Tim for a chap who is prepared to put pen to paper, you had better include
for comparison the single rotor and the aluminum housings or your
credibility might well be shot to pieces, when considering C of G, weight,
power and reliability comparisons.
George (down under)

Hey, George (Down Under),

I was merely offering some facts on the VW, not offering a comparison or a
rebuttal to a rotary. When I see reference to "145 pound" VWs, I get
skeptical. When I hear about a need for "50-hour valve jobs," I realize that
somebody is doing something terribly wrong.

I offered my observations to try to keep the discussion somewhere near
reality. I don't sell VW engines, and I have no stake in them. I just want
people to understand what they're looking at. You can't make a good choice,
given bad information.

As for a certified engine that "weighs the same, costs twice as much and
makes half the power," you know there are a lot of reasons behind that
equation. For one thing, you don't have to build the certified engine
yourself; all the engineering is proven; there is a viable warranty;
components, materials, and manufacturers are tracked and tested; and best of
all, it does what it says it does.

On the "costs for their own sake" side: the FAA seal of approval costs
something, too, as do the layers of lawyers outside the factory gates,
waiting for a pilot to run out of luck and then have his widow blame the
engine.

That's the great thing about aviation: you can do pretty much whatever you
want to do. Looking at the flight line at Oshkosh or any other EAA or PFA
airshow, it's obvious that there is more than one way to get into the air.

You love rotaries. That's fine. I don't criticize them. In fact, I think
there is a lot of evidence in their favor. A properly-built rotary
conversion is a thing of power and beauty... but it isn't magic. Pistons
work, too, in two or four strokes, or in diesels; and so do turbines. If one
design were clearly superior, we'd all be flying it.

Tim Kern

Tim, I have always been curios about something. Are sodium cooled
exhaust valves available for VW engines? There are some new
turbocharged cars on the market with sodium cooled
exhaust valves. Other than older Volvos the brand names escape
me right at the moment.

I had to adjust my VW valves on a regular basis or I was looking
at a frequent valve job. I went through SCCA road racing drivers
school in my old modified split window VW way back around 1964 at
Marlborough Maryland.  I average 500 hours on my O-470 exhaust
valves in my C182. At least one needs to be replaced every 500
hours. Perhaps I am doing something wrong. The turbo compound
rotary unlike the turbo compound R3350 will not have this problem.

Pilots are a very conservative lot. They are all from Missouri.
It takes years and years of flying by hundreds of rotary powered
airplanes before the rotary will be widely excepted.

This would be speeded up if only the air racing organizations would
relax their engine limitation rules. For example the Reno race organizer
have already limited the rotary to a 3 rotor turbo version while
recently allowing piston engines up to 800 or 900 cubic inches
as I recall. This is easy to confirm by calling the right people.
That is a handicap that will be difficult to over come
with a 3.9 liter or 238 cubic inch turbo charged three rotor.
A 317 cubic inch turbo charged four rotor will be required :)
The same thing has widely happened in auto racing. In other words
there are very powerful commercial interest in play that don't
want to see the rotary succeed.

Way back in 1997 or there abouts, when Sun & Fun were running the time
to climb race Allan Tolle set the all time, time to climb from a dead
stop on the runway to 3000 feet race, time of less than a minute using
a p-port rotary powered RV4 I think. (It could have been an RV3 I
forgot exactly.) The next year the time to climb race was done away
with.  Allan also went 238 MPH in the Sun 100 Race in the same airplane.

Tracy Crook went 217 MPH in his RV4 a few years back winning his class
and and beating half of the next class up in a side port normally
aspirated rotary. Now Sun & Fun has done away with the Sun 100 race
unfortunately. If the race had been held indefinitely rotaries would
have dominated eventually as they have dominated car racing world wide
until outlawed. Mazda won Lemans outright in 1991 and then the French
changed the rules to severely handicap rotaries. Imagine what would
have happened if the rotary was allowed to dominate Lemans year after
year on a strictly displacement  based rule system. People in Europe
would start to question why their cars did not have rotaries. Billions
if not trillions  of dollars of piston engine based manufacturing
infrastructure would have been needed to be scraped.

All this has been extremely frustrating for me and a lot of rotor
heads around the world. I personally have owned seven Mazda rotary powered
cars starting in 1973. Some of them used cars with over 100,000 miles
when I bought them. Adding the miles I put on them the cars had an
accumulated  driving miles of well over one million miles. I currently
own a 2004 RX8 with 30,000 trouble free miles that gets 25 MPG on the
freeway.

The better mouse trap does not always rise to the top.

Paul Lamar ...No rotor no motor.

Tim to add to Paul's comments, and we don't always agree, there is the
inability through 'lack of exposure' to all above mentioned areas, to further
develop the rotary to it's full potential by way of universal acceptance and
volume sales.
For instance, I feel sure that an all aluminum rotary would have been
developed by now if there were sufficient demand to justify the development
cost.
You need to just look at the proposed certification of the rotary for
Aviation use, to see the awesome potential for the rotary.

Personally I consider the single rotary to be the most overlooked engine for
power, reliability and 'cost effectiveness' - in the 100 to 125HP category.
The reciprocating engines are OK but can be quite expensive for what they
are, a basic engine with high quality ( read expensive) components. The
Rotary doesn't need expensive components to be reliable in high end use!
George ( down under)

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