Here's one to be going on with....

Automatic transmission fluid !

Looking at an email from my mate it appears he has used... straight 30 SAE mineral oil - avoid the multigrades with their additives. He also used commercial 2 stroke oil and reckons some people swear by automatic transmission fluid. He believes that one fuel manufacturer uses this for high stress engines such as those in ducted fan which have to run at about twice their design speed to produce effective power.

Anyone got any auto transmission fluid to hand that they can try in an etherless mix. ?
What is the viscosity of auto transmission oil like compared to ordinary engine oil ?

I have left a series of questions which I hope he will answer which might be of some use.

The caveat is.... he only ran his mixes in control line models with venturi instead of RC carb. His choice of oils may well have worked with an engine running flat out but will they work with one which needs to be throttled and is capable of good idling ?

Anyone got any comments/ideas about the use of automatic transmission fluid ? I know it is often recommended as an afterrun oil.

Reg