Europe. The book also notes, that while the proposed Merlin powered P-38 would have been faster than the Allison powered version, it would also have had shorter range, which was one of the P-38's great advantages. Thanks again for a great video.
That's true, I cover that aspect in other videos. Yes, the USAAF was married to the idea of using the exhaust driven turbosupercharger, thus Allison didn't bother with a mechanical second stage until very late in the war.
@@GregsAirplanesandAutomobiles I gather that the turbo is a more economical way to get more power as the compression is gained from otherwise wasted exhaust gas pressure whereas a mechanical supercharger has a substantial and continuing cost in power to drive the turbo disc from the crank or an accessory shaft with that power requiring fuel burn. That is why a Merlin P38 would have suffered significant range loss. Its takes a lot of power to achieve more power - the Wasp Major as fitted to the B36 achieved a gain of about 2000 HP at 30,000 feet by supercharging at a cost of 500HP so a useful net gain but not cheap. This is figure is my recollection from the great book "Magnesium Overcast".
@@terrybrown8539 Also, V for Victory made an interesting point about the Allison's needed to pass a rigorous 100 hour test stand run before type acceptance by the Army, which I found very interesting.
@@terrybrown8539 the numbers all point to the turbocharger as the way to go but it was a big step technologically to actually make one back then. Very high speed shafts and discs to balance. The early ones were huge and heavy...cast iron etc. Halfway to a turbojet really
@@johnp3937 It's an odd detail, but ME262s had a much lower production cost then often thought because of this. A high power engine like this is very hard to make, and very expensive, and while jet power was of course very new and revolutionary, requiring massive engineering and physics work to be done, mechanically they're a lot simpler to make.
Greg, you're incredible with your explanations. One thing I have to confess, I was always taken by the beauty of the P-38 and the P-51-D, but after watching al your videos, I'm all in for the P-47-D, H and J! I always thought of them as big, lumbering slowpokes. Was I EVER wrong! Thanks for helping us get better informed.
My dad’s favorite plane was the Lightning
Gotta admit, it’s a beautiful airplane
Another excellent video! I'd like to point out that the P-38 had only one production facility which was in Burbank. Another production facility didn't open until very late in the war. A Consolidation-Vultee IIRC. Working up various experimental a/c along with ramping up the P-80 in only one plant probably forestalled any major modifications to the already quite capable P-38J/L as Greg points out. Meanwhile the P-47D and P-51D were being produced in two facilities respectively, allowing modifications to be introduced without completely shutting down production.
I have to say as a fan of the P-38 the "K" would have been a winner with climb and acceleration outweighing compressablity issues IMO.
There was a mod center in Dallas where the photo recon and bomber noses were installed.
Compressibility was the dangerous aerodynamic behaviour at dive speeds, no?
So in demand was the P-38K that Material Command requested it again in April/June 1944, because they needed *more* fighters.
It was the War Production Board that forestalled nearly every single advance in the P-38, either slowing or preventing them completely.
Consider that half the plant capacity where the P-38 was built was utterly *wasted* building B-17 bombers. If you have fighters preventing your bombers from being shot down, you don't need to build as many replacement bombers or train as many replacement crews.
Using 100% of Lockheed Burbank to build the highest demand fighter only made good common sense. Consider that you'd have nearly twice as many P-38's available. That's advantage one. But then consider you'd have skipped the J, and gone to the K, and it would have been 2-3 months ahead of schedule. Now, you have the K built, and you build on that, not the J. So you have even more HP, and you quickly move to a *four* blade Hamilton Standard High Activity paddle prop. Next, with double capacity, you phase in improvements one line at a time, allowing the updates to the center wing and nacelle, including the new radii fillets to improve dive performance, and moving the inlets and outlets for radiators and oil coolers.
If you do away with the arrogance, stupidity, and politics of the War Production Board, you change everything.
Yes, even with all the valid arguments, I just cannot see that it would not have been worthwhile to put the "K" into production...and I'll never understand, given all the problems with the R-3350 at it's introduction and deployment in the B-29, they didn't switch over to the Allison V-3420 on at least one production line, considering the performance improvements(and reliability improvements also no doubt)....@@AlanRoehrich9651
Lockheed, Love Field handled much more types of modifications than P-38 mission specific mods.
The B-17 & P-51 were Love products too just to name two others.
Very many B-17G-VE were H2X mods. That BTO capability had great effect on the CBO strategy of 1944.
Thanks for pointing out how incredibly complicated this whole issue was. Even with these problems the P38 was a great warplane. I heard once it had the highest kill ration of the American aircraft which, of course included the Pacific theater.
hubris. Oil cooling problems , terrible gunsites ,one high-speed turn only .
@@georgesheffield1580 your funny 😄
@@georgesheffield1580
Pfui - ask about Richard Bong. BOOM AND ZOOM; drop the flaps and out-turn them till they stall; rake things with multiple MGs (and a few cannon just for fun) all with ZERO CONVERGENCE.
Pfui.
Concerning the paddle props-the 3 bladed paddle props fitted on the "K" prototypes not only was wider, but longer (bigger diameter). The extra diameter was the issue-to keep the tip speed subsonic the prop had to turn slower. To turn slower meant different reduction gearing (2.35 vs 2.0 IIRC). The different reduction gearing meant a different distance between the crankshaft and the prop centerline-which was the real issue. That meant structural changes to keep the thrust axis located properly and new sheet metal to make that all work. So-the issue was the bigger diameter, 3 bladed (paddle) props. The question I've never seen answered is why didn't it get 4 bladed props, with the same OD as the standard, 3 bladed one, like virtually every other fighter did? The extra blade lets the high activity paddle "work" at the same RPM as the standard, 3-bladed one, eliminating the need for different reduction gearing and revising the thrust axis. Seems like it would have been a much simpler way to go.
The other issue, why not a liquid to air intercooler like the Merlin got? Much more streamlined to put a small liquid cooled heat exchanger in the intake air stream, rather than duct all the intake air out to and back from to the air to air one. The original design with the wing leading edge intercoolers was a great concept-intercooling with no added drag. Unfortunately it ran out of cooling capacity at much over 1200hp. The big, chin-mounted intercoolers did the job properly, but added drag-even though they made a lot more power, J & L models were only marginally faster than the G. A liquid cooled intercooler offered more packaging options for the secondary side, potentially utilizing the Meredith effect like the Mustang did to reduce drag. It would also eliminate all that duct work in a crowded engine compartment.
Big issue was still compressibility. At high altitudes the standard P-38s weren't far from compressibility speed even in level flight-more power would have got them there quicker. Granted, the huge boost in clime rate alone would have justified it.
