Fred Osborn wrote:

Paul,

Can you recommend some "Needle Bearings for Dummies" material. Some time
ago you indicated that your hollow shaft concept would be an ideal way
to implement a cog belt PSRU. I agree and would like to do a first cut
design of a PSRU for a single rotor 6.5B using elements of that
concept.  I need enough information to get a basic sizing layout to the
point where it can be turned over to a competent engineer. Any ideas,
suggestions, or critical comments from the group would certainly be
appreciated.

Fred Osborn

You need to get some bearing manuals from the makers of needle
bearings like Fafnir Torrington Kilian. The one I have is
called the Service Catalog $10.00 1988.

Also Marks Standard Hand Book for Mechanical Engineers will give 
you a nice over view. Needles don't like high speed so you
want to use the largest hollow shaft that won't over speed the
needles.

Real large hollow shafts with very very thin walls potentially  have 
problem with buckling so you might want to fill the shaft with a 
high temp foam or a cross made from aluminum sheet to stabilize it. 
It all becomes a weight trade off. My guess is around 3 inches is 
about optimum. Wall about .1 inch. Just a wild ass guess.
Perhaps a carbon fiber shaft with hard steel bearing races bonded 
on might work.

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2003 All world wide rights reserved.