ORIGINAL: Bax
The Hanno isn't really a BPA-type of engine. It was designed to turn an APC 12 x 12 prop at about 9,600 RPM when on the pipe. The pipe was required because that's how the engine was ported. The Hanno was designed for the early type of turnaround pattern that replaced the old ballistic pattern.
Ballistic-types needed a high-revving engine to enable the speed.
For late-60's-style pattern, then you might be able to do OK with a Hanno, but, again, the pipe is a necessity for the Hanno's performance.
Bill,
it's hard for me to imagine any RE 2c 61 without a pipe. I suppose there are (were?) some mini-pipes of sorts that were essentially mufflers but without a pipe, a RE engine such as the Hanno is essentially a fireball spitter! I don't even want to think about about what would happen to the aircraft with a RE engine running without an exhaust system - not to mention the complaints from surrounding folk.
Maybe I've missed it over the years but aside from a pipe, is there any other option for a RE engine? (I actually recall that in the day the F1 guys used to run a thin straight header out the back of their K&B 6.5's. I actually have one of those but I might pass away before I run it... Unless you had ear protection, I remember that you had to be at least 50 yards away when those puppies were fired up!
David.