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Tilt rotor in JSBSim?

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

Tilt rotor in JSBSim?

Postby skytracker » Thu Nov 01, 2018 10:16 pm

Is there a way to change propeller or rotor orientation at run time with JSBSim? I currently have a new aircraft FDM working with propellers, and I can test different orientations by modifying the <orient> section within the <thruster> definition in my JSBSim xml. But I'd like to be able to control that orientation in flight (like a V-22, for example), either directly from a pilot command or perhaps computed automatically with a nasal script based on other parameters.

Is there a way modify this <orient> section via the property tree? Do you know of any other aircraft examples I could look at that might do something similar? I know there's a V-22 FDM in YASim but I'd like to stick with JSBSim if possible. It seems like the YASim rotor model might have an allowance for tilt that JSBSim doesn't.

Any other ideas on how to achieve this? Thanks!
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Re: Tilt rotor in JSBSim?

Postby Necolatis » Thu Nov 01, 2018 10:55 pm

fdm/jsbsim/propulsion/engine[0]/pitch-angle-rad

same for yaw
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Re: Tilt rotor in JSBSim?

Postby skytracker » Fri Nov 02, 2018 12:29 am

Okay great, I should have seen that! It does appear that the pitch specified in <orient> of the <thruster> matches what shows up for pitch-angle-rad in the property tree, and changing that at run time does affect the propulsion.

There's also a separate <orient> section in the <engine> parent of the thruster. Changing this orientation does not, however, affect pitch-angle-rad (which I might have expected given the name in the tree). What effect does the engine orientation have, and is it connected in any way to the thruster orientation?

Thanks.
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Re: Tilt rotor in JSBSim?

Postby Necolatis » Fri Nov 02, 2018 6:16 pm

I am not sure, but I think the engine orientation is only for piston engine gyroscopic effect.
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