On Friday, June 28, 2013 11:50:30 AM UTC-6, wrote:

Furthermore excessive acceleration can cause some glider types to rotate too fast in that rate of rotation can increse the stall speed at this critical time.


This is waaay over rated. Pick any glider you think is vulnerable and I'm sure there's a video on the Internet of it being launched with less than a 2-second ground roll. Acceleration alone does not cause uncommanded pitch-up.

Is an inertial-couple induced pitch-up real? Yes. But it can't happen with a tailwheel in contact with the runway and the pilot can oppose it with down elevator above the 50 knots Vw-min. That leaves the 40 to 50 knot window lasting 1/2 second at 1G acceleration where a glider's natural rotational inertia about the pitch axis and it's aerodynamic stability will prevent excessive pitch-up.

What CAN go wrong is if the pilot gets impatient with a slow acceleration and pulls up in the window of vulnerability so the inertial couple combines with up elevator to produce an excessive pitch-up. There are dozens of videos showing UK pilots doing exactly that on YouTube. The cure is simple - teach pilot to hold the nose down and wait for Vw-min before allowing the glider to rotate into a climb.