Here is my suggestions on porting the waste gate Bulent.

Plus and air cooled exhaust manifold to knock 100 F or so off the air temp
going in. Every little bit helps.

BTW Inconel is only good for 100 to 150 F higher EGT.

Paul Lamar

Paul, I have done some work along your suggestions. But looks like it will
only delay the same failure? We had 3 turbos fail in the same exact manner
in flight under similar conditions. I still have few months to go before
flying and being able to test the changes.
Bulent

Well perhaps. All the stock turbos that have failed so far and so far as I know have
failed at altitude and at manifold pressure levels well above 30 inches of Hg.

As I said before going from 30 inches to 32 inches is 6% more RPM and 13% more 
stress on the blades or more depending on the additional amount of heat flux flowing
into the turbine blades. What I mean by this last statement is; if you use the same turbine
fed by a 180 HP wankel verses a 200 HP wankel, the turbine on the 200 HP wankel
will run hotter, despite the fact the exhaust temps are the same.
The turbine blades are cooled somewhat by conduction to the shaft and by radiation
to the exhaust down pipe. Every little bit helps in this scenario.

30 inches at Hg is called flat rating and gives roughly up to 30% more HP at altitude.
At some red line turbo RPM IMHO the stock turbo will live. I will work on a
design for a turbo tachometer. A good idea even for a TO4 just to see exactly where
on the compressor map you really are.
 
Paul Lamar
 
The Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2004 All world wide rights reserved.