Are there any clubs using ducted fans in combat?
Are ther any rules prohibiting more modern jet type designs?
Thanx

For sanctioned combat here in the US, the scale planes must have been designed or in service between 1939 and 1955. I suppose you could make a ducted-fan P-80 or F-86, but it wouldn't be very competitive for the way we fly. Combat's all about quick acceleration and tight turns. We also use the propeller to cut the streamers, in addition to the wing.

If you're not flying in sanctioned contests, the rules are what you make them. You could have an all-jet class if you wanted.

Frankly, I don't know how well the powerplant would hold up. You never see scale turbine/jet/ducted-fan powered planes doing snaps and spins because the powerplants can't withstand the high-G loadings. They'll flex a little, and the impeller will hit the side of the duct. Ouch! I can't imagine the kind of internal damage that would be done in the inevitable midair collision. With standard propeller-based stuff, the prop absorbs most of the damage when it breaks, and engines are rarely damaged compared to the number of midairs.

If your talking about impeller strength, well, you're right some impellers aren't that strong. However there are ways to reduce the G stress.

-One is to make the fuselage's inner diameter match exactly the outer diameter of the Ducted Fan's case
-Another possible idea is to use a more efficient and balanced motor like a hacker and such
-You could also possibly make the impeller mount stronger somehow