Ken Powell wrote:

Paul,
Mike and I are both planning to use a cowling like Steve Beckham used on
the Powersport RV-4.  This is a chin intake, not the annular intake that
Alan Tolle used.  A chin intake will have some prop blast for cooling
while in ground operations while the annular opening does not.  I am
playing with a mockup and am trying to fit a muffler next to the
footbox.  When I get a configuration that I like I would like to run it
by you guys to see what you think.  BTW, a side mounted alternator on a
RV-4 requires a larger cowl bump than an alternator in the stock
location.  I built the side mount brackets and tried it.  I don't have a
scanner or a digital camera or I would send pictures now.  As of now, I
have a radiator mockup of 15.75" x 27.5" x 2" (including tanks) and have
31" long exhaust pipes running to a muffler under the engine and next to
the footbox (down low).  I will have to shield the radiator and motor
mount tubes, but that is doable.  The big issue now is the crossbracing
of the motor mount, but I think I have this worked out.   BTW, if I used
a side exit exhaust I could install a much larger radiator.

Ken P.

Ken, why don't you copy Mike's mount? His is properly cross braced.
You don't need a cross tube the way he did it. The junction of
three tubes adequately locates a point in space. 
Actually those tubes are required by Van's design to brace 
the landing gear and feed landing loads into the mass of the 
engine through the motor mount.

If you don't have a 13B engine with the motor mounts on the intermediate
housing you can mount a 4130 steel hat section through the pan
under the engine right at the intermediate housing. See the ACRE 
web site for details. This position for the hat section 
and the rubber mounts pulled in tight to the side of the engine gives good 
clearance for exhaust pipes on an RV4. A 1/2 inch thick aluminum extrusion
would also work with an aluminum pan instead of the 4130 steel hat 
section with a steel pan.

Paul Lamar
 
The Aircraft Rotary Engine Newsletter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org