The other big question-why were no other plants built to produce the P-38? Every other fighter was built in multiple facilities, meaning that new designs could be cut in at one plant, without impacting production at the others. The '38 was only built at Lockheed's Burbank plant until very late in the war, when Vultee built ~100, none of which made it into combat IIRC. Until the P-51-B finally saw combat in December 1943, the Lightning was our only high performance, long range, high altitude fighter. Seems like it would have been obvious that more plants needed to be building them.
This one is for Greg. Your videos always discuss very complex technical issues, but even I, complete noob, understand what you are talking about. Great job. It also shows how complex designing an aeroplane had become by then.
Great Video! I didn't think, that there were people actually thinking that an engine replacement in the P-38 was needed and possible, even less - beneficial.
Ultimately, this question is resolved by this video.
This has already been resolved in advance, within the video about superchargers, where Turbo- and Mechanical Superchargers were compared with their pro-s and con-s.
There have been several just on Gregs vids, tons upon ton on other 38 vids on YT. Its very much the pop culture view that the Merlin is always better than the Allison when in fact the 51 was more of a special case than most realize
Some people can't seem to understand complexity beyond Merlin: Good, Allison: Bad.
*in Sept 1943 Lockheed delivered to the AAF at Eglin field, a P-38 fitted with 1,875 bhp Allisons and Paddle-Bladed Propellers.*
*it had a Top Speed of 432 mph on Military Power, and >450 mph on War Emergency Power. 4,800 ft/min climb rate and 5 mins to 20,000 ft*
Yup, and Lockheed estimated they would have to stop production for at least 6 weeks to update the lines to implement the modifications IF Allison could even mass produce the engines needed. A loss of 6 weeks of production was considered unacceptable, so the "K" was relegated to a historical footnote of P-38 "could-have-been."
@@everking3767 *- it wasn't that Lockheed didn't have the Knowledge or the Expertise to Engineer a Superior Aircraft, but the Decision not to go forward was strictly political.*
@Keith Johnson when you say “political”, do you mean a “rational logistical decision”, or “interference for non-military purposes”?
@@gerardlabelle9626 *- if in the middle of a WW your Bombers are Suffering Heavy Losses, and a company like Lockheed upgrades their Lightning to the next level. Superior in Speed and Climb, with additional Range and Payload, to anything the Allies had at that time, and you're going to reject it because you don't want to interrupt production for 2-3 weeks.*
*What would you call that?*
It would have required 2-4 weeks of production halt. Of course, it would also require the props to be produced. Allison was more than ready to produce the engines.
Unfortunately, half of the production capacity of the plant that produced the P-38, Lockheed Burbank, was being used to produce B-17 bombers, the U.S. was desperately trying to keep up with losses due to unescorted bombing. There were also multiple theaters literally begging for the P-38, remember that there were no P-51's at the time.
Had the War Production Board chosen wisely, and moved the B-17 production out of Lockheed Burbank, the P-38 improvement curve would have been radically accelerated. Every theater would have been flooded with the P-38K by August or September 1943. Flooded as in the 20th and 55th would have been able to put up at least double what they did, maybe 3-4 times as many aircraft.
The dive flaps, boosted ailerons, and flat armor glass would have been there in late 1943, not early to mid 1944.
The P-38L could then have been equipped with an even more improved four blade prop, and the G series Allison V-1710 would have been available. So would the unified power control for the throttles, props, and mixture.
Would the P-38 have still been limited in dive speed and top speed? Yes, of course. However, the dramatic improvement in rate of climb, acceleration rate, and combat radius would more than make up for the dive limits. The P-38 would have been able to sustain climb and turn rates far superior to most anything except jets. Combat radius allows you to be nearly everywhere. Being able to out climb, out turn, out roll, and out accelerate your enemy means more than dive speed.
Excellent! You have covered this well here and previously. I believe we have all viewed "P-38 A Personal Story". The second quote in the beginning "Once the P-38 received the aileron boost and dive brakes... ". Also, General Kenney made it abundantly clear, he wanted all available P-38s in the Pacific theater. This was for obvious reasons. The P-38 did better in warmer climates and did not handle the high altitude low temperature in the European theater as well as the P-47 and P-51. Lastly, I believe we all want 2 engines over water with very little landing choices available.
Actually, it was the PILOTS flying out of England, that didn't handle high altitude low temperatures well. Not surprising, in a non-pressurized, poorly-heated cockpit. Plus, the compressibility dive danger before the -J-25 models hit the squadrons just destroyed the P-38 in 8th Fighter Command. Of course, the idiot RAF pilot who mistook a C-54 for an FW-200 and Shot Down a plane load of dive flap refit kits for ALL the P-38's then in England, didn't help matters either.
I hate rookies...
I think Kenney was less concerned about Cold Weather performance as much as he was with viable and effective range. Especially over open ocean. While the P-47 wasn’t that far behind the lightning in terms of it’s textbook combat range, the Lightning’s 3000+ mile Ferry range was an often unheralded key feature in the Pacific. They could move the planes where they needed them quickly and without a ton of complex logistics or borrowing a Carrier for ferry duty.
@@jameskratzer4538 I'm glad you brought that point up about that C-47 getting shot out of the air. Tragic really. I'm not as well read as some of you are on this, but I think that the P-38 at cold, high altitudes in Europe with the turbocharger and gasoline octane issues may have contributed to a significant amount of detonation. BTW, Greg did a great study/dissertation on the P-47 with the proper external fuel tanks what it could have really done at altitude escorting bombers deeper into Europe.
@@jameskratzer4538 not really. the P-38's early GE turbochargers were not well designed and insulated for VERY low temperatures at high altitudes, and the condensing water in the exhaust gases froze up the turbos just where they were vital for horsepower at altitudes where the B-17s flew. Without boost the P-38 had about 200kt speed.
Peter Snell from what I've been able to find, purely in published documents, the turbochargers weren't so much the problem as the poorly heated cockpits and the gasoline separating the lead out at altitude (yes, probably, but not definitely, because of the turbochargers). This separation caused extreme octane loss, with resulting engine detonation.
The biggest turbocharger malfunction problem at altitude over Northern Europe was the controls freezing up; I'm not sure whether this was a runway water-spray issue, or cable and linkage lubricant icing. The end result, however, was a turbo power setting that was either too low to sustain flight, or too high to maintain the engine and turbocharger as a serviceable unit.
For a more in-depth explanation of the "teething troubles" of the P-38, I recommend Martin Caidin's book, "Fork-Tailed Devil: The P-38." It's a head first, no holds barred dive into the history of one of the greatest propeller driven fighters ever built.
