RE: FOX 50 runs HOT
Well, the only Fox I owned was the 50 and I had two of them. They ran like dreams pulling nicely with a 3 blade 10x7.5 prop. I flew them on Sig Kougars with tuned pipes. I was no master tuner back then (or now really) but had no trouble with them. Low nitro, average plug heat in the palm springs desert.
They were great; I would buy another if I hadn't moved on to mostly 4 strokes (though I am building another Kougar right now).