Re: Wankel Rotaries

[RangeR BoB <samurai@xxxxxxxxxxxx>]

Christopher Bourk makes a good point about the rotors on a rotary,
their path is somewhat reciprocating.  (BTW, the shape of the hole is
called a "peritrochoid", which is a fancy term for a figure eight.)

	Strictly speaking, the rev limit in a rotary is higher because the
reciprocation is much less than that of a piston.  There is also no
connecting rod to break.  The real upper rev limit of the rotary is the
seals on the rotors.  Mazda uses a carbon composition seal on each apec,
backed by leaf springs, and a set of round rings on each side of the
rotor to keep oil pressure around the eccentric shaft.  These latter
ring seals need oil, so Mazda put an oil pump in the engine to squirt a
bit of crankcase oil in the airstream to keep them from galling the
engine sideplates.

	Great point about the side ports making them drivable.  Perimiter ports
(NSU, Norton) are great for high revs, but don't breathe as well down
low.

	Obligatory BMW content:  Did BMW ever try and make a rotary?  I haven't
heard of it.

	Thanks for the bandwidth,
- -- 

 RangeR
   BoB
 Hembrook
 
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