I've gained respect for the Alison engine now. I thought it was sub-par but with turbocharging, it produces a power level at altitude that surprised me.
It is much maligned.
Also keep in mind that the P-39 was supposed to get the turbo'd Allison as well. That would have completely changed the Aircobras reputation
@@Silverhks the king cobra had the turbo supercharger. Soviets got a lot of those
@@JohnRodriguesPhotographer wait the king cobra didn't have turbo supercharger most of them have superchargers optimizes low and mid level altitude due to the frequent air combat in that level in the eastern front.
@@aker1993 the king cobra used to totally different system for boost then the p38. It had a turbocharger with a secondary supercharger that was mechanically driven. This gave the aircraft a service selling your 40,000 ft. An altitude that cannot be attained by a single turbocharger.
Your knowledge and ability to explain things in lamens terms regarding aviation are unmatched on YT
Thanks.
I really enjoy these videos you are doing. The depth and detail is quite good. It's a huge step up from the very basic summaries that are more common. I'd really enjoy a series on early war developments in planes like the P-40, F4F, Dauntless, etc, or even some Pacific theater content.
I have two videos up on the F4F, few people watch them.
@@GregsAirplanesandAutomobiles That’s a shame it was the F4F was the plane that won the critical battles in the Pacific. Like the P 47 in in the ETO it did the heavy lifting before the P 51 and F4U showed up.
At 15:37, that's a shot of a P-38 flying west -- going "feet wet" just south of Ventura, CA. Great country for motorcycling, which I used to do in the 1970's and 1980's.
I grew up in Ventura County.
Thorough, high quality engineering analysis of Merlin versus Allison forced induction power plants in the p-38. Really excellent
Thank you for the latest P-38 video Greg and I thoroughly enjoyed every minute of it. I'm an admin to a Lockheed P-38 Lightning Facebook group and like you said I see a lot of posts/questions as to why the P-38 wasn't fitted with Merlin engines like the P-51 Mustang did. So I'll share this video to my group and this should help to explain to everyone why the swap from an Allison to Merlin engine wasn't as simple straight swap.
Thanks again Greg and I'm looking forward to the next Lightning video.
More P-38 stuff is coming, and thanks for sharing my videos. I really appreciate it.
I've seen three 38 videos, is there more?
@@caseylee4266 Only the three so far
Thanks Greg, the P-38 has always been my favorite. It's great to know the details!
P-38 is and always will be my favorite WW II fighter, even as I learn more about its problems. But as others have said, every design is full of compromises (or something like that)
And look at the list of top American aces, you'll see the P-38 is very well represented there, 3 of the top 10 flew P-38s Hard to argue with success.
I've never got the hang of those planes on a technical level. Until I started watching these videos. Thanks !
*in Sept 1943 Lockheed delivered to the AAF at Eglin field, a P38 with 1,875 hp Allison's fitted with Paddle-Blade Propellers,*
*but the U.S. War Board didn't want to pause production for 2-3 weeks for Retooling.*
If they were having to fly the missions they would have
@@kenneth9874
No, the actyally did well, I think. The planners and tacticians had good data: that they already had the P-52 and P-47 for escort AND ground attack (and the P-47 had more flak/small-arms survivable radial engines). US industrial production was HUGE but not LIMITless, and they had to use it wisely. If nothing else, you wind up choking the rail lines with airplanes you DON'T need but are on the rails instead of the ones you just made that you DO need. Not simple, war.
P-47 and P-51 show up for long range escort; P-38 struggles at altitude. P-38 winds up all over the Pacific and at low altitude in Europe. Go find P-38 specific gun cam footage from 43 - 44. >> CRY HAVOC AND LOOSE THE DOGS OF WAR
Warren M Bode wrote a secondary source book on the P-38. In summary, the Merlin engine had a higher fuel consumption per brake horsepower than the turbo charged Allison. His point is the Merlin P-38 would have reduced range compared to the Allison. He does not address the possibility of converting the space from the turbocharger system into additional fuel supply. He also addresses the possibility of the paddle blade propellers. He agrees this would have increased the performance of the P-38. However at this point the US was already winning the war and the current production P-38 were doing a great job in the Pacific. Upgrading to the paddle propellers would have required Lockheed to shut down production to make the conversion to paddle blade propellers. His position is the military wanted more P-38s not a better one. Another great video Greg.
I'm so glad he still makes these videos. It's such a treat.
You have a knack for turning nuanced, complex topics into easily digestible videos for the interested laymen, without dumbing it down too much. I really appreciate your work.
Very informative video! Had no idea that the P-38's turbo charged Allisons generated consistent power over such a wide range of altitude.
I may not be smarter after watching one of Greg’s videos, but I feel like I’m smarter, and the algorithm needs to know that.
Thank you for the very logical and concise explanation that I have been been wanting to hear for 55 years, from the first time my father (a WWII Pacific theater veteran) and I made a model of a P-38 for my 7th B-Day. I remember my dad showing me the turbo chargers on top of each engine boom, and explaining that this was what made the P-38 a superior high altitude fighter. I also remember him saying the P-38 pilots knew never to get into a turning dogfight with a Zero. Hit & run the best tactic even for this mighty plane. He got me a Zero, and a Hellcat too, all 1/48 scale, and I still have these planes today.
That was early on. Later models of P-38's had Fowler flaps installed that tightened up their turning radius. Some German airplanes also had Fowler flaps. Lightnings that were so equipped could turn with the Japanese 'Zero', but by that stage of the war it didn't matter. The handwriting was already on the wall.
How is this of any value to anyone but you?
Turbos are amazing additions to an engine, even in 1943.
And Saab will be much missed for making them common in cars.
@@TzunSu I believe turbos are more common now than ever in road cars
@Juan Ordóñez Galbán [whoosh]
@@ctrlaltdebug whoosh poping jimbo
@@juanordonezgalban2278 Now, yes, but Saab was the company that took turbos from being only on high-performance aircraft and racing cars, and some dieasel trucks, to making them common in ordinary cars back in the 70s.
Standard atmospheric pressure is 29.92 inches. So at 56.8 inches manifold pressure, we have 26.88 inches of boost.
Since boost pressure typically these days is measured in pounds, and atmospheric pressure is about 14.7 pounds per square inch at sea level, or 0.4913 pounds per inch of mercury, we can calculate an approximate boost pressure of 13.2 psi. Really, if you subtract 30 from the inches of manifold pressure and divide that by half, you get an idea of how much boost these old engines actually ran.
