Hi all,

Thanks for your replies.

The a/c in question is:
http://www.bharat-rakshak.com/IAF/Im...nt/Deepak.html

The wingdrop problem has been solved (some years back). Just learnt
that all the engineers did was to replace the counter-sunk flat top
rivets on the wing-top (holding the skin to the ribs) were replaced by
protruding pan-head rivets, which apparently energised the flow (made
it more turbulent?). There were rivets all over the wing, but more
towards the wing-root side. This solved the wing drop problem i.e. the
wing drop while stalling was then gentle enough to be handled by
novice pilots. I still am not completely satisfied with the turbulence
explaination... why should a more "energised" flow make the wing drop
less violent?

One character who worked on this kite several years ago said that the
stall actually started mid-wing, and progressed very quickly, so that
one wing (entire wing, not just the tip or root) stalled and dropped.
Dunno if he was farting or not.

Has anybody used the protruding rivet approach before to solve wing
aerodynamic problems before? Quite a minimalist solution!

Drake Lars