On Mon, 27 Oct 2003 05:44:36 GMT, Rick Tyler
wrote:



Actually, Dave Gerr claims a one-bladed prop would be even better, if
you could only solve that pesky vibration problem.

- Rick Tyler

Hehe
I read that too, and I reckon he's right. If I had to take a wild
guess, I'd say the reason this composite prop is using 4 blades is
because it allows for shorter blades and therefore less flex.

-m

There's an airplane motor with a one-blade propeller on it in Portland,
Oregon at a museum. The propeller and motor are from a real airplane that
flew, and apparently it the one blade prop is the most efficient for
aircraft too. On the side where the second blade should've gone, there was
a short stub that acted as a counterweight. The prop ran smoothly and had
zero problems, but never sold well because people just didn't feel
comfortable with the idea.

I'd almost bet that something along the same lines has been used for boats,
and I'll be there's more to it besides counterbalancing. No matter what
though, even if efficient, the one bladed prop will put a side load on the
bearing because the forward thrust creates leverage from one side only.

Brian


"sour (max camirand)" wrote in message
...
On Mon, 27 Oct 2003 05:44:36 GMT, Rick Tyler
wrote:



Actually, Dave Gerr claims a one-bladed prop would be even better, if
you could only solve that pesky vibration problem.

- Rick Tyler

Hehe
I read that too, and I reckon he's right. If I had to take a wild
guess, I'd say the reason this composite prop is using 4 blades is
because it allows for shorter blades and therefore less flex.

-m

I don't know if they still do but back in the 50's and 60's they used
one blade props on model airplanes for speed records. The prop was
balanced with a metal counter weight. I think I remember seeing them on
high speeds boats too. Isn't a two bladed surface piercing prop
essentially only one blade in the water to reduce drag?

Regards, Ron