This channel has the right amount of in-depth detail I want on my aviation content. Usally you get a simple "this plane, big engine, very fast" video and that's it. But Greg goes to discussing the possible origins of the nuts that hold the horizontal stabilizer actuator.
@@clazy8 in his older videos Greg goes over the various charts, how to read them and how he gets them. Unfortunately it's not all in one place as he will explain it in full the first time uses it. If you don't understand after seeing his explanations, well I get that. Some of it goes over my head too.
Greg bringing the highest quality aero and engine content to the world, as always! As to the metallurgy, a trusted friend, welder, machinist, and metallurgist said when viewing that report - "Wow, thats a triple alloy steel, same as Early Tiger Is very impressive even for today standards, very close to todays 4340 and if it had less phosphorus and sulfur contaminates it would pass MIL-DTL-12560 for armor plating for today's US Main Battle Tanks. Im surprised the Japanese was able to make them considering their situation in 1944-45."
In addition to Greg's unmatched, deep, detailed examinations of these aircraft, I just want to thank knowledgeable commenters from around the world who provide even more detail and context to WW2 Japanese aviation. I always read the comments in Greg's channel and I can't think of anything more praiseworthy.
13:58 I'd think the 加速ポンプ(acceleration pump) in the upper right corner is the hand operated fuel boost pump. It seems crazy to try pumping fuel with that handle whilst trying to fly with a center stick control and a throttle on the left side...
Imagine deflection shooting in a dogfight: Pulling 7G, having to put 65 pounds on the centre stick just to turn with the enemy and using a trigger mounted on the throttle while also pumping fuel. An impossible task even for Mr. Sakai
Been a fan of Japanese aircraft since I was a kid, probably because little is generally known about them. I've had the Aero publishers book on the Ki 84 since the '70s. So these are a rare treat. One often overlooked favorite of mine was the Mitsubishi Ki-46 Dinah Recon Plane.
@@GregsAirplanesandAutomobiles Major Yohei HInoki of the 64th Sentai lost his leg to .50 cal of a Mustang in a Ki 43, completely in the aircraft, tied it off tight and made it back to his base. The 64th was full of 4 year veterans by the end of '41 and considered prestigious while in Indochina and thereafter. So they likely had the latest Oscars with armor and self sealing tanks by the time Mustangs were in the Pacific. I believe he had a case of target fixation and let one get right up onto his 6 real close. Just that some of these guys survived those kinds of circumstantial odds seems to evidence quick thinking pilotry as much as their claims numbers. (His was 12, mostly if not all in Oscars and an unconfirmed "probable" in a Ki 100 with an artificial leg and out of balance propeller. Our records that day showed one Mustang MIA and two Returning Mustangs damaged, one badly) And I believe I remember reading somewhere about one of the tested Ki 84s, probably the first, having been taken from the Philippines.upon our take-back-over there..
@@demetridar506 I don't think it a disagreement to say 50 cals penetrate whatever Oscar armor was behind the pilot, squared up on his 6, from 100 yards or so. And what should also be kept in mind are raw material shortages in Japan during our ongoing submarine blockade of the Home Islands that affected the alloys used or skipped altogether. Even the US went through this problem. A lot of guys building dragster frames on the west coast in the '60s were getting 4130 tubing cheap from surplus yards because it was WW2 era material that didn't meet the standards for whatever it was used for in something requiring the correct metallurgy. Aircraft industry being an example. They used it when they had to but not thereafter. . If you had a contract with Boeing requiring some of that they'd want to see receipts from where you got it. So if you bought a genuine vintage Woody Gilmore slingshot AA fuel dragster chassis made in. his shop out in Santee CA in the '60s it probably ain't made from exactly genuine 4130 tubing. What i'm saying is that armor plating in shortage situations could be the correct alloy or it could be hot rolled plate..
One thing about having a high quality channel - is the quality and contributions of viewers who would provide things like rare technical manuals and - translations of them. Kudos here to all involved. .
Greg, as a professional involved with research and data reporting I would like to commend you for setting straight people's misconceptions regarding survivorship bias. Wonderful video, as always!
First time commenter, I've really enjoyed all of your videos sir. As a former Naval Aviator, I greatly appreciate the level of detail provided in all your videos. I'm very biased towards anything Navy/USMC aviation of course, so topics covering the Pacific Theater are always of great interest to me. I enjoyed the first video on the Ki-84 so much, it inspired me to order a couple of books on the subject and I even ordered Arma Hobby's 1/72 scale Ki-84 model. Ironically, it arrived this morning just prior to me watching this video. While watching the video, at around time stamp 19:30 there is a picture of an abandoned Ki-84 with no description about the date/time/location but I immediately recognized that aircraft from the artwork on the Arma Hobby box I received this morning so I paused the video and went and grabbed the box to look at the artwork again. Sure enough, on the back panel of the box, there are 6 examples of Ki-84s with different markings/color schemes. Per the info provided on the box, that exact aircraft is one of the six represented on the box and is aircraft serial number 1446 of the 2 Chutai 11 Sentai squadron/unit based in the Philippines in the 1944-45 period.
I feel like this video really highlights that Greg has built more than a UA-cam channel here. He’s built a community with the breadth of knowledge and the real passion needed to give these machines the definitive accounts they deserve.
Regarding the individual exhaust pipes, the publications that I saw (also Japanese) suggested that it was the individual exhaust type that was destined for mass production, instead of the collective. This was due to the superior volume of the "jet" exhaust, that thos individual exhaust stacks created instead lower volume by collective system. This makes sense if you look at it in the context of other airframes being modified to that exhaust stack arrangement or by all newly procured airframes (N1K1-J) which sported such solution. Both Japanese Army and Navy started using individual exhaust systems on all their aircraft since 1943. You can see that even with a Zero. A 1941 A6M2 or 1942 A6M3 had collective exhaust system, with gasses directed below the fuselage. In 1943 the A6M5 model 52 Zeros started appearing with individual exahust stacks, which blew the gasses directly behind the aircraft, and they indicated a small, but nevertheless worth mentioning, performance improvement with top speed jumping from 292-294 knots to 302 knots. Similarly in 1943 you would start seeing G4M1 Betty, Ki-43-II Oscar or Ki-44-II Tojo with such individual exhaust arrangements. I have a Japanese 1943 G4M1 Betty 11 report, which studied that "jet exhaust" effect and results for a bomber were similar, increasing top speed by 5 to 10 knots and climb rate.
I thought they only did it to cut production costs and reduce glares during night intercepting mission. So there is a small performance benefit of the single exhaust setup after all.
@@thanakonpraepanich4284 Yes, the amount of "jet thrust" from the engine exhaust is significant. As Greg mentioned, engines that need to send the exhaust to drive a turbo-supercharger don't benefit much, if at all from this effect.
@@givenfirstnamefamilyfirstn3935 An exhaust-driven turbo-supercharger uses the power from the exhaust gasses to compress intake air rather than providing jet thrust. Mechanical superchargers on the other hand, eat up a lot of engine power to generate boost. Overall, exhaust-driven turbos are more efficient. That is why modern aircraft with piston engines use exhaust-driven turbochargers. During WWII, mechanically driven superchargers were more significantly compact as well as being less expensive. Exhaust-driven turbo-supercharger systems were very large and could not fit into smaller, sleeker fighters. Compare at the relative sizes of the Corsair vs the Thunderbolt, since both used the same base engine.
@@jfess1911 All true but some previous comparisons had near vertical P-47 ‘power’ graphs compared with supercharged V-12s which sloped a bit more to the left from reduced boost with altitude, a total thrust graph would correct for overlooked exhaust jet thrust from the supercharged engines, absent with (closed wastegate) turbocharged motors.
Well done, Greg - as usual, and my thanks as a viewer to both of your new sources of information. Since my Dad flew a water-injected F6F-5 with VF-19 in the fall of 1944, and shot down three Japanese fighters during the Leyte campaign (an A6M and a pair of Ki-44 Tojos), but - to my knowledge - never encountered a Ki-84, I'm really looking forward to the performance comparison. He had squadron mates who DID encounter at least one Ki-84, which they dispatched in a low-level fight, but that might easily have been a case of a single Frank vs. multiple Hellcats.
My grandfather was an Navy AD-2 (powerplants mechanic) during the war as part of joint program between the Navy and Pan American (basically experienced aviation mechanics "lent" to the Navy to provide skilled labor to relieve staffing/training issues) and while he never served in combat, he met a LOT of aircrews with plenty of experience/stories about air combat in the Pacific Theater. Long story short, his stories repeated to me was that by 1944-1945, Japanese fighter effectiveness was pretty much nil just do to the overwhelming number of US/allied fighter aircraft airborne at any given time in relative terms to the number of Japanese aircraft that could get airborne. As in, it didn't matter how good the Japanese fighters were, they were highly outnumbered, going against better trained/experienced pilots at this point, and US/allied aircraft were just as good if not better than what the Japanese could get in the air at this point in the war. This doesn't even take into account such variables as radar and fighter direction control services provided to US/allied crews from the US Navy ships etc. that were operating in the areas where allied aircraft were patrolling.
