I don't recall the name of the flying club at Biggin Hill (Sportair?) who operated Fournier RF 3s in the 70s. The hire cost was the engine by tachometer and the chock to chock airframe time by the hour. On one occasion someone hired one of these and learnt soaring very quickly and stayed aloft for over 6 hours having used the engine for less than half an hour. He was able to log 6+ hours P1 powered flight and was very unpopular with the club and the 5 people who never got to fly the aircraft that day. I forget the aftermath but I think the CAA put a stop to this practice. Bitches. On a different matter, I think there were a few English Electric Lightning pilots who were able to get automatic multi engines stamped on their UK civil PPL licence until some spoil-sport advised the CAA that the Lightning engines were one above the other and not side by side. Bitches.