Hello Paul, Is there any Ivoprop users in the group. Any comment from
the group are welcome.

Best regards,
 ddunbar                          mailto:ddunbar@echidna.id.au

Ivo props have serious problems around the hub. The flat part of
the blade goes into a negative angle of attack at about
180 MPH giving a brick wall effect. Might work OK with a 14 inch
dia. spinner. Nobody has tried that yet to my knowledge.

Paul Lamar

-Gordon Robertson wrote:

Has anybody contacted Ivo and asked if they will redesign the prop with a
deeper bite hub?   I agree that the inner portion goes negative aoa at high
speed.  But the rest of the prop seems so well suited to the rotary engine,
that I would have thought he might be interested in a redesign.   In my mind
it should be optimized at about 220 mph, and use the blade twist to get some
extra oomph at takeoff.

Gordon Robertson

Gordon,

I have personal experience with the IVO. In addition to the problem with AOA at
the blade root, on 4 cyl Lycs the blades have a tendency to move in the hub. It
might not be a problem with rotaries, but it deserves a very cautious look.

Others have suggested that IVO isn't highly motivated to design a high speed
blade since he's selling all the props he can make to the ultralite & airboat
folks.

I can tell you that it does give excellent climb rates relative to a f/p wood
prop & if the design cruise of your plane is less than ~180 mph then the
performance is excellent. (Just don't forget the safety concerns.)

Charlie England

 
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