The sales of engines in r/c car market is driven very much by the horsepower ratings published by the manufacturer . I know when I started out eons ago, the I remember asking the store owner, "Gimmie the fastest, most powerful engine you got!". And I'm pretty much sure that's how many still buy their engines.

By their nature 4 strokes can never bost the same hp figures as the 2 strokes, in addition 2 strokes are cheaper to build, have fewer moving parts, need less parts support etc.

I guess it boils down to this.... r/c car and boat people want hp/rpms which = 2 stroke screamer. Plane people need (notice I said 'need' vs' 'want) torque = thumpers.

Personally, I'm now way past sky high hp figures & I go for realism/novelty. I don't race competitively so this is usually not a problem. Right now, I'm at the stage that if I can squeeze a thumper in place of a 2 stroke, I'd do it!

So DP, if you do come up with a new reliable 4 stroke, I'd certainly be willing to buy one from you.