I was at 'Malvern' hills flying off the top of the beacon some years ago on a lovely sunny day, blue sky again with no clouds.
My model was doing well even though there was little wind. I was with a few pals and my Boss from work who had his Orange Box with him. Because I was quite up high by now after 20 mins or so, I offered it to my boss to flyand He took over for the next 20 mins then suddenly a loud bang. My 6ft glider had just exploded into a whirling mass. What could have happened. Someone said "CAT" but all we said "What is CAT". It turns out that its invisible and it is 'Clear Air Turbulance'. I think my plane was about 1000ft up and all we saw was it started turnig to the right by its self but upon trying to correct that the turn, it just over stressed it.
A sequal to this is that I ran down the hill to see a motorcar drive off from where my glider had gone into some bushes. Because my name and address was on it , a couple of days later a chap came to my door with his son and said "we found this at Malvern hills and my son has tried throwing it about but it won't fly. Can we collect the reward". Well no wonder, it was already broken up, just hanging together by the covering. But at least I got the radio back., Robin Andrew,UK