ORIGINAL: bgw45
I have a bunch of questions also. I would like to have a SPA legal plane. This might fit the bill for me since I don't want to build. The manual suggests an Evo .60NX. I'm thinking, since I can't use a pipe, that an OS .55 AX might be more reliable as far as throttle transition goes. Would it be legal? Would it be enough engine for the airframe. I know the OS 55 is about 2 oz. heavier than the Evo .60, but lighter than a .91 FS ( the only one I have in my stable is a Saito ).
Is anyone actually flying this airframe in SPA? What is your set-up and what would you do different?
For SPA, the OS55AX with the Jett muffler is a popular combination. Standard TT-40 jett-stream, and I think you need a 1/4 spacer to fit on the P-7. Lots of experience with this combination, 11x6 or 11x7 prop you will be amazed. Use the blue version available from Horizon if you wish, tuning is approximately the same. REALLY wakes up the engine.
The Evo 60 is a very good engine - always a good choice with the tuned muffler installed.
A handful of folks are flying the Jett SJ-56LX and SJ-60L in SPA aircraft. With good prop selection they work great in the older 1970's designs where the Webra 60 speed, webra 60 blackhead, ST bluehead 60, Lee K&B .61, HP61, older OS 60FSR were utilized - keep in mind these were smaller crank case engines so current design "small block 46 size" engines drop right in.
Careful evaluating the engine weights - be sure you get weights with and without the muffler.