I don't know but it is really risky. I did not know you wanted hydraulic
constant speed props. That opens a whole new can of worms. There would
be a lot of oil in a 3 foot long 3.5 inch diameter hollow carbon fiber prop
shaft.
200 F oil is bound to have a serious effect on the strength of the epoxy.

Here is some stuff on helicopter AKA thin section bearings.
http://www.timken.com/en-us/Pages/Home.aspx
http://www.timken.com/en-us/products/Pages/Catalogs.aspx

Paul Lamar

Paul,
Marcotte and several others are now using a single plain bearing section to
input the hyd. oil to the prop. Mistral uses a helical drive gear on the
output shaft, which I was going to suggest for the govenor drive. I like that
solution better than the bevel gear, but that is personal preference. If
yoou wanted to do that on the pusher project idea, I would suggest a bearing on
the small section of the spool with a closed cone. Then you need only have
feed lines which are much simpler than filling the shafts with oil. none of
the carbon fiber need even be exposed to the oil.
Bill Jepson

How about a 3D of what you have in mind Bill. I was trying to avoid that
situation due to extra weight and complication. I am trying to get the
weight down to reduce the severe weight penalty of using shaft driven props.
Hence the carbon fiber shafts.

Paul Lamar

Paul

I like the Mark-18 design wich we can play around  and with a spline
propeller shaft similar to tracy with an additional lateral bearing and seal.

I know it will be a bit more weight but they have light weight
spool 7 lbs available and easier to built.

the cage can be reduce to lower the oil capacity and taper at
he end of spool.

the spline prop shaft can be built to meet the proper lenght
with his own housing bolted to the end of main housing.

I dont drop my idea of this drive project until i do testing
and see what kind of result i will obtain.

Jean Prudhomme

Send a sketch of what you have in mind for the prop shaft and outer
bearing where you get prop pitch control oil into the prop.
Put some dimensions on the sketch.

Paul Lamar