On Fri, 17 Aug 2007 02:13:06 GMT, Brian Whatcott
wrote:

On Thu, 16 Aug 2007 09:59:09 -0700, Frogwatch
wrote:

I will defend my suggestion although it sounds impractical for the
Alberg. A coupler properly made...


Here's a little engineering insight. If a drive shaft is lightened
by drilling out an axial hole whose diameter is one half the outer
diameter - the shaft's strength in torque is reduced by 5% and its
weight is reduced by 25% This is important in aircraft
construction.

So as applied to cutting and shutting a propellor shaft, if its
diameter is x, and it is cut then bridged with a coupler,
the coupler's diameter ought to be just over twice the shaft's
diameter, to bridge across the gap.
....
Brian Whatcott Altus OK


I knew, sure as sure, as soon as I wrote "engineering insight" there
would be a screw-up. And there was.
If you want to maintain torque capacity though a coupling, it doesn't
need to be TWICE the shaft diameter. That's three times the cross
section area, at about twice the distance from the axis.
The coupler diameter doesn't need to be even 1.5 times the diameter
of the shaft. 1.3 times the shaft diameter would do it.
So a coupler whose diameter is about one inch bigger than the shaft
could handle up to a three inch shaft, if well connected. Yeah Baby!

Brian W