This 13.2 pounds of boost was on an Allison V-1710 48 valve SOHC V12 engine with 1710 cubic inches/28.0 liters of displacement. Granted, these engines only ran about 6.65:1 compression, and operated at a maximum speed of 3200 rpm, so you can see why these produced "only" about 1450 hp~
Great video!
Compression is measured without boost.
@@JohnRodriguesPhotographer That compression ratio I mentioned was static compression ratio.
These engines were making about one pound of torque per cubic inch, not to shabby for 80+ years ago.
@@jimgoff1170 A valid point. Especially when you consider how far metallurgy has come since then!
@@Flies2FLL These aircraft engines back then were very modern and complex , if you look at car engines today . A DB 605 for example , there are components in that only hyper cars today have . Aluminum engine with steel cylinder liner's , SOHC driven by a mechanical master shaft (Königswelle , I hope the english translation is right ), direct fuel injection , 2 sodium cooled exhaust valves .
For an 80 year old engine this is astonishing in my opinion . 😉
Wonderful job explaining why the Allison v-1710 engine remained in the Lightning. The British, who received P-38's, were pissed off as they got them without the then, "highly classified" proprietary turbo superchargers that the U.S. withheld for itself, and they called them, "castrated Lightnings."
I have Flying Iron's P-38L for Microsoft Flight Sim 2020 and it's become my favorite warbird to fly. It's just a dream machine to fly. I have a P-51D, a FG-1D Corsair, A BF-109 G6, a Spitfire Mk IXc and a Grumman F6F Hellcat...all fantastic computer sim recreations of the real aircraft, but the P-38L is BY FAR my favorite warbird aircraft to fly. It's simply superb. Good ol Kelly Johnson sure knew what he was doing. I totally understand why Richard Bong loved it so much. It's nickname of, "Cadillac of the skies" was well earned.
For any interested, here's a short video I filmed of the ending to a flight I made from San Diego to Burbank CA, in the Flying Iron P-38L on my computer for those not familiar with how accurate and well done modern flight sim aircraft are recreated digitally. ua-cam.com/video/2lh7mnvi46U/v-deo.html
Excellent video sir. You answered the question I had about why the P-38 never switched to Merlins. Thank you!
GM owned Allison. Also, a new Allison plant had been financed by USAAC and built in 1941. It's all about $ and influence. Lockheed engineers were upset with the lack of development on the Allison and the problems with the Allison and GE turbos, etc... They wanted Merlins; ie reliable engines at altitude.
They didn't have the turbo superchargers because it would have violated the neutrality act....
One point you didn't bring up was that the Allison was designed from the ground up for opposite rotation with the exchange of a minimal number of components. An opposite rotating Merlin would have been more of problem.
Merlin 130/131 left and right rotation Merlins for the Hornet/Sea Hornet.
@@givenfirstnamefamilyfirstn3935 It is reasonable, according to the WW2 time frame, to deduct these Merlin counter rotating 130/131 engines were much too late to see any action in WW2, thereby making them useless to P38s or any other aircraft to see WW2 service.
Powerplant: 1 × Rolls-Royce Merlin 76 V-12 liquid-cooled piston engine, 1,710 hp (1,280 kW) fitted to LHS
Powerplant: 1 × Rolls-Royce Merlin 77 V-12 liquid-cooled piston engine, 1,710 hp (1,280 kW) RHS fitted with a blower for cabin pressurisation
The Mosquito.
@@snipersl270 Never seen or heard about a Mosquito with handed props. How about some documentation to prove that. 🤔
@@stanhathcoat920 Just the wiki page for the Mossie. Wiki says its from Janes. Data from Jane's Fighting Aircraft of World War II,[205] World War II Warbirds[206].
Damnit Gregg! You did it again! A question that I've pondered for 25 years, you put to rest in 25 minutes!
There is a lot of aviation history buffs out there that are WAY gooder stuff - knowers thanks to you and these videos. I think you may be the "Ken Burns" of airplane videos!
Thank you for all you do for us.
Always great info and love your videos. An interesting side note, an early photo shows the P-38 over a city by the ocean. The city is Ventura,CA, Very interesting to see it in the 1940's without the harbor that I am living in now.
Yup, I grew up just south of there off the 101, and I have flown over that same spot.
Great breakdown for those of us who love the P38
Mostly the cost I would have thought...
A Merlin P-51 was SO much cheaper than a P-38, and it was "good enough".
Why spend any time or effort on P-38 upgrades after mid/late 1943.
The P-38 carried the US through the first couple of years of the war when it was most needed, and did a great job.
But then after that, there were just other more cost effective solutions for the high altitude roles over Germany.
And the P-38's could then be transferred to a few select specialty roles, where its other qualities were very useful - and re-engining wasn't necessary.
You got it Greg did address this in another video the P-51 was almost half as costly as a P-38 and about 2/3 the cost of a P-47 I seem to recall something like 55 k for a P-51 vs over 90 K for a P-38 and something in the 70's or 80's for a P-47 ( sorry I m not exact I'm too lazy today and the internet is at your fingertips if you care to look)
Well put.
Actually, the P-38 was the preferred aircraft in the PTO since the start of the war. General Kenney constantly begged General Marshall for P-38s throughout Pacific campaign. Long range and the safety of two engines were paramount in that theater. Once Iwo Jima and Okinawa were captured the range issue was eliminated for the planning of Operation Olympic. However because, “Europe First” was the hierarchy of defeating the Axis, Material Command prioritized aircraft to the ETO and MTO over the PTO. Only after D-Day, and then the breakout across France in late summer 44, did P-38 priority was shifted to the PTO.
I do think they should have let Lockheed make a “kit” for adding new propellers to late model Lightnings. I feel that would have been a small enough delay to be offset by the improved Thrust
@@spindash64 a “kit” would have been considered a maintenance depot assignment. Just switching props wouldn’t be the process. The gearing and cowling changes for the new propellers themselves and possibly a new prop center wouldn’t have been possible for change in the field.
It's fun to listen to Greg's earlier videos and then the later ones and see how much better he's gotten at narration. Great vid.
Another great presentation Greg.
I thing a subject for you to speak about is the actual power at the prop vs the drain by the engine accessories. This I think would be a natural progression of your talks so far.
Once again thanks for all your efforts with quality vids.
Thanks again for covering the P-38! I am very glad you are giving it your best treatment!
Fantastic video. This guy has a great ability to explain and teach. That's undervalued and rare.
I studied philosophy in college and was watching Monday Night Football. Ended up muting it and being fully wrapped up in this. Thanks internet guy Greg. Really good work. Really good.
