Your rpm limit is more likely a result of the prop you are trying to turn
than the exhaust backpressure.

B2

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Ernest Christley
Sent: Tuesday, May 29, 2012 2:12 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Exhaust temp

Lehanover@aol.com wrote:
> I was hoping you wouldn't see this, but now that the cat is out of the
> bag............
>  
> You can see the need for some shielding between the headers and any
> items that you don't want at the same temperature. Radiant energy is
> line of sight. If the header can see it, up goes the temperature.
>  
> Pieces of .015" stainless stood off the header about 1/2" to 3/4" breaks
> the line of sight. Building such on the header reduces the amount of
> material involved. It is easier to not heat things up than it is to cool
> it after you have. Use 1/4" hose clamps to hold onto the shielding.
>  
> A small blast tube to keep things moving past the headers is helpful.
> I can make a picture if you like. Helps keep heat out of the intake
> system and thus more power. Very easy. Amazing results.
>  
> Lynn E. Hanover
>  
>  
My exhaust is encased in a .015 stainless box down to the end of the
collector.  The down pipe and muffler are exposed,
and I see where it is blistering the belly paint already.  I'll be wrapping
more of the exhaust in the thin stainless.
I will also open the stainless box up to allow some blast air through. First
I have to change that down pipe from 1.5"
dia to 3".  I can't seem to get above 5100RPM, and I think exhaust
backpressure is my issue.

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