Hi all -
I have the older Fox 35 stunt and attached an Aero Products tongue muffler with a 10x6 prop. The engine quits early and I'm believing it's getting a bit too hot.
Yes, I have to use a muffler - field rules.
Yes, I'm running 5% nitro, 29% all castor fuel.
I saw posts recommending dropping to a prop with lower lower loading like a 9x6, so I can try that.
Next I measured exhaust areas.
The stack on the Fox has 0.246 sq in of total open-face exhaust area. Granted, that's much larger than the actual exhaust area right where the piston actually opens up into the stack, but it's what I measured.
The Aero Products tongue muffler has 14 holes at 0.076" diameter (#48 drill just fits). That's only about 0.064 sq" of area, which is only 25% of the open face of the stack.
Whaddayallthink?
Drill out another 14 holes?
I suppose I could drill out enough holes to equal the area of the engines stack, but then it would just "look" like a muffler full of tons of holes.