Auto conversions & gear boxes

Tim Ward wrote:

"Norman Yarvin" wrote in message
...
In article ,
Badwater Bill wrote:

When I was the test pilot on the OMABP RV-6A project, we used the
Chevy Vortec V-6 engine, the PSRU was specifically designed to turn
the prop at tip speed below 80% the speed of sound. Jess Meyers also
used a reduction ratio number that was about equal to the square root
of 2 to eliminate harmonics that could have resulted in reversed
torque pulses reflecting back into the engine. By using a reduction
ratio of 1.41 (or close to it) he eliminated many sympathetic
harmonics that may have occured.

What, in order to have the ratio between the two be an irrational number?
That's not actually going to help eliminate resonances, unless you get
lucky -- and you are about equally likely to get lucky with any number of
about the same size, irrational or not.



--
Norman Yarvin http://yarchive.net

Just out of curiosity, how would you get any ratio to be an irrational
number?

Tim Ward

There is another word I don't recall. Basically, the idea is to even out
the wear in the gearbox--especially if it is a spur gear system--to give
dramatically longer life to the psru.

Peter