Raptor Aircraft

455 Bravo Uniform said:
I’m supposing he’s scared of an unrecoverable spin when stall testing. I don’t blame him. But that’s no excuse for not getting the data.

Can he complete the 40 hrs without following some regimented test program that includes stalls?
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I highly suspect he believes the 40 hours is the magic benchmark, even if he hasn't accomplished any part of a test program.
 
david.h said:
The real danger of a canard stall is getting in a deep stall where the main wing is stalled also. I think 3 velocities have done this, two survived (one in water) and the Raytheon guy didn't make.it.
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Yes, testing new aircraft designs is dangerous. If you can't stand the heat, stay out of the kitchen.

If you get into a deep stall, either you didn't set the canard or wing incidence properly or your CG is too far aft. But stall speed of the canard has to be tested. So either strap on a parachute (or maybe install the one that is supposed to be on the plane) or put some weight on a sled in the cabin so you can break the deep stall if it happens.
 
Omalley1537 said:
If so, it’s a testament to Audi’s durability as opposed to any victory by this guy...
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Brand has nothing to do with what I'm talking about, engines in general are far more durable than people give them credit for. In the engine test lab in which I work we routinely see temperatures like what is being reported here and we sustain them for long periods of time. Is it ideal? No, nor would I accept them for a final solution. But, as we've already seen, the engine will not expire immediately like some here have believed will happen.
 
I think part of it is because we are used to babying our aircraft engines at low RPM and relatively low operating temperatures.. and we still have people who need major work done only 1,000 hrs in and almost daily threads trying to diagnose a weird vibration or other anomaly

Contrast that to somebody routinely running an engine at 4,000 RPM with temperatures well outside of what we would consider normal.. so far outside of cooling issues that engine has been a stable platform

**I don't believe Peter's engine will grenade itself and I don't think he will crash.. I think he is ultimately going to end up with a poorly constructed and underperforming airplane of which he's run out of ways to improve. Thete will be a nice novelty to it and someday maybe somebody can work out the kinks with it but just watching the Wasabi video seeing how portions of the plane are already delaminating and how Mickey Mouse his flight control rigging is it honestly seems like this aircraft could benefit from a complete rework

Anybody with a few hundred bucks to spare and a Home Depot within driving distance can build a small boat.. but it takes special skill and talent to build a beautiful lapstrake canoe
 
That VAG (Volkswagen) engine is plenty tough and can easily take excessive boost and temperatures, as proven in many high performance marine and off-road applications.

The one in my car runs at 210 degrees with four radiators and is making more power and torque that the best guesses from the Raptor version.

The one wearout item that might be worthy of concern is the high pressure pump. They don't like dirty or improper spec oil...
 
kyleb said:
I'll put the over/under at 20 hours. That includes the PSRU.
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I'm considering it. What are your constraints? What constitutes 'an hour'...RPM? Ground runs? Min/max temps? How much are you in? And what happens at 20 hours? Grenade? Oil/coolant change?

Nauga,
and analysis by proxy
 
Tantalum said:
Anybody with a few hundred bucks to spare and a Home Depot within driving distance can build a small boat.. but it takes special skill and talent to build a beautiful lapstrake canoe
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...and it takes no talent at all to sit in the Home Depot parking lot and tell your friends both of them are doing it all wrong.

Nauga,
who knows some of what he doesn't know
 
nauga said:
I'm considering it. What are your constraints? What constitutes 'an hour'...RPM? Ground runs? Min/max temps? How much are you in? And what happens at 20 hours? Grenade? Oil/coolant change?

Nauga,
and analysis by proxy
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The pay-off is a beer at SOS Brothers (but if you're there, first round is on me anyway). I will pay for the beer bong delivery method if you choose to go that direction. The over/under is based on flight hours. The deciding event is that something aft of the firewall fails (a failure that would leave him dead-stick or soon to be dead-stick) or has a pending failure that is (hopefully) caught in a post-flight inspection.
 
david.h said:
:) @donjohnston totally agree. Incidence, CG, and airfoil are how a canard is safer than stalling a traditional planform.
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"Safer" is relative. The traditional canard stall will just drop the nose but it will happen at a higher airspeed than a conventional wing/tail configuration with all other things (area, airfoil, weight, etc) being equal, since the wing can't get to maximum lift coefficient on the canard configuration. If you (AKA 'the manufacturer') define stall as the AOA the canard configured airplane reaches when the canard stalls then the conventional configuration won't drop a wing or anything you might think of as 'unsafe' either.

