On Sunday, December 11, 2016 at 3:15:02 AM UTC-7, Peter Whitehead wrote:
On Tuesday, 6 December 2016 14:15:05 UTC, Jock Proudfoot wrote:


Modern winches are powerful so the ground run is shorter, and it is this which allows greater height on launch (you are effectively lengthening the airfield compared to those with "anaemic winches"). The problem is the acceleration and reduction in time to sort out the problem with wing drop on the ground, and also a stall and wing drop (to inverted ) in the rotation (to climb).This can all happen too quickly for human responses. It kills "smart" people.

Please do read and digest (and disseminate) the following link from experts in the field, the BGA. This programme of "safe winching" has shown reduction (evidence based) in accidents and fatalities in this mode of launching..

https://www.bfgc.co.uk/Documents/Winching.pdf

Pete Whitehead

I read every new issue of the BGA safe winching and note a slow movement toward scientific rationality such as the deletion of the ridiculous graphic showing a glider pitching up due to acceleration.

There is NO time to "sort out problems" in the ground roll - the only option is to prevent them in the first place.

1. Balance the wing, not just level it.
2. Point the glider EXACTLY at the winch.
3. PRECISELY center all controls and don't wag the stick around in the roll..
4. Above all, don't force a pilot to wobble along during an extended ground roll while struggling to keep the wings level.

A normal winch acceleration is 19 knots per second (1G) which gets the glider to aileron control airspeed in less than a second and airborne in about two seconds. If rules 1 - 3 above are followed it's almost impossible to imagine a wing drop before the glider is airborne and out of danger.