On Mon, 07 Mar 2011 13:14:04 -0800, Eric Greenwell wrote:

On 3/7/2011 7:24 AM, Mike the Strike wrote:


We have discussed this many times before. The nose-up attitude of the
glider results in extra forces that have to be overcome by the wings
and tail surfaces. In particular, modern standard-class ships with a
low angle of incidence of the wing have a pronounced nose-up attitude
that results in loss of control at speeds well above free-flight stall
speed.

I'm having trouble picturing the influence of a low angle of incidence
of the wing (I assume that's compared to the fuselage) on loss of
control. Why would the wing be affected by the fuselage attitude being a
few degrees higher, relative to the air, than on an older glider?

I should add that there was plenty of speed - the Pawnee had its tail
well up. From where I was sitting its fuselage looked to be pretty much
horizontal. The Ventus looked to be well under control - it was flying
very steadily. I ascribed most of the glider's nose-high attitude to the
fact that it was flying in the downwash field behind the tug.

Don't forget that the downwash behind a lift generating wing is roughly
1/3 of the wing's AOA, so this was actually a great visualisation of the
downwash.


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