Nauga,
hanging on the blades
 
kyleb said:
The pay-off is a beer at SOS Brothers (but if you're there, first round is on me anyway). I will pay for the beer bong delivery method if you choose to go that direction. The over/under is based on flight hours. The deciding event is that something aft of the firewall fails (a failure that would leave him dead-stick or soon to be dead-stick) or has a pending failure that is (hopefully) caught in a post-flight inspection.
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I can't think of a single new design auto conversion where I'd feel safe taking that bet...but since I'm the one that called you on it I'll take it. :D

Who's keeping time?

Nauga,
who needs a riverboat
 
kyleb said:
The deciding event is that something aft of the firewall fails (a failure that would leave him dead-stick or soon to be dead-stick)...
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Just curious...

...at what point in test flying is power-off gliding performance tested? Logic would have it fairly early on, for obvious reasons. A further assumption might be that in a pusher configuration there’s less aerodynamic effect when the fan stops. Correct?
 
Salty said:
Another flight in the pattern https://flightaware.com/live/flight/N352TD
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44 minutes, a record! Look at the speed, I'm assuming he's still flying it with the power pulled way way back, probably 55% or less, to keep the heat down. At this point I'd want to get up to altitude to either at least test the cruise speed or do some flight envelope testing. Not sure what spending 45 minutes at pattern altitude flying circles at low power accomplishes in a flight test program other than the pilot's endurance.
 
midwestpa24 said:
44 minutes, a record! Look at the speed, I'm assuming he's still flying it with the power pulled way way back, probably 55% or less, to keep the heat down. At this point I'd want to get up to altitude to either at least test the cruise speed or do some flight envelope testing. Not sure what spending 45 minutes at pattern altitude flying circles at low power accomplishes in a flight test program other than the pilot's endurance.
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Depends on whether he could get the landing gear back down, I suppose, lol.
 
Did someone make a side bet with Peter as to the date that @nauga and @kyleb know the outcome of their bet?
 
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midwestpa24 said:
44 minutes, a record! Look at the speed, I'm assuming he's still flying it with the power pulled way way back, probably 55% or less, to keep the heat down. At this point I'd want to get up to altitude to either at least test the cruise speed or do some flight envelope testing. Not sure what spending 45 minutes at pattern altitude flying circles at low power accomplishes in a flight test program other than the pilot's endurance.
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I'm not a homebuilder or engineer, but some of you are :)

If we assume he's using 55% power and the GPS track shows something in the 130-145 MPH range (roughly trying to average the upwind and downwind legs via FlightAware's observations, which jumped around quite a bit), and we assume the engine can sustain say 75% power without self-immolating (big assumption, I know), can we extrapolate that out to a reasonable guess at the high cruise speed at say 10,000 feet? 15,000? 20,000? It seems unlikely to me that it'll be anywhere near the original predictions, but I'm curious as to just how near this is looking so far.

If it's easier, maybe we could run that in in reverse - what *should* this be cruising at with 55% power at 2,000 feet if it were going to perform in high cruise as he originally predicted?
 
Today's flight brings him up to 2.2 hours going by Flight Aware's numbers. Not the most accurate, but close enough for a beer bet.
 
FastEddieB said:
Just curious...

...at what point in test flying is power-off gliding performance tested? Logic would have it fairly early on, for obvious reasons. A further assumption might be that in a pusher configuration there’s less aerodynamic effect when the fan stops. Correct?
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Yes. I did mine pretty early in Phase I. But... It does require enough altitude so you can get some good consistent numbers. I did mine starting around 5-6,000'. I don't think that airplane could get up that high before the engine started glowing red.
 
FastEddieB said:
Just curious...

...at what point in test flying is power-off gliding performance tested? Logic would have it fairly early on, for obvious reasons. A further assumption might be that in a pusher configuration there’s less aerodynamic effect when the fan stops. Correct?
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With this guy, probably never...after all, he apparently doesn’t even think stall-testing is necessary...SMH
 
Omalley1537 said:
With this guy, probably never...after all, he apparently doesn’t even think stall-testing is necessary...SMH
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I agree that stall testing is absolutely necessary, and in that (or any new design) airplane I wouldn't do it on a dare without a parachute -- for me, not the airplane -- and a lot of altitude, and a very good way to exit the airplane if I felt a compelling need to do so. I might stall test an RV or something that has well known flight characteristics, but something like this... oh, hell no. If I ever do finish the biplane I'm building, it will get stall tested. That will be done either by someone way more experienced at the controls, or if I do it it will be about as high as I can get it, and you can bet your sweet bippy I'll have a chute on. I can't imagine test flying something new like that thing without a good exit strategy.
 
