On Fri, 5 Sep 2003 16:01:59 +0100 James Turner <[EMAIL PROTECTED]> wrote:
- a similar elevator effect to that martin described, when deploying the flaps at high speeds
- very odd high pitch angle behavior ... I can't really describe it, alas. It seems like way too much lift is getting developed at high angles of attack, without a corresponding increase in drag to slow the aircraft.
The aerodynamics will only be as good as the coefficient data that is input. :-)
Essentially, the aircraft flies pretty well (if a bit twitchy) providing you stick to a 'good' flight regime, but handling deteriorates exponentially when I go even moderately beyond it. I'm aware that part of this may be running 'past the end of the data' in JSBsim, but other models do not seem to have these problems. Can this be alleviated by tuning the last data point for various coefficients, which I assume is what JSBsim extrapolates from?
IIRC, the JSBSim data tables are NOT extrapolated. If you fly in conditions outside envelopes for which there is data IN the tables, you will get the value for a coefficient that corresponds to the most xtreme data point available - but not outside the table (is that clear?). So, the advice is to make sure you have made your tables cover all of the regime you want it to cover - e.g. if your table has alpha as a lookup index, make sure it goes to 90 degrees.
Jon
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