You're welcome.
You must use a lot of Zen to remain philosophical while watching Monday Night Football.
This is why the P-38 was such a fabulous fighter.
Excellent presentation. This is a very impressive video
Excellent explanation. The P80 was clearly the focus of engineering. The P38 clearly had adequate performance against its opponents - so no need.
Great analysis as usual. The advertisement at 11:00 is from Fafnir Bearing, a factory in nearby New Britain CT. They made high quality bearings for airplanes in to 30's and 40's , then space in the 60's. Now part of Timken.
I had no idea that changing to Paddle props would have meant such a big effort, in cost, time and man hours...
Perhaps it should be pointed out that in addition to paddle blades, both the P-47 and P-51 were fitted with propeller cuffs from the base of the blade extending about two feet towards the tip. They squeezed a bit more thrust out of the blades at their hubs, and may have helped cool the R-2800 in the P-47 a bit.
@@georgettewolf6743 Well, I recall the P-51 blades look very thin and elongated compared to the prop blades of the Thunderbolt, that look way beefier ...
@@doncarlo5 They were. However, just like the P-47, cuffs were added to the props.
It would have been justified if it saved some pilots,but that's not how bean counters whose life's aren't on the line think
@@georgettewolf6743 Not much it still had a lousy climb
This is an EXCELLENT discussion Greg!! VERY nicely done! One other aspect of the difficulty of switching to the Merlin from the Allison (that you actually briefly touched upon, when you briefly mentioned weight) is that the Merlins are typically 300 pounds heavier each than the Allisons, so changing over would have required a DRASTIC redesign of the booms! If you look at the installation of the Allisons in the '38, as you very correctly point out, the ENTIRE DESIGN of the nacelles/booms was around the engine and the necessary ducting for the turbosuperchargers, AND the main landing gear. Adding 300 pounds at the very front of each boom would have required either the powerplant to be mounted further back into the nacelle or ballast being added to the tail. The way the Allisons are mounted, IRRESPECTIVE of the turbocharging ducting, the engine mounts not only carry the engine itself, but they also carry the hydraulic actuators for the main landing gear BETWEEN the engine and the firewall RIGHT WHERE the lower-slung Merlin updraft carburetor would be, so THAT actuator and ITS plumbing would have to be redesigned into an otherwise ALREADY space-starved area around the gear well somewhere, so there's just ONE major redesign problem. Also, they wouldn't JUST be ADDING 300 pounds out front, but they would ALSO be DELEATING the ENTIRE aft-of-CG turbosupercharger units, which would FURTHER complicate the weight and balance issues...another MAJOR redesign issue. AND by repositioning the engine placement, necessitated as already mentioned, it is VERY likely that the propeller discs would be in a different fore-aft position and/or up-down position relative to the wings and central gondola. As EVERYONE knows (or should know), the P-38 was plagued from very early on with SERIOUS AERODYNAMIC issues of tail buffeting and compressibility. By the time the P-38F was fielded, the tail buffeting had largely been eliminated through VERY CAREFUL filleting of the wing root/center gondola junction and the addition of external counterweights to the elevator (when you look at these weight closely, they are TOTAL "AFTER-THOUGHTS"!! ....the streamlined tube that holds the weight in position is simply welded to a flat plate and BUTT-JOINT SCREWED to the surfaces of the elevator structure, and the weights themselves are nothing more than BIG CHUNKS OF LEAD, JUST LIKE BIG FISHING LINE WEIGHTS, BOLTED to a plate welded to the end of the streamlined tubing!!). And, of course, the compressibility "tuck" issue was alleviated with the addition of the underwing "dive flaps." These "fixes" for these issues were very SPECIFICALLY sorted out for the existing layout and orientations of the various elements causing the various pesky airflow perturbations that precipitated them. If the props started getting moved around in this "equation," as they most likely would have HAD to have been with Merlins, that ENTIRE airflow environment gets altered, and the engineers likely would have had to go through the ENTIRE mitigation process ALL OVER AGAIN. The North American guys made the transition to the Merlin LOOK EASY, because, as you correctly point out, Ed Schmued's boys were ALREADY looking toward that eventuality very early on with the Mustang. Over at Lockheed, on the other hand, they were ALREADY looking at "improved" P-38 alternatives, in the form of the XP-49 and XP-58, along with development of the XP-80, so it wouldn't surprise me one bit if Lockheed had the LOUDEST VOICE AGAINST P-38s switching over to Merlins!!
GREG! Thank you. I simply feel smarter listening to you content, despite barely understanding it!
P-38 note: At the Sacramento Capital Airshow, (in 2013 maybe) I had the pleasure of witnessing Four (4) P-38's fly in formation over the city of Rancho Cordova out of Mather Field.
Quite the treat I must say! (And a rare one at that!)
Thanks for being who you are!!!
duhGlez
FOUR airworthy P-38s in one place in the air at one time?! What dreamland fantasy was this?! I don't think I would have been able to control myself... amazing. That sound...
Our flying mentors in the '60's, Ex-WWll pilots and instructors, often talked of missing the 145 octane gas used in hi-perf fighters of that era...
Look at the propellers at 13:45. You can see they are counter-rotating, but they rotate the wrong way. This reduces drag since the descending propellor blade always produces more thrust than the ascending blade, and the proximity of the fuselage would cause interference. This of course produces atrocious engine out characteristics, since this effectively shifts the live engine farther out on the wing, requiring more rudder to compensate.
I talked to a WWII pilot who flew P-38's and he said that often times if you lost an engine in one of these you would eventually reach Vmc with enough thrust to keep it in the air so you flew it to a place with less than full throttle in a slow descent to a place where you could bail out safely.
Pretty crazy what these guys were up against back then~
you tube has AAF/ Lockheed videos that prove otherwise.
What you're describing with descending and ascending blades delivering differential thrust is known as 'P-factor' and manifests only with aircraft flying through a high angle of attack (such as takeoff or landing).
Loss of engine at takeoff was manageable (ie survivable) if you knew well enough to throttle back on the live engine to mitigate the asymmetric thrust that was worsened by the P-factor. It's the reason the prescribed takeoff procedure called for a takeoff with no flaps-- it was a precautionary move to ensure you reached safe single-engine speed as soon as you can during takeoff.
A P-38 can climb and cruise on one engine. The only conditions a P-38 cannot maintain altitude on one engine is when _both_ the flaps and gear are down.
