Pete,

I think that the K-80 is an inexpensive engine, but its performance is not at the top end. Its heavier and lower thrust than equivalent engines from other manufacturers.

The Rabbit is a better alternative, and personally, I'd look at the Merlin M-90. A friend has one and its really small and light, but has all of the 20 lbs of thrust that they claim. I think it would be great in the FEJ Rafale.

Bob