ORIGINAL: FNQFLYER
What I am looking to do is obtain the horse power of the early 1990's fourstrokes especially the 120s, so I can then compare that with what is available today in smaller engines.
The cowl I have to fit it in is 103mm long and 194 in diameter. (for a Marutaka / Royal Stinson Reliant). As an example the Saito 91 puts out 1.6hp I think and the Saito 82 puts out 1.5 hp (this would make it a suitable substitute, and most importantly it would fit in the cowl. and the new 120 puts out 2.2hp but it is to long to fit the cowl with the current f/wall position
I could set the engine back inside the fuselarge (as I would have to do with a FG20 or 125) but I am trying not to. The reason for all of this is is because the model is being built to scale F4C rules and if I can totally enclose the engine and exhaust inside the cowl I get a K bonus of 10 points
You might want to consider a RCV engine, either the inline gear reduced version so you can run larger more scale sized propellers or the CD version because of its low profile. The CD version has the same vertical height of a 2 stroke engine but it is a 4 stroke engine. The gear reduced version has the cylinder pointing forward making it ideal for those narrow cowled airplanes. I have two of their 58CD engines and I like them a lot. I am planning to stick them in a twin one of these days.