Sorry, I forgot to add that there are a few types where holding the stick
hard forward to contain an over-rotation is not a good idea, as you can
stall the elevator/tailplane and make the situation even worse! These are
mostly gliders with all-flying tailplanes, such as the Standard Cirrus.

Again, all these unpleasantries can be avoided by just a slight moderation
of the ground run acceleration, if you have a powerful winch.

Derek C


At 13:00 20 March 2009, Derek Copeland wrote:
As I have tried to explain to Bill on numerous occasions, and on various
forums, the uncontrollable over-rotation you get from an over-powered
winch launch is caused by the pull line to the belly hook being below
the
glider's centre of gravity and centre of pressure. This causes a
rotation
for mechanical rather than aerodynamic control reasons. This is why high
winged gliders, such as the K6 and K8 are most at risk.

If you get such a launch, even holding the stick hard forward all the
time
from 'take up slack' will not prevent the over-rotation, although it
might slightly reduce your chances of instant death from a flick spin.

Such events can be easily avoided by by controlling the winch so that
the
ground run acceleration is not more than about 1.0g (or less for the
types
mentioned above). This will still get you airborne and climbing within
about 3-4 seconds, which most pilots find quite fast enough! It will
also
make very little difference to the achieved height.

Derek Copeland