Perry Mick wrote:

MUCH GOOD DATA deleted here for brevity ... DRS

Great work Perry. Can't wait to see those blades. Sooner or later we are
going to blow those silly piston guys into the weeds :-)

Paul Lamar

Peter Cowan/Lexi Cameron wrote:

Are these narrow chord props significantly more efficient than the 6" blades
I see on a Hatzell sitting here or are there other reasons for going this
route?
Peter.

I think Perry sized these for 150 HP. It is not the final design yet.
I am voting for 250 HP so the blades are likely to get wider as
the committee negotiates further :-)

Paul Lamar

Please allow me to vote for 300 HP.  This seems almost a "done deal" already if the
new side port engine is putting out 289 HP in stock normally aspirated
(non-modified for aviation) form.  HEY ... there's a future out there past 13Bs.
We are lucky not to be hampered by environmental restrictions, so we can go for
efficiency and not be concerned with the emmissions levels.

It might thusly be assumed that 300 HP out of a NA "well massaged" rotary is, at
very least, already on the horizon for two rotors.  20B guys are already past
that.  Why go in with a design that will be at the "edge of the envelope?

Or is this easily changed upon construction i.e. just going wider with the blades?
But, then again,  why not leave a little "headroom" in overcapacity?  Please
educate me.

I know you reach a point where you just don't want to pay the fuel bill by pushing
the "money spending lever" up any further, and 300 HP should satisfy all but the
really hard core racers, I would  assume.  How much of an efficiency "hit" is taken
by using a 300HP design on a 150 HP engine, maybe even a one rotor?

Dale Smith

I agree with this idea. Another huge advantage of a VP prop.
You will need to run a PSRU with a 3:1 ratio or higher and 8500-9000 RPM or so to get
that 
amount of HP out of a Mazda NA engine side exhaust or peripheral port. Given that 
takeoff and climb RPM is acceptable a variable pitch prop could reduce the cruise RPM 
down to a more reasonable 5000 RPM or so and still be efficient.

Paul Lamar
 
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