> Paul.
     >
     > We are back from Kyoto now. It was a nice autumn this year.
     >
     >
     > Say I have heard  about the Ford PSRU  and its ability to handle 650
     > ft.lbs
     > of torque many times now.  No doubt the gear sets are robust but
    with all
     > due respect is that  statement 100% accurate?  Perhaps the Ford
    set that
     > Ross and Tracy selected doesn't see all of that torque but just
    part of it
     > since it is embedded in a power train with loads in series and in
     > parallel.
     > The trucks' rear end would be series while some load paths in the
     > transmission appear to function in parallel.
     >
     > About the bearing and planetary speeds of the Bell, I agree with
    you 100%.
     > Gear line speeds seem to be within the realm of possibility but
     > centrifugal
     > loading is a challenge. Obviously Mistral came up a bearing solution.
     >
     >   Both Bell and  Mistral are well engineered products, with each
    component
     > selected  for use using proven aviation tough components and
    developed
     > with
     > extensive.  For the majority of the people on this newsletter though
     > Tracy's
     > unit appears to be sized just fine. It is a quality item but is
    limited to
     > fixed wood props. I happen to personally think a  3:1 or a
    slightly higher
     > ratio has some advantageous for my particular application.  Still
    because
     > Bell's design point was originally  focused on helicopters I look
    at the
     > design as a good  starting point, not the finished product.
     >
     >   Here are a few pictures of all of the components shot from both
    sides.
     > Only the inner race of the TRW thrust and support bearing is
    shown in the
     > upper left.   No prop shaft is made yet.
     >
     > Note  the planetary gear shaft has a hard bearing  sleeve that
    slips over
     > it
     > and then the bearings ride between this sleeve and the inner part
    of the
     > gear.  This set-up lowers the rpms the roller bearings actually see
     > because
     > the sleeve is also moving in relationship to the shaft.
     >
     > Is that analogous to your stacking thrust bearings?
     >
     >
     > George
     >
     >
     > The 'one inch' referred to the thickness of the gears.  Yes gear line
     > contact would be  less than the Ford helical gears and spurs are
    noisier
     > but
     > I don't want to have to deal with thrusting issues. I doubt noise
    will be
     > a
     > concern though as it will be masked by greater engine noises.
     >
     > I haven't seen the gear sizes of the primary planetary that feeds
    into the
     > one I have.  You can see a cut off plate of the primary planet
    set on the
     > left in the picture. Its' shafts are 14.5 mm in diameter  and the
     > planetary
     > set diameter is  about 144.5mm + 0.2 - 0 on shaft center.
     >
     >
     >
     > Doug Fir
     >
     > That pretty lady is with a strange looking Japanese gentleman :)
     >
     > Paul Lamar

    Doug,
    Some questions please!
    The ring gear seems integral to the Bell Housing is that a press - fit?
    The piece to the right of that seems like the seal holder cover
    plate to the
    front of the Bell Housing.
    The large ring looks like a spacer ?
    Below that is the planetary gears and gear holder.
    To the left of that is the sun gear I assume?

    The 3 items to the left have me puzzled - what is a cut-off plate,
    is that
    one side of the other planetary gear holder?
    The bearing is for ?
    The center piece of those 3 items is power in? power out?

    Also what is that part that is just showing to the right of the picture?


    I have this ratio work sheet for you, if you send me your e-mail address
    again!
    George ( down under)

    I forgot to answer some of your questions Doug. All gear sets
    in a auto transmission of the Ford type in question are in series
    and not parallel. In fact the first set in the chain sees more
    than 650 foot pounds because there is a torque converter ahead of
    it. The torque converter, at stall, can multiply the torque up
    to a factor of two. In other words the very first set of planetaries
    (there are as many as three in series) sees as much as 1300 foot
    pounds and every set after that see more depending on the reduction
    ratio. The amount of torque load depends on the weight of the truck,
    the load in the bed, the grade, the acceleration and the towing load.
    If the bed load is 3/4 of a ton or 1500 pounds and the truck
    weighs 4000 pounds empty with 1500 pounds on the rear the torque
    going into the third member could be as much as 1100 foot pounds
    or more depending on the rest of the additive factors.

    The most torque Tracy and Ross boxes behind a side port NA rotary
    will be about 160 foot pounds. 240 pounds for a side port NA 3 rotor
    and probably around 300 ft pound for a p-port 3 rotor.

    It is easy enough to test. Lock down the Ford planet carrier
    on a test stand and connect a long lever to the sun gear. Apply
    weight to the end of the lever until the planetary fails.
    I'll wager it will take well over a 1000 foot pounds to
    break it. That is 200 pounds on the end of a five foot lever.

    Paul Lamar ...No rotor no motor.



Nit to pick:  The load in the bed, the grade and the gearing having no
effect on (peak) system torque.  Pressing the fuel pedal torques the
system.  The load in the bed and the grade being climbed control the
duration of the torque (in places with a speed limit)..


Matt-

Yes of course.
I think the worst case is anchoring the truck to an immovable
object and stalling the torque converter.


Paul Lamar ...No rotor no motor.

Paul & Matt,
You are both correct and incorrect.  The torque converter only
multiplies torque when it is "slipping" and the maximum multiplication
occurs at stall.  But, with a stock torque converter, the engine will
not rev to its maximum torque RPM in the stalled situation.  So,
maximum torque in  the transmission occurs at some RPM between stall and
the peak torque RPM of the engine.

Aubrey

Perhaps a diesel engine could hit max torque at converter stall RPM.