Don't know if you two do MSFS, but Flying Iron has an absolutely beautiful F6F-5 Hellcat out for it. It is such a comfortable plane. I can see why it's pilots loved it.
@@motocracy4828 All true, I think, but there's no way to effectively eliminate the role(s) of luck and, more importantly, individual pilot skill. I don't think Dad's Hellcat was ever hit by a single bullet from a Japanese plane, but he was twice very nearly shot down by AAA ground fire. One side effect of the "numbers" factor is that, by late 1944, there was no guarantee that a given Allied pilot would even encounter a Japanese opponent. Some pilots in VF-19 (this seems true for other Navy squadrons, too, and the Marines) either never encountered a Japanese opponent during the combat tour, or didn't manage to shoot one down. I haven't researched it, but that tendency might be true for combat pilots in general, in that a smaller number of pilots accounted for a disproportionate number of enemy kills. Unlike most of his squadron-mates, Dad had a degree in mechanical engineering, so - almost by default - ended up as the squadron engineering officer, a role he was assigned in his next squadron (VBF-150) as well.
@@rayschoch5882 I agree to all and no doubt that was the impression I got from my grandpa's stories...was that by that point in the war if US/allied aircraft came across any aircraft they were usually few in number piloted by new/inexperienced pilots going up against a numerically superior foe who was well trained/experienced by this point. I don't remember where I read it, but I remember reading somewhere that one of the major differences between US aviation doctrine and that of both Germany and Japan, the US was very stringent on sending combat experienced pilots back to the states to be instructors. In Germany and Japan, this was highly unusual as most experienced aircrews stayed on the front lines until death, incapacitation, and/or were one of the few to actually survive to the end of the war. I have met a couple of former WWII Luftwaffe pilots earlier in my life, including Gunther Rall, and the overall gist of what they said seems to corroborate this information. I actually got spend an afternoon talking to Oscar Bosch about 20 years ago after he performed at an air show where I was stationed and he game me a list (that I still have) of all the pilots he served with over the last 2 years of the war and almost all of them were listed as KIA/MIA on the list he gave me!
@@motocracy4828 Agreed. After his combat tour with VF-19, Dad got a month's leave in the U.S., and was then assigned to a new squadron (VBF-150), once again as the engineering officer, but also as an instructor as they were transitioning from the F6F-5 to the F4U-4, preparing for the invasion of Japan that (fortunately) never happened.
I checked several Japanese books about Ki-84 and there was no cockpit heating system. One of the books mentions that IJA did not require heating system inside cockpit in their specs. So, Nakajima did not go beyond IJA’s specs and left Ki-84 pilot’s life in the cockpit cold and miserable. However, IJA provided Ki-84 pilots electric heated flight suit. There was a switch for that in electrical switch panel installed to the pilot’s right-hand side. Ki-84 came back and flew over Japan’s sky in 1973. I was in the university which was a part of former Nakajima factory. Our university was next to Chofu Airport (former IJA air base). One day, I was lying on the lawn skipping the class as usual, there suddenly came thundering airplane engine sound. That was not the engine sound from familiar Cessna or Piper. When I looked up the sky, green aircraft with Hinomaru on its fuselage and wings climbing over our university’s main building. That was Ki-84! Later, I learned that our university’s main building was the place where Ki-84 was designed. I do not know whether the pilot of that time, Mr. Lykins, knew he was flying over Ki-84’s birthplace or not. I can still remember the engine sound and the view of climbing Hayate over its birthplace as if it happened a minute ago.
It is actually a pleasure to hear somebody go over the differences between sources and models. It is silly to do any kind of comparison of aircraft without doing this. Ya gotta compare oranges to oranges.
In regards to the exhaust on the KI-84 only the first few prototypes had the single exhaust on each side of the fuselage. The multiple exhaust were implemented used as it was proven to give a slight speed increase due to thrust augmentation. This is also well documented in regards to the A6M5 Koi/Otsu/and Hei models as the A6M1,2 and A6M3 Model22 Zero had single exhaust exiting at the bottom of the cowling. With the A6M5 the speed was increased to 352 mph due to the slightly more powerful engine combined with said thrust augmentation exhaust stacks. This can also be seen in the late models of the KI-43 III Ko Oscar as well as other such aircraft 1943 to late war such as the N1K1-J Shiden, N1K2-J Shiden Kai, J2m3 Raiden, and many other fighter and bomber types used by Japan in WW II.
This is so good, when I am among such WW2 aeroplane fanatics I feel at home, and not like the nutter my Mrs tells me I am - I just wish some of you were round my house for a beer!
@@avipatable Actually, what Greg should do is to hold a livestream where his audience can ask questions using SuperChat - so gains some income for his work! We should work in UTC - although, as usual, Australia wil be a problem :)
Hi Greg, thanks for the update. The armour steel looks pretty good stuff, particularly the charpy value which is a measure of toughness which is good energy absorbtion. The rubber mounting of the plate would undoubtably aid in impact resistance. I would be surprised if the tests included the rubber but obviously I don't know. If the testing didnot include it then the resistance to penetration is an under estimate. Water used for head cooling is indirectly an anti-knock since hot spots cause knock too. Basically another great video and thanks to your contributors who provided the info.
Closing words: " if you haven't seen them, please watch them". I don't think that really applies to the vast majority on this channel. Outstanding as usual, Thank You.
Seriously, instead of the mindless garbage on television....I get so much more out of Greg's channel, along with: Tips from a Shipwright, with Louis Sauzedde, and even Steve1989mreinfo. Just....captivating channels of folks with a passion.
Thanks Edward, yes many viewers here have seen all the videos on this channel, but you would be surprised at how many people show up mid story and seem lost.
Thanks Chris, this one is now Part 2. What started as an attempt to fix minor errors and omissions sort of turned into it's own video. Part 3 is next, coming soon! One benefit of being stuck on couch is I can get videos out more quickly.
Goodwin and Starking's book on Japanese Aero-Engines indicates that the Ki-84 prototype used the Army equivalent of a Homare 11 which was switched to the Ha-45 (army equivalent to the Homare 12--revised cylinder heads for improved cooling) with the single exhausts in early trials aircraft. Fairly early on, exhaust was switched to ejector style. The engine still didn't perform at altitude as hoped but even that engine in the Ki-84 resulted in it being too powerful for the airframe and propeller at lower levels with resulting better airplane performance available at higher altitude for pilots. Engine was then updated to [Ha-45]12 which improved fuel pressure (which had been an issue) among other changes. At the end of 1943, deliveries of next revision [Ha-45]21 with a more powerful supercharger and higher compression ratio began and when enough engines were available, update was introduced for Ki-84 production. Later in the production run, some aircraft received [Ha-45]23 engines (Homare 23 equivalent) which definitely had newer indirect fuel injection.
Excellent as always Greg! WWII japanese airplanes have typically been “in the shadows” save for the Zero, exploring them this way is most interesting! Are you planning on studying the J2M Raiden or tej C6N Saiun? That would be awesome!
The J2M is another one that has WILDLY varying performance stats, with "top speeds" pretty much in the same range as the Ki-84 (from high 380s to mid 420s). I suspect data on the C6N will be almost impossible to acquire.
Thanks for the superior quality content!! Yeah, if we want to compare apples to apples it's just right that we compare the very best of them, despite quality differences, just the best scenario...the reality I guess, is history😁
So. Japanese, wwII, aviation enthusiasts... I've never considered that for some reason. But of !Course! they're out there! Thank you for your contribution!
Unbelievable content sir. I've watched a dozen or so of your stuff, but for some reason the engineering and design analytics, especially the engine related stuff, in these two videos really blew me away.
Thank you Greg. ! Anyone interested in the details of WW2 Aviation needs to view your posts...! Love the depth of your knowledge... Keep these coming bud...!
Congrats on great success with these videos. Just being honest, video games like War Thunder have sparked curiosity in many people's hearts. It's as if there are more WW2 and conceptual technologically aware people than ever, thanks to content like this.
Trust. That is what we have when we listen to, and believe, this stuff. I am electronics technical, not mechanical technical - perhaps that is what makes this so interesting for me. Also, a reliance on proper sources without getting bogged.
Apart from the excellent work and videos you do, I really want to say I like listening to you. People who speak like that usually know what they are doing or saying. It is maybe not the compliment you are expecting doing technical videos, but hey !
I am so glad that I have discovered this channel. As someone interested in military engineering I love the deep dives into the aircraft of WW2 etc. And it is great to see some info of the Japanese aircraft, they are much better than I had imagined. Keep up the good work!
Any chance of a review of the Ki-44? IIRC, it was the 1st Japanese fighter to buck the entrenched Japanese Military doctrine of a fighter being highly maneuverable.
Regarding the manual fuel pump, it seems to be the rightmost of the two long handled rods with balls on the end on the right side of the cockpit. The word 'pump' （ポンプ）is very legible but the kanji for fuel (燃料）is not. In 'The Miraculous Torpedo Squadron' the autobiography of Juzo Mori, he describes one of his early sorties in China when his engine began to lose power. Having been trained to crash his airplane (a Kate) into an enemy position if unable to make it back to friendly territory, he asked his backseaters if they were okay with that (they were) and began looking for an enemy position to crash into. However, he did start using the manual fuel pump and that kept the engine going long enough for them to make back to their lines.