@@BogeyTheBear We are saying the same thing. What the man who flew the plane told me was different from what you are saying. He did not specify that this was the case in an effects of configuration scenario as you have posited; He simply said you flew the plane at lower power to a point where you could land it or bail out safely. It makes sense when you see how small those rudders are.
Why would they not keep full power and descend _if necessary_ to maintain the best single engine climb speed. That would surely give better performance than creeping down to the more draggy minimum control speed? Current multi engine training is superior to what was taught back then.
I'd imagine that there were more than enough customers for the Merlin's as it was too. It would make sense to have several engines being built and developed.
Thats another worth while point to make. The list of aircraft being built in large numbers using the Merlins was... extensive. Hell its why when they started designing the Typhoon it was planned to use either the Napier Sabre or the Rolls Royce Vulture specifically to avoid yet more stress on the supply of Merlins elsewhere, and the Typhoon was not the only mid to late war aircraft designed with other engines in mind specifically for that reason. And its not only complete engines, but also a ready supply of spares, which means a constant production of those as well.
And the perfect weekend is now complete. Thanks Greg!
The nose art and vintage advertising are candy. Subbed
Great job Greg. As usual another unbiased, truth based video. While the 38 is not my favorite {P-47} I do rate this AC above the 51. {IMO} She really showed her metal in the PTO. Hub Zemke {in his bio} mentioned this was a very difficult AC for the novice to fly into battle, to many things to accomplish in a very short time if bounced. That being said, afterall the top two USAAF Aces did fly her. Great job, Thanks!
Despite it's issues, P-38 is still may favorite fighter, closely followed by the P-47. Great treatment of the issue. Thanks Greg!!
What people fail to understand is that engines iterate endlessly. An Allison early or mid-war is nothing compared to a late war Allison, same as any other engine that was used throughout the whole war.
I used to think I was the ultimate old warbird nerd before I found Greg's channel. Kudos for another outstanding video Greg.
Great explanation. I always assumed it had to do with the large turbo superchargers, but I've never heard it explained before (or at all) in such detail. Thanks! Also, the graphs were great and made the choice very clear.
Since the last video on the P38, I've been wondering what could have been done with this aircraft had they cleaned up the aerodynamics mid war. For example: lose the exposed turbo, clean up the collection of assorted scoops, and finally, get rid of the ridiculous double cruciform tail. It could have been replaced with something like the F82 tail . Getting the stabilizer up higher might have helped with the compressibility issues as well.
I can understand why later in the war, like the decision concerning paddle props, they opted not to invest further in the design since the aircraft was effective enough at its job and with the wars end in sight was becoming less relevant. But what I never got was some of Greg's earlier points about parasitic drag, not just from the scoops (which might require some redesigned engine support systems) but things like gun ports which NACA testing clearly showed to be a major source of drag. Sure, they didn't know about this until further along its evolution but it seems to be such a simple retrofit to resolve on the production line. Why wasn't some of the low hanging fruit addressed to further improve the type?
Finally, a definitive well researched and presented answer to a question I have had for a very long time. Thank you for all your hard work, you now have a new subscriber!
Great video. Reinforces my view of the P-38- a great design that pushed performance into uncharted territory, but necessarily committed to production because of the war and thus less able to exploit the principles that it itself had uncovered.
Greg, thanks for your short video of the Bismarckturm. That brought back many fond memories.
I'm a mechanical engineer specialising in automotive performance improvements, so when I make the following statements, keep that in mind. (1) while superchargers have a fixed relationship to the crankshaft, turbochargers do not. If you have a turbo on your car (likely) the position will be literally anywhere the manufacturer can find the room for the turbo whorl and the rather blocky intercooler of course. (2) turbos have lag, but this is not a negative on planes, which do not have to race quarter mile drags. (3) in wartime, secrecy and time pressures negatively affect engineerring idealism. Then you separate Kelly's skunkworks and RR's secret rural Coventry 'guerilla garages' by a big submarine-filled pond called the north atlantic, and you have a recipe for NOT using the (bird) engine in the bush for the (bird) engine in hand. I could crap on about RR's better sodium-filled valves (friction welding was pioneered) etc etc ,but tthough true, its not the reason for the actual choice. Blame Tojo/Adolf if you really want to allocate brickbats.
The best design is a compromise of many good designs. This I learned after 13 years employment working as a Detail Drafter in airframe design at McDonnell Douglas.
Another great Doc!
Your academic detail & overall delivery are Superb!🤗
A superb explanation of what was a very complex decision on the part of Lockheed, and making clear just how vital an aspect of warfare are considerations of manufacture and production logistics (a point frequently overlooked even by military professionals!).
Cheers, Greg!
Looking forward to the video on the GE turbos, and their charge air cooling ductwork, etc. I've always been fascinated by them. I've only seen Max Millar's drawings of them.
I have a whole series on the P-47 where I talk about turbos quite a bit.
This video explains quite well that a extremely important factor of engines is packaging. Planes are often built around their engines, the P38 especially so.
Thank you for this video. It solves a lot of my questions about an engine swap. I would loved to have seen the P-38K!
I’ve got to thank you for a great video on why not Merlin engines. Now I can only hope to get into a heated discussion at a bar someday where I can debate the efficacy of turbocharging versus supercharging on world war two piston driven aircraft engines with special emphasis on second-stage turbo versus supercharging. Awesome information to have at one’s fingertips and I owe it to you for putting it together and putting it out so clearly, and understandably.
HA! But I have had that heated discussion with some jetski mechanics at their shop over some cylinder head and turbo swaps. Their collective lack of understanding of the very technology they were turning wrenches on was so profoundly disturbing I sent them Greg's two videos on the topic before meeting with next to explain my concerns. That led to much more productive follow-on conversations. The scary thing is the most mechanics today don't even know what the HEAT RANGE of a spark plug really is so they just open the gap instaed... Priceless. I do prefer teaching them to fish instead...
Great video.
For WWII aircraft engines the super/turbo charging system was key. Allison did have the V1710-119 with more advanced mech supercharger but that was later and never fully developed.
The place where Allison did make more advanced 1710's (the only place I know of) was in the P82 Twin mustang. Here you had no room for turbo system. Supposedly Rolls Royce wanted large royalty per engine for Packard-Merlins so NA went with Allison. According wikipedia "The G-series V-1710s installed on the F-82 E/F/G models had only anti-detonation injection (ADI) to deal with these problems, and not surprisingly had severe reliability and maintenance problems. In one record, it was stated that the F-82 required 33 hours of maintenance for each hour of flight. Supposedly these could make > 2000 HP?
The Allison-equipped Twin Mustangs are under appreciated they filled the gap when US got caught off guard in Korean War. They were not most advanced in 1950 but they may have saved the day.
