Not sure if this one has been talked about. Anyone thinking about try one of these in a pattern ship?
Hobby King has 9cc gas engine and Fox has a converted .50 for gas use also. I just thought I would
throw this out for your points of view on these type of small gassers and their possible classic
pattern use.

Ron

I visited the engine forum and the evolution 60GX is equivelent to a 40 sized nitro engine.

A tuned exhaust should significately boost performance but not enough for a 60 sized Classic Pattern Plane. I imagine a .90 (15cc) sized  engine would be the ticket for Classic Pattern.

The new Os 95AX converted to gas would fit perfect. I've thought about buying the Evolution 60GX conrod just to see if it could be used on another engine.

Bryan

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Aren't today's 40 engines comparable to yesterday's 60s? It might fly a smaller '70s pattern ship, authentically that is..

I decided to do some comparison shopping.

Evolution 10cc gas engine: $199.99
Hobby King 9cc gas engine: $127.99
Fox .50 gas engine: $275.00

What they mean by that is today's 40's can probably spin a bigger prop at lower rpm than what the old 60's could which is great if you want to fly around at 30-40mph, hang on the prop and do 3d stuff, but the 1000ft loop at 70-80mph still needs cubic inches (you need at least a 500ft loop to do a proper cuban 8)....

There are a few YouTube video reports (flight and rpm) on the engine. Pipe use would be almost a must by today standards for pattern use.
I read a few of the post in the engine forum. Somewhere near the beginning of the thread there was talk about plug life. I hope this has
improved as it could take a beating with pipe use.

I think there's more to it than that. I've heard that the physical size of engines changed at some point. The old 60 became the new 40. The new 60 became a larger size altogether.

I'm not so sure about that or it was a really long time ago (back before the 70's).

I'd bet a good .46-.55 sized motor in a lightly built Kaos or something like that today would offer great performance over the older heavier (due to radio equipment and vibration resistance) Kaos' with something like a MAX .60RC, but I doubt any general muffled .46-.55 would hold much of a candle to the piped and pumped .61's in the 8.5-9lb rocket ships that followed.

Now if somebody wants to build a 5.5lb unsheeted wing, taildragger Curare, and fit a .55AX and 12x6 prop I'm sure it'll bounce off the ground like a scalded cat and have unlimited vertical but it's like putting a motorcycle engine in a paper mache Ferrari and boasting about the staggering 0-30mph acceleration time....