Kenley 67
Yes, you are right POBJOY. George Nunn was an engineer and did not trust transistors and thermistors and stuff like that, so his mechanical system used windscreen wiper motors to drive a wheel with raised cams which operated microswitches, hence the need to have fully charged batteries. The control lever for his system was a joy to behold!!
When I introduced my little grey box he would only allow me to install it in parallel to his system and run it for a month's trial.......
He reluctantly agreed that transistors were the way forward........and a year later we were supplied with an "official" system from CGS, as they too had been experimenting along these lines.
Note to myself....must post another picture of gliding as we knew it!!