Paul Lamar wrote:

OK here it is. I think this will do it. Two one way clutches.
One for one direction and the other for the other direction.
Super small and super cheap 300 HP boat tranny :)
The one way clutches are standard auto tranny parts.

Russell Kent disagreed:

Uh, no.  I'm pretty sure that if one puts two one way clutches on the same shaft,
then both clutches have to have their "slip" directions aligned.  Otherwise, clutch
"A" drives the shaft (working properly), and then the shaft drives clutch "B"
backwards (not what you want).  Since the output shaft has to be driven both
forwards and reverse, you'd have to mount the one way clutches in opposition.  That
won't work.

Vance's design (two planetary sets) works.

Paul responded:

I don't agree Russell. One way clutches are free to rotate in the opposite
direction. The sprags will just slip along the shaft surface.
When the planet carrier is held  the forward sprags slip on the output
shaft. When the ring gear is held the aft sprags slip on the out
out shaft.

Nope.  One way clutches are free to rotate in the *same* direction.  Think about it this
way: one way clutches (as used here) allow the driven shaft to continue to rotate in the
driven direction without the driving collar (to which the clutch is attached) continuing
in that direction.  So if the "forward sprags slip on the output shaft", then the forward
sprags can only drive the shaft in the direction that it is currently turning (call it
"forward").  If you turn the collar of the clutch in the opposite direction in an attempt
to turn the driven shaft in the "reverse" direction, then the sprags will continue to
slip, as the relative rotational motion is exactly the same.  So in order to make the
forward sprags turn the driven shaft in the reverse direction you've got to reverse the
clutch.  As soon as you do that, the sprags will no longer slip when the driven shaft
rotates in the forward direction.

Russell Kent

Look closely the clutches are reversed. The driven shaft will never
drive the clutches.

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2002 All world wide rights reserved.