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Old October 9th 13, 03:44 PM posted to rec.aviation.soaring
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Default Keep your hand off the release handle during aero tows!

Time for pogo sticks.

The idea of launching a glider by having someone run the wing originated with wooden gliders and quite low speeds for stall and aileron effectiveness. Those speeds have gradually crept up through the years, to the point that really nobody can run the wing of a modern glider, with waterballast, and anything less than 10 mph straight down the runway, to the point of aileron effectiveness. Mostly we hope that the wing runner lets go, with the aircraft in balanced position, and it picks up speed faster than one wing drops. That often isn't true.

For airtows the results are usually just some scraped gel coat; sometimes a collision with a runway light, and occasionally a ground loop. There have been accidents where wing down gliders hurt bystanders, the Tonopah 15 m nationals being the one I remember best.

Clearly, for winching, wing-down events are much more serious.

The answer: either retractable or disposable pogo sticks on the wingtips, or mid-wing. Something that keeps the wings level to 25 mph and then either drops off or retracts into the wing.

Reading the UK Nimbus 3 report, it would seem that a video link between winch driver and launch point would be a good idea, and quite cheap with current technology. It would cut a crucial second or so out of the abort-the-launch loop

John Cochrane