Good evening Paul

 I almost complete my gear box design layout with may be some
 minor changes on bearings fits and also  during machining,i
 did,t show all bolting system but it will be on details part
 dwgs.
 All finish my contract with ALIBRE and i will go back with Rheno
 to design all separate parts.
 The fact my plane will be a pusher i am using a taper roller
 bearing for the front and dept grooved ball bearing at the back.


 Jean Prudhomme


 What does it weigh Jean?

 If that is the mini sprint car bell that has an 85 mm
 prop side bearing and can scale that with rhino.

 What prop flange are you using?


 Paul Lamar

Jean,  I was looking at the drawings and sketches you recently posted. It
shows a prop shaft of 1.630 outside diameter with a wall thickness of .315
(5/16" would be .312). Also shown is a shaft part number  P107 which shows a
bearing with 1.968 ID

     Intuition tells me these sizes are too small. You can calculate loads
on the material to see if it is less than the yield point of the material,
However it comes down to what you use for the safety factor, gyroscopic
loads (which are large) and G loads. You might be able to use 1.25 as a
safety factor for static airframe components but parts with dynamic loads
must be much higher. I personally use 3.0 times the worst case loading. If
you increase the diameter and reduce wall thickness where bending loads are
lower the weight penalty would be lower. The prop flange bearing would of
course be larger (heavier) but I can't compare the weight of a too small
component with one able to carry the expected loads.

       The mini stock housing looks good for weight but has no structure for
mounting the planetary gear set. After adding a separate part machined to
mount the gearset, bearings, and seals it seems inevitable that it will
weight much more. I am assuming there is a gear set since you are describing
the prop flange as part of this assembly.  Also I am under the  impression
that the goal is to have a hydraulic controllable pitch prop PSRU which can't
be accommodated with Tracy"s PSRU.  This leads me to wonder how you might
seal the hot oil at the junction af the flange and shaft across the straight
splined connection.

george grimes

The trick is use needle bearings on the large hollow prop shaft
as they are much lighter.

Ross did it right. Just copy it. Some airplanes have flown
them for years with the sun gear thrust bearing fix.

Paul Lamar