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From: dalexan424@aol.comSpamaway (DAlexan424)
Newsgroups: rec.aviation.homebuilt
Subject: Re: Auto engine stuff, sorry
Date: 16 Jun 2000 16:33:18 GMT

>Subject: Auto engine stuff, sorry
>I have been lurking in this ng for about 2 years off and on.  This is my
>second post.
>I am somewhat confused about auto engine conversion choices.  It would
>seem that the Mazda 13b is the obvious auto engine to convert due to
>its power to weight ratio, simplicity and smoothness.  The only draw
>back would seem to be thermal inefficiency causing lower fuel economy.

Two other issues come to mind. The cooling system must be perfect or immediate
problems will result from the slightest loss of water. I can say this because
of the years in I have as a Mazda master tech. The rotor models have cooling
system hoses on the left side of the rotor housing. When the oil filter stand
off O-rings leak after about 100K miles, these hoses become saturated with oil
and burst. The owners don't have enough time to pull over to the curb before
their engines are history.

 The rotary engine is ALWAYS making power (part of the fuel consumption
problem) as something is always going on inside. This means it developes plenty
of heat. Looking inside the cooling jacket of the engine will reveal that the
factory has biased the cooling flow towards the bottom of the rotor housing by
making the passages smaller on top (intake side) and larger on the bottom
(exhaust side) to keep water where it is needed. ANY loss of water in the rotor
housing is disasterous as the side plates and rotor housing will warp out of
speck in a moments notice, especially at the power requirements for flight. I'm
not saying it can't be done as obviously I would look like a fool in the
presence of Tracy Crook. Just plan things out very well and use the best

 The second issue comes from the fact that the engine is always exhausting with
very little rest between pulses. Ths makes the engine very loud but more
importantly, the exhaust never gets a chance to "rest" between pulses and is
always subject to incredible heat. Stainless for headers AT LEAST and Titanium
would probably be better. So expect to spend a small fortune in the exhaust

Hope this helps,

Dale Alexander
Velocity 173 RG Elite
IO-360 ( no rotaries, please)

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