Paul,

 I found a good paper on traction drives (34MB) complete with
 illustration. It is interesting to note the researchers references to
 the bearing like attributes of the device and the need for similar
 alloys, hardness and tolerances.

 http://www.grc.nasa.gov/WWW/StructuresMaterials/TribMech/research/A_gear_high_speed.html

 Regards

 Doug in Japan

 I could not get this to load.
 If somebody can get it to load please screen capture
 the interesting parts and send them as jpg.

 Paul Lamar


 Paul

 That is strange. Â I just clicked on the address and it instantanty
 loaded. Â Do you want me to send the PDF to you? It has some history of
 traction drives as well. Â Did you know they have been around for about
 100 years and an early car, Â the Carter used a form of them. Â GM did as
 well but and was ready to mass produced it in the early days when top
 management said "Nay".


 Doug in Japan


 I just tried it again and it worked.
 The server must have been down at the time.

 Paul Lamar


BTW, if a link loads "instantly" when you click on it, probably it's
coming from your browser's cache..  In Firefox, if you want the
browser to actually reload a page, hold the shift key and click the
reload button.  A link which shows some of the keystrokes for Firefox:

http://www.mouserunner.com/FF_Shortcuts1Printable.html


Regards,

Matt-

I clear my cache when I exit the browser. I think the patent office
server was down at the same time.

-------------------------------------------------------------------

BTW I notice they mentioned 15,000 feet per minute pitch line velocity
which is a lot faster than I could find previously. Encouraging for
a simple turbo charger based turbo compound engine.


Paul Lamar


Paul,

Yes I was actually searching for gear line velocity when I came across
that site.  I had calculated at if my engine redline was 9,000 rpms, the
Bell 47 planetary gear line velocity would be 9400 feet per min.

Planetary roller (needle bearings) would be at 12,000 rpm.

Cruise is much more benign but even worst case operation still have
significant safety margins.

Good paper  on planetary gear boxes there as well. Tandem reversed
helical planetaries with a innovative profile seems to produce a PSRU
devoid of backlash. Cancels out thrusting moment as well.  Unfortunately
all units are HUGE.

Doug in Japan.