Back around 1977, a discount house had Fox stunt 35's for $12.95. I bought four and took up flying stunt. I lapped the piston and cylinder with DuPont white rubbing compound. Gave each one several rich runs on a 9 x 4, and went flying. Could not get the Fox NVA to be consistant so put in ST NVA's. I was somewhat serious for several years and put a bunch of flights on them. They all ran the same, but I ended up using one as the workhorse. I don't recall what fuel I ran, 10% nitro and probably all castor.

About three years ago I built a Herns Demon for Old Time Stunt. Put the workhorse Fox in it. It has several hundred flights on Sig Champion 10% nitro, 20% oil-half castor, half synthetic. I am running a stuffer backplate and a stock head. I took the hemihead off because the engine was too powerful. One could not ask for better compression. Usually one flip starts and runs the same every time. I'm running a Taipan 11 x 5 propeller, turning about 7,800 on the ground but noticably faster in the air. The engine sounds terrible, but the airplane trucks right along. It's on 62 ft lines and is a hair faster than I really like.