Greg, Your videos are the best and you have one of my favorite channels on UA-cam! These KI-84 videos have been really fascinating. Watching the last video raised a question regarding the engine design that I wondered if you might address moving forward. The reason given for the engines lower displacement, higher RPM levels, and higher compression ratio, were primarily smaller frontal area. I'm positive this was a big factor, but I can't help but see some commonality with the trends presently occurring in the automotive space; could one of the reasons for this change in design philosophy be an effort to reduce specific fuel consumption? I would be curious to see a comparison of fuel consumption with larger allied engines at given power settings. I imagine conserving fuel must have been on the radar of the Japanese in the latter stages of the war. I wonder if the increase in RPM and associated frictional losses were offset by the reduced throttling losses and higher efficiency of the increased compression ratio. Any insight you could offer would be greatly appreciated. Thank you for all that you do for us aircraft buffs!
You should give a really obvious analogy for survivorship bias for the people still complaining. Something to the effect of: "The planes that came home were not hit in the cockpit, engines, or fuel tanks; so it must be hard to aim for those. We should armor wingtips snd empty fuselage." - Survivorship Bias Conclusion "The planes that came home were not hit in the cockpit, engine, or fuel tanks; so we should armor those areas instead of empty fuselage or wingtip areas" -Normal Conclusion
The graph at ~ 14:00 top right corner 8th from the top, 油圧ポンプレバー, which translates to oil pump lever, which points to a big lever just next to the right leg paddle, that *should* be the hand oil pump Edit: i got it wrong, it should be translated to hydraulic oil pump lever which has nothing to do with fuel
From my experience 油圧 usually means hydraulic pressure, which pumps the hydraulic backup reservoir or even directly into the system's consumer components (as in DHC-8's parking brake). Makes sense to place a HYD hand pump there for backup gear extension and brakes too!
Regarding the fracturing of the armor plate, the heat treat used (according to the specifications you'd supplied) showed the outer "casing" was done to a depth of a tenth of an inch as was also listed on the Rockwell "C" scale, a hardness of 64. That is VERY HARD. Almost 40 years ago, I hand engraved (on a Deckel GK21 pantograph milling machine) quite a few Poco 3 (graphite) electrodes for use in an Electro-Static Discharge Machine (E.D.M.) This was in order to burn in very fine detail for plastic injection molding inserts of S-7 tool steel, heat treat hardened to that same Rockwell 64 on the "C" scale. The applicatrion was for Hewlet Packard's yet to be released consumer line of ink-jet printers, specifically, these were the nozzle design's test molds. I had to hold to .0002" accuracy (I managed) using CNC generated aluminum templates supplied by Hewlet Packard, and for over forty versions of these nozzle designs, each requiring some 6-8 electrodes. One bad Friday, as Tom Magee removed form the oil tank of the E.D.M., a fully finished, identical hardness to the Frank's armor plate, Rockwell 64 "C" scale, S-7 tool steel insert , the surface oil remaining caused him to lose grip on the approximately one cubic inch insert. From a height of little more than three feet up, it hit the shop's concrete floor shattering as though it was made of cheap glass. That "64" is rather hard, but also rather brittle. We both laughed as that represented a better part of a week's work for each of us. What else could we do?
My Fav Japanese fighter of the war. I’ve got a beautiful 1/32 model set in a revetment on Clark field. Thank you for the excellent work on this aircraft.
I'm glad to see that rare manuals have found their way to capable hands. Greg's analysis is top notch, and his conclusions are probably about as close as you can get to unbiased.
"Sometimes new information raises as many questions as it answers." I think that's the nature of almost all scientific and historical research. I've never come away from a project satisfied that I found all the answers - and when I thought I did, I was wrong.
Have you done one about the Ki-100, the evolution of the Ki-61, I think. And I'll give one special credit to the Ki-84 - it has the most beautiful fuselage lines of almost any aircraft in WWII. Oh! You've already done it, and i just saw it! GREAT as usual, thanks!!!!
The Ki 102 "Randy" looked like the ground attack aircraft that they never really got out of the Ki46. The Dinah as a recon and run aircraft though has always been a favorite aesthetically, especially the Ki46 III. Even just having the Ki84 and Ki100 reviewed in this depth though, is way beyond what I ever expected and Greg said the later is also in his future list.
I'm simply amazed at your research and the lengths you are going to educate all of us, you can call me crazy, but I simply can't stop watching all these presentations. Thankyou so very much for all your continuing work.
As a young boy I started collecting William Green's War planes of the second world war. In vol. 3 he says this about the Ki.84: "It compared favorably with the best of its antagonists; it was slightly slower than the P-51H Mustang and the P-47N Thunderbolt, but it could out-climb and out-manoeuvre both American fighters." The top speed for the Ki.84 is listed at 388 mph @ 19,680 ft. In volume 4 , the P-51H top speed is listed as 487 mph @ 25,000 ft. and the P-47N top speed as 460 mph @ 30,000. I could never figure out how it could "compare favorably" with my favorite US fighters. Fifty-some years later you are helping me understand. Great video! Now how about addressing Mr. Green's comment about the Kawanishi N1K2-J Shiden-Kai (George 21) when he says "the Shinden-Kai, was undoubtedly the finest J.N.A.F. production fighter of the war." How does it compare with the J.A.A.F. Ki 84?
8:30 Just about every picture I've seen of Ki-84-Ia,b, and c at Sentai level has the thrust augmented exhaust. The first preproduction series of a hundred or so had the single per side collector exhaust. I don't recall a single picture of these early collector exhaust Hayates with Sentai markings.
MW Injection: When you compress air in a cylinder (or in anything else), the temperature increases. This is basic physics and gas laws. If the temperature reaches the ignition temperature of vapourized fuel, it ignites. Fuel igniting prior to top dead centre (TDC) is engine knock. If you spray methanol and/or water into the intake manifold, it vapourizes, using up heat and reducing the air temperature. The colder the air is, the more you can compress it without reaching the fuel ignition temperature. You want to increase manifold pressure. Your problem is air temperature inside the cylinder. MW injection allows you to increase manifold pressure. Otherwise, this is a great presentation!
Howard, I think you missed the previous episode when I went over this specifically. You're coming into the conversation in the middle. It's not MW injection in this specific case.
Hey Jack. The system isn't just for anti-knock. It's to control the cylinder temps. I covered this in the previous episode. That's the reason for injecting ethyl alcohol vs methanol. Water:Methanol is more effective as an anti-knock agent, but Water:Ethyl alcohol is more effective in controlling cylinder head temps. This is covered in at least two places in the documentation for the Ki-84 (where they specifically reference cylinder or cylinder head temp issue which are controlled by the system. This is mentioned separately from the threat of knock). It's also the conclusion of a very detailed NACA report about the various things you can injectin, water vs. water:methanol vs. Water:ethyl alcohol and so on. Of course knock is a factor here too, but it's not the only factor.
Ah, that makes sense. Keep in mind, the way these come into my feed, I just see your comments by themselves, I don't see the comment you are responding to.
@@GregsAirplanesandAutomobiles Thanks for all the content ^^ I’ll be sending you a video of me flipping through the manual so you can compare with what you have already :) Just a sec~
As to the metallurgy of the armor, another older and more commonly used term for "carburizing," is case-hardening. It is done by heating the plate in an oven, surrounded by a source of carbon (generally wood charcoal), in the absence of oxygen, and then allowing it to cool slowly. This allows carbon from the charcoal to migrate into the outer surface of the metal, making it very hard, compared to rest of the mass of the metal in the interior of the part, whatever it may be. I'm not sure how long the process has been around, but I'm familiar with it from experience with antique firearms, where it was used in revolver frames and rifle receivers prior to the availability of stronger alloys starting in the late 19th century.
Also, case hardening was common for cylinder barrels. This will not help the armor plate, the armor plate needs strength throughout the material. Case hardening helps in wear, which affects the surface.
It's called Krupp armor process for battle ships It can make it brittle if not controlled, i wonder if it must have been poor high carbon steel armor any thoughts? Any way the pilot would survive unless it Spalded (Fragments would spray in to the cockpit) armor did its job.
Great stuff! Just a note on the armor thickness: I suspect the variation in thickness between the armor of the two planes tested could well be just down the the manufacturing tolerance of the sheet metal used. This variance is within the current manufacturing tolerance of normal hot-rolled sheet. I am not sure if armor plate is held to a tighter tolerance.
