What a great news, so temp is sorted, and the landing was awsome, thanks for the update and tuning for the coming, you are doing very well, all the best.
I always look forward to your videos ....especially when you make a noticeable improvement, please keep up the tweaking and things will fall into place and you will end up with a fantastic plane.
Very glad to see the cooling troubles getting under control. Great work! As I watch your flights it’s hard to see if there is turbulence or not but my mind goes to how stable of an instrument platform the Raptor will be in its current configuration. The roll oscillations particularly concern me. I look forward to you flying an ILS and seeing how it performs. Excited for you!
Looks like the proof of concept on the cowl vents worked great! Probably already thought of this, but it shouldn't be too hard to design some cowl flaps in that area to make the openings adjustable. Congratulations on the major improvements!
Petr I am happy to see that progress is being made. Cooling is always an issue with pusher configurations. Enclosed en article from a Shell lub specialist.
It's so great to watch this process. So often with new designs we see the first flight and then wait for it to be available for delivery a few years later. Thanks for your transparency and for letting us see your thinking.
Congrats on the eureka moment. I had on on my Glasair Sportsman build and it’s great when every thing just seems to fall into place. But that cliff hanger hurts😩. Hoping you will knock off the 40 and scream westwards at god knows what FL doing 200 knots sipping thimble fulls of jet A1. It’s been great to follow along. Looking forward to the next one. 👍
Just imagine if you had not cut the ducts in the wing skirts and placed a temp probe in there you may have not found out this issue and not discovered the thermostat setting issue. Its not a common issue on a normal vehicle to have a power controlled thermostat. So kudos on the find, well on your way to getting the rest of the program completed and the 40hrs of flight. by the way that was an awesome landing!
Nicely done Peter! Satisfying improvements all around! As I’ve said before progress has proven your approach( pun intended), keep posting & happy landings!
You know you’ve made it big, when UA-cam places this many ads which are un- clickable to stop, on your videos. Congratulations, Peter. You deserve everything you’ve got coming to you.
Upon thermostat wax failure....does it fault and stic on the 230 deg or the 185 deg setting? Might be a better idea to see if you can just set an 180 deg thermostat in there so it has less fail potential.
Don’t think you want a lower temp thermostat, it’s designed for 185 deg which on a diesel is low, I believe he said he can set the open temp lower via ECU setting or even open it manually
@@SniperJuice I thought the thermostat opened at 230, and he was trying to get temps down to 180-185. heating the thermostat with the ECU lets it open lower, and that's what he's done to get the temps down. It also looks like there are high-flow versions (bigger valve so more water will flow when they are open) as well as different temp options.
Great work Peter. 1. Curious on the next flight if leaving the heater loop off, and allowing only the thermostat to do it’s job if it can keep normal parameters without all the nose addons. 2. Would venting all hot air to a point further out on the wing allow cooler air through the prop. I wonder what the temp rise of the spinner opening, exhaust, exhaust opening, bottom cowling, and the new vents together do to the air temperature through the propeller, vs ambient OAT? Could the Prop itself be suffering from a “higher density altitude” than in a conventional tractor prop setup? On a previous video someone had commented on a configuration that would allow hot exhaust to be vent further out, keeping the prop in clean, colder air.
Absotively posilutely awesome progress Peter! Bonus room for more cooling possibilities with reduced drag if needed. I think you have opened some doors and windows with this. Congratulations!
For the people that want one on each side, that could always come for production. I think you proved it out now that its a good solution. I agree with having two at some point also, but this is a prototype. Doing good Peter!
Thats such great news! looking forward to see the shift to higher and longer flights. Flightaware had you hit some pretty high speed on this flight too. 173mph level flight.
I realise that the airframe is a writeoff now....but the pitch oscillations remind me of a Piper Aztec that I once loaded incorrectly when i was a young lad starting out in Aviation and put it way out of c of g position...after takeoff it the nose would pitch up and down until i got some speed to correct it....also...it does not appear that your lateral accelerometer is connected up as the slip ball does not move at all.
Congrats on the cooling progress. Have you considered adjusting (closing) the inlet scoop to see if cooling is still acceptable and lessen drag during level flight?
I dont understand why the scoops are better that grills? Is there a difference in aerodynamics? Or you dont want grill because you could get water inside? Thank you
YES, YES, CONGRANTS!!!! You dont need any extra radiators anymore. It is all about vacum-low pressure. I believe you keep temps with closed upper scube aswell, Looking forward to watch your progress.
