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Date: Tue, 25 Jul 2006 08:41:38 -0600
From: Bob White <rlwhite@comcast.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: More cooling Tests
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Thanks for the link Steve.  Interesting stuff.

Bob W.


On Tue, 25 Jul 2006 07:57:44 -0400
"Steve Brooks" <prvt_pilot@yahoo.com> wrote:

> 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/
> > >
> > > --
> > > Homepage:  http://www.flyrotary.com/
> > > Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
> > >
> >
> >
> >
> 
> 
> --
> 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/
> 
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
> 
> 
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/


-- 
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/