Thanks for the in-depth updates. Regarding the fuel pump lever in the cockpit diagram I think it might be the aft one of the two long ones to the right of the flight stick. That one is labeled “Acceleration pump lever” the lever forward of that one is labeled “oil pressure pump” fyi
A generic comment about the alloy for the armor: Many alloys that has nickel as the base belongs to the so called "super alloys" group. From a machining point of view these stand out enough to give them their own class due to how difficult they are to machine, quickly wearing out the tools even when everything is done correctly. Crome and molybdenum in high amounts give steel very strong characteristics so I wouldn't be surprised if they also worked similar in a nickel base. (And a bit of rant about metal properties, many people confuse hardness, tensile strength and impact resistance, the relation between these can vary quite a bit and the difference between elastic and plastic deformation must be considered as well. Material technology is a fascinating subject that I wish I had more then scratched the surface of.)
Inconel is about the toughest stuff I ever had to touch carbide to. I'm glad i didn't have to see much of that stuff because I did not have whatever the right combo was for turning or milling it quickly..
@@icewaterslim7260 Well "quickly" is a rarely used word with those alloys! Personally I quite like them. It's a challenge to get right (aka stable process). Ceramic inserts for rough turning is a good starting point. For carbide inserts a life span of each edge 5 min working time is good. Also the slightly odd wear on inserts where it's usually not the tip that shows signs of wear first but the flank that meets the surface of the stock (turning). And cutting fluids... tons of it. Leave the cutter dry for a split second and it heats up and then cracks when cooled again. Another thing I like is the dimensional stability one gets. Ask the machine to change the diameter by 0.004 mm and that's what one get repeatedly at an absurd level compared to stainless steel and other simple alloys. (At least that's my experience in the machine's I've been running it in.)
A nice looking plane to be sure, very different to US Navy types with mighty fins to help with carrier TO/landing performance. I have a preference for the Mitsubishi J2M just for its pork barrel looks and the ingenious idea of the prop extender shaft. I think one of its weakness was also with spindly undercarriage.
Very interesting video Greg. As an engineer I find it very interesting how modern the american production methods and therefore consistency was when compared to the Japanese. The differences between individual models of the Ki84 really shows that the Japanese worked in a manfactory-type of environment when compared to the all out industrial approach of the USA. This is even more interesting when looking at the big achievements japanese car makers such as Toyota have made after the war with regards to efficient production. It really seems that they have learned their lesson while still keeping their approach with a focus individual responsibility (at Toyota every employee is allowed to stop production when he/she sees a way to improve it). Anyways: Very good work Greg! If you are looking for another plane to cover I would be very interested in seeing some content on the N1K or a follow-up on your first Mosquito video. Have a nice day and recover well!
In the 80s, when Japan was the darling of the world of production, some Ford engineers visited a Toyota factory, marvelling at its complete soup to nuts manufacturing efficiency from raw materials to finished product. When asked how they came up with all of this, a Toyota exec said that they just did what Henry Ford did at his River Rouge Plant 60 years previously.
Ref mechanical fuel pump: that’s the standard T-6 set-up, you gotta use the wobble pump if you notice the loss of fuel pressure. Fuel pressure going up under Gs, May happen by gravity if the fuel tank is higher than the mechanical fuel pump, just by increased weight of fuel under Gs.
Amazing to get hold of proper historical documents so many years later. Interesting the Japanese armour was quite high quality, there must have been lots of material shortages by 1944 so it seems to have been a deliberate effort.
Very interesting. I'll look forward to the next installment. Considering that Japanese industry was being bombed into oblivion by the time this plane was in production, I am not surprised at the variation in performance. It is actually surprising that they did as well as they did. Just as well for the Allied this plane came about as late as it did.
Didn't they have undetected aircraft production facilities in the hills turning out a large volume of some quite sophisticated aircraft? I vaguely recall a documentary about that claiming that an Allied invasion force would have been shocked by the air assault they would have faced.
On the exhaust stacks. the plumbing to trunk all the exhaust to a single exit would mass more and require more room under the cowling. I suspect the real reason for the multiple exhaust is it saved weight, and added to engine by reducing exhaust back pressure. Exhaust thrust might be reduced slightly but weight savings I suspect more then make up the difference.
Wow. Running a wobble pump in a fight would be a pain. I'd like to know more about that. I feel like there may be more to that. Perhaps somthing done just prior to pulling more than 3Gs? Somthing done just prior to entering combat?
From the engineering point of view, Nakajima (like their German comrades) had to design a high performance engine based on the tyranny of low grade fuel, bad lubrication oil and bad material (substitutes) for the main bearing. All their technological effort went into addressing this. All later problems in production and maintenance were due to these three factors. Was it an success? Well, operation "Strangulation" - the mining of the Japanese Sea by B-29 - went on mostly unopposed. And this very operation was the most decisive factor in forcing the Empire of Japan to surrender in 1945 without the need of invasion.
I would definitely like to see a comparison of data for a Ki-84 that is up to spec with the F4U-4 (famous "Dash four") Corsair variant. Most enjoyable content. Thank you!
A Civil War (US) historian stated that whenever he hit a dead-end on research he would post what he had and invariably someone would come back with something like a copy of a letter from their great-great-grandfather detailing how the commander of the XX Alabama was killed at Antietam/Shiloh/Gettysburg. This internet thingie can be useful.
I once asked a question on a blog I 'infest' vis a vis: the 'future' of WW2 research, once all the veterans have passed away. Would it become like archeology? Delving thru files and letters from men long dead, instead of digging thru dirt and ruins?
If you use Google Translate on your phone, put it in camera mode, you can translate the print. I just did it on computer screen. No wobble pump is listed on the call outs on the cockpit drawing. Interesting thing I found.... was the #21 Methanol fuel pressure guage, #23 Fuel tank pressurization tank switch cock. #25 Rapid Plan (?), #26 Boost Pull (?),
Hi Greg, I hope my email about a better way to translate japanese manuals than Google Translate (using an OCR website in between) reached you - by now, several helpful folks with actual knowledge of japanese have basically confirmed what my guesstimated results were, but perhaps the same problem comes up in the future as well, and I suppose it's a good tool to have for simpler questions (i.e., that method does work for the instrument panel components quite completely). Also, I can add that using a different translation engine such as "deepl" gave me a lot better results when I tried to translate the scanned Kanji symbols compared to Google. Cheers and I hope all is well with your recovery!
@@GregsAirplanesandAutomobiles First I sent it to gregsairplanes (with google mail, think I can't type a proper mail adress in here), which was returned as "address does not exist" - I then sent it to gregsairplanesandautomobiles (with google mail), which didn't return an error - so I figured that was probably alright. But I guess not... :)
This channel has the right amount of in-depth detail I want on my aviation content. Usally you get a simple "this plane, big engine, very fast" video and that's it. But Greg goes to discussing the possible origins of the nuts that hold the horizontal stabilizer actuator.
I don't understand half of it, but me too
@@clazy8 learn as much as you can. These videos are worth knowing as much as possible. 😃
I totally agree. Such a unique channel. I love it
@@clazy8 hahaha I’m glad I’m not the only one
@@clazy8 in his older videos Greg goes over the various charts, how to read them and how he gets them. Unfortunately it's not all in one place as he will explain it in full the first time uses it.
If you don't understand after seeing his explanations, well I get that. Some of it goes over my head too.
Greg bringing the highest quality aero and engine content to the world, as always!
As to the metallurgy, a trusted friend, welder, machinist, and metallurgist said when viewing that report - "Wow, thats a triple alloy steel, same as Early Tiger Is very impressive even for today standards, very close to todays 4340 and if it had less phosphorus and sulfur contaminates it would pass MIL-DTL-12560 for armor plating for today's US Main Battle Tanks. Im surprised the Japanese was able to make them considering their situation in 1944-45."
“Necessity is the mother of invention.”
― Plato
Sounds like a top grade racing bicycle frame material - before they went polymer.
@@givenfirstnamefamilyfirstn3935 Yep. Chromoly, Nivachrome and Thermachrome describes formulation of steel. Cold drawn tubes allowed for variable wall thickness.
It looks like a similar metallurgy to AR500 steel.
Greg really knocks it out of the park with these deep dives. I'm having a great day when it has "Greetings this is Greg " in it .
In addition to Greg's unmatched, deep, detailed examinations of these aircraft, I just want to thank knowledgeable commenters from around the world who provide even more detail and context to WW2 Japanese aviation. I always read the comments in Greg's channel and I can't think of anything more praiseworthy.
Well said
13:58 I'd think the 加速ポンプ(acceleration pump) in the upper right corner is the hand operated fuel boost pump. It seems crazy to try pumping fuel with that handle whilst trying to fly with a center stick control and a throttle on the left side...
thank you
Imagine deflection shooting in a dogfight: Pulling 7G, having to put 65 pounds on the centre stick just to turn with the enemy and using a trigger mounted on the throttle while also pumping fuel. An impossible task even for Mr. Sakai
Been a fan of Japanese aircraft since I was a kid, probably because little is generally known about them. I've had the Aero publishers book on the Ki 84 since the '70s. So these are a rare treat.
One often overlooked favorite of mine was the Mitsubishi Ki-46 Dinah Recon Plane.
If you watch this video really closely you will see some Ki-48 info, but no Ki-46. As time goes on I'll cover more and more Japanese aircraft.
