Hi all:

I would submit that if the spring temperature gets so high that inconel is
required, there will be other problems as well. High spring temperature means
high rotor temperature. The temperature at the hub of the rotor will be near
oil temperature, and if the temperature at the periphery of the rotor is,
say, 700 deg F hotter, there will be considerable thermal stresses induced in
the rotor. Fine for drag racing perhaps, but not good for even moderately
long life. We battled this problem extensively at Deere and RPI. It is also
not clear to me that a relaxed apex seal spring should cause an apex seal
failure. At normal operating conditions the spring force is somewhat
superfluous compared to the gas pressure forces acting on the seal.

Jon Lauter
Rotary Power Marine Corporation
www.rotarymarine.com

I am sure you are right Jon. I also wonder how the spring found it's
way out with out without breaking the apex seal. Notice there are no signs
of a broken seal jamming between the rotor housing and the peripheral
ports. Common with broken apex seals. Perhaps what is happening is the 
springs from Mazda are way less than 700 degrees as this area of 
the rotor at high power runs roughly 500 degrees.

When the springs go the engine is hard to start. Jeff told me
the Prescott Pusher with the ducted fan turbo three rotor has
this problem now.

Paul Lamar
 
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