Well, wikipedia is garbage. The G series Allison is a much improved V-1710, capable of higher RPM, with better superchargers, better intake manifolds, and a host of other improvements. It was tested at 70+ inches of boost, at 3400RPM, for hours on end. It didn't require excessive maintenance.
@@AlanRoehrich9651 Wikipedia is good or bad depending on sources they list these
P47's would have been better, look at the job they did for Taiwan defending against the red chinese
They would have been better off to figure out how to put a turbo on the mustang than to put the Merlin in the p38. Only takes a quick glance at the speed and altitude charts to know the swap would be pointless. Greg has put the information out there in his videos and gives us the knowledge to have a decent understanding of what he's talking about. Even a casual fan such as myself should be able to answer this question with no trouble at all. You're doing great work Greg, thank you.
People say this about the Westland Whirlwind as well, not knowing that to accommodate the Merlin's, the Whirlwind would have needed a complete re-design. New wing, fuselage, possibly a new tail...
To my eye that is one dead sexy warbird. Both it and the men that flew it into combat don't get the credit they deserve. Shame it was forced to the wayside basically due to stretched resources not allowing the redesign that could have made it a war winner. At least it was able to acquit itself well unlike so many other aircraft that ended up in the what if category of history.
@@indydurtdigger2867 All the Merlin's under production at the time were earmarked for Spitfire's & Hurricanes, then later, the Mosquito. By the time we had the Mosquito, there was no need for the Whirlwind so it was withdrawn from service. That aside, the Whirlwind used the R/R Kestrel engine, hence the reason why it would have been such a pain to fit Merlin's to her.
@@navnig We had numerous aircraft over here that the same fate befell them. Several that like the Whirlwind the designers couldn't get the engine they wanted and had to make do with what was made available often with less than desirable results. Some that just weren't feasible to sink the resources into a redesign. And several that the leg work was done on but the result was either not enough improvement or by the time they were ready something else had been introduced that rendered all the work moot. I just did a bunch of reading on derivative aircraft of the Republic P-47. The amount of time and resources sunk into putting a liquid cooled engine on the airframe is astonishing and not a one of them went on to be a production machine. Just one of many what could have been scenarios from countries across the globe.
@@indydurtdigger2867 There's a book called 'Tumult in the clouds' by (I think) James W Goodson, it covers his time at the start of the war flying spitfires in the RAF's eagle squadrons, then on to the USAF in the P-47 and then Mustang....Its an amazing read, I could hardly put it down after I began reading it!
That double wasp was a true giant of its time....In the book I mentioned, it tells a story of how one American p-47 had either 6 or 8 of the cylinders smashed in a dogfight over France and it still got home....Incredibly tough engines, paired with that 'Thud' airframe.....It was a flying tank! 🙂
@@navnig I will most certainly check that out and add it to my collection. Thank you
Got a used very good condition hard back on the way. And holy krupp new uncirculated copies of that are over 500 US dollars!?
in the UK we have an enduring love affair with the Merlin. Every year the Battle of Britain flight makes appearances around the country, sowing nostalgia & reinforcing the hyperbole of how Merlin's won the war..... more recently, I was reading how Handley Page had to upgrade from Merlin's to radials for their Halifax bombers, since the merlin's at the time weren't powerful enough. & taking stock, the amount of high performance radial powered aircraft on both sides puts things into perspective. UK also had the Napier H engine used in Typhoons & Tempest which are worth mentioning.
Many thanks for the vid.
this is my new favorite video! so many people dog on the allison v1710 so much, personally its my favorite engine of the war, was an absolute work horse on the eastern front and pacific!
Additional comment based on additional personal research is that the type 61 did not apparently have counter rotating version (wasn't used in the mossie) and both Tony Lavier and Robin Olds both attested to the advantage that was in combat. I also worked for a gentleman in Sante Fe NM in the late '80's who was an instructor on P38's in Washington State during the war.
Another great video! Thank you, your research is impeccable as always. I’ve read about ww2 aircraft since the 70’s and thanks to you I’m still learning a few things.
From when I was a kid, looking at WWII figher planes, I always thought the P-38 and P-51 were of similar design. The P-38 being something like two P-51's put together (in design). Your explanation of engine swapping shows just how much they're two separate and different planes, in their designs.
Weirdly enough, there was a twin-engine Mustang, the F-82: en.wikipedia.org/wiki/North_American_F-82_Twin_Mustang
@@soaringvulture I know of this but, only learned of it a few years ago. I've seen some videos on it and it's quite an interesting plane.😁
Anybody else mind boggled they had a Alison screaming at 2000hp for 7 hours straight? That's kind of nuts.
It's an impressive feat for a piston engine, no doubt. Also "War Emergency Power" is the coolest term ever.
3000 rpm at 75 inches, that's nuts indeed!
@@TurboHappyCar Look out. "War Emergency Power" could be available on a Tesla soon.
Apparently you’ve never heard of the Allison 3420, two V-12 Allison’s siamesed together. That engine sits in the “Superprop” section of fighters at Wright Patterson Air Force museum. Would you giggle at 3500 h.p.?
!!!WHAT???!!!
Great video. Very informative. You explained why the Allison V12 was the engine for the P38.
Great video! Hope you had a nice trip Greg.
Thanks Enigma. I passed the time with your videos. I really like the Mig 19 cold war one, I'll comment on your channel about it.
@@GregsAirplanesandAutomobiles Great looking forward to it!
Excellent video and right on. Similar is mentioned in Bodie, and back in the late 70s at Planes of Fame Kelly Johnson noted much the same, as did Tony LaVier. And spot on, in 1943, Lockheed couldn't keep up production for demand, much less a 6-10 month delay or stoppage of production. Note, Merlin install planning in the P-51 started in the UK and NAA in the summer of 1942, and the first Merlin aircraft didn't come off the line until early 1943, and get into combat until December 43. P-51A production of 1200 aircraft was halted at 350 or so. The P-38 would have undoubtedly taken longer, and that year to re-engine, in a 42 to 43 time frame when you all ready had a decent high altitude fighter, would indeed have been a waste, and unacceptable given very small if any gain in horsepower or overall performance. Big gains in the P-51, small gains in the 38.
Thank you Greg for answering a question I have had for years, Why Allison engine worked on the P38 but not on the P40/P51. Now I know that is was all about the super charging system. Correct me if I am wrong but it appears to me that if the P40 and P51 had been designed and built with the same engine and super charger system as the P38 both the P40 and P51A would have performed much better. This video reveals the rapid pace of aircraft engine (really all aspects of aircraft design) development during WWII.