He wanted to mirror the last flight he did and see the difference in temps at same time and elevation etc. He likes to test after each little mod....this time it was like 2 mods at same time
Now that you know the system is very capable of keeping the coolant in the desired Range - is there any benefit to eliminating the variable of the t-stat? You could replace it with a restrictor custom milled to the size of an open t-stat. Would be just like it being open all the time. Downside is it would extend warmup time. But you would eliminate a situation where it did not open...just a thought. Keep up the great work. Btw - I have almost 100k miles on the same Tdi engine as in the raptor. Not a single mechanical issue and still does not use oil. Beast of an engine!
Peter explained this in the last video. He’s working on a minimum flying speed (MFS) of about 85 kias for now. Being a canard, the aircraft (main wing) doesn’t really “stall”, only the foreplane, so talking about MFS makes more sense with these airframes.
Congratulations, I do have a question/suggestion. Do you really think it is necessary to have a thermostat? I have had them fail on cars causing the engine to quickly overheat. It seems like a potential point of engine failure / emergency landing and not worth heating up the engine a little quicker. Just my 2 cents.
Agreed that thermostats are unreliable mechanisms, but there needs to be a mechanism for controlling the coolant temperature. Maybe a backup mechanically actuated ball valve to bypass the thermostat in the event of an inflight failure?
@@rodgerhecht3623 that is a mechanical thermostat (just like on cars), there is just a way to trick it to come on sooner. to more efficiently burn the fuel, you want the engine hotter, but you don't want it too hot for your materials.
Hahaahahaha it now seems obvious that the outlet was the restriction for the air look at those graph dips. It ran fine on the stand it was awful until now but it works great!
@@RaptorAircraft How do you anticipate the CG shifting with reduced vacuum bag layup weights? It seems like you will be shedding lots of weight in the rear in the facotry...
fantastic take offs and landings!!! skill, I sees it!!! Happy, Happy, Happy ,KOOOOLLLL!!! love to see progress!!! Q, would you put an air scoop where the cut out is for the oil cooler? Would that give it more fresh air as well? Great engineering on your part!!. Glad to see another issue resolved. 10,000,000 attabits for you!!!! Q, how much air time on the beast? 40 hrs up yet? Glad to see the over all progress. Love the stability in the air and on landings and take offs. Inspiring!!!! Kudos to you sir!!! what is next?
I think that real inlet is pulling in the air it needs because of the low pressure on the rear. So no scoop is really necessary. About 7.7 hours now. Going to take it a bit higher and stay up longer. I want to have some flights where I don't have to change anything in between flights. Then I'll feel more comfortable flying a little further from the airport.
That was a major find on the thermostat electrical control along with the additional venting of the engine cowling. Very well done Peter! Will this help your A/C work better while on the ground? I'm very interested in your top speed numbers and ceiling numbers. Will you repair the window to do pressurized testing or just get an oxygen tank? How are things coming out west? Please tell me that you've had all the molds and plugs moved out there and that they are incorporating changes based on your findings and laying up prototype #2 as we speak... :) Keep up the excellent work!
So did the thermostat really get tested today? Would like to have seen how the thermostat handled. Seems like this flight mostly just tested the new ducts.
Yes it did, without it open the temps would not have dropped as much as they did as the thermostat would have been trying to keep the coolant at 230f rather than 185f.
Anybody knows if he is running the AC or not?? Other question he was talking about a oil thermostat the last time. Does this also have an electronic control same as the cooling water thermostat??
I totally agree with you. Been there, done that and got the sweat soaked t-shirt to prove it. Had to “ hold short” on a 35 ‘C day for 20 minutes with the plane parked at 90 degrees to the prevailing wind and 3 other planes close behind me on the taxiway.
Peter, I have cautiously commented that you have built a better airplane than I could, now I will Rephrase my comment Much better airplane "than I could" . Good show
Can't remember which aircraft manufacturer's video I was watching, but they mentioned that about 35% of an airplanes parasitic drag was due to engine cooling.
