Bob,
For your exhaust, you may want to consider ceramic coating.  I had my
exhaust pipe coated by a company called Jet-Hot.  As I recall it
only cost
about $50 to do mine, but it's only about 18" long, coming from the
turbo.

Here is their web link:
http://www.jet-hot.com/

What I got was the Jet-Hot 2000 coating, which is good to 2000
degrees.
Mine has held up very well, and shows no signs of deterioration.

Steve Brooks


-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On
Behalf Of Bob White
Sent: Tuesday, July 25, 2006 1:30 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: More cooling Tests


Thanks Dave,

The fuel return to the tank is the next item on my todo list.  The
tank
developed a leak so I have to open it up anyway.  It seemed like the
right time to fix it.

The exhaust system is a large can with a tube thru the middle that
supplies cooling air (theoretically) so the temps on the down tube
should be lower than normal for a rotary.  However, it's still too hot
for this material, whatever it is.

I hope I haven't given the impression that I'm flying yet.  This is
all
taxi and static stuff. :(  I am getting pretty close though.

I hope you are doing well.  I check your blog occasionally and I'm
glad I don't have to deal with the temps shown in your July 13
photo.  I
could probably get close in Phoenix some days.  Best of luck and hope
the rest of your tour passes quickly.

Bob W.



On Tue, 25 Jul 2006 07:43:51 +0400
"David Leonard" <wdleonard@gmail.com> wrote:

Hi Bob,

I can tell from experience that even most stuff that is intended
to go
directly onto exhausts will quickly desintigrate in the rotary.
The stuff
that is supposed to be good up to 1400 deg will start falling
apart after

a

few hours.  That stuff you have will be done after the first flight.
Don't forget that your exhaust temps will go above 1600!

I did find some exhaust wrap that was good up to 2000 deg. and it
is good
for about 100 hrs before becoming a little brittle and falling
off.  It

was

worth it and made a big difference in my under cowl temps, but it
was not
cheap.

As for your fuel system....   I am sure SOMEONE has said this
before (I

have

not been reading the list very regularly because I am in Iraq), so
let me
repeat for effect.  RETURN THAT FUEL ALL THE WAY TO THE TANK!
One of the
great things about this high flow fuel injection system is that it is
possible to essentially eliminate ANY chance of vapor lock.  Vapor
lock
HAPPENS even in certified planes.  It is serious. It can be
fatal.  Route
that fuel back to the tank and it basically can't happen.... you
have a
better system than a typicl lyc set-up.  Route that fuel back to
the pump
and you may even be making things worse than a lyc set up.

Sounds like you have decided to make a change, so this is just to

re-enforce

that decision and send the message to anyone else considering the
easy way
out for fuel return....

JMHO, & congratas on getting flying by the way! cant wait to see
it in
person some day..

Dave Leonard


On 7/25/06, Bob White <rlwhite@comcast.net> wrote:

I finished putting a layer of insulation around the exhaust
system.  I
placed thermocouples in a few key locations.  One inside the
insulation, one outside, and one on the fuel rail.  OAT was 80-85F.

I ran the engine at 2200 rpm until the temps stabilized at 197
oil and
water.  I increased rpm's to 3100 and temps went up to 200 oil
and 207
water. They were still increasing very slowly.  I can taxi at
3100 rpm
or less and getting a little movement should help cooling.  Also,
when
I reduced power back to 2200 rpm, the temps started decreasing.
So on a
not too hot day I think the cooling will be OK for taxiing.

The insulation is a layer of reflective insulation I bough at the
speed
shop that is good to 1000F.  It has a metalized layer on each
side and
some kind of fibrous layer on the inside.  (The stuff itches like
fiberglass when you get it on you.)  At the end of the test, the
thermocouple on the inside layer was reading 235F and the one in the
same place on the outside of the insulation was 167F.

I still don't have the fuel return to the tank.  It's going directly
back to the fuel pump input.  So the fuel rail temps were getting
pretty high.  The fuel rail was 145F and the engine was starting
to run
a little rough, presumably due to incipient vapor lock.

Next step is to open the tank and install the fuel return line.
I ran
the line from the firewall to the wing root this afternoon, so
the easy
part is done.

Bob W.

--
http://www.bob-white.com
N93BD - Rotary Powered BD-4 (first engine start 1/7/06)
Custom Cables for your rotary installation -
http://www.roblinphoto.com/shop/

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N93BD - Rotary Powered BD-4 (first engine start 1/7/06)
Custom Cables for your rotary installation -
http://www.roblinphoto.com/shop/

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