- Oct 18, 2003
- Saline Michigan
There a bunch of modes, so what would happen depends upon the failure that occurs. I do not feel like going through all of them, so let's get to consequences on this rear engine canard airplane:For those more knowledgeable than me, what is the likely scenario should the PSRU haul in flight? Just prop stoppage! Prop loss? If he sheds the prop and maybe a bit more hardware, will Raptor be controllable with a sudden CG shift?
- If the prop stops, it drags;
- If the prop windmills, it drags;
- If the prop departs the airplane, drag is low, and CG shifts forward slightly - ship is still stable, might have issue with lifting the nose for flare and landing;
- If the prop pieces hit anything, it can cause controllability problems;
- If the prop and prop bearing system and/or engine or all come loose but do not leave the airplane, the CG will shift slightly aft, potentially rendering the airplane unstable in pitch and/or yaw;
- If the prop and prop bearing system and/or engine or all come loose and leave the airplane, the CG aft will shift forward, the airplane will become very stable in pitch and yaw, may not be able to hold the nose up, may have compromised maneuverability and may not be able to slow down then flare for landing;
- If equipment carrying oil and/or fuel is damaged during any of these events, a fire becomes possible.
In short, just about all failure modes lead to a forced landing, some may adversely affect stability and/or control, some may force that landing to higher speeds and/or prevent flare for landing, and the plane may burn.
As to likely modes, the most likely is in several types. I can imagine:
- Isolator failing with a loss of drive to the prop;
- Belts failing in sequence with a loss of drive to the prop;
- Propshaft or crankshaft extension bending or breaking, stopping the prop;
- Propshaft or its bearing sets failing and the prop departing the airplane;
- Parts from disintegrating drive and or damaged systems make for oil and/or fuel spill and fire;
- Prop sheds a blade, then prop imbalance tears either the prop mount or the entire engine mount from the airplane;
- Loss of drive to the prop results in immediate engine over rev and broken crankcase, oil and fuel spill, and fire.