That seems about right for the average GA aircraft, with the caveat that it depends on airspeed, as the faster you go, the lower that percentage becomes relative to the rest of the aircraft. Air flowing across relatively smooth surfaces contributes a lot less parasitic drag than one would think. Everything inside the cowling is the antithesis to aerodynamic efficiency, and an aircraft would have quite a bit less drag if you didn't do anything other than plug up the holes in the front of the cowling. That's one of the reasons why a turboprop gains so much speed when compared to a piston equipped aircraft, even if the power output is identical...a turbine doesn't need any cooling air besides that blanket of air around the flame front.
@@Skinflaps_Meatslapper Parasitic drag increases exponentially with airspeed - doesn’t matter where it comes from, but cooling drag is something that can be varied with cowl flaps, air scoops etc. The faster you fly, the less induced drag and the more parasitic. Also, air-cooled engines generate more drag (generally) than an equivalent power plant which is water-cooled. Turboprops have a lot less cooling drag, and higher power/weight which combined leads to higher speeds (assuming all other factors remain the same), but the BSFC is much higher on a turbine, which is why Peter is determined to get this Audi diesel dialled in 👍🏻
@@DiverJames That's what I meant when I said the percentage of cooling drag would be lower at higher airspeeds. At twice the airspeed, cooling air remains a constant while drag increases 4x, so the percentage goes way down. For two aircraft with the same engine and cooling requirements, one being twice as fast as the other, the cowling inlet can be made roughly a fourth the size for the faster aircraft. However, if the fast aircraft is going at the same speed as the slow aircraft, it has 1/4th the cooling air available as compared to the slow one. You don't want to size the inlets for slow speed, you want them sized for cruise speeds so you're not racking up tons of unnecessary drag. You have to temper that with the ability to keep the engine cool at slower airspeeds for at least a little while, since that's likely the airspeed you'll be climbing at with full throttle. That's one of the problems that Peter is running into, he's flying an aircraft meant for high speed at low speeds and the cooling air is harder to get. Hopefully once he gets the inlets and outlets and coolers and thermostat all working together, he'll be able to retract that inlet at higher speed and cut the drag down a bit.
@@Skinflaps_Meatslapper All good. Like I said; cooling drag can be reduced in cruise where additional cooling is less of an issue. For Peter’s current configuration, that may be tricky. However, this *IS* an R&D prototype and no doubt the learning from this airframe will be fed into serial number 2 👍🏻 I have every faith he’ll work it out, and now with the thermostat discovery, some of the other changes might be reversible to improve the weight/drag numbers. Onwards and upwards!
@@rv6ejguy Good man, I appreciate the explanation. Even though this is all knowledge I have, it's nice to see someone else offering it up as well in a different format. Also nice to see a fellow RV owner here, I'm in an RV8 👍
Please have your air-data system checked. Any performance measures are meaningless without accurate airspeed and altitude information. When you touched down your altimeter was about 50 feet above field elevations and as you de-rotated your altitude jumped up about 70 ft. On the takeoff roll your altitude also increased by about 100 ft. There is definitely position error in your system that needs to be tracked down before any serious performance testing.
@@gmcf6895 I just happened to be looking at the computer when the notification for the new video came up I'm really looking forward to this Raptor I think it's going to be an awesome airplane and now that he's got that heating problem worked out I'll tell you this diesel engine is going to be a thousand times more efficient then the old fashioned fuel to a cool models
8:40 beautiful landing my man. Peter, you’re killing it!
So much inspiration. Thanks for taking us on your journey!
Wow.. a thermostat with an electrically operated wax motor controlling oil flow. Who'da thought?! Amazing detective work Peter.
Coolant not oil.
Wax on Wax off, You've done Mr Miyagi proud.
Getting closer to a flight where you can feel comfortable about flying the aircraft and the temps take care of themselves.. Cheers Peter..
What a great news, so temp is sorted, and the landing was awsome, thanks for the update and tuning for the coming, you are doing very well, all the best.
glad that got figured out, something seemed not to be right from the start. love it!
I always look forward to your videos ....especially when you make a noticeable improvement, please keep up the tweaking and things will fall into place and you will end up with a fantastic plane.
Congrats on the breakthrough. It just keeps getting better. Now I have to get serious about finding that fountain of youth.
Data collection for future analysis is key
Great job
That's awesome! You need to get that valve working for you. It's like playing with a broken leg without it. Glad you found the gremlin.
Didn't have to wait too long which is great. Shadow of the Raptor on the ground is awesome!!
Pete, I am so pleased for you! This is a great news and a huge step forward in your project. Thanks for sharing!
Good job on systematically ironing out these cooling issues!!
