Michael McGee wrote:

Segueing from the rotary displacement thread, the following comments got my
attention when I had too much coffee.  Follow on below...

BTW the tooth contact is not a fulcrum as the pressure on the face
of the rotor is considered perpendicular, uniform and centered over the
eccentric.
The measured tooth loads confirm that tooth load is totally unrelated
to anything but RPM. I have some charts of tooth loads in case you
are interested.

VJ - OK, I give you that - it is mostly a timing and anti tipping device -
but the engine will  self destruct if one breaks.

Yes of course. See the chart below. Improvements in gear mounting
technology have been made since this chart was published.

The phasing gear loading chart showed virtual no load at up to ~4500
rpm.  Recalling the rotor bearing loading chart from a while back (this
file dates from May, '99 ACRE NL), the bearing load was lowest around 5900
rpm.  The rotor bearing load would be a function of rotor mass so if we
adjusted the rotor mass so the bearing load is lowest at around the same
range as the phase gear we would have a virtual floating mechanical system
(upstream of the flywheel) at cruise rpm.  Can you say TBO.... !?

Possibly the step up in phase gear load between 5000 and 6000 rpm is a
function of the intake charge/compression/power expansion syncing up with
the orbiting mass of the rotor unloading the rotor bearing.  So, we could
be chasing our tails.

The real loads on the phase gear is probably much more complex.  As the
intake charge / compression / expansion / exhaust sloshes back and forth in
the orbiting chamber along with colliding flame fronts, the rotor would be
tipping back and forth in the lash of the phase gear.  Higher rotor mass
would help suppress this.

(hhhmmmm........that was good coffee......back to work)
MGM

Mike McGee, RV-4 N996RV, O320-E2G, Hillsboro, OR
13B in gestation mode

Well nobody has measured phasing gear wear and nobody talks about it.
TBO seems to be solely a function of apex seal wear and Mazda 
says 20,000 hours at 3600 RPM with ceramic seals. They said nothing about
changing the phasing gears during that time.

Paul Lamar
 
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