From: n36f@pnet16.cts.com (Et2 Ellingson)
Subject: Re: Mazda's Rotary Engine
Organization: People-Net [pnet16], NCTAMS EASTPAC
Date: Fri, 6 Nov 1992 19:16:03 GMT

Charles.K.Scott@dartmouth.edu (Charles K. Scott) writes:
>In article <1992Nov3.214530.7657@tamsun.tamu.edu>
>cgc5437@cs.tamu.edu (Graydon Cecil Chenault) writes:
>
>> Anyway,  has anyone out there looked into this engine?
>> Can you tell me what you know.  I'd appreciate any info.
>
>I picked up a 1986 Mazda 13B engine last weekend for my Christavia IV. 
>I'm an ex auto mechanic and understand engines fairly well but never
>took one of these things apart before.  The latest Kitplanes has an
>article about the Mazda engine and even mentions the company I'm in
>contact with for the PSRU, Ross Aero.  They don't mind talking on the
>phone and even stay late at the business to answer technical questions
>from builders.  The toughest thing about it will be the induction
>system.  In order to lubricate the rotor tip seals, there is a little
>oil pump that meters oil to the induction runners and it has to be able
>to vary the rate of drip depending on throttle movement.  The oil is
>sent to the induction runners via external plastic tubing. The easiest
>thing to do is to use the original fuel injection set up but that's
>also the tough part.  The thing is a mass of tubes, vacume lines and
>solenoids and requires the cars computer to work properly.  Ross
>recommended I use their fabricated intake manifold and an aviation
>carburator they modify to work with it.  Sounded good to me, I like the
>idea of simplicity.  But while talking with Chris Ross last week, he
>told me he was having an electronics wizz from Maryland work out the
>electronics to operate the fuel injection and ignition for their
>purposes.  He wants me to hang on to the factory injection manifold
>because it's a little more efficient than their fabricated
>manifold/carburator set up.
>
>I like that idea because the Mazda manifold and injection set up is
>already optimised for use with the rotory engine and all the
>peripherals.  So that would be my first choice.  I haven't spoken with
>him since then but I intend to give him a call in the evening soon so
>we can discuss this more.
>
>The engine itself has one supreme advantage over conventional piston
>engines of any type: it has literally only three moving parts and no
>connecting rods.  There's nothing that can bust off and stick through
>the crankcase.  Plus, the rotors spin at 1/3 eccentric shaft speed
>(they spin on gears) so at a speed of 6,000 rpm at the eccentric shaft,
>the rotors are only going 2,000 rpm.  The engine runs so smoothly that
>one builder bragged he could balance a quarter edgewise on his engine
>block and rev the engine through various rpm ranges without having it
>fall over.  If so, that's pretty impressive. He might not have had a
>prop attached.  Now for the downside.  Rotory's aren't quite as
>efficient as a piston engine can be so fuel burn is not as good.  It
>isn't horrible, but horse power for horse power, it will burn a little
>bit more gas.  Secondly, the exaust is obnoxiously raucous and
>extremely loud and runs significantly hotter than conventional engines.
> A muffler is STRONGLY recommended and it had better be stainless
>steel.  You should have a look at the muffler on the RX-7's, it's
>monsterous, it practically goes the entire length of the car.
>
>Have a look at the article in Kitplanes, it shows the engine installed
>in a homebuilt and also gives a head on look so you get an idea of how
>narrow the profile is which is yet another advantage.
>
>Corky Scott

I had a 1979 RX7 and it had a carb and manifold set up. The manifold may
be reworked to accomadate a airplane carb.  One major advantage you will find
with rotary engines is weight to h.p., and another is that above 2500 rpms
the engine has a constant i.e. smooooooooth power band.  The down side is
it has low power output at rpms under say 2500.  It is all aluminium except
for the main shaft and the fins very very low weight.  One man can lift the
completed block.  Well that's my $.02 p.s. I love rotary engines!
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