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-   -   Stuck pedal FAA book text (https://www.pprune.org/rotorheads/554989-stuck-pedal-faa-book-text.html)

seneca2e 20th Jan 2015 14:22

Stuck pedal FAA book text
 
The FAA Helicopter Book says for a stuck right pedal that "once the helicopter has landed and is sliding to a stop aft cyclic will turn the nose to the right and forward cyclic will turn it to the left".

Do they have this right?

Of course the collective and throttle would be how most would be doing this but I was curious about them adding the above on cyclic use in this situation.

rugmuncher 20th Jan 2015 14:48

Depends which way your blades are turning.

(90 deg precession effect)

seneca2e 20th Jan 2015 23:31

FAA book is talking about USA counterclockwise rotation machines I believe.

Ascend Charlie 21st Jan 2015 00:18

If you are on the ground and skidding, aft cyclic will probably chop your tail off - which won't matter in this case, because your tail rotor is stuck. It might also lift you off the ground again and make you hit in a tail-low attitude and smack the fuselage back onto the ground. Not a desirable outcome.

Forward cyclic might tip you up on your nose. Leave it flat, use throttle and lever.

seneca2e 21st Jan 2015 12:14

I agree which is so puzzling about that being in the FAA book that students will read and ask about. Don't quite get that nor do I really see how the cyclic would effect the left right of the nose much even if you did manage to not cut the tail off or tip it on its nose!

Phoinix 21st Jan 2015 20:15

While sliding the cyclic left/right will cause the skids on left/right to have more friction and will help direction wise, the more the collective is lowered the less effect you will see. But cyclic fwd/aft - never heard of that effect before. Aft cyclic is no-go if you want to keep the tail on anyway.

seneca2e 22nd Jan 2015 03:28

I think it might just be an error in the FAA book.

NickLappos 22nd Jan 2015 11:50

Nice pickup, seneca2e. I think the effect is small, I think the FAA has it backwards, and I think Ascend Charlie is right, leave the fore and aft cyclic alone, your tail cone will thank you.

SimFlightTest 22nd Jan 2015 16:27

Perhaps it has something to do with changing skidding forces along the skids. The skids will have the ground reaction loads distributed about them in some asymmetric manner depending on the pitch, bank, and yaw moments they are counteracting. The aircraft will yaw if the aft portion of the left skid has a different frictional load on it compared to the aft portion of the right skid.


This would be similar to the reason why an inverted cup that is spinning and sliding across a table will also translate laterally.


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