Paul what do you think about front drive but i dont know the ratio if it
close to 3 to 1 from 2005 Jeep Liberty
Jean
Have you priced the Arrow gear?
http://www.arrowgear.com/
They supply drawings that I can use to design the spool.
Also the actual strength is known as the material specs
are there.
Paul Lamar
yes Paul
Jean Prudhomme
What was the price?
Paul Lamar
6P45L15&6P15R45 IS $741.00
I THINK WE CAN USE THE FORD RATIO 3 TO 1, 7.5 DIA IS MUCH CHEAPER AND MAIN
GEAR HAVE CIRCLE HOLE FOR MAIN SHAFT ATTACHEMENT AND ALSO THOSE BEARINGS
ARE AVAILABLE EVERYWHERE AND CHEAP
Jean Prudhomme
OK Jean get a set and ship them to me with out the spool
for drawing purposes as we will have to build a spool
and housing anyway.
Paul Lamar
Ok Paul I will ship one set
Jean Prudhomme
What I have in mind for a large thin section ball bearing
will be a minor breakthrough in the weight of angle gear
boxes if it works (patent applied for :)).
The one bearing does double duty. It takes prop thrust
as well as locating the ring gear to the pinion gear.
It also takes the bending load out of the spool and
shortens the gear separating load path to the spool bearing.
I'll know more with the help of Jarret doing an FEA on
the idea.
Paul Lamar
Paul you will need also small taper roller bearing for main
gear lateral load at rear cover position.
Jean Prudhomme
Maybe not. Hold off on buying that.
I am thinking of doing something else as I have reduced the load
on that bearing.
-------------------------------------------------
Here is a 3D of a traditional rear axle spool. It has a couple of features
we don't need. Namely there are two axles coming out. One on each side.
This means the bearings need to be rather small to support the axles.
This also means there is considerable bending loads on the spool due
to the gear separating forces. These must be reacted in the bearings
as shown by the red arrows. All and all a very heavy design.
We have a carbon fiber prop shaft coming out only only one side
so we don't need those bearings. The gear separating forces will be directly
reacted by the large diameter thin section bearing in compression.
No bending moments. The shortest possible load path. Thin section bearings are
a recent development. They are sometimes called helicopter bearings because
light weight is every thing in a helicopter.
BTW The history of shaft driven propellers has not been good.
Every designer has had trouble from the P39 through the early Northrop
prop driven flying wings and the B36. Not to mention a bunch of small
aircraft designs. A prop at the end of a long shaft is a tough
engineering problem.
The reason I am undertaking this design is the advent of hollow large
diameter carbon fiber shafts could mitigate the problem due to the high
stiffness to weight ratio. We will use Tracy's design on the torque pulse
isolator or a copy of it which hopefully will allow us to tune out
the inevitable torsional vibrations.
I suggest Jean build a ground test rig to try this system out before
he builds an aircraft around this idea. You don't want to get it all done
and then find out you have a serious problem.
Paul Lamar
Jean Prudhomme wrote:
Yes Paul this is my intention to built one unit and tested prior to built
the airplane and i have to design it around
the special drive.
The carbon drive shaft have to be protected with a light carbon fiber tubing or kevlar
in the wing in case of break so i still spinning inside of the tube before cutting the engine
Jean Prudhomme
Could you reword that? I am not following you here.
Do you want a stationary tube over the 3.5 inch diameter carbon fiber prop shaft?
Carbon fiber tubes fail differently than steel drive shafts. They fail into
a bunch of fibers. It would be a good idea to put a stationary safety tube around
the lateral carbon fiber drive shafts from the engines to the gear boxes in case
and out u-joint failed.
Paul Lamar
This is exactly what i mean a tube over the drive shaft between engine
and gearbox for safety device
Jean Prudhomme
No problem for me.
Paul Lamar
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