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

G'day Paul,
Yep, the anti servo tab made all the difference. I'm having problems with
controlling the prop pitch. I think there is still air in the hydraulic
pipe
somewhere as the pitch doesn't stay stable. The aircraft is stable and
yesterday ( in rough turbulent air ) I recorded the following OAT 25C [77
F],
elevation 475', take off with reduced power ( 4300 rpm ) 500metres, climb
90
knots @ 1500 '/min to 5,500'. Temps on climb coolant 88C [190 F], oil 98C
[208 F],  Straight
and level 4600 rpm, 136 knots TAS,  fuel flow 33 litres[8.7 gal]/ hour,
coolant [80C 176 F],
oil 90C [194 f].
The prop pitch seems to wander a lot which leads me to believe there is
air
in the system. Apart from that the engine is super smooth but a bit
noisy.
The reduced power on take off was because the prop pitch isn't stable and
I
didn't want to overspeed the engine.
Obviously there is still work to do but getting there. I'm still very
nervous about it after those first two flights but as it proves itself to
me
I will get more confidence in it.

Baz

Thanks Baz and thanks for including the OAT. A lot of people
forget that. Looks like your cooling system is working well.

I take it there are some louvers in the cowl somewhere
to let the air out. Got any recent pictures of the cowl?

Can't wait to see how fast that little bugger is when you
get the prop fixed.

Don't worry about over speeding
the engine. When the prop tips go supersonic regardless of the pitch
the engine RPM will stop increasing. The engine RPM will go to
9000 RPM or so without hurting it.

What is the PSRU ratio? Who builds the PSRU?

I think the engine is running a bit rich.

Paul Lamar ...No rotor no motor.

Hey Baz how close is that exhaust to your nose gear (?) bungees ? Sure
looks close. Glad to hear you have the stability issues worked through,
sounds like you had a tiger by the tail those first couple of flights.
Good
luck.

John

Hi Paul,
There are no louvers in the cowl. I attach a pic of the cowl. The bottom
inlet feeds the bottom radiator, the one on the left feeds the side radiator
and the other one feeds the oil cooler. Great care was taken sealing up all
the inlets and I would think more than 95 % of the air is being used
effectively. There is a large lipped outlet on the rear of the bottom cowl
to get the air out.
I don't know the manufacturer of the PRSU but it is 2.3 :1 reduction.
The bungee is not quite as close to the exhaust as it looks in the other
pic. I read with interest the comments on exhaust wrap recently as I have
just done that to keep heat away from the bungee. The jury is still out on
whether it stays on or not.
How do I go about finding out if its running rich or not and what can I do
if it is?
I wish I was over in W.A. to have a look at that Jabiru.

Baz


You will never over rev the engine with a 2.3:1 PSRU.

If you are running unleaded auto gas an O2 sensor/mixture monitor
works fine. There are many on the market.
http://www.knfilters.com/airfuelmonitors.htm

Are you Electronic Fuel Iinjection or carb? Does your carb
have a mixture control?

The other way is using Exhaust Gas Temperature sensors
and an EGT gage.

You change the mixture until you  see peak EGT
then slowly lean the mixture to about 150 F (65C) lean of peak.

If EFI many EFI computers have mixture controls. Some you must
program it off line.

In that case you need the O2 sensor/mixture monitor.

Paul Lamar ...No rotor no motor.

G'day Paul,
I'm using Avgas, the engine is Electronic fuel injection and a Wolf ECU.
Maybe when I've got the rest right I will get the ECU adjusted.
Thanks

Baz


The problem with AvGas it destroys O2 sensors.
It also eats rotary spark plugs.
Change your plugs every 50 hours or so.
The first thing you will notice is a reduction in
power. Auto gas they may be good for 100 hours.