Paul wrote:

BTW this prop design was used in the 30's by the British on a Sword Fish biplane
and abandoned. IVO's are OK for slow low HP airplanes.

Paul,

Frank and Dorothy wrote:

Do your comments above apply to the 'deep pitch' IVO props? I understood
that they had been designed to overcome the 170mph limitation of the
original IVOProp.

Frank.

They did not change the flat inner part of the blade so these comments still apply.
You could probably fix the fixed pitch version with cuffs made from foam and fiberglass.
Check the cuffs on a B50 or a Lockheed Electra. 

The variable pitch version is a joke.
It is a variable twist *prop* and not variable *pitch* prop. There is an optimum pitch
and an optimum twist. IVO change the twist in the wrong way to increase the pitch
on the outer portions of the blade only while destroying the optimum twist.
The only reason they get away with this in the market place is because propellors
are poorly understood. Check the fast planes. You won't see a IVO on any of them.

BTW Chuck Harbert should have been going 220 to 250 MPH with his turbo 3 rotor
in a standard size Velocity and not just 200 MPH.
 
Paul Lamar
 
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