Is there any reason why the particular gear ratio between the rotor and
the
 output shaft (not sure if this is the proper term) was chosen?  Would
there
 be a way to modify this so that the PSRU was essentially integrated into
 the
 motor?  So, for example, so that 4 turns of the rotor were necessary for
 one
 turn of the shaft instead of 2?

 Just a thought, but might save alot of weight and one of the major risk
 factors of auto conversions.

 Thanks,
 Brannon

 I am not sure what you mean by "integrated".
 Can you come up with a sketch?

 Paul Lamar


 Brannon, The PSRU ratio ideally is the engine RPM at max power for take
off devided by the RPM where the prop tips are going supersonic.  The next
factor is that in our case we don't particularly want the added weight of
offsetting the thrust line above the E-shaft center.  The planetary gear
arrangement puts the output shaft directly in line with the e_shaft with the
added benefit of driving through 6 planet gears for a minimum of 6 teeth
transmitting the power rather than one tooth on a gear to gear drive.  There
is also a lot of cumulative line contact on the gears with the planetary,
therefore a relatively small gearset can be used.  The gearset of choice is
from Real World Solutions designed by Tracy Crook.  This PSRU uses a
superduty ford diesel (E40D) low range planetary which happens to be 2.85
ratio when the ring gear is held and the planetary drives the prop Holding
the ring gear also turns the prop the same direction as the engine rather
than reversing the rotation allowing a larger selection of props to use..
Ideally we could use more gearing in the range of 3.20 to 1 but to use mass
produced gearsets we have to choose something commonly available.  In my
case (6 Rotor) I need a larger gearbox for 700 HP and after looking at
photographs of planetary gearsets for sale on E-bay I chose the 4 wheel
drive transfer case planetary from the same superduty Ford F350
transmission.  The ratio is 2.64 to one.  More gear would be better,
however, this gearset needs no machining off of extra parts and is well
supported with bearings.  It is also 4 pounds heavier than the E40D but I
can't compare the weight of something not strong enough with something that
is overkill.  This planetary is only used when the 4-wheel drive is in low
lock so even used there are very few hours of operation on the parts.  I
bought my set for $45 and it looks like new.  I entered all the Ford parts
in Rhino4 last weekend and am designing the housing next weekend.  I still
don't have the shaft mounted oil pump that fits around the input shaft in
the truck which I will use for pressure lubrication after running the oil
through a cooler.  This will allow useing gear lube in the PSRU rather than
engine oil.  I well attempt to attach a JPEG image of the Rhino4 drawing
showing the Ford parts and the thin wall prop shaft designed to use this
gearset.  All drive is thru splines including one that has to be cut near
the end of the propshaft The rest of the splines are used as is..The JPEG
named geartrane shows the Ford parts which are used as they come out of the
truck.  The JPEG named PSRU componets includes the propshaft as well as the
parts assembled for use.  In both images there are two lineups of the parts
showing the view e from both ends.



 george grimes

  Hi George, when I was looking into BW marine reduction units it was
suggested that I use ATF.

   Murry

Murry could you add about ten characters to your line lenght wrap in your email
editor?

Paul Lamar

Incredibly interesting George.  I understand a lot more about what Paul and you guys ate talking about.  Thanks.

Van