Tantalum said:
**I don't believe Peter's engine will grenade itself and I don't think he will crash.. I think he is ultimately going to end up with a poorly constructed and underperforming airplane of which he's run out of ways to improve. ...honestly seems like this aircraft could benefit from a complete rework
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We're on the same wavelength. Many successful aircraft have gone through more than 1 prototype to arrive at a stable, well performing, & manufacturable platform. Especially without the benefit of sophisticated computer aided modeling and simulation.

Peter is on both on learning curve of his own and developmental curve for the program. Kinesthetic learning by doing is a common American approach, but much lower probably of successful outcome on a first attempt when learning by doing. We are watching a guy get a blue collar aeronautics degree in the process.

Probably with great certainty we can speculate Peter would make many design & assembly changes with the knowledge learned, which could be rolled forward into a new and likely necessary 2nd prototype.
 
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nauga said:
...and it takes no talent at all to sit in the Home Depot parking lot and tell your friends both of them are doing it all wrong.
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I got no dog in this hunt (neither interested in the class of airplane involved, or possessing qualifications that allow me to analyze knowledgeably), but have to say the evolution of the comments in this thread have been interesting...

"He'll never get it off the ground!"
"It was just a little crow-hop, doesn't mean anything!"
"He just flew around the pattern to an emergency landing!"
"He's just flying around the airport!"
"He's just flying off the forty hours!"

It's like there's an oom-pah band warming up, getting ready to play the Schadenfreude Polka....

Gotta lot of respect for Kyle, Nauga, and Marc Z on HBA, though.

Was reminded of the Raptor controversy the other day. I've been spending the joyous holiday season in my usual way, doing an in-depth review of the previous year's homebuilt accidents. Came across ERA19FA134.

"The pilot, who was also the owner/designer/builder of the experimental amateur-built airplane, had no recent flight experience and a medical certificate that had expired about 20 years before the accident flight. Despite assurances to his employees that he would not fly the airplane on what was its second test flight, video from inside the accident airplane showed that the pilot departed on the accident flight and the airplane immediately displayed rapid divergences in both the pitch and roll axis that were demonstrated on the airplane's first test flight. The airplane remained at treetop height throughout the upwind leg and into the crosswind turn and reached about 200 ft above ground level in level flight on the downwind leg.

"As the airplane accelerated, rapid pitch oscillations (phugoid) were exhibited. A handheld radio secured to the copilot's seat shoulder harness and the pilot himself were seen to "float" in the cockpit each time the airplane pitched nose down as the amplitude of the phugoid progressively increased, the duration of weightlessness displayed each time also increased. During one phugoid, an audible "oil pressure" warning was heard. The video ended abruptly as the pilot became unseated for about the fourth time and as the airplane appeared near treetop height. The airplane then impacted
terrain.

"The pilot had no experience in the accident airplane, which was the prototype for an airplane he intended to mass produce. A test pilot had completed the airplane's first flight in the traffic pattern. He described significant stability issues, which were captured by onboard video, and said the airplane departed controlled flight uncommanded about a dozen times. After the test pilot was able to safely land the airplane, it was disassembled, returned to the factory, modified according to the accident pilot's specifications based on captured data and the test pilot's observations, and then brought back to the departure airport for taxi testing the day before the accident...."

(ERA19FA134, March 23, 2019)

PM seems to be doing MUCH better than this guy....

Ron Wanttaja
 
DaleB said:
PM seems to be doing MUCH better than this guy....

Ron Wanttaja
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That was a bad deal. I happened to be at the airport just before the accident. Luckily my son and I left before the crash. Neither of us needed to see that.
 
wanttaja said:
PM seems to be doing MUCH better than this guy....
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Perhaps, but I also think PM should heed a sadly prescient statement from this 2018 interview with Hogan (at 2:24) and consider the resulting aftermath of not heeding it.


"As soon as everyone feels comfortable then we'll get it into the air. The one thing we won't rush is flight test."
 
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wanttaja said:
PM seems to be doing MUCH better than this guy....

Ron Wanttaja
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He is doing much better, but I suspect that is more luck than ability or skill. He also hired test pilots then dismissed them when he didn't like their answers. He was just lucky the airplane has some level of stability or he would have been in the same smoking hole. Even now the Raptor seems to show some instability on every flight that he always blames on the less than 5 knots of wind.
 
New video. Mysterious oil leak. Wrap some paper towels around it, zip tie in place, go flying. Figure it out later. Seems about right.
 
I swear, if he had a light bulb burn out, instead of replacing the bulb he'd rig up some complicated rig of mirrors to reflect and focus the sunlight.
 
231TC said:
New video. Mysterious oil leak. Wrap some paper towels around it, zip tie in place, go flying. Figure it out later. Seems about right.
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Yeah, what could go wrong with a wad of oil soaked paper towels near all of those hot items like a turbo and the exhaust system.
 
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