A Public Domain Disclosure- A Passive Counter-rotating Auxillary Propellor.

"Jim Fisher" wrote in message et...
wrote in message
It
may have been invented already by somebody else, and I have not read
about it.

It has. Submarines use this technology to reduce cavitation and noise.

Either way, if I am the first, it is now a public domain
invention, for all to use!!!

As soon as you come up with a way to offset the added weight and complexity
(gotta ad a gear box there somewhere, ya' know) I'm sure you are sitting on
a million dollars, Doug. Got for it, buddy!

The test prop is a light wood, ultralight prop, 20 inchs shorter than
the C-150 prop. It can be bolted to the hub bearing wise. A small
inch shaft is used and a pair of normal flange bearings. It should be
suitable for flight, and its harmonic is expected to be about 300 rpm.
So it should then vibrate again at about 40 rpm Meaning it will be
stable in high rpm moving conditions because the power is applied by
the air movement and not the shaft!

The shorter prop will have the air redirected onto the part of the
prop that looks like it is incapable of making wind. The thick near
the hub parts.
The need for the rather odd twist on the aircraft is vibration. A
boat design with the pitch fully carried to the hub will vibrate and
fatiuge the wood fibers even.

An STC for a C-150 is easy if the weight change is nose down weight.
Adding weight to the tail is the hard STC to obtain. Adding a lighter
starter, as an STC, is the same type of stability change.

Douglas Eagleson
Gaithersburg, MD USA