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01-18-2007, 06:24 PM

Michael Press writes:

>>> But how about this concept:

http://www.starrotor.com/Engine.htm

>> After gazing at hundreds of "miracle engine" articles over the
>> years, I've decided to ignore any reports that don't include tests
>> of working models. The only one of those hundreds of designs that
>> gained any traction was the Wankel, and it didn't set the world on
>> fire.

>> That page is way too full of phrases like "...is projected to
>> have...", "...should be...," "...is expected to be..."

> Can you can tell me why gas turbine engines are not practical? They
> have run well in races.

Interestingly, the Wankel first found real fertile soil at NSU in
Neckarsulm (from which the name arises) just north of Stuttgart where
I was working at the time. n R&D engineer came rolling in into our
shop at Porsche to demonstrate this new concept.

At the time I mentioned to the engineers to mark my words, that this
engine will not survive, to their utter amazement... and that of all
the others who wanted to believe in it. My thermodynamics Professor
had shown us running rotary prototypes in the lab from years past and
explained why they cannot work. They all have the same feet of clay
as they address only the mechanical part of the machine and fail to
see that this is a heat engine and thermodynamics its main focus.

Essentially one spark plug for multiple rotating combustion chambers
is what kills it. At the spark plug, temperatures in the 1000's degF
occur if the engine has any reasonable efficiency, while the intake
zone is below freezing (carburetor icing). Both areas remain a steady
state.

It's the reciprocation that makes it work. We use aluminum pistons in
a mundane engine block with steel valves that see temperatures from
freezing to flaming in one cycle. The average temperature when seen
through a boundary layer of gas is mundane. Meanwhile the Wankel
burns up! To make it work, compression had to be low giving poor
performance, requiring higher engine speed to make up for that poor
performance. The result is a short lived machine with poor fuel
economy.

When I read about propelling bicycles with the arms in a sprint or why
mechanical stress relieving doesn't work, I recall these engineering
moments where conventional thinking stymies understanding. You can be
sure that I found no takers at Porsche. Professor Kays at LSJU had it
right, although I believe his class failed to see the importance of
his lecture and that was years before Felix Wankel presented his
engine. That's often the way school is.

The Wankel is dead!

Jobst Brandt

01-18-2007, 06:24 PM	#27 (permalink)
jobst.brandt@stanfordalumni.org Guest Posts: n/a	Re: OT Interesting video Michael Press writes: >>> But how about this concept: http://www.starrotor.com/Engine.htm >> After gazing at hundreds of "miracle engine" articles over the >> years, I've decided to ignore any reports that don't include tests >> of working models. The only one of those hundreds of designs that >> gained any traction was the Wankel, and it didn't set the world on >> fire. >> That page is way too full of phrases like "...is projected to >> have...", "...should be...," "...is expected to be..." > Can you can tell me why gas turbine engines are not practical? They > have run well in races. Interestingly, the Wankel first found real fertile soil at NSU in Neckarsulm (from which the name arises) just north of Stuttgart where I was working at the time. n R&D engineer came rolling in into our shop at Porsche to demonstrate this new concept. At the time I mentioned to the engineers to mark my words, that this engine will not survive, to their utter amazement... and that of all the others who wanted to believe in it. My thermodynamics Professor had shown us running rotary prototypes in the lab from years past and explained why they cannot work. They all have the same feet of clay as they address only the mechanical part of the machine and fail to see that this is a heat engine and thermodynamics its main focus. Essentially one spark plug for multiple rotating combustion chambers is what kills it. At the spark plug, temperatures in the 1000's degF occur if the engine has any reasonable efficiency, while the intake zone is below freezing (carburetor icing). Both areas remain a steady state. It's the reciprocation that makes it work. We use aluminum pistons in a mundane engine block with steel valves that see temperatures from freezing to flaming in one cycle. The average temperature when seen through a boundary layer of gas is mundane. Meanwhile the Wankel burns up! To make it work, compression had to be low giving poor performance, requiring higher engine speed to make up for that poor performance. The result is a short lived machine with poor fuel economy. When I read about propelling bicycles with the arms in a sprint or why mechanical stress relieving doesn't work, I recall these engineering moments where conventional thinking stymies understanding. You can be sure that I found no takers at Porsche. Professor Kays at LSJU had it right, although I believe his class failed to see the importance of his lecture and that was years before Felix Wankel presented his engine. That's often the way school is. The Wankel is dead! Jobst Brandt