What does "Medium Ivoprop" refer to?

Paul Lamar

Ivoprop has four different size prop.  An Ultralight prop, a Medium prop, a
Magnum prop, and a Magnum Wide prop.

The Magnum Wide prop is designed for airboats which can have 600+ hp.

The Ultralight prop is obviously designed for Ultralights.
It does not work on any four cylinder four cycle engine, as far as I know.  A
three blade version is destroyed in two hours of running time on a Lycoming
O-290-G 125 hp engine.

The Magnum prop has a 5 1/2" chord with a 60" to 76" diameter.  It is
designed to take 150 hp per blade.  However, Ivoprop does not sell them for
the Cadillac gear reduction or Lycoming engines at this time.

The Medium prop has a 4 1/2" chord with a 60" to 74" diameter (I think).  It
is designed to operate with engines around 100 hp.  It is still pretty new.
Again, Ivoprop does not sell them for use on the Cadillac gear reduction, or
Lycoming engines.

I have a three blade medium prop to try on my LOM engine.  However, I still
need to finish reinstalling an electrical system so I can get my RV-3 flying
again.

Jim Ayers
RV-3 N47RV Maroon Marauder

BTW for anybody interested in trouble shooting props it is a good idea to
use a velocity rake vertically mounted on top of the cowling just behind
the prop. Use a water manometer to compare the slip stream velocity over
the length of the blade using the airspeed or dynamic pressure as a reference.

Any negative or near zero flow near the hub will then show up.
A velocity rake is merely a series of small pito tubes.
The idea is to maximize the area under the velocity curve to
indicate maximized thrust at that speed.

BTW Ran across an interesting new SAE paper on props. 1999-01-1581
Math Modeling of Propeller Geometry and Aerodynamics
J. Phillp Barnes Northrop.

Paul Lamar

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