Very glad to see the cooling troubles getting under control. Great work! As I watch your flights it’s hard to see if there is turbulence or not but my mind goes to how stable of an instrument platform the Raptor will be in its current configuration. The roll oscillations particularly concern me. I look forward to you flying an ILS and seeing how it performs. Excited for you!
With one open and one closed to regulate the temperature and so on, you are clearly in the happy zone. Great great work Peter!!
Congrats on the cooling! Also nice app and landing. Can’t wait for my raptor one day :)
Have a great weekend. Looking forward to the performance numbers.
Looks like the proof of concept on the cowl vents worked great! Probably already thought of this, but it shouldn't be too hard to design some cowl flaps in that area to make the openings adjustable. Congratulations on the major improvements!
Petr I am happy to see that progress is being made. Cooling is always an issue with pusher configurations. Enclosed en article from a Shell lub specialist.
Looks like a real breakthrough! Good work!
You’ve got to be jacked. Great results. 🇨🇦
It's so great to watch this process. So often with new designs we see the first flight and then wait for it to be available for delivery a few years later. Thanks for your transparency and for letting us see your thinking.
Man you have a deft touch with the landings!
Was that a bloodsport reference? :)
Congrats on the eureka moment. I had on on my Glasair Sportsman build and it’s great when every thing just seems to fall into place. But that cliff hanger hurts😩. Hoping you will knock off the 40 and scream westwards at god knows what FL doing 200 knots sipping thimble fulls of jet A1. It’s been great to follow along. Looking forward to the next one. 👍
You could do a layup on your new vents . Use them as molds. Or carve some foam for plugs.
Kewl stuff onward and upper . Very happy for you.
That is good news that you have made good headway on the cooling.
Just imagine if you had not cut the ducts in the wing skirts and placed a temp probe in there you may have not found out this issue and not discovered the thermostat setting issue. Its not a common issue on a normal vehicle to have a power controlled thermostat. So kudos on the find, well on your way to getting the rest of the program completed and the 40hrs of flight. by the way that was an awesome landing!
Nicely done Peter! Satisfying improvements all around! As I’ve said before progress has proven your approach( pun intended), keep posting & happy landings!
Buttered the bread on the landing, well done
Excellent progress. I assume this mean there’s now room to lower the cowling scoop during cruise to reduce profile drag. ( ? ).
Very well done Peter
Good flight and I think two smaller air vents in on the airfoils would perform and look better in future planes.
Taming the raptor.
Well done Peter very interesting
! Thank yoi, have a good weekend.
This is great! Popping Champagne! :)
You know you’ve made it big, when UA-cam places this many ads which are un- clickable to stop, on your videos. Congratulations, Peter. You deserve everything you’ve got coming to you.
Seems like it just needed the cowl opened up in the back for some more flow. Great work!
The thermostat is working now also.
Tower: traffic is a RAPTOR
Upon thermostat wax failure....does it fault and stic on the 230 deg or the 185 deg setting? Might be a better idea to see if you can just set an 180 deg thermostat in there so it has less fail potential.
Nice Job!!!
you should also be able to get a lower temp thermostat module to go inside that assembly
Or even just find a normal totally mechanical thermostat that doesn't rely on the ecu, would be one less thing to mess around with or go wrong.
Don’t think you want a lower temp thermostat, it’s designed for 185 deg which on a diesel is low, I believe he said he can set the open temp lower via ECU setting or even open it manually
@@SniperJuice I thought the thermostat opened at 230, and he was trying to get temps down to 180-185. heating the thermostat with the ECU lets it open lower, and that's what he's done to get the temps down.
It also looks like there are high-flow versions (bigger valve so more water will flow when they are open) as well as different temp options.
Awesome!!! Congratulations Peter, now I can't wait to see an all out full power climb to 10k
Your making huge headway! Congratulations Peter!
Awesome!
Does this mean that you are ready to try some high power climb outs and start taking it up to higher alts?
Super thrilling progress! ⭐⭐⭐
Very happy for you! Cheers!
going to be great when you get some sustained climbs and cruise to get it tweaked out
238° in the winter. Can you interpolate the data for summer air temps?
Great work Peter.
1. Curious on the next flight if leaving the heater loop off, and allowing only the thermostat to do it’s job if it can keep normal parameters without all the nose addons.
