Greg,

A number of years ago (20+) I visited a fellow in Chino Cal.
Youngblood was his name.  He was putting together a rotary package with his
own PSRU and it was turbo'ed.  The turbo was on the side of the engine
fairly close to the water pump and exited straight out the side via a 3"
pipe no more than 12" long.

The engine was mounted on a test stand with a 3 bladed prop.  He
fired it up for me and I was expecting a kidney splitting sound to come from
it.  That did not happen.  At idle it just purred.  At full throttle, most
of the noise was from the prop... and not bad at that.  He ran it for about
3-4 minutes at full throttle as I stood not more than 10 feet away.

I think you'll be alright.  Just remember the exhaust is still very
hot and you have a plastic airplane.

Neil


-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Greg Ward
Sent: Saturday, June 07, 2008 10:25 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Muffler failed designs.

A little off of the subject, but close.  Just got my engine and turbo
mounted on the Lancair, and was wondering if anyone had ever exited the 3"
downpipe right out of the side of the cowling, ala turbine exhaust types,
(thrust???)  it would eliminate 2 bends, and about 3' of pipe, and with the
turbo, it should be relatively quiet.  Any thoughts?
Greg Ward;
Lancair Legacy RG 20B getting closer to startup.......

----- Original Message ----- From: <neilak@sympatico.ca>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, June 07, 2008 4:08 PM
Subject: [FlyRotary] Muffler failed designs.

Al,

If you go through the archives, you'll find lots of examples of
failed muffler designs.  Many by your's truly.  I think I've tried every
concoction known to man and the Swiss.  They all worked...  for a while.

Actually, the many variations of the Swiss muffler I tried had the
best exhaust note by far.  None lasted more than an hour, some less than a
few minutes.  Heat wasn't so much the problem since I had found many
materials good to 2200F but none could stand the pounding.
http://www.piteraq.dk/flight/muffler.html

My best overall design (see attached) is a 2" tube, full of holes
inside a 5" tube.  All made of 16ga SS, all welded together.  Needless to
say, the flange is more like 3/16" - 1/4" SS.  The inside end of the 2"
tube
is welded to the end cap of the 5" tube.  That blocks off the one end of
the
2" tube and secures it from movement.  The exhaust end of the 2" tube is
welded through a 2" hole in the other 5" end cap.  Rather than drilling
the
2" tube full of round holes, we cut slots with a saw.  Then take a big
flat
blade screwdriver, stick it in the slot and bend it over.  This creates an
oblong hole.  (Much easier than drilling into SS.  This is what will go on
the Volmer.

The sound is quite acceptable, it fits inside the cowl and Jim M.'s
version lasted the life of the aircraft... 600+ hours.

Neil

PS: Are you considering Rough River?



-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Al Wick
Sent: Saturday, June 07, 2008 4:57 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Mistral Crash Analysis

C'mon guys. You do this every time there's a crash. Instantly go into
rationalization mode. It's unhealthy. Greatly increases risk builders
won't
take action. Increases risk you won't research it thoroughly.

A healthy response would be:" Here's another example of how our engines
produce unusually destructive exhaust temperature and pulses. We have a
rich

history of broken exhaust components. We need to be very thorough when
designing and building exhaust."

I designed my own muffler. It had two inlets, two outlets. So if (when) my
muffler failed, it could never block both pipes. I also put loose safety
wire around my pipes, because on a pusher loosing pipe wipes out prop. So
basically, I assume stuff will  fail, then design it to control the way it
fails. I've heard of rotary guys doing same type of thing. This is a good
time to share those key items.

On your car, they deliberately design products to fail a certain way. They
will make a component weak, so it fails first. They do that with wheels
and
hubs. So when the muffler fails, little pieces come apart, not big
sections?

You guys do a great job of sharing successes, design and construction
details. This is another opportunity.

-al wick




<No doubt you are on the money, Rusty.  When folks are already predisposed
to bad mouth the rotary - this will only be more ammunition.  "See! even
with umpteen million dollars you can't get one to fly"  {:>).  But, I
serious doubt it will effect many who have researched the rotary and come
to

understand its benefits - as for the rest, who cares {:>)

 I'm certain it was a relief to Mistral that the culprit was not one of
their engine components.



 Whew! a close one for sure.



 Hi Ed,



 Unfortunately, I bet the majority of people will only hear "Mistral
rotary", "lost power", and "crash"  :-(



 Rusty (RV-3 taking forever.)

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