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JSBSim: p-rad_sec vs p-aero-rad_sec

Good sims require good FDMs (the "thing" that makes an aircraft behave like an aircraft).

JSBSim: p-rad_sec vs p-aero-rad_sec

Postby Necolatis » Wed Nov 29, 2017 1:20 am

To my surprise there is a difference between:

p-rad_sec vs p-aero-rad_sec
r-rad_sec vs r-aero-rad_sec
q-rad_sec vs q-aero-rad_sec

Take an aircraft, sit on the runway, turn on some wind, and you will see them diverge at times, although they mostly follow each other.

So the -aero variant takes rotational wind into account and the other do not? I guess that cause the -aero seems more affected by winds.

I guess this means we should use the -aero in our aerodynamics and the opposite in our flight controls input (since such inputs is measured using gyros I think).

Am I correct on this?
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Re: JSBSim: p-rad_sec vs p-aero-rad_sec

Postby Thorsten » Wed Nov 29, 2017 7:10 am

That was my impression as well.
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Re: JSBSim: p-rad_sec vs p-aero-rad_sec

Postby Richard » Wed Nov 29, 2017 2:08 pm

p-rad_sec Retrieves a body frame angular velocity component relative to the ECEF frame.
p-aero-rad_sec is p-rad_sec with wind applied (still in the body axes).

So yes we I think we should be using the aero versions in the aerodynamics to take into account winds; and where these are measured in the aircraft we use the non aero version.
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Re: JSBSim: p-rad_sec vs p-aero-rad_sec

Postby Necolatis » Wed Nov 29, 2017 6:39 pm

cool, wiki updated.
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