Gliding on the gravel plain east of Sharjah in the mid 60s, we could only launch to about 450ft due to lack of winch cable. We would wait for the approach of a dust devil and launch our Ka8 into it. They were visible to about 4000ft, but then continued up to 10-11000 ft. Soaring round the edge of the funnel looking down the hole in the centre gave me the only feeling of vertigo I've experienced flying. Good fun followed by suitably fortified deep sleep in the open back of a 3-tonner.