On Dec 31, 9:40*am, "Doug" wrote:
As an aerodynamicist/flight dynamicist recently re-soloed after 25 years
off, people keep asking me hard questions. *One that has come up recently is
why a heavy glider on tow feels horrible, but thermalling in the same glider
at lower speeds is fine? (see also Mike Fox's article on aerotowing in the
October issue of S&G).

I did some calculations, and I reckon it's probably due to the tug wing wake
(tip vortices generating a downwash inboard, upwash outboard) changing the
lift distribution on the glider wing - with an increased angle of attack out
at the tips reducing aileron effectiveness. *There's possibly an interesting
academic research project here, but it's always best to get a reality check
first ...

Is poor handling at low speed on tow a common experience? *I'd appreciate
any thoughts/comments/war stories ... particularly bad tug/glider/speed
combinations, incidents of wing drop during a tow etc etc?

Doug Greenwell

Sure, even more with flaps equipped ships! But yaw control seems to be
more affected than roll. Can we explain that?
Just a little faster please is what doctor ordered here...usually 5
mph more is enough to a more pleasant tow.