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.
You know you’ve made it big, when RU-vid places this many ads which are un- clickable to stop, on your videos. Congratulations, Peter. You deserve everything you’ve got coming to you.
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.
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. 👍
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!
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!
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!
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 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!
Nicely done Peter! Satisfying improvements all around! As I’ve said before progress has proven your approach( pun intended), keep posting & happy landings!
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.
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.
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!
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.
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.
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.
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.
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
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!
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!
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
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?
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
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.
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!
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 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...
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.
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 👍
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??
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
