I have had very good success with a Warp Drive ground-adjustable propeller on
the Renegade that I completed in 2000. Since I'm using a Rotax 582C two-cycle
engine, I have to change the pitch from winter to summer to achieve the proper
takeoff rpm (temperature has a major effect on horsepower from two-cycles).
Almost all ground adjustable wood and composite propellers have straight
blades. This works well when there is less than a two-to-one ratio between
takeoff speed and cruise. When this ratio can be four-to-one on a KR, the
propeller becomes very inefficient at high cruise speeds and reduces the
maximum cruise for a given power setting. There has to be twist in the
propeller to maintain efficiency at cruise while achieving a decent climb
angle. That's why I bought an Ed Sterba prop for my KR-2. He is the only
propeller manufacturer that seems to understand the unique requirements of our
pocket rockets.
I'll be able to tell you how it performs by the 2004 KR Gathering.
Jim Vance
[email protected]
