I sat through a talk by Paul Lipps at Gene Nevada at the alternative
engine seminar put on by Contact Magazine several years ago.
He flew in his home built, with his propeller. Its outer blades
were the size of a 12" ruler. Imagine model sail plane wings, or bread knife
blades. He placed split tennis balls on the tips so guests did not stab
themselves on the blades.
Later, he helped a guy design new wings for a biplane racer, and those
wings looked just like his propeller
blades. It had a 4 bladed Lipps propeller as well.
Not mentioned was the low wetted area of the blades would allow greater
span with less drag. The high angle of attack at the root allowed playing
card sized cooling inlets.
In the event of failed engine his prop has less than a 3rd of the
frontal area of a conventional prop.
Not exactly full feathering, but better than anything else.
So, if the blade has less drag for each unit of lift, then you could
add span until you get close to the ground, and then add blade count until
you have accounted for all of the available HP. Then you port the rotary to
get more HP.
Warning, looking at a Lipps propeller blade may hurt your
mind......................
Lynn E. Hanover
Is this a time warp?
I found this picture in Flieger Revue 09/2010. The picture was taken
sometime during 1926-27 flight testing.
Just look at the prop.
Richard Sohn
N2071U