I am responding with regard to Mark Hull's letter. As he stated,
Kudos to Kitplanes for allowing people to express their viewpoint.
 I am a 30 year auto and heavy duty mechanic with instrument
mechanic for 10 years.  Mark, I congratulate you on a 30 year
career. How ever I think you should do a little more research on
this topic.  First, log into the rotaryeng@earthlink.net web site
and read who Paul Lamar is. While there you can also read some of
the articles on there. There is also articles by other writers
expounding the rotary engine.  Two, Paul is not expressing the idea
that rotary engines are infallible. It is the stresses on
reciprocating engines that is a concern. No, rods do not get shot
out of the crank case regularly, and Paul is not saying that. It is
the low stresses in the rotary he is trying to explain.  Three, a
lot of the article is aimed at auto engine conversions. Certified
engines are heavy duty engines on the vein that highway truck
engines and large industrial engines are. They are designed with a
high duty cycle engineered in. These engines run for thousands of
hours before overhaul. Auto engines run at low duty cycles with
brief blasts of full power. When subjected to aircraft use and 75%
power for hours, the TBO is going to be reduced.  With regard to the
tuner racers blowing rotary engines, yes they do. But they are
pushing the boost and tune envelope. Log into Mazdatrix site and
they show some destruction that testing develops.  Four, if you are
going to quote, please get the whole sentence in. The sentence
should read,"If the wear of seals and sliding surfaces can be
reduced to low levels the, the life of the rotary could be 10,000
hours or more. This is not an admission of rotary reliability issues
when taken IN CONTEXT. It is a statement that with more development
what we MAY expect.  Five, with respect to exotic rotor materials;
Paul presents a possible advantage. If you subscribe to the news
letter, you will find out Paul has advocated staying with the cast
iron rotors for aircraft use. The reason is twofold. First is cost
and second is that at the RPM required the exotic pats are not
required. For racing that is a different story; according to Paul.
If you read the article on the Le Mans 26B engine, they used Cermet
coated side and rotor housings but kept the RPM down to 9,000 for
engine life. There was minimal wear in the engine at the completion
of the race.  Six, balance. Rotaries are very smooth as compared to
a recip. engine. They do not have the other frequencies propegated
by the reciprocating motion. A horizontally  opposed engine is well
balanced for the mechanical balance. It is the dynamic balance with
respect to torsional vibration that large bore engines suffer from.
The vibration you refer to in the turbine can be illustrated be an
example of a car with a slight wheel balance imperfection. All tires
have a slight difference in circumference. If a few of the wheels
are out just a bit, you will not notice it if they are out of phase.
But due to the circumference difference they will all come into
phase and out. The car will have a vibration when they are in phase.
The turbine with segments at can rotate at different speeds does the
same. And as you stated, no balance is perfect which produces the harmonic.
  Thank you Kitplanes for letting me vent my spleen.

Dale Davies

Good job Dale. Thanks.

Paul Lamar


Well Paul, we will just have to see what response this brings. Whether they
print it or not. Hopefully they do. There is a wide experience and knowledge
base with a lot of intelligent people on this news letter. We do not all agree
all the time. As long as we can all discuss things without getting offended is
a good thing. Just maybe some advances can come forward to accomplish getting
these engines in the lime light where they belong.

Dale Davies

It is happening. It is just taking longer than I thought.
My goals are to enter a few 500 mile races with a p-port engine
in Mike Wills RV4.

Paul Lamnar