I am fascinated with the simplicity of the Wankel engine, and its
capabilities
far exceed what I really need.  I am building a Bearhawk Patrol, and an
O-360
would probably exceed my performance needs. A Lycoming install would be
rather painless, but the cost involved in either buying a Lycoming or
building one seems a bit beyond reasonable.

The simplicity of the Mazda engine is one of its most attractive features,
and
the ease to rebuild one is an added attraction. So I am at least willing to
consider Mazda power.

Let's say I am looking for 200HP at the maximum. Also want to limit weight
and
noise levels to that of a 360.  Would also want fuel consumption to be
somewhere in the range of the O-360 at cruise power.

So I would like an opinion. Should I consider a rotary option.?
If so...could I get by with a carburated engine? What port option(s) would
be
recommend? I want to keep-it-simple.

In spending the last week or two reading the group's posts, I have been very
impressed with the engineering capabilities of the various builders when
dealing with intakes, exhausts, mounts, etc.  But the cooling systems all
too
often look like kludge-jobs in the photos; take a basic engine with nearly
the geometric simplicity of a basket ball, add a gearbox, fuel system,
exhaust, pipes, hoses, cables, wires, and a radiator or two off a '55 Chevy
and try fit it under the cowl of an RV4.  Has anyone ever tried to create
custom radiator(s) that are shaped to conform with space, curvature, and
airflow requirements of the typical experimental aircraft? I somehow suspect
that it might be time well spent.

Robin Berglund

The p-port is the simplest way to go. 200 HP with a Holley 500CFM carb is no
problem.
No custom rads needed. Any number of auto rads will work with a properly
designed scoop and duct. I have a book called "How to Cool Your Wankel"
you can buy at AC Spruce or Mazdatrix.

Paul Lamar



I agree Paul..  I like the Holley - saves a few hundred dollars..  I
also think that a large Ellison, Rotec or even a Marvel-Schebler might
be a reasonably good value which would make gravity feed fuel a
reality for certain high wing airframes.  On a high wing airplane if
you could eliminate the need for a fuel pump and the associated
redundancy and plumbing, the cost of a low pressure TBI or updraft
carb might be a wash.

And I would add that the RV-4 cowl is a fairly tight fit for a
Lycoming O-360.  It fits because the cowl shape (and the rest of the
airframe) was designed around a 4 cylinder Lycoming.  Coming up with a
different cowl shape for the rotary seems like a good idea.  Maybe
cheek cooling exhausts like the Thorp T-18 has would be a good
adaptation for a rotary engine.

http://futurshox.net/aeroimagestamp-logo.php?dir=planes6&filename=aa-thorpe-gblit.jpg


Matt-