J2M would be great, especially talk about the J2M4 experimental turbo supercharged models
@@GregsAirplanesandAutomobiles Major Yohei HInoki of the 64th Sentai lost his leg to .50 cal of a Mustang in a Ki 43, completely in the aircraft, tied it off tight and made it back to his base. The 64th was full of 4 year veterans by the end of '41 and considered prestigious while in Indochina and thereafter. So they likely had the latest Oscars with armor and self sealing tanks by the time Mustangs were in the Pacific.
I believe he had a case of target fixation and let one get right up onto his 6 real close. Just that some of these guys survived those kinds of circumstantial odds seems to evidence quick thinking pilotry as much as their claims numbers.
(His was 12, mostly if not all in Oscars and an unconfirmed "probable" in a Ki 100 with an artificial leg and out of balance propeller. Our records that day showed one Mustang MIA and two Returning Mustangs damaged, one badly)
And I believe I remember reading somewhere about one of the tested Ki 84s, probably the first, having been taken from the Philippines.upon our take-back-over there..
@@icewaterslim7260 He also does not delete comments that disagree with his opinion. Others do.
@@demetridar506 I don't think it a disagreement to say 50 cals penetrate whatever Oscar armor was behind the pilot, squared up on his 6, from 100 yards or so.
And what should also be kept in mind are raw material shortages in Japan during our ongoing submarine blockade of the Home Islands that affected the alloys used or skipped altogether. Even the US went through this problem. A lot of guys building dragster frames on the west coast in the '60s were getting 4130 tubing cheap from surplus yards because it was WW2 era material that didn't meet the standards for whatever it was used for in something requiring the correct metallurgy. Aircraft industry being an example. They used it when they had to but not thereafter. . If you had a contract with Boeing requiring some of that they'd want to see receipts from where you got it.
So if you bought a genuine vintage Woody Gilmore slingshot AA fuel dragster chassis made in. his shop out in Santee CA in the '60s it probably ain't made from exactly genuine 4130 tubing.
What i'm saying is that armor plating in shortage situations could be the correct alloy or it could be hot rolled plate..
One thing about having a high quality channel - is the quality and contributions of viewers who would provide things like rare technical manuals and - translations of them.
Kudos here to all involved.
.
Here here!
Greg, as a professional involved with research and data reporting I would like to commend you for setting straight people's misconceptions regarding survivorship bias.
Wonderful video, as always!
First time commenter, I've really enjoyed all of your videos sir. As a former Naval Aviator, I greatly appreciate the level of detail provided in all your videos. I'm very biased towards anything Navy/USMC aviation of course, so topics covering the Pacific Theater are always of great interest to me. I enjoyed the first video on the Ki-84 so much, it inspired me to order a couple of books on the subject and I even ordered Arma Hobby's 1/72 scale Ki-84 model. Ironically, it arrived this morning just prior to me watching this video. While watching the video, at around time stamp 19:30 there is a picture of an abandoned Ki-84 with no description about the date/time/location but I immediately recognized that aircraft from the artwork on the Arma Hobby box I received this morning so I paused the video and went and grabbed the box to look at the artwork again. Sure enough, on the back panel of the box, there are 6 examples of Ki-84s with different markings/color schemes. Per the info provided on the box, that exact aircraft is one of the six represented on the box and is aircraft serial number 1446 of the 2 Chutai 11 Sentai squadron/unit based in the Philippines in the 1944-45 period.
I feel like this video really highlights that Greg has built more than a UA-cam channel here. He’s built a community with the breadth of knowledge and the real passion needed to give these machines the definitive accounts they deserve.
Regarding the individual exhaust pipes, the publications that I saw (also Japanese) suggested that it was the individual exhaust type that was destined for mass production, instead of the collective. This was due to the superior volume of the "jet" exhaust, that thos individual exhaust stacks created instead lower volume by collective system. This makes sense if you look at it in the context of other airframes being modified to that exhaust stack arrangement or by all newly procured airframes (N1K1-J) which sported such solution.
Both Japanese Army and Navy started using individual exhaust systems on all their aircraft since 1943. You can see that even with a Zero. A 1941 A6M2 or 1942 A6M3 had collective exhaust system, with gasses directed below the fuselage. In 1943 the A6M5 model 52 Zeros started appearing with individual exahust stacks, which blew the gasses directly behind the aircraft, and they indicated a small, but nevertheless worth mentioning, performance improvement with top speed jumping from 292-294 knots to 302 knots.
Similarly in 1943 you would start seeing G4M1 Betty, Ki-43-II Oscar or Ki-44-II Tojo with such individual exhaust arrangements. I have a Japanese 1943 G4M1 Betty 11 report, which studied that "jet exhaust" effect and results for a bomber were similar, increasing top speed by 5 to 10 knots and climb rate.
I thought they only did it to cut production costs and reduce glares during night intercepting mission.
So there is a small performance benefit of the single exhaust setup after all.
@@thanakonpraepanich4284 Yes, the amount of "jet thrust" from the engine exhaust is significant. As Greg mentioned, engines that need to send the exhaust to drive a turbo-supercharger don't benefit much, if at all from this effect.
@@jfess1911 Our friend seems to ignore this when lauding the perfection of the P-47.
@@givenfirstnamefamilyfirstn3935 An exhaust-driven turbo-supercharger uses the power from the exhaust gasses to compress intake air rather than providing jet thrust. Mechanical superchargers on the other hand, eat up a lot of engine power to generate boost. Overall, exhaust-driven turbos are more efficient. That is why modern aircraft with piston engines use exhaust-driven turbochargers.
During WWII, mechanically driven superchargers were more significantly compact as well as being less expensive. Exhaust-driven turbo-supercharger systems were very large and could not fit into smaller, sleeker fighters. Compare at the relative sizes of the Corsair vs the Thunderbolt, since both used the same base engine.
@@jfess1911 All true but some previous comparisons had near vertical P-47 ‘power’ graphs compared with supercharged V-12s which sloped a bit more to the left from reduced boost with altitude, a total thrust graph would correct for overlooked exhaust jet thrust from the supercharged engines, absent with (closed wastegate) turbocharged motors.
Well done, Greg - as usual, and my thanks as a viewer to both of your new sources of information. Since my Dad flew a water-injected F6F-5 with VF-19 in the fall of 1944, and shot down three Japanese fighters during the Leyte campaign (an A6M and a pair of Ki-44 Tojos), but - to my knowledge - never encountered a Ki-84, I'm really looking forward to the performance comparison. He had squadron mates who DID encounter at least one Ki-84, which they dispatched in a low-level fight, but that might easily have been a case of a single Frank vs. multiple Hellcats.
My grandfather was an Navy AD-2 (powerplants mechanic) during the war as part of joint program between the Navy and Pan American (basically experienced aviation mechanics "lent" to the Navy to provide skilled labor to relieve staffing/training issues) and while he never served in combat, he met a LOT of aircrews with plenty of experience/stories about air combat in the Pacific Theater. Long story short, his stories repeated to me was that by 1944-1945, Japanese fighter effectiveness was pretty much nil just do to the overwhelming number of US/allied fighter aircraft airborne at any given time in relative terms to the number of Japanese aircraft that could get airborne. As in, it didn't matter how good the Japanese fighters were, they were highly outnumbered, going against better trained/experienced pilots at this point, and US/allied aircraft were just as good if not better than what the Japanese could get in the air at this point in the war. This doesn't even take into account such variables as radar and fighter direction control services provided to US/allied crews from the US Navy ships etc. that were operating in the areas where allied aircraft were patrolling.
Don't know if you two do MSFS, but Flying Iron has an absolutely beautiful F6F-5 Hellcat out for it.
It is such a comfortable plane. I can see why it's pilots loved it.
@@motocracy4828 All true, I think, but there's no way to effectively eliminate the role(s) of luck and, more importantly, individual pilot skill. I don't think Dad's Hellcat was ever hit by a single bullet from a Japanese plane, but he was twice very nearly shot down by AAA ground fire. One side effect of the "numbers" factor is that, by late 1944, there was no guarantee that a given Allied pilot would even encounter a Japanese opponent. Some pilots in VF-19 (this seems true for other Navy squadrons, too, and the Marines) either never encountered a Japanese opponent during the combat tour, or didn't manage to shoot one down. I haven't researched it, but that tendency might be true for combat pilots in general, in that a smaller number of pilots accounted for a disproportionate number of enemy kills. Unlike most of his squadron-mates, Dad had a degree in mechanical engineering, so - almost by default - ended up as the squadron engineering officer, a role he was assigned in his next squadron (VBF-150) as well.
@@rayschoch5882 I agree to all and no doubt that was the impression I got from my grandpa's stories...was that by that point in the war if US/allied aircraft came across any aircraft they were usually few in number piloted by new/inexperienced pilots going up against a numerically superior foe who was well trained/experienced by this point. I don't remember where I read it, but I remember reading somewhere that one of the major differences between US aviation doctrine and that of both Germany and Japan, the US was very stringent on sending combat experienced pilots back to the states to be instructors. In Germany and Japan, this was highly unusual as most experienced aircrews stayed on the front lines until death, incapacitation, and/or were one of the few to actually survive to the end of the war. I have met a couple of former WWII Luftwaffe pilots earlier in my life, including Gunther Rall, and the overall gist of what they said seems to corroborate this information. I actually got spend an afternoon talking to Oscar Bosch about 20 years ago after he performed at an air show where I was stationed and he game me a list (that I still have) of all the pilots he served with over the last 2 years of the war and almost all of them were listed as KIA/MIA on the list he gave me!
