RE: EU-1A Engine Choice
The EU-1A nose is extremely tight when using a 61 rear exhaust - I believe the OS 140 would be out of the question especially considering the height of the exhaust port relative to the crankshaft centerline - would position the tuned pipe well above the fuse tunnel. Unfortunately, the plane was designed exclusively around the 61 rear exhaust engines. I believe Rossi still manufactures the 61 rear exhaust and is a real powerhouse - don't use more than 5% nitro - too much compression.