AVIONAGUJA@att.net wrote:

Paul.........I'm getting some funky numbers here :-)

I need you to crunch the numbers ASAP:

Start out with the 12 volt motor that puts out 1091.5
oz/in of torque, turning the 5/16-24 shaft and Yoke.

-What Force do you come up with at the Yoke?
-What Torque do you come up with at the Shanks?

                              Thanks........Butch

>From what little I remember about screw threads, the ramp angle essentially
drops out, and the primary force
required to turn is the friction - smooth surface well lubed - use about o.1,
but there is a multiplier because
the thrust surface is 30 degrees - I would estimate that you could possibly
develop something close to 3000
pounds - plenty for the job.

I mentioned connecting rods - the attached pic may give you a feel for the
possible configuration.
This was my quick and dirty 2 blade, the 3 blade in progress will be similar -
Vance

Ah So! Tricky Vance. I think we could do something like that
and feed the spacer block ("piston") either down the motor tube or up from
the prop flange end. 

Wait a minute where is your prop mounting flange? 
How are you going to get your con rods in there
with that attached? I still don't see how you are going to assemble
a unit with motor tube and prop flange. Place it in the truck and 
I will stop over at Rich's next week to have a look.

BTW We are using steel on steel which is less likely to gaul than aluminum 
pitch change pins.

Paul