Originally Posted by
Prangster
Theory of flight ACP had a page or two on glider aerodynamics and the met APC discussed thermal generation though I suspect the latter was included tongue in cheek given the MK 111 brick tendency, then again I recall and incident where a Corps Barge ended up being sucked into a cu nim handing the crew some sort of endurance record. Can anyone throw light on the incident ? Our CO was always wary of any latent thunder in the area and quick to call a halt if it looked to be heading our way.
Derek Piggott and Cadet Brian Whatley
Detling ran a series of week-long courses for gliding school instructors. The staff instructors there also visited all the week-end schools twice a year to spread the word. The number of pupils qualifying for their ‘A’ and ‘B’ certificate increased and the accident rate fell dramatically. To raise the School’s profile they entered two T-21 Sedbergh gliders in the 1953 National Championships, the justification being that it would be valuable experience for the ATC cadets they took with them to help rig and de-rig the gliders. The T-21 was a hopeless competition glider. Its slow, stately tight circles were good for gaining height in thermals but with a gliding angle of just 18:1 got it nowhere when trying to travel cross country.
Derek launched on a distance task one day when clouds were building rapidly. He soon found a good thermal which lifted him to the base of a large cloud building over Sheffield. The Sedbergh had only basic instruments - airspeed indicator, turn and slip indicator, variometer, to show rate of climb/descent and altimeter – there was no artificial horizon. Most pilots would avoid flying in cloud with such a limited panel. It is very easy for a turn to develop into a spiral dive. Derek was skilled enough to keep the Sedbergh circling in the rapidly lifting thermal and enjoyed a remarkable rate of climb. The cloud was building into a thunderstorm.
The altimeter wound past 10,000 ft. Alongside Derek sat Cadet Whalley. With nothing to do or see he was bored, getting colder and increasingly frightened. He kept asking to go down. Derek tried to keep him interested in the possibility of breaking a record – the gain of height in a two seater glider was becoming a possible achievement. Derek couldn’t remember what the figure was so he determined to extract the maximum from the cloud’s lift. Continuing the climb he encouraged Brian Whalley to keep awake and to breathe deeply to improve his oxygen intake. The occasional sharp elbow was needed from time to time. Eventually, the thermal became ragged and they could climb no higher. Derek straightened up to head downwind. They popped out of the side of the cu-nim at 17,000 ft. The record for this unlikely glider was firmly in the bag (without oxygen, without parachutes and improperly dressed). From such a height, even a Sedbergh can go a long way. They still had height to burn off when they reached the coast and landed in a field near Grimsby.