I'm setting up my Brodak Oriental (ARC), running a Brodak 40.  What is a good starting point for the prop.  Can the engine handle a 11x4.5 prop?

Best regards,

Brew

Yes  the   Cyclone TT  or   Yoshioka  Cyclone  11 x 4.5  is a good choice,  many people use these

Randy

Blocking off cooling to the cylinder head fins can help prevent "cold" running or seizing up during the early flight testing period. They often seize on the dives. Caused by sudden cooling after heating up during the climbs of the RWO, etc.  "Pipemaker Mike" made a nice "head muff" for his B.40 at my suggestion, and cured the stopping.

I didn't know what to expect after 20+ flights with the head muff, but it seemed to be a non-issue at some point. The key thing was keeping heat in the head, which protrudes down into the cylinder bore. When hot, this keep the cylinder round and helps loosen up the piston fit at the top of the stroke. The tight head fit in the cylinder is an old speed engine tuner trick, and resulted in banding stock heads, or making 2 piece "button heads".      Steve