On Wednesday 28 July 2004 01:45, Andy Ross wrote: > Jim Wilson wrote: > > Have I had this backwards all along? I knew of the incidence angle > > on the hstab, but always thought that positive values meant the > > leading edge was higher than with a negative incidence angle > > The number is a (conventional, right handed) rotation about the Y > axis, which in YASim's coordinate system points out the left wingtip. > So a positive incidence points down. Unless there's a sign bug (or > three, or five...) in there somewhere. > > And Lee's surprise was right: you *can't* map a control to "INCIDENCE" > in the control mapper. My head was ahead of the implementation. I've > definitely intended to do this (and maybe I've worked on it at some > point) but looking at CVS the code just ain't there. Sorry. > > Andy
Heh! - I'm still a bit confused:) I had a look at the dc3 update, where the incidence had been set on the hstab but when I tried using it, it made no difference to the solution, and I couldn't detect any change in the behaviour. I was sure that the hstab incidence was set by the solver (as the 'tail incidence') The incidence +- issue threw me as well - like the others, I've been using +ve incidence to angle the wing up at the leading edge. It does seem to work that way though... My 2p on the 'does lift suck or blow', just to stir it up a bit more, is that the Wrights found that the lift was not perpendicular to the wing/aerofoil axis but was angled forward (they attached spring balances to their kites and measured the force required to hold them, and found that this force was lower that they'd calculated). On more refined aerofoils most of the lift comes from the leading edge region, where the acceleration is highest, although some of the more recent 'super-critical' aerofoils produce lift further back. There again, while I'm reasonably up on physics, I'd only claim to understand about 2/3rds of what I read about aerodynamics. Curiously enough, I was only quite recently discussing bow-waves and drag in relation to sprint racing kayaks with someone:) LeeE _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
