Am at the stage in the building of a Sig 4 * 40 that I need to mount an engine to the firewall. I have two choices of engines. The first is an OS Max .46SF with Slimline Pitts muffler (the only muffler I have for this engine). Probably have to mount the engine horizontally if I go that way. The other engine is an Austrian built HP .40. Had one of these some years ago and it was an absolute screamer. This one has the original flow thru stock muffler with it. Any input from you guys on the pros and cons of each will be appreciated. Thanks in advance.
Max

I would try the hp due to the fact that it has the stock muffler & you will be able to mount it upright. If it dosent perform to your satisfaction you can get a stock muffler for the os & mount it upright also. I wouldn't mount the engine horizontal on a four*, its just not right.

Gil

If you do mount the O.S. horizontally, cowl in the engine like Tom Pierce did.
http://www.renderwurx.com/rc/sig4star/

John

Thank you Gil and John for your input. You have a point, Gil, one that I had considered also. I am not real sure how the 4* would look with an engine head sticking through the side of it. As for John's suggestion, I looked at the site and it has some very interesting ideas in it. Another option is FiberGlass Specialties told me some time ago that they were going to begin producing cowls for the 4 * 40. I'm like John in that I absolutely HATE those silly looking cheeks on the 4*. Looks like they just kind of ran out of ideas of what to do there. I built a Sig Astro Hog Bipe earlier this year and fit a cowl on it from FiberGlass Specialties and it improved the appearance of the aircraft immensely. Thanks again, guys.
Max