16th Aug 2012, 02:51
I'm currently working on KC-130 flight simulator(Training device). The trainer has problems with pitch when flaps are extended. As the flaps are extended past 50% the aircraft does not pitch down but pitches up! I been looking at the equations computing CL and see no problems 1) what flight tests could be used to identify the issues. 2) because this is a mathematically determined flight i could diddle with the equations for lift, drag etc but I'd like to diddle equations that ought to have some bearing n the problem.
comments will be gratefully received.
19th Aug 2012, 21:02
I assume you have a simulator data pack from Lockheed for the KC130?
From what you describe the wing body pitch moment of the flaps has been missed off (usually this is nose down but it could have the wrong sign). There should also be an increase to the downwash at the tail which would give a nose up pitching moment so that is likely to be there.
Cross check your sim's tail plane angle to trim versus flight speed for flaps up and flap settings with flight test data.
You don't say whether this is an old issue or a new problem. If you have an original MQTG I would check whether the original Flap Dynamics tests were OK. If yes, then someone has introduced the problem. Hopefully reviewing previous QTG results should allow you to at least determine when the problem was introduced.