Geriaviator,
As A rigger (airframe trade) my knowledge of the fuel requirements of the Gypsy Major engine is a little limited. I do know that when I served on University Engineering Flight at Abingdon 77-79, all of our aircraft were fuelled from the same bowser, which contained 100LL. Oxford and London UAS with their Bulldogs, and 6 AEF with the Chipmunk all seemed to get along fine on the stuff. I can only assume that 6 AEFs chippies had the required mods. Now, a small diversion.
I was sent to RAF Topcliffe to help RN EFTS push through a backlog of students, due to the imminent arrival of HRH Prince Andrew. The only bonus was being able to claim fuel mileage back to Abingdon at weekends. In an attempt to help the meagre allowance, my car was "conveniently parked" to accept the ullage from the 100LL bowser on a Friday lunchtime. As the four of us from Abingdon had travelled together in my Triumph Herald Convertible, I was on a sure fire winner
On the third weekend, halfway home down the A1, the engine blew, big time, with something metal coming through the bonnet and just missing my mates in the back seats. I have no doubts now of the error of my ways, and hopefully the statute of limitations prevents my prosecution on the abuse of aviation fuel front. I never "borrowed" fuel from Aunty Betty again during my career, but I know a few gliding clubs who found a blend of Avtur and OM15 to run their winches.
Smudge