@@motocracy4828 Agreed. After his combat tour with VF-19, Dad got a month's leave in the U.S., and was then assigned to a new squadron (VBF-150), once again as the engineering officer, but also as an instructor as they were transitioning from the F6F-5 to the F4U-4, preparing for the invasion of Japan that (fortunately) never happened.
I checked several Japanese books about Ki-84 and there was no cockpit heating system. One of the books mentions that IJA did not require heating system inside cockpit in their specs. So, Nakajima did not go beyond IJA’s specs and left Ki-84 pilot’s life in the cockpit cold and miserable. However, IJA provided Ki-84 pilots electric heated flight suit. There was a switch for that in electrical switch panel installed to the pilot’s right-hand side.
Ki-84 came back and flew over Japan’s sky in 1973. I was in the university which was a part of former Nakajima factory. Our university was next to Chofu Airport (former IJA air base). One day, I was lying on the lawn skipping the class as usual, there suddenly came thundering airplane engine sound. That was not the engine sound from familiar Cessna or Piper. When I looked up the sky, green aircraft with Hinomaru on its fuselage and wings climbing over our university’s main building.
That was Ki-84!
Later, I learned that our university’s main building was the place where Ki-84 was designed. I do not know whether the pilot of that time, Mr. Lykins, knew he was flying over Ki-84’s birthplace or not. I can still remember the engine sound and the view of climbing Hayate over its birthplace as if it happened a minute ago.
It is actually a pleasure to hear somebody go over the differences between sources and models. It is silly to do any kind of comparison of aircraft without doing this. Ya gotta compare oranges to oranges.
In regards to the exhaust on the KI-84 only the first few prototypes had the single exhaust on each side of the fuselage. The multiple exhaust were implemented used as it was proven to give a slight speed increase due to thrust augmentation. This is also well documented in regards to the A6M5 Koi/Otsu/and Hei models as the A6M1,2 and A6M3 Model22 Zero had single exhaust exiting at the bottom of the cowling. With the A6M5 the speed was increased to 352 mph due to the slightly more powerful engine combined with said thrust augmentation exhaust stacks. This can also be seen in the late models of the KI-43 III Ko Oscar as well as other such aircraft 1943 to late war such as the N1K1-J Shiden, N1K2-J Shiden Kai, J2m3 Raiden, and many other fighter and bomber types used by Japan in WW II.
This is so good, when I am among such WW2 aeroplane fanatics I feel at home, and not like the nutter my Mrs tells me I am - I just wish some of you were round my house for a beer!
You know, we should organise a simultaneous global livestream of Greg's channel viewers.. somehow!
@@Mango62uk that could be pretty fun :)
@@avipatable Actually, what Greg should do is to hold a livestream where his audience can ask questions using SuperChat - so gains some income for his work! We should work in UTC - although, as usual, Australia wil be a problem :)
We need more in-depth analysis of imperial Japanese aircraft. Keep up the good work
Hi Greg, thanks for the update. The armour steel looks pretty good stuff, particularly the charpy value which is a measure of toughness which is good energy absorbtion.
The rubber mounting of the plate would undoubtably aid in impact resistance. I would be surprised if the tests included the rubber but obviously I don't know. If the testing didnot include it then the resistance to penetration is an under estimate.
Water used for head cooling is indirectly an anti-knock since hot spots cause knock too.
Basically another great video and thanks to your contributors who provided the info.
Another well researched and effectively presented aviation history lesson. We thank you Sir.
13:53 8th line on the right says "oil pressure pump lever" (油圧ポンプレバー). It points to the second stick on the right.
Closing words: " if you haven't seen them, please watch them".
I don't think that really applies to the vast majority on this channel.
Outstanding as usual, Thank You.
Seriously, instead of the mindless garbage on television....I get so much more out of Greg's channel, along with: Tips from a Shipwright, with Louis Sauzedde, and even Steve1989mreinfo. Just....captivating channels of folks with a passion.
Thanks Edward, yes many viewers here have seen all the videos on this channel, but you would be surprised at how many people show up mid story and seem lost.
Sound was fine for me. Early Festivus gifts for Greg. Looking forward to part 2!
Thanks Chris, this one is now Part 2. What started as an attempt to fix minor errors and omissions sort of turned into it's own video. Part 3 is next, coming soon! One benefit of being stuck on couch is I can get videos out more quickly.
Goodwin and Starking's book on Japanese Aero-Engines indicates that the Ki-84 prototype used the Army equivalent of a Homare 11 which was switched to the Ha-45 (army equivalent to the Homare 12--revised cylinder heads for improved cooling) with the single exhausts in early trials aircraft. Fairly early on, exhaust was switched to ejector style. The engine still didn't perform at altitude as hoped but even that engine in the Ki-84 resulted in it being too powerful for the airframe and propeller at lower levels with resulting better airplane performance available at higher altitude for pilots. Engine was then updated to [Ha-45]12 which improved fuel pressure (which had been an issue) among other changes.
At the end of 1943, deliveries of next revision [Ha-45]21 with a more powerful supercharger and higher compression ratio began and when enough engines were available, update was introduced for Ki-84 production. Later in the production run, some aircraft received [Ha-45]23 engines (Homare 23 equivalent) which definitely had newer indirect fuel injection.
I sure glad i ran onto this channel, its got a lot of interesting information. Thanks for all you do
Excellent as always Greg! WWII japanese airplanes have typically been “in the shadows” save for the Zero, exploring them this way is most interesting! Are you planning on studying the J2M Raiden or tej C6N Saiun? That would be awesome!
The J2M is another one that has WILDLY varying performance stats, with "top speeds" pretty much in the same range as the Ki-84 (from high 380s to mid 420s).
I suspect data on the C6N will be almost impossible to acquire.
The audio is much better, thank you.
Thanks for the superior quality content!! Yeah, if we want to compare apples to apples it's just right that we compare the very best of them, despite quality differences, just the best scenario...the reality I guess, is history😁
Sound quality is much improved. Thanx Greg.
So. Japanese, wwII, aviation enthusiasts... I've never considered that for some reason. But of !Course! they're out there!
Thank you for your contribution!
7:19 yup, that's another great aviation channel👍🏻
Unbelievable content sir. I've watched a dozen or so of your stuff, but for some reason the engineering and design analytics, especially the engine related stuff, in these two videos really blew me away.
The sound quality is good.
Concur
me 3. consistently good throughout
Thank you Greg. ! Anyone interested in the details of WW2 Aviation needs to view your posts...! Love the depth of your knowledge... Keep these coming bud...!
Very impressive sources! Thank you to those that brought them forward.
Congrats on great success with these videos. Just being honest, video games like War Thunder have sparked curiosity in many people's hearts. It's as if there are more WW2 and conceptual technologically aware people than ever, thanks to content like this.
It looks like a P-47 Thunderbolt and a A6M Zero had a love child.
Thank you for the dedication to the depth of detail. Your work has not gone unnoticed.
Trust.
That is what we have when we listen to, and believe, this stuff.
I am electronics technical, not mechanical technical - perhaps that is what makes this so interesting for me.
Also, a reliance on proper sources without getting bogged.
Exceptional aviation research. Thank you Greg
Thank You Greg 😀😊😀 Great Part 1.5 and Thank you Too The Kind Person Who Provided The Missing Links By Providing The Original Manuals 😊😀👍🏼
Apart from the excellent work and videos you do, I really want to say I like listening to you. People who speak like that usually know what they are doing or saying.
It is maybe not the compliment you are expecting doing technical videos, but hey !
I am so glad that I have discovered this channel. As someone interested in military engineering I love the deep dives into the aircraft of WW2 etc. And it is great to see some info of the Japanese aircraft, they are much better than I had imagined. Keep up the good work!
Any chance of a review of the Ki-44? IIRC, it was the 1st Japanese fighter to buck the entrenched Japanese Military doctrine of a fighter being highly maneuverable.
If this series does well I just might do that.
Regarding the manual fuel pump, it seems to be the rightmost of the two long handled rods with balls on the end on the right side of the cockpit. The word 'pump' （ポンプ）is very legible but the kanji for fuel (燃料）is not.
In 'The Miraculous Torpedo Squadron' the autobiography of Juzo Mori, he describes one of his early sorties in China when his engine began to lose power. Having been trained to crash his airplane (a Kate) into an enemy position if unable to make it back to friendly territory, he asked his backseaters if they were okay with that (they were) and began looking for an enemy position to crash into. However, he did start using the manual fuel pump and that kept the engine going long enough for them to make back to their lines.
Greg,
Your videos are the best and you have one of my favorite channels on UA-cam!