2. Would venting all hot air to a point further out on the wing allow cooler air through the prop. I wonder what the temp rise of the spinner opening, exhaust, exhaust opening, bottom cowling, and the new vents together do to the air temperature through the propeller, vs ambient OAT? Could the Prop itself be suffering from a “higher density altitude” than in a conventional tractor prop setup? On a previous video someone had commented on a configuration that would allow hot exhaust to be vent further out, keeping the prop in clean, colder air.
Absotively posilutely awesome progress Peter! Bonus room for more cooling possibilities with reduced drag if needed. I think you have opened some doors and windows with this. Congratulations!
For the people that want one on each side, that could always come for production. I think you proved it out now that its a good solution. I agree with having two at some point also, but this is a prototype. Doing good Peter!
I assume the thermostat discovery was a classic "Doh!" moment? Onwards and Upwards.
i,m thinking, he might have felt that way. but those motec boys that wired up the harness could have been more pro-active.
@@horseshoe182 they were definitely playing it lazzy bastard style
@@mccallumcra thats right, i wouldn't have been to happy about it.
Thats such great news! looking forward to see the shift to higher and longer flights. Flightaware had you hit some pretty high speed on this flight too. 173mph level flight.
Getting extremely excited now. shoot for the stars
Those two vents are not high tech but they are very impressive!
Really cool ❄️
very nice......
I realise that the airframe is a writeoff now....but the pitch oscillations remind me of a Piper Aztec that I once loaded incorrectly when i was a young lad starting out in Aviation and put it way out of c of g position...after takeoff it the nose would pitch up and down until i got some speed to correct it....also...it does not appear that your lateral accelerometer is connected up as the slip ball does not move at all.
Congrats on the cooling progress. Have you considered adjusting (closing) the inlet scoop to see if cooling is still acceptable and lessen drag during level flight?
Nice work at fault finding the temp problem.. Is it up to scratch on a hot day..
I dont understand why the scoops are better that grills? Is there a difference in aerodynamics? Or you dont want grill because you could get water inside? Thank you
I LOVE the videos and progression!
* Is it possible to please turn down the ATC audio track? *
NICE!
Will you be able to remove the forward nose rad?
Great project. Great work
So potentially you will be able to remove the forward cooling system extension yeah?
i think he needed some weight in the nose for stability. and a little extra cooling doesn't hurt.
YES, YES, CONGRANTS!!!! You dont need any extra radiators anymore. It is all about vacum-low pressure. I believe you keep temps with closed upper scube aswell, Looking forward to watch your progress.
Will those new vents be disturbing the air flow through the prop and making it less efficient?
I dont' understand why you don't leave the thermostat open all the time, climb at 100% power for a while to see how the temps run.
He wanted to mirror the last flight he did and see the difference in temps at same time and elevation etc. He likes to test after each little mod....this time it was like 2 mods at same time
Because there’s no way to pick a good apple from a bad apple if the second fruit you eat is not an apple.
@@cirrusflyerh2843 very witty!
What engine is it a continental and is liquid cooled using a coolant reservoir
now thats got to feel good,
did you figure out the pitch roll?
Since you've figured out the cooling issue with the thermostat, Are you gonna remove all the extra coolant lines & tank? For weight reduction?
Peter, will the mods like the new vents and such be put into the plans?
Probably needs to figure out if they're actually even necessary first
👍🏽👍🏽👍🏽👍🏽👍🏽👍🏽👍🏽
Now that you know the system is very capable of keeping the coolant in the desired Range - is there any benefit to eliminating the variable of the t-stat? You could replace it with a restrictor custom milled to the size of an open t-stat. Would be just like it being open all the time. Downside is it would extend warmup time. But you would eliminate a situation where it did not open...just a thought. Keep up the great work.
Btw - I have almost 100k miles on the same Tdi engine as in the raptor. Not a single mechanical issue and still does not use oil. Beast of an engine!
What is the stall speed like in any configuration ¿
Peter explained this in the last video. He’s working on a minimum flying speed (MFS) of about 85 kias for now. Being a canard, the aircraft (main wing) doesn’t really “stall”, only the foreplane, so talking about MFS makes more sense with these airframes.
Congratulations, I do have a question/suggestion. Do you really think it is necessary to have a thermostat? I have had them fail on cars causing the engine to quickly overheat. It seems like a potential point of engine failure / emergency landing and not worth heating up the engine a little quicker. Just my 2 cents.
