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Reverse prop torque - 582 engine

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Posted

I've been curious how much the torque of the reverse-turning prop offsets engine torque. Do you have to use left pedal on takeoff? Might be hard to get used to.

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Posted

I've been curious how much the torque of the reverse-turning prop offsets engine torque. Do you have to use left pedal on takeoff? Might be hard to get used to.

During the 5 second takeoff rolls you won’t notice it. I don’t notice it on climb out either. These planes require more rudder period than spam cans.

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Posted

Engine torque is not a factor in yaw on airplanes, but many instructors use that term to get pilots to center the ball on initial climbout. The real factor that drives the ball out on takeoff and climbout is propeller P factor, which makes us use Left rudder on rotax Avids, and right rudder on most Cessnas.

Basically, when the aircraft is slow and operating at high angle of attack, the downsweeping prop blade has a higher angle of attack, and more thrust that the up sweeping blade, so the center of prop thrust moves to the left on an Avid, driving the nose right, and asking us to put more left pedal in.

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Posted

The P factor is definatly the noticeable but small difference.A slight variation on initial swing is evident but nothing that should be a problem.I have students that swap between a 582 and 912 without a problem.

If your 582 powered machine is light be prepared, as it will be flying before you may be ready.:bugeyes:

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Posted (edited)

I understand the theory of P factor, torque, gyroscopic precession, spiral propwash. All 4 cause a plane to pull to the left on takeoff. (Actually, precession makes a plane pull one way when the tail lifts and the other when the plane rotates). In a geared engine though, P factor and spiral propwash will be opposite the normal direction. But torque and gyroscopic precession will be offset by the prop turning opposite the crankshaft. I was just wondering what the net effect is. Guess I'll find out in a few months, with a little luck. Hope to be ready to cover by summer.

 

Edited by Shipl14
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Posted

Depends on the model of plane you have.  The early avids have the vertical stab offset a bit to compensate.  When the 912 came out the MK IV and some very late C models had the stab neutral.  At any rate, it is not as significant as say a 180 HP cub on the amount of rudder you have to hold in for TO.  At the end of the day, your feet a re programmed to do what is needed to point the nose in the correct direction so it is a non issue.

:BC:

 

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