I had the opportunity to hear a renesis motor on a Jabaru yesterday.
    It had
    NO muffler at all and made less noise than a Lyco.  I was expecting
    to be
    deafened but I was extremely impressed with the note.

    I was standing about 12 feet to the side at one point and when the pilot
    revved it up to 4000rpm I was standing at the tail holding it down
    and the
    noise was not overly loud.  The cowls were off at the time so I
    imagine that
    it would be even quieter with them on.

    The white wrapping on the exhaust pipe is some old asbestos wrap.

    Greg


    That exhaust wrap is very dangerous. First; the rotary exhaust
    temperature
    and frequency is higher so it is very hard on metal pipes. Two; it
    is difficult
    to inspect for cracks. Not recommended. We have had a couple
    of crashes for this reason.

    --
    Paul Lamar ...No rotor no motor.

Hey Greg, what prop is that.  Looks ground adjustable at a minimun.  Is
it a warp drive?
BTW, I mostly agree with Paul about the wrap.  Besides it being
ASBESTOS, they are problematic but can be made to work.  You need
something rated to 2000 deg., don't let it cover any welds, and it is
best to have a cerramic coating on the exhaust to minimize corrosion..
Will corrode very quickly under the wrap without the coating.
-- 
David Leonard

Thanks for you're comment and I'll pass them on.
The prop is branded Cobra Aviation (Australian), but I thnk it's made by
Bolly.  It is variable pitch controlled by oil pressure using a Sub4 PSRU. I
can't remember whether it was constant speed or not.

Greg

The prop is probably made by Bolly for Cobra Aviation and the hub is in
flight adjustable ( hydraulic ) but not a true constant speed. There are 2
methods of in flight adjustment. One is electric pump, the other is manual
knob on a master cylinder instead of electric pump.

Baz

How are you doing Baz? I take it you and your rotary powered airplane are
now living happily together after you got the pitch stability
fixed. Got any performance or cooling data to report?