What happens when you are at high altitudes in the winter, and the temperatures are extremely cold? I think you will need a thermostat for that.
Agreed that thermostats are unreliable mechanisms, but there needs to be a mechanism for controlling the coolant temperature. Maybe a backup mechanically actuated ball valve to bypass the thermostat in the event of an inflight failure?
I would think some sort of mechanical thermostat might be safer ???? But not very high tech. But i get it as failure point .
@@rodgerhecht3623 that is a mechanical thermostat (just like on cars), there is just a way to trick it to come on sooner.
to more efficiently burn the fuel, you want the engine hotter, but you don't want it too hot for your materials.
I’ve never had a thermostat fail closed and cause overheating...they’ve always failed open and caused the engine to run too cool. 🤔
Hahaahahaha it now seems obvious that the outlet was the restriction for the air look at those graph dips. It ran fine on the stand it was awful until now but it works great!
The thermostat fix is also significant.
Hi. Will you build back all additional items in order to proof your basic concept?
Does this success mean that you can reduce some weight/complexity by removing the front cooler and loop?
Well, I need the weight up front presently to keep the CG in range but potentially it may no longer be needed.
@@RaptorAircraft , More room for your air-travel suitcase? Me thinks your going places!!!
@@RaptorAircraft How do you anticipate the CG shifting with reduced vacuum bag layup weights? It seems like you will be shedding lots of weight in the rear in the facotry...
"Pretty happy with that landing... "
What's it take to make you exctatic?
Looked pretty close to perfect IMO.
Whooowho.
Can we all come see you off before you leave the sunny south for the left coast? - Alabama Flyer
What happens when it rains?
Water falls from the clouds, relative humidity goes up and the ground gets wet.
@@cirrusflyerh2843 hahaha, very nice!
Dope
fantastic take offs and landings!!! skill, I sees it!!! Happy, Happy, Happy ,KOOOOLLLL!!! love to see progress!!! Q, would you put an air scoop where the cut out is for the oil cooler? Would that give it more fresh air as well? Great engineering on your part!!. Glad to see another issue resolved. 10,000,000 attabits for you!!!! Q, how much air time on the beast? 40 hrs up yet? Glad to see the over all progress. Love the stability in the air and on landings and take offs. Inspiring!!!! Kudos to you sir!!! what is next?
I think that real inlet is pulling in the air it needs because of the low pressure on the rear. So no scoop is really necessary. About 7.7 hours now. Going to take it a bit higher and stay up longer. I want to have some flights where I don't have to change anything in between flights. Then I'll feel more comfortable flying a little further from the airport.
@@RaptorAircraft , I'm sure it feels more comfortable to have plenty of power now with room to dissipate heat for a go around if wanted/needed.
That was a major find on the thermostat electrical control along with the additional venting of the engine cowling. Very well done Peter! Will this help your A/C work better while on the ground? I'm very interested in your top speed numbers and ceiling numbers.
Will you repair the window to do pressurized testing or just get an oxygen tank?
How are things coming out west? Please tell me that you've had all the molds and plugs moved out there and that they are incorporating changes based on your findings and laying up prototype #2 as we speak... :)
Keep up the excellent work!
So did the thermostat really get tested today? Would like to have seen how the thermostat handled. Seems like this flight mostly just tested the new ducts.
Yes it did, without it open the temps would not have dropped as much as they did as the thermostat would have been trying to keep the coolant at 230f rather than 185f.
@@RaptorAircraft Okay I see. So the coolant system as it is will still be needed in the future?
Looking forward to see this Raptor to fly higher than 200 kts. That is what we are waiting for.
Anybody knows if he is running the AC or not?? Other question he was talking about a oil thermostat the last time. Does this also have an electronic control same as the cooling water thermostat??
Heater. It's cold out.
This begs the question. Would knowing about the thermostat prevent you from turning the raptor into Swiss cheese?
Someone even mentioned an oil thermostat a few videos back.
Go for an excess of cooling because someday it will be 100 degrees F. and a pilot will be stuck in a long taxi line.
I totally agree with you. Been there, done that and got the sweat soaked t-shirt to prove it. Had to “ hold short” on a 35 ‘C day for 20 minutes with the plane parked at 90 degrees to the prevailing wind and 3 other planes close behind me on the taxiway.
