Gentlemen,
I am considering in building a P-40 Warhawk that requires a .25 cu in engine.
Which manufacture and model number is considered a good .25 cubic inch engine that has the following characteristics:
light weight
steady running
effective muffler
light muffler
reasonable economical
Depends on how big a model we are talking about. As you know, all 25's are not alike and "25-sized airplane"s are not alike. I had an OS 25S baffle-piston motor on a Jr. Nobler and it wasn't unreasonable. Put a 25FP or a 25FSR on the same airplane and it's insanely overpowered and would be difficult to control. As far as I am concerned, a "25" could mean anything from a Shark 15 to a Green Box Nobler.
The choices available right now, new, are fairly limited - either a Brodak 25 or a OS 25LA. I haven't been very impressed with the power of the 25LA compared to either the 20 or 25FP, but it's pretty reliable once you seal up the backplate. I have no experience with the Brodak engine but Bob Reeves says its pretty good. I think both are pretty inexpensive and reasonably light, but you *want* the good muffler on the LA, and it's not outrageously heavy on an appropriately-sized airplane.
Brett