dkavolis / Ferram-Aerospace-Research

Aerodynamics model for Kerbal Space Program
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Wings inside of fairings don't behave as if shielded from aero forces. #143

Open Akaliwolf opened 1 year ago

Akaliwolf commented 1 year ago

I've been having FAR trouble with a rocket in RO/RP-1 using Proceedural Wings/Fairings, and its aerophysics. Said rocket houses a small unmanned spaceplane within and a transfer stage intended to send it to mars. This payload is stored inside a fairing, and is not opened or exposed to atmosphere until above 40km above sea-level.

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When I have the wings, control surfaces, and such mounted, the center of aero forces ends up raised vertically by a significant amount despite the fairing, causing rocket instability and flipping in flight. Pictured below is the CoM versus Aero, and FAR transonic/stability numbers

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When one removes the wings (b9 procedural space-plane wings), aero surfaces, landing gear(dynasoar skids) or even the air brakes(stock airbrakes config for ro/rp-1), the editor aero markers and flight behavior changes—despite being in a fairing—to something more inline with what is expected. This can be recreated by putting a small plane in a fairing on a rocket using similar parts.

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Removing individual parts of the wings, surfaces, and so on also has a similar effect, suggesting all the aero surfaces are the culprit— or the fairing itself. Perhaps an interaction of the two?