The P40 and P51 could not easily contain the turbocharger system such as was used by the P-38. Their Fusilages would have
required extensive redesign. The designers have to pick the engine systems which POSSIBLY would be used and then do the designs, not afterward.
The American P-40s that were first deployed in North Africa, also were powered by Merlin Engines. I recall seeing photos of those P-40s on the deck of the WASP, headed for their destination.
Are you sure it was the USS Wasp (CV-7) and not the USS Ranger (CV-4) that transported the planes? USS Wasp (CV-7) was sunk on September 15, 1942 by a Japanese submarine south of Guadalcanal in the South Pacific.
@@robertdendooven7258 - Roger, of course Your correct. I must have WASP "on the brain" !
Also, counterrotating engines would have been a problem with the Merlin engine. The counterrotating props made the thing much more forgiving in low speed flight. Yeah, the Brits called theirs "Casterated Lightnings.
Can't say this for a fact but I suspect tha Mosquito would have to have had counter rotating Merlins for it to have handled as well as it did
Actually the XP38 had the correct counterrotating engines. After the XP38 crashed Lockheed erred and reversed the engine rotation thus creating "2" critical engines. By the time this was discovered it was decided not to switch back as too much redesign work was needed and the updates were coming so fast it was put on the back burner.
The critical engine issue is covered in many P38 books.
@@giantgeoff the mosquito did "not" have counterrotating engines...
@@michaelwillette5738 There would have been zero redesign work to swap the rotation of each engine. A small kit for each engine, and mounting the correct propeller to each side.
As a matter of fact, one of the things that made the P-38 so popular is that there was one engine for the aircraft, with only a small kit installed in an engine to reverse its running rotation, and installation of the proper propeller.
@@immikeurnot This may be true of the Allison engines, but what works for one brand/model of engine won't always work for others.
Also remember the Merlin was developed by Rolls-Royce, and had a tendency to be considered somewhat of a finicky thoroughbred. The Allison was on the other hand considered to be more utilitarian and versatile, as it was also used as the engines that equipped the PT boats of the U.S. Navy.
Great video, I don’t know how I have never seen your channel before but I couldn’t help but subscribe after this.
Hi Luke, welcome aboard.
Thanks for all the information Greg. I'm always very impressed with your level of knowledge. You must spend a lot of time doing your research.
I enjoyed this presentation very much. Never gave much thought to put a Merlin in a P-38. But you are correct in your opinion, that it would have taken a massive redesign of both nacelles, plus the assorted plumbing. And during this time of the war priority was given for a certain plane certain engine. Production lines were stretched to the limits with the orders they already had. Along with continuing improvements and the next model.
Great video! As a future idea, would you please consider covering the Merlin powered P-40s? I know very little about them and would love to know more.
Hi Brian, you're not the first to comment on that. I just might cover them. I'll put up a poll tomorrow to see what you folks think the next video release should be.
@@GregsAirplanesandAutomobiles THANK YOU!
Was curious about that as well- the P-40 was supposed to be a very responsive craft- was wondering if it would have the high speed control issues that the Mustang was reported to have with the more powerful engine.
Good video. I had no idea that anyone outside of UA-cam wanted to try out the Merlin on the P-38. I'll stand correction, but as I understand it, by mid-1944 Lockheed and the USAAF were backing off on P-38 production. As Greg notes, the jet was the future. In addition, the P-38 - an innovative design and very good fighter in the right arena - was in essence two airplanes stuck together, almost doubling the maintenance routine - no small thing in an air force already sporting Jugs and Mustangs. All P38 fans should check the memoirs of Gen Ben Kelsey "The Dragon's Teeth?" Kelsey was the head of the USAAF fighter project and was deeply involved with the P38. He also gives an insider's view on how insiders viewed aircraft - they weren't thinking of creating machines for a joust.
The question should really be “why didn’t the P-51 get the dual stage turbocharged Allison engine?”
Swapping the engine would also have impact on ballance. C.G. would move quite a bit forward, so it would require a whole lot of redesing, so it made no sense.
I was always under the impression that as phenomenal as the P-38 was, it was somewhat hobbled by a less than an ideal engine - boy did you just school me! Fantastic work!
That's why they used 2 of them. And the Allison can be easily configured to turn in either direction, making it particularly well suited to a twin engine plane. And we had shitloads of them.
Great video. I never even thought of switching but you explained it perfectly.
Fantastic, as usual. I like the details you bring in every video.
One P-38 pilot said that when the later models added power assisted controls(from 1:1 to 1:12) they could roll & turn with anything. A shame they & the 'dive flaps' weren't added sooner. Great plane though.
It's great to see this questions addressed properly as it comes up almost as often as, "Why dont they just build more A-10's or restart production of them".
ugh the a10... a sign somebody(not you) knows nothing.
@@joshwilliams9843 not really
@@Hornet135
Well, actually really. The A-10 is obsolete. It the history, not the future, of close air support. Don't take it from me , take it from the commander of Air Combat Command:
"China is our…pacing threat. If we’re going to keep pace with what they’re doing … you’re not going to do it by refurbishing a fleet of 40-year-old, single-mission, 210-knot airplanes. You’re just not, regardless of how much they’re loved and the great performance they’ve done."
Gen. Mark D. Kelly, commander, Air Combat Command, offering his view of the long-term effectiveness of keeping the A-10 in the combat air forces, Air Force Life Cycle Management Center Life Cycle Industry Days streaming seminar, Aug. 3.
@@gort8203 Why are you taking to me? I only implied that just because someone mentions the A-10 doesn’t mean they know nothing, as the previous commenter suggested. It’s kinda weird he calls it a 210 knot aircraft though.
@@Hornet135 You're right, I actually shouldn't have replied at all. It seems I misinterpreted your comment as being in support of the idea of building more A-10s. I now see my first error was in misinterpreting the original comment. I jumped to the wrong conclusion after reading too many "brrrt boy" comments in other places lately. My apologies.
@Greg's Airplanes and Automobiles Greg, I am a Riddle grad, life long WWII aviation guy, you are the only channel where I am stumped by what you can document, explain. Please, Please, Please, in your next P 38 video, compare the Grumman Skyrocket to the Lighting and Mossie. If the Navy/FDR had the smallest amount of foresight, the Skyrocket would have shorten the war by a year. The tech to build the Skyrocket was proven/available in 37, the F7 could have been built in '40. Imagine the US mass producing a twin navy fighter in 1940. The F7 would have dominated the skies in every theater Instead we built the P 39.