# Aileron deflection with stick movements

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Hello,Can someone explain me how the aileron deflection varies with the yoke movements?In fact, I noticed that when the stick is moved at around 50% if its course, the aileron deflection is only 32% and it is not linear.Do you know where this is defined?(it looks like it is the same for all the aircrafts)Thanks,Eric

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Eric,I'm not able to reproduce that using any of the following:(A:AILERON RIGHT DEFLECTION PCT, percent)(A:YOKE X POSITION, percent)(A:AILERON POSITION, percent)All three read -99.999 (left) to 99.999 (right)Is it possible some scaling is is being applied to your JS inputs?--Jon

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Hello Jon,You're perfectly right, and you use the right variables:(A:AILERON RIGHT DEFLECTION PCT, percent)(A:YOKE X POSITION, percent)(A:AILERON POSITION, percent)On my system, they also show -99.99 to 99.99 for full deflection on the left or right. But try to look at the values when the joystick is moved halfway to the left. On my system, I get:- around 15% for YOKE X POSITION- around 50% for AILERON POSITION- around 32% for AILERON RIGHT DEFLECTIONPlease try it and let me know if you have the same values.Reading these values, I thought there was some kind of factor to transform the joystick movement (50%) into the aileron deflection (32%). This is what I am looking for.Thanks for your help !!Eric

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Hi Eric,I can't try it out right now, but do you apply a nullzone to these axis in the FS9 sensitivities menu ? (because that will probably cause non-lineairity).Regards, Rob Barendregt

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Rob,This is what I thought, but the null zone doesn't really impact these values. The only difference when you define a BIG null zone is that you need a bigger joystick movement to get the same values.Eric

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Hi Eric,This is what I read for the default Cessna 172:(A:AILERON POSITION, percent): 0(A:AILERON RIGHT DEFLECTION PCT, percent): 0(A:AILERON POSITION, percent): 50(A:AILERON RIGHT DEFLECTION PCT, percent): 37(A:AILERON POSITION, percent): 75(A:AILERON RIGHT DEFLECTION PCT, percent): 75(A:AILERON POSITION, percent): 99(A:AILERON RIGHT DEFLECTION PCT, percent): 116I don

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The nonlinearity is probably explained by the effects of applying table 342 in the airfile to the joystick input. There is also a factor in table 1101 (Cl_da) but that factor is applied to the roll moment, not the amount of deflection for a given control input.RegardsBob ScottATP IMEL Gulfstream II-III-IV-V L-300Santiago de Chile

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I'm sorry, I misinterpreted the question in my first reply, but I can also confirm non-linearity for my values (also different). I believe we're talking about Aileron deflection vs q (518). I think you'll also find elevator and rudder to be similarly non-linear.I didn't specifically test this, but it makes sense and brings up a good point: DON'T use POSITION and DEFLECTION interchangeably!--Jon

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Thanks to all for your answers.Jon, it looks like the table 518 is inteeresting, but do you know what is "q" ?Eric

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Eric, q = "Dynamic pressure" which is the second term in Bernoulli's equation. The first being static pressure.Static pressure + dynamic pressure "q" = total pressure which is measured by the pitot. The static pressure is then subtracted from the total pressure to leave q, which can then be used to find the velocity after calibration with density.q is calculated as 0.5 * density * Velocity^2. V = sqrt( 2*(Pt-Ps) / density)The deflection tables use "q" because it correlates with respect to density, and therefore represents the true aerodynamic forces acting on the surfaces.--Jon

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