These KI-84 videos have been really fascinating. Watching the last video raised a question regarding the engine design that I wondered if you might address moving forward. The reason given for the engines lower displacement, higher RPM levels, and higher compression ratio, were primarily smaller frontal area. I'm positive this was a big factor, but I can't help but see some commonality with the trends presently occurring in the automotive space; could one of the reasons for this change in design philosophy be an effort to reduce specific fuel consumption? I would be curious to see a comparison of fuel consumption with larger allied engines at given power settings. I imagine conserving fuel must have been on the radar of the Japanese in the latter stages of the war. I wonder if the increase in RPM and associated frictional losses were offset by the reduced throttling losses and higher efficiency of the increased compression ratio.
Any insight you could offer would be greatly appreciated.
Thank you for all that you do for us aircraft buffs!
Sounds like some kind of Mazda Skyactiv voodoo going on.....
You should give a really obvious analogy for survivorship bias for the people still complaining.
Something to the effect of:
"The planes that came home were not hit in the cockpit, engines, or fuel tanks; so it must be hard to aim for those. We should armor wingtips snd empty fuselage." - Survivorship Bias Conclusion
"The planes that came home were not hit in the cockpit, engine, or fuel tanks; so we should armor those areas instead of empty fuselage or wingtip areas" -Normal Conclusion
The graph at ~ 14:00 top right corner 8th from the top, 油圧ポンプレバー, which translates to oil pump lever, which points to a big lever just next to the right leg paddle, that *should* be the hand oil pump
Edit: i got it wrong, it should be translated to hydraulic oil pump lever which has nothing to do with fuel
"Hand oil pump" = hand fuel pump?
From my experience 油圧 usually means hydraulic pressure, which pumps the hydraulic backup reservoir or even directly into the system's consumer components (as in DHC-8's parking brake). Makes sense to place a HYD hand pump there for backup gear extension and brakes too!
@@noranekonekomatagi3261 ah yes it should be hydraulics, fuel is 燃料 in Japanese but genrally any oil is 油 thats what gets me wrong
@@noranekonekomatagi3261 that makes sense
The boost pump is just to the right of it.
Regarding the fracturing of the armor plate, the heat treat used (according to the specifications you'd supplied) showed the outer "casing" was done to a depth of a tenth of an inch as was also listed on the Rockwell "C" scale, a hardness of 64. That is VERY HARD.
Almost 40 years ago, I hand engraved (on a Deckel GK21 pantograph milling machine) quite a few Poco 3 (graphite) electrodes for use in an Electro-Static Discharge Machine (E.D.M.) This was in order to burn in very fine detail for plastic injection molding inserts of S-7 tool steel, heat treat hardened to that same Rockwell 64 on the "C" scale. The applicatrion was for Hewlet Packard's yet to be released consumer line of ink-jet printers, specifically, these were the nozzle design's test molds.
I had to hold to .0002" accuracy (I managed) using CNC generated aluminum templates supplied by Hewlet Packard, and for over forty versions of these nozzle designs, each requiring some 6-8 electrodes.
One bad Friday, as Tom Magee removed form the oil tank of the E.D.M., a fully finished, identical hardness to the Frank's armor plate, Rockwell 64 "C" scale, S-7 tool steel insert , the surface oil remaining caused him to lose grip on the approximately one cubic inch insert. From a height of little more than three feet up, it hit the shop's concrete floor shattering as though it was made of cheap glass. That "64" is rather hard, but also rather brittle. We both laughed as that represented a better part of a week's work for each of us. What else could we do?
00:26 "I've got information man, new shot has come to light!"
My Fav Japanese fighter of the war. I’ve got a beautiful 1/32 model set in a revetment on Clark field. Thank you for the excellent work on this aircraft.
Definitely love the Japanese aircraft, they’re so unique and have interesting stories
I'm glad to see that rare manuals have found their way to capable hands. Greg's analysis is top notch, and his conclusions are probably about as close as you can get to unbiased.
Great presentation, Greg. Your videos give an outstanding degree of technical information.
"Sometimes new information raises as many questions as it answers."
I think that's the nature of almost all scientific and historical research. I've never come away from a project satisfied that I found all the answers - and when I thought I did, I was wrong.
Have you done one about the Ki-100, the evolution of the Ki-61, I think. And I'll give one special credit to the Ki-84 - it has the most beautiful fuselage lines of almost any aircraft in WWII. Oh! You've already done it, and i just saw it! GREAT as usual, thanks!!!!
I absolutely love the Frank. Next to the Nick and the Dinah, of course.
The Ki 102 "Randy" looked like the ground attack aircraft that they never really got out of the Ki46. The Dinah as a recon and run aircraft though has always been a favorite aesthetically, especially the Ki46 III. Even just having the Ki84 and Ki100 reviewed in this depth though, is way beyond what I ever expected and Greg said the later is also in his future list.
I'm simply amazed at your research and the lengths you are going to educate all of us, you can call me crazy, but I simply can't stop watching all these presentations. Thankyou so very much for all your continuing work.
I'm thankful for every view. If you watch a video twice, that means I'm doing my job so I'm really glad to hear it.
As a young boy I started collecting William Green's War planes of the second world war. In vol. 3 he says this about the Ki.84: "It compared favorably with the best of its antagonists; it was slightly slower than the P-51H Mustang and the P-47N Thunderbolt, but it could out-climb and out-manoeuvre both American fighters." The top speed for the Ki.84 is listed at 388 mph @ 19,680 ft. In volume 4 , the P-51H top speed is listed as 487 mph @ 25,000 ft. and the P-47N top speed as 460 mph @ 30,000. I could never figure out how it could "compare favorably" with my favorite US fighters. Fifty-some years later you are helping me understand. Great video! Now how about addressing Mr. Green's comment about the Kawanishi N1K2-J Shiden-Kai (George 21) when he says "the Shinden-Kai, was undoubtedly the finest J.N.A.F. production fighter of the war." How does it compare with the J.A.A.F. Ki 84?
The next Ki-84 video will go into plenty of detail about the plane's speed. The N1K will be another video another time.
Thanks again Greg your stuff is the best. I'm waiting now for part 3 on the Hayate.
8:30 Just about every picture I've seen of Ki-84-Ia,b, and c at Sentai level has the thrust augmented exhaust. The first preproduction series of a hundred or so had the single per side collector exhaust. I don't recall a single picture of these early collector exhaust Hayates with Sentai markings.
Love this channel. If you want to fly this, it’s in world of warplanes.
MW Injection: When you compress air in a cylinder (or in anything else), the temperature increases. This is basic physics and gas laws. If the temperature reaches the ignition temperature of vapourized fuel, it ignites. Fuel igniting prior to top dead centre (TDC) is engine knock. If you spray methanol and/or water into the intake manifold, it vapourizes, using up heat and reducing the air temperature. The colder the air is, the more you can compress it without reaching the fuel ignition temperature. You want to increase manifold pressure. Your problem is air temperature inside the cylinder. MW injection allows you to increase manifold pressure.
Otherwise, this is a great presentation!
Howard, I think you missed the previous episode when I went over this specifically. You're coming into the conversation in the middle. It's not MW injection in this specific case.
Hey Jack. The system isn't just for anti-knock. It's to control the cylinder temps. I covered this in the previous episode. That's the reason for injecting ethyl alcohol vs methanol. Water:Methanol is more effective as an anti-knock agent, but Water:Ethyl alcohol is more effective in controlling cylinder head temps. This is covered in at least two places in the documentation for the Ki-84 (where they specifically reference cylinder or cylinder head temp issue which are controlled by the system. This is mentioned separately from the threat of knock). It's also the conclusion of a very detailed NACA report about the various things you can injectin, water vs. water:methanol vs. Water:ethyl alcohol and so on. Of course knock is a factor here too, but it's not the only factor.
Ah, that makes sense. Keep in mind, the way these come into my feed, I just see your comments by themselves, I don't see the comment you are responding to.
Brilliant! Can't wait for the next one!
Glad I could contribute. Looking forward to Pt. 3 :D
Thanks for your help :)
@@GregsAirplanesandAutomobiles Thanks for all the content ^^
I’ll be sending you a video of me flipping through the manual so you can compare with what you have already :)
Just a sec~
As to the metallurgy of the armor, another older and more commonly used term for "carburizing," is case-hardening. It is done by heating the plate in an oven, surrounded by a source of carbon (generally wood charcoal), in the absence of oxygen, and then allowing it to cool slowly. This allows carbon from the charcoal to migrate into the outer surface of the metal, making it very hard, compared to rest of the mass of the metal in the interior of the part, whatever it may be. I'm not sure how long the process has been around, but I'm familiar with it from experience with antique firearms, where it was used in revolver frames and rifle receivers prior to the availability of stronger alloys starting in the late 19th century.
Case hardening was used for sword blades during the renaissance period. I don't know if the technique dates back to medieval times or not.
Also, case hardening was common for cylinder barrels. This will not help the armor plate, the armor plate needs strength throughout the material. Case hardening helps in wear, which affects the surface.
