> >  > Paul,

 >>
 >>  I have a Ross 2.17 also that needs the thrust bearings.
Checked with Tracy
 >>  as you suggested previously.  He said he was to busy to do it.
 >>
 >>  It would seem that with the number of Ross units that are out
there, there
 >>  would be someone interested in doing this work on a on-going basis.
 >>
 >>  Do you recall the mfg./part number for the needle bearings
that were finally
 >>  settled on by the group?
 >>
 >>  What do you think about the substitution of brass spacers for
 >>needle bearings
 >>  in this application?  I would think that the brass spacers would be less
 >>  prone to failure than the needle bearings.
 >>
 >>  Joe Graham

 >Brass spacers would not last unless they were provided with high
 >pressure oil.
 >
 >Any needle bearing with an ID that would fit
 >the ground down sun gear will work. For example a 1.75" bore 2.5"
 >OD Torrington needle bearing has a static load rating of 26,000 pounds.
 >Part number NTA2840. Dynamic load is 4640 pounds or more than enough.
 >The limit speed is 6900 RPM. If you assume the dynamic load capabilities
 >are zero at 6900 RPM worst case you would want to use three
 >back to back. That would reduce the individual RPM to about
 >2300. The thickness with one hardened thrust washer is
 >about .078" plus .032" or about .11 per bearing. Three times
 >that is .33 so you would need that much space plus a bit for
 >an extra thrust washer between the shoulder on the sun gear
 >and the Ross bell housing bulkhead. Every Ross appears to be
 >slightly different so I would need dimensions to determine
 >how far the sun gear needs to be ground down.
 >
 >Jerry Hey has a friend with a machine shop. Jerry can you contact him
 >and ask him if he is interested? I can provide some engineering
 >details as we have accumulated quite a few drawings of modifications
 >that are now successfully flying. This modification should be worth
 >a couple of hundred dollars as the Ross is near useless with out it.
 >
 >Paul Lamar

Jerry Hey wrote:

   Paul,   I will be glad to give Danny the details.  He does not have
 a surface grinder but of course, he knows someone who does.  Out here
 in the country we all work together.   Jerry

 Tailwind & Rotary Engine Support

 http://www.j-winddesigns.com

 mailto:j-winddesigns@thegrid.net

A shaft grinder is all that is needed.

Tracy made his own shaft grinder by mounting a low cost 110 volt
bench grinder on the carriage of his lathe. Got a spare bench
grinder lying around?

BTW I looked up the price of those needle bearings in McMaster
Carr Part # 5909K42 $2.98 for the bearing and $1.38 for each
thrust washer.

Paul Lamar

Another possibility is Ray Baker at Baker Motor Sports who has
modified several Ross Drives already although I don't recall the
nature of those modifications.  Ray's phone is 206-367-1314.  Not
that Danny would not be interested, but  Ray is worth checking out.
Jerry

Tailwind & Rotary Engine Support

http://www.j-winddesigns.com

mailto:j-winddesigns@thegrid.net

 
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