Peter, I have cautiously commented that you have built a better airplane than I could,
now I will Rephrase my comment Much better airplane "than I could" . Good show
The comment on reducing drag shows you have more brain cells on the problem than the peanut gallery.. well done Peter.
First! Peter, will you be doing the next takeoff at max power? I am curious to see the climb rate and takeoffrun required, given the higher weight.
Traffic is a white raptor...... awesome
@@micjbaron 2:20 "Traffic is a Raptor..." :-)
Problem solver!
Can't remember which aircraft manufacturer's video I was watching, but they mentioned that about 35% of an airplanes parasitic drag was due to engine cooling.
That seems about right for the average GA aircraft, with the caveat that it depends on airspeed, as the faster you go, the lower that percentage becomes relative to the rest of the aircraft. Air flowing across relatively smooth surfaces contributes a lot less parasitic drag than one would think. Everything inside the cowling is the antithesis to aerodynamic efficiency, and an aircraft would have quite a bit less drag if you didn't do anything other than plug up the holes in the front of the cowling. That's one of the reasons why a turboprop gains so much speed when compared to a piston equipped aircraft, even if the power output is identical...a turbine doesn't need any cooling air besides that blanket of air around the flame front.
@@Skinflaps_Meatslapper Parasitic drag increases exponentially with airspeed - doesn’t matter where it comes from, but cooling drag is something that can be varied with cowl flaps, air scoops etc. The faster you fly, the less induced drag and the more parasitic. Also, air-cooled engines generate more drag (generally) than an equivalent power plant which is water-cooled. Turboprops have a lot less cooling drag, and higher power/weight which combined leads to higher speeds (assuming all other factors remain the same), but the BSFC is much higher on a turbine, which is why Peter is determined to get this Audi diesel dialled in 👍🏻
@@DiverJames That's what I meant when I said the percentage of cooling drag would be lower at higher airspeeds. At twice the airspeed, cooling air remains a constant while drag increases 4x, so the percentage goes way down. For two aircraft with the same engine and cooling requirements, one being twice as fast as the other, the cowling inlet can be made roughly a fourth the size for the faster aircraft. However, if the fast aircraft is going at the same speed as the slow aircraft, it has 1/4th the cooling air available as compared to the slow one. You don't want to size the inlets for slow speed, you want them sized for cruise speeds so you're not racking up tons of unnecessary drag. You have to temper that with the ability to keep the engine cool at slower airspeeds for at least a little while, since that's likely the airspeed you'll be climbing at with full throttle. That's one of the problems that Peter is running into, he's flying an aircraft meant for high speed at low speeds and the cooling air is harder to get. Hopefully once he gets the inlets and outlets and coolers and thermostat all working together, he'll be able to retract that inlet at higher speed and cut the drag down a bit.
@@Skinflaps_Meatslapper All good. Like I said; cooling drag can be reduced in cruise where additional cooling is less of an issue. For Peter’s current configuration, that may be tricky. However, this *IS* an R&D prototype and no doubt the learning from this airframe will be fed into serial number 2 👍🏻 I have every faith he’ll work it out, and now with the thermostat discovery, some of the other changes might be reversible to improve the weight/drag numbers. Onwards and upwards!
@@rv6ejguy Good man, I appreciate the explanation. Even though this is all knowledge I have, it's nice to see someone else offering it up as well in a different format. Also nice to see a fellow RV owner here, I'm in an RV8 👍
NO views either. That makes me #1 Raptor FAN !!
Well deserved, Sir Newton!
You are late! Someone beat you to it!😄
Please have your air-data system checked. Any performance measures are meaningless without accurate airspeed and altitude information. When you touched down your altimeter was about 50 feet above field elevations and as you de-rotated your altitude jumped up about 70 ft. On the takeoff roll your altitude also increased by about 100 ft. There is definitely position error in your system that needs to be tracked down before any serious performance testing.
1st to comment!! LOL
No you weren't!
@@gmcf6895 Yes I was! 🤣
@sir Newton. At best, a deadheat!😄 You got beat my friend!😊
@@gmcf6895 I just happened to be looking at the computer when the notification for the new video came up I'm really looking forward to this Raptor I think it's going to be an awesome airplane and now that he's got that heating problem worked out I'll tell you this diesel engine is going to be a thousand times more efficient then the old fashioned fuel to a cool models
@sir Newton: It has everything that I want in an airplane, and I wish Peter would hustle so that I can get mine!😁😊