Hello 603DX,
My source is "Slingsby Sailpanes" by Martin Simons,Airlife,1996 pages 62/63. To summize the rear edge of the plywood leading edge skin was attached indirectly to the wing spars. This was done on Cadets,Tutors and many other gliders. Between each pair of ribs a narrow packing strip of wood was cut and glued to the top and bottom flanges of the spar,planed and sanded level with the ribs. The plywood skin was wrapped over the leading-edge ribs and glued to them and also to the packing strips.
The packing pieces,ending abruptly at each rib station created an abrupt change of stiffness in the spar. When the wing flexed under load,concentrations of stress occurred in the spar at every rib. With long hard use(winching loads and heavy landings) the stress concentrations caused by the packing strips encouraged compression shakes which are difficult to detect. Once recognised modification schedules were issued ,Mod 80 circa 1962. I have no doubt that all ATC gliders were very well maintained to strict airworthiness requirements.
The small strut was to prevent vibration on aero-towing.
There must be many glider engineers or someone from the Vintage gliding scene who can elaborate further on this ?
Last edited by T-21; 17th Dec 2011 at 14:41.