PPRuNe Forums - View Single Post - Is trim linear with speed?
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Old 2nd Apr 2021, 18:30
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Vessbot
 
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Rearranging the lift equation, CL varies by the inverse of the square of speed (or, speed varies by the inverse square root of CL), so no. There are further relationships to consider (CL to AOA, and AOA to stab angle) which, even if they are linear, there's already a square link in the way.

Put simply, as speed increases, every further knot is a smaller decrease of AOA. Conversely as AOA decreases, every next degree of AOA decrease, is a bigger speed gain. Or, as speed decreases, every next knot is a smaller AOA decrease. That's why on final in rough air, a ham fisted pilot can saw the yoke nearly from stop to stop and it's little more than an annoyance; while in cruise, that would rip the wings off.

Last edited by Vessbot; 2nd Apr 2021 at 18:52.
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