On Sun, 14 Dec 2008 10:48:58 -0500, "Peter Dohm"
wrote:



However, I also suspect that far too much can be made of the eccentric
thrust problem.

Over the decades, there have been a number of experiments with single blade
propellers--primarily on helicopters--with an opposing counterweight. While
my intuitive reaction was to question the probable bending force applied to
the crank shaft--or drive shaft--I have never actually heard of that being a
problem.

I think that that is because the eccentric thrust and load is not a
reversing load and so is not a fatigue factor on the crankshaft.

Therefore, I can only presume that the lack of popularity is due to other
factors, such as:
1) Reduced capacity for any given disk area.
2) Poor streamlining at speed in airplane propeller applications.
3) Strange appearance.


it is actually easier and stronger to build a two bladed wooden prop.




OTOH, it does make variable pitch ridiculously simple!

Peter

BTW, I still can't quite accept the idea either.