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Raptor Composite Aircraft

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lelievre12

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So we are giving Raptor a built-in advantage here, simply because that run from 20 to 79 knots is the only data we have. Here is that clip starting at 3:36.

So let's review what we found already in my previous analysis. Measuring from
20 knots to 79 knots groundspeed, as shown on his display, we found 22 seconds, which works out to an average thrust of just 478 lbf. Now let's give the Raptor the benefit of the doubt and call it 20 seconds. That pushes his average net thrust up to 526 lbf.
I agree 20 seconds is kind of long.

Here is a clip of me flying the old P210N in the Texas STOL comp.


I am taking off from grass and am in the air in about 10 seconds from a dead stop! The plane is light with 1POB and ~200# in fuel. I estimate around 3200# gross. I am 310HP takeoff power.

As its comp flying I am yanking the plane off the ground as soon as it can fly so Vr is probably only 55KIAS. Still 10 seconds is a long long way from 20 seconds and grass is harder than smooth asphalt.
 
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Wild Bill

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Vidalia, GA
Scary sight of the video: 50lb of loose ballast under the left seat! Why is loose ballast scary?
I noticed that too. Looked as if it had been just laying there. Surely it was secured by some method.
Or at least I hope.
Would like to see the ballast in the nose.
 

BBerson

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Question for Marc Zeitlin:
Could the canard incidence be adjusted with shims? I think raising the canard incidence for testing would improve the canard lift efficiency and reduce need for trim.
But I wouldn't suggest it without your thoughts since I don't know canards. My initial test flight was encumbered with excess elevator drag almost fully deflected.
I know you don't see a value in further flight test. But he may do it anyway.
 

rbarnes

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Where did he mention "dutch roll" in the video?
Dutch roll / "out of trim in the roll axis" ... potatoe / PotAtoe.
I think PM is blaming a dutch roll problem on a weight imbalance problem. ... I mean what kind of plane cant fly level without 100lbs of "ballast" in the passenger seat.
 

donjohnston

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Panama City, FL
Question for Marc Zeitlin:
Could the canard incidence be adjusted with shims? I think raising the canard incidence for testing would improve the canard lift efficiency and reduce need for trim.
But I wouldn't suggest it without your thoughts since I don't know canards. My initial test flight was encumbered with excess elevator drag almost fully deflected.
I know you don't see a value in further flight test. But he may do it anyway.
Not Mark, but on the Velocity the canard can't be shimmed to changed the incidence. We can shim the mains though. I don't know how the raptor has the canard attached so it's possible.

But I think that's the least of his problems.
 

TFF

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I think the weight answer is if the control circuit is soft on the ailerons, trim like the elevator is not effective. He is hoping it will help. Like any aircraft if you want it to fly straight down the runway, fly it down the runway. As much as trim is helpful, you have to move the controls and fly the airplane no matter what it does unexpected.
 

pictsidhe

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For lateral weight trim, a spring on the aileron circuit would work a whole lot better than tabs. It would be a lot more palatable to pilots to twist a knob than weight wingtips. Having seen Peter's spring 'design' technique, he's probably in no hurry to repeat it. Another alternative is weight the controls. That would also compensate for g loading. Both require an estimate of control effectiveness. Again, something well beyond Peter. A bar with a moveable weight would give a lot of adjustability and is likely the optimum for production if this widebody needs lateral trim.

I bet more than a few customers are getting put off by the constant kludges. He'd have been better off keeping quiet about it and just flying the aeroplane.

The blind loyalty of his fans is hard to believe.
 
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pictsidhe

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Current weight with Peter and ballast: 3493 lbs. Not sure how much fuel still on board when he made that measurement, but that's a lotta weight.

Bold move of him to let us see the scale (I never step on a scale with anybody else in viewing distance).
He clearly needs to back off on the sugar.
 
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