Author: "Dan Checkoway" <dan@...> Time: Sun Jan 13, 2002 10:52 pm PST Link
I bopped up to Flabob today for the Dynacam engine demo and the EAA BBQ.
Great time. Random meaningless pictures here:
http://www.rvproject.com:8000/images/flabob/
A couple RVs (one really beautiful RV-6A, other than that nosewheel), a few
other interesting planes, great folks, lots of chicken.
The Dynacam engine seems like it has possibilities. For those who aren't
familiar with it, it's a 12-cylinder engine. There are 6 pairs of
connected, outwardly opposing pistons. Basically 6 double-sided pistons.
They fire back and forth along the engine's longitudinal axis, which is
aligned with the aircraft's longitudinal axis (or vertical in a heli).
There is a large "cam wheel" centrally located on the drive shaft. This cam
"wobbles" back and forth, so to speak, pushing the piston pairs back and
forth. There are valves on each end of the engine.
Very interesting design. It's supposed to be a bit lighter than a
traditional 4-banger, and apparently it's smooth to boot. They claim 210
hp. Dammit...I left the brochure up there on the picnic table! Duh.
Well, anyway, my opinion (I know, you didn't ask) is that this engine ain't
for me. I'm not comfortable with the forces imparted on the cam wheel.
There are roller bearings all over this engine, and I don't like that. The
engine's redline is 2000 RPM, and cruise power setting is 1700 RPM. What
kind of prop can you swing at that speed? I don't know much about gear
reduction other than the fact that I don't want to mess with it. And I
don't know props well enough either. Somebody needs to tell me what would
be involved in properly thrusting an RV-7 with an engine only turning
1700-2000 RPM.
One more thing...the engine config Dynacam is using has dual carbs (not for
me), although they say there's a fuel injection system that produces
identical power. Hm.
I'd like to see how these engines perform over hundreds of thousands of
collective flight hours. They've got an Arrow flying with one of these
suckers right now. We'll see. Anyway, it was really interesting to see a
different design. Good food for thought.
Who wants to buy my Mooney? http://www.m20j.com:8000 I need to sell it so
I can buy the rest of my RV-7. Argh!
)_( Dan
dan@r...
http://www.rvproject.com:8000