Jon Potter wrote:

I am not a pilot or an engineer, but couldn't resist your site (I have at
least driven an RX-7)

Why not devote all this energy to perfecting small turbine engines?  That
seems to be the direction of these rotary innovations. See Eclipse 500
aircraft, etc.

Thanks in advance.

The laws of geometric scaling are against small turbofans.
IMHO the Eclipse 500 is a stock scam and $100 million tax fraud.

Each year I ask Williams at OSH what the ratio of
the weight of fuel burned to pound of thrust developed by the
Williams small turbofan engine installed in the Eclipse 500.
They refuse to answer.

If you never build anything or build something
and don't put it in the hands of an objective observer to test
it...  it becomes just more vapor wear. Don't hold your breath
and don't invest until (or if) it becomes a proven product.

Paul Lamar

They just had their first flight and don't sell stock...  Of course that
doesn't mean that it is going to perform like they say it will.  I too have
my doubts about that engine, but eclipse appears pretty solid.

Hans

http://www.eclipseaviation.com/

Perhaps not.
But they do take deposits. As I understand it the deposits are 
non-refundable after the first flight. They can now go bankrupt
at any moment with no financial obligations.

The other thing about small jets is range. The storage volume of
a fuel tank goes up with the cube of the linear dimensions.

Let us say a Cessna Citation tank is equivalent to a tank
of 10' by 1' by 5' or 50 cubic feet.  Fuel volume would be  378 
gallons. Lets say the Eclipse is half scale. 

Lets say the Eclipse tank is equivalent to a tank 5' by .5' by 
2.5' or 6.25 cubic feet or 47 gallons. Lets give it the benefit 
of the doubt and say they somehow squeezed in 100 gallons. Typical 
for larger four place airplanes like the 182. How far do 
you think you are going to get in a twin jet with 100 gallons? 

Can we really believe the Williams engine fuel burn is going 
to be 100/375 or 26% of what a Citation burns for the same range?
The smaller Citations already have limited range.
Long range is a safety issue. I have had to turn back after
flying for several hours in SE Alaska due to bad weather. All the
way back!

As I said.... a scam pure and simple. 

Paul Lamar
 
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