> The heat flow path from combustion chamber to the rotor
    > bearing and then on to the e-shaft is very short in Wankel
    > engines. See the attached jpg.s. The rotor combustion
    > chamber surface runs up to 500 F. This heat transfer
    > path must be blocked or the rotor cooled to prevent
    > the rotor bearing and e-shaft from over heating.
    >
    > The rotor bearing integrity is key to the maximum RPM
    > of any Wankel engine. Since HP is a direct function of RPM
    > the power to weight ratio of a rotary is also a function
    > of the maximum RPM the engine can achieve.
    > The current oil cooled rotor Mazda engine is limited to about
    > 11,000 RPM in racing and about 9,000 RPM street.
    >
    > It seems to me this problem or feature needs to be addressed
    > in future rotary engine designs. SAE paper 900035 addresses this
   issue
    > for charged cooled (CCR) rotaries but it may be applicably to
    > oil cooled (OCR) rotor Wankel engines such as the Mazda as well.
    >
    > http://www.rotaryeng.net/
    > "Down load tech paper on charged cooled Rotamax type rotary engines."
    >
    > What this SAE paper suggest is making the e-shaft hollow and cooling
    > the rotor bearing area from within the e-shaft by oil or glycol/water
    > coolant. How this is achieved is through relatively new technology
    > called hydro-forming. The frame rails on a Corvette are hydro-formed.
    > It has the potential for cutting the cost of the e-shaft as well.
    >
    > A length of 4340 steel tube is placed in a very strong female mold
    > and super high pressure is applied. A hardenable steel alloy is
   chosen
    > as the hardness of the rotor bearing e-shaft surface is critical.
    >
    > The wall thickness of the tube could be pre-machined to better
   control
    > the wall thickness of the final product. FEA or Finite Element
   Analysis
    > would be used to determine the wall stresses so local wall
   thickness can
    > be tailored to equalize the stress and minimize the weight
    > and maximize the heat transfer to the coolant.
    >
    > http://en.wikipedia.org/wiki/Hydroforming-
    >
    > Something as simple as a glorified fire cracker placed in the tube
    > could also do the job. US coins are made by explosively bonding
    > dissimilar metals.
    >
    >
    > Paul Lamar ...No rotor no motor.

   Paul,
   That is a great subject and good information on the heat flow and to
   provide good cooling to the rotor bearing.
   We received page 3 and page 5. How about page 4 and  later? Is that from
   the SAE paper 900035?

   If possible I, and I am sure others as well, would be happy to get more
   on the subject.

   Thank you.
   Rolf Pfeiffer


   Yes.

   You can download the whole paper in pdf form by going to:

   http://www.rotaryeng.net/

   And scrolling down to:

   "Down load tech paper on charged cooled Rotamax type rotary engines."

   On the front page.

   --
   Paul Lamar ...No rotor no motor.


You can get there directly:

http://www.rotaryeng.net/Wankel-CC-paper.pdf

:)


Matt-


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