Greg Arnold wrote:

Marc Ramsey wrote:



If these figures aren't available, is the use of CG hooks being
discouraged based simply on the assumed lack of positive longitudinal
stability during aerotow?



Is the pull on a CG hook during aerotow ever great enough to have much
effect on the longitudinal stability of the glider? I have never
noticed such an effect, so I wonder if pilots who fly from a winch (very
quick acceleration and doubtless a significant effect on longitudinal
stability) are unfairly extrapolating their experience there to the
aerotow situation.

Doubtless a nose hook is better for aerotow, but I wonder if the alleged
advantages aren't being oversold by some posters to this thread.


Following up on my own post -- during aerotow, acceleration is greatest
at the beginning of the takeoff run, where airspeed is low. By the
time that airspeed gets to the point where the glider can fly,
acceleration is minimal. So the pull on the tow line shouldn't have
much effect on longitudinal stability when the glider is near takeoff speed.

I am sure that a glider with a CG hook will be inclined to climb more
steeply once it has a high angle of attack -- this is due to the pivot
point being further aft on the glider. However, in the initial stages
of going to that high angle of attack, does it matter whether the glider
has a CG hook or a nose hook? It is that initial stage that causes
problems on aerotow. Once a glider achieves a high angle of attack, the
towplane is well past the point of no return.