It's called Krupp armor process for battle ships
It can make it brittle if not controlled, i wonder if it must have been poor high carbon steel armor any thoughts?
Any way the pilot would survive unless it Spalded
(Fragments would spray in to the cockpit) armor did its job.
@@demetridar506 t does help armour. Common in naval plate
Great to get really detailed discussion on a Japanese aircraft - thank you
Wow, nothing like Christmas coming early. Or really for St Nicholas day, 12/6. Thanks
Great video, thanks for sharing this information
Great stuff! Just a note on the armor thickness: I suspect the variation in thickness between the armor of the two planes tested could well be just down the the manufacturing tolerance of the sheet metal used. This variance is within the current manufacturing tolerance of normal hot-rolled sheet. I am not sure if armor plate is held to a tighter tolerance.
Thanks for the in-depth updates. Regarding the fuel pump lever in the cockpit diagram I think it might be the aft one of the two long ones to the right of the flight stick. That one is labeled “Acceleration pump lever” the lever forward of that one is labeled “oil pressure pump” fyi
A generic comment about the alloy for the armor: Many alloys that has nickel as the base belongs to the so called "super alloys" group. From a machining point of view these stand out enough to give them their own class due to how difficult they are to machine, quickly wearing out the tools even when everything is done correctly.
Crome and molybdenum in high amounts give steel very strong characteristics so I wouldn't be surprised if they also worked similar in a nickel base.
(And a bit of rant about metal properties, many people confuse hardness, tensile strength and impact resistance, the relation between these can vary quite a bit and the difference between elastic and plastic deformation must be considered as well.
Material technology is a fascinating subject that I wish I had more then scratched the surface of.)
There aren't enough metallurgy puns.
I'm going to steal that one.
@@thomasjoyce7910 Feel free to make a copper or two from it!
I've heard of these nickel-based super alloys being used for jet engine turbine fan blades, but not for armor plate. Any more info on this topic?
Inconel is about the toughest stuff I ever had to touch carbide to. I'm glad i didn't have to see much of that stuff because I did not have whatever the right combo was for turning or milling it quickly..
@@icewaterslim7260 Well "quickly" is a rarely used word with those alloys!
Personally I quite like them. It's a challenge to get right (aka stable process). Ceramic inserts for rough turning is a good starting point. For carbide inserts a life span of each edge 5 min working time is good.
Also the slightly odd wear on inserts where it's usually not the tip that shows signs of wear first but the flank that meets the surface of the stock (turning).
And cutting fluids... tons of it. Leave the cutter dry for a split second and it heats up and then cracks when cooled again.
Another thing I like is the dimensional stability one gets. Ask the machine to change the diameter by 0.004 mm and that's what one get repeatedly at an absurd level compared to stainless steel and other simple alloys. (At least that's my experience in the machine's I've been running it in.)
Great work Greg!
Sound was great. Thanks Greg
Awesome greg thanks again,im try to find stuff on the Japanese answer to p-38, all can remember is its nickname, Randy, twin engine pilot & gunner
Very interesting! Looking forward to the next video!
wobble pump ! yea ! for years i've wondered what is a wobble pump.
Greg, is a treasure of the interwebbies...........that Al Gore invented!
Awesome video as usual Greg. Really enjoying this series on the Ki-84.
A nice looking plane to be sure, very different to US Navy types with mighty fins to help with carrier TO/landing performance. I have a preference for the Mitsubishi J2M just for its pork barrel looks and the ingenious idea of the prop extender shaft. I think one of its weakness was also with spindly undercarriage.
Very interesting video Greg. As an engineer I find it very interesting how modern the american production methods and therefore consistency was when compared to the Japanese.
The differences between individual models of the Ki84 really shows that the Japanese worked in a manfactory-type of environment when compared to the all out industrial approach of the USA.
This is even more interesting when looking at the big achievements japanese car makers such as Toyota have made after the war with regards to efficient production. It really seems that they have learned their lesson while still keeping their approach with a focus individual responsibility (at Toyota every employee is allowed to stop production when he/she sees a way to improve it).
Anyways: Very good work Greg!
If you are looking for another plane to cover I would be very interested in seeing some content on the N1K or a follow-up on your first Mosquito video.
Have a nice day and recover well!
In the 80s, when Japan was the darling of the world of production, some Ford engineers visited a Toyota factory, marvelling at its complete soup to nuts manufacturing efficiency from raw materials to finished product.
When asked how they came up with all of this, a Toyota exec said that they just did what Henry Ford did at his River Rouge Plant 60 years previously.
Great content, thanks Greg.
Ref mechanical fuel pump: that’s the standard T-6 set-up, you gotta use the wobble pump if you notice the loss of fuel pressure.
Fuel pressure going up under Gs, May happen by gravity if the fuel tank is higher than the mechanical fuel pump, just by increased weight of fuel under Gs.
Love Greg / no interest in Japanese warbirds. My brain can only be interested in so much. I am sure its great !
Amazing to get hold of proper historical documents so many years later. Interesting the Japanese armour was quite high quality, there must have been lots of material shortages by 1944 so it seems to have been a deliberate effort.
As soon as I hear that mouse click I'm IN
Greg
Great video in an excellent series.
I’d love a comparison of the Ki-84 with the P-51D & FW190 Dora at some later stage
Exciting stuff
Very interesting. I'll look forward to the next installment. Considering that Japanese industry was being bombed into oblivion by the time this plane was in production, I am not surprised at the variation in performance. It is actually surprising that they did as well as they did. Just as well for the Allied this plane came about as late as it did.
Didn't they have undetected aircraft production facilities in the hills turning out a large volume of some quite sophisticated aircraft? I vaguely recall a documentary about that claiming that an Allied invasion force would have been shocked by the air assault they would have faced.
Wouldnt have mattered
On the exhaust stacks. the plumbing to trunk all the exhaust to a single exit would mass more and require more room under the cowling. I suspect the real reason for the multiple exhaust is it saved weight, and added to engine by reducing exhaust back pressure. Exhaust thrust might be reduced slightly but weight savings I suspect more then make up the difference.
Wow. Running a wobble pump in a fight would be a pain. I'd like to know more about that. I feel like there may be more to that. Perhaps somthing done just prior to pulling more than 3Gs? Somthing done just prior to entering combat?
I'm thinking the same thing, but it's not clear. Perhaps a few pumps prior to combat and it's OK for 5 mins? It could have been something like that.
From the engineering point of view, Nakajima (like their German comrades) had to design a high performance engine based on the tyranny of low grade fuel, bad lubrication oil and bad material (substitutes) for the main bearing. All their technological effort went into addressing this. All later problems in production and maintenance were due to these three factors. Was it an success? Well, operation "Strangulation" - the mining of the Japanese Sea by B-29 - went on mostly unopposed. And this very operation was the most decisive factor in forcing the Empire of Japan to surrender in 1945 without the need of invasion.
Has to be my favourite Japanese plane of the war. Kinda looks like their version of a P-47 Thunderbolt.
Yep! It nearly looks like a P-47 in American markings.
I would definitely like to see a comparison of data for a Ki-84 that is up to spec with the F4U-4 (famous "Dash four") Corsair variant.
Most enjoyable content. Thank you!
Outstanding Greg! Maybe include the P-51 for the performance comparison, as they were also fighting each other?
A Civil War (US) historian stated that whenever he hit a dead-end on research he would post what he had and invariably someone would come back with something like a copy of a letter from their great-great-grandfather detailing how the commander of the XX Alabama was killed at Antietam/Shiloh/Gettysburg. This internet thingie can be useful.
I once asked a question on a blog I 'infest' vis a vis: the 'future' of WW2 research, once all the veterans have passed away. Would it become like archeology? Delving thru files and letters from men long dead, instead of digging thru dirt and ruins?
Fantastic stuff GAaA.
Thank you
It's amazing what Japan achieved in technology and numbers with so little resources.
Japan used huge amount of resources for armament.
Bangin, best possible versions please, lets get optimistic
If you use Google Translate on your phone, put it in camera mode, you can translate the print. I just did it on computer screen. No wobble pump is listed on the call outs on the cockpit drawing.
Interesting thing I found.... was the #21 Methanol fuel pressure guage, #23 Fuel tank pressurization tank switch cock. #25 Rapid Plan (?), #26 Boost Pull (?),
Hi Greg, I hope my email about a better way to translate japanese manuals than Google Translate (using an OCR website in between) reached you - by now, several helpful folks with actual knowledge of japanese have basically confirmed what my guesstimated results were, but perhaps the same problem comes up in the future as well, and I suppose it's a good tool to have for simpler questions (i.e., that method does work for the instrument panel components quite completely). Also, I can add that using a different translation engine such as "deepl" gave me a lot better results when I tried to translate the scanned Kanji symbols compared to Google. Cheers and I hope all is well with your recovery!
Where did you send it?
@@GregsAirplanesandAutomobiles First I sent it to gregsairplanes (with google mail, think I can't type a proper mail adress in here), which was returned as "address does not exist" - I then sent it to gregsairplanesandautomobiles (with google mail), which didn't return an error - so I figured that was probably alright. But I guess not... :)