<Snip!>

This is the 40,000 HP planetary I think they are using or perhaps one a

bit

smaller. Cell phone and car keys for scale. Taken at the P&W museum
in Connecticut last year. At 70% to 100% P&W claims this psru is over

99.5%

efficient.

Paul Lamar

Interesting details:

Note that the gears are all double helical cut ("herringbone").  This
permits the train to be self-centering / aligning.  As long as one or the
other of the gears in mesh are allowed to float axially, the axial thrust
from each of the opposed sets cancels out the other.  Also maintains many
more teeth in mesh than a regular spur gear, ensures continuous contact, and
minimizes (virtually eliminates) lash.  The continuous rolling contact also
can be used to make the gear set act as it's own oil pump with oil being
forced along the teeth as the go through a mesh cycle.

Looks like the planet carrier has oil galleries drilled for each of the 5
planet/sun // planet/ring contact points too.  The P&W guys are building a
real nice PRSU here.  Too bad limitations in size and cost don't permit such
niceties on their little brothers!

Tom Kendall

 
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