Perhaps what is also happening is silicon nitride ceramic roller
   rotor bearings and
   silicon nitride ceramic apex seals are being used so it is less
   important to cool
   the rotors. Ceramic roller bearings are less affected by high heat
   than steel
   bearings. Same goes for apex seals. Some of the reasons for oil
   cooling the rotors
   in the Mazda is to cool the rotor bearings and help cool the apex
   seals. Most of
   the apex seal cooling is now done by the injected apex seal oil in
   the Mazda engine.

   With less rotor cooling there is less waste cooling heat.

   Paul Lamar ...No rotor no motor.

Paul,
Since the Mazda uses plain bearings anyway it would seem oil cooling
would be more of a natural solution. The first company that ever did the
pass-thru charge cooling, (to my knowledge anyway), was BSA. They had a
full road going prototype motorcycle shortly before going bankrupt. Some
people say that was the basis for the Norton rotary, others tell me that
it was an independent effort. Mazda was impressed enough with the BSA
effort to buy several of the new patents they filed. I often wondered if
a blended variant might work well. The idea would be to use air cooling
for the rotor, with the standard water for the housings. The rotors
could be considerably lighter that way. Just thinking out loud.
Bill Jepson


The Norton and Midwest, now Diamond, engines use air cooling.
It is not free however as it take HP to drive the required
air pump.


Paul Lamar ...No rotor no motor.

The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2007 All world wide rights reserved.