> 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.
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