They have a history of the Fox combat 35X and 36X engines here as written by Bill Ives:
http://www.clcombat.info/foxhistory.html
a Fox 36X instruction manual can be acquired here: http://www.rcgroups.com/forums/showa...p;d=1298465475
more Fox Engine manuals here too http://www.rcgroups.com/forums/showt...29&page=11
The props ranged from a 10x6 for stunt to a 9x7 for combat and a 8x8 for rat racing.
The fuel was Fox Missile Mist. Which was 24% nitromethane and 17% castor oil, the rest methanol and some special additives.
http://www.foxmanufacturing.com/inde...oducts_id=1488
I do not remember anyone running 50% nitro glow fuel in them at the time I was using mine many years ago. But maybe they did in some speed racing events.

I happen to still have several of the older model engines myself. I used them many years ago for CL combat at the time and also stunt flying too.


I even flew one where I glued a Kavan RC carb on it.



The engines had a venturi insert that you used for slow combat. This restricted the engine more but you didn't need to pressurize the fuel tank either.


You removed the intake venturi restrictor for fast combat or rat racing, and you then used pressure to force feed fuel into the engine.
Either crankcase pressure or a bladder tank was used then. The later Fox engines had a even more simplified needle spray bar for pressure tanks.