I dont know where you got the idea that rotaries are more fuel efficient. Lycosaurs/Continentals typically have BSFCs in the low .40s. The commonly accepted number for a rotary is about .50. Some here seem to do better, others worse.

 

Mike;

 

I’m not disagreeing with the points in your message; but I am wondering if you know anybody actually flying a Lyc/Cont and achieving BSFC in the low 40’s.  I see numbers like .43 or .45 bandied about, but I guess no one leans enough when flying to get that for fear of burning out a valve – or worse.  I’ve yet to hear from anyone flying a Velocity like mine with a Lyc who can surpass the speed/fuel burn that I get with the 20B. I don’t know why – it surprised me; but there it is.

 

I think in the real world operation the BSFCs are comparable.  I may have a bit lower drag because of smaller cowl; or other factors.

 

Al