Don't give me that. I offered to do a UBH casting pattern for you for free

and

you ignored me :) This would get the total weight of the housing down to

about 11

pounds and short light weight bolts could be used to bolt it to the

engine.

Also it would look ten times more professional. Don't underestimate that

point.

No way would a UBH casting and hollow output shaft add $2000 to the cost
of the PSRU if done right. If you believe that you are deluding
yourself because somebody will figure out how to do it at the same
or lower cost. Here is a bit of subtle biz advice from an old businessman:
You are vulnerable on these points Tracy. It is easy to get lulled into
a state of complacency but believe me things can change in an instant.
Unless you continue to improve your product to the best of your ability
and imagination you could become obsolete overnight. Been there and done

that.

So too was Henry Ford with the Model T.

Here is the latest iteration on the hollow 4130 steel hydroformed output

shaft.

The low stress prop flange and prop pilot are aluminum and slip over the

steel prop

drive pins.

Paul Lamar

George Lendich wrote:

Paul,

Can you explain Hydroformed to me, I'm wanting to do a 3" prop shaft - I
can't say I'm convinced about the needle bearings though. Taper roller
bearings still look good to me.
Your prop drive pins - are they welded onto the shaft!?

George

Hydroforming is a process where steel tubing is placed in a mold and 
high pressure water is used to expand and form the tube.

Yes they are.

Not only are needle bearings low in cost but they save weight
in the housing too. All other types of bearings would require
a larger, heavier housing. In normal flight there is no load
on the prop bearings when the prop shaft is driven by a planetary
gear set. Only during maneuvers do the prop bearings see any load.
This cannot be said about all other types of gear sets therefore
the life of the prop shaft bearings are longer when driven
by a planetary gear set... all other things being equal.

Paul Lamar
 
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