I got the hub back today Paul.
When will the dimension drawings be available?
Tell Frank I will spring for the $250 if you will handle the sales
Milo
Jim Rudholm found some heat sink surplus and much cheaper. I called
them and
they have 175 in stock. The size is enough for 3 heat sinks. The cost
for 3
would be $25.
Here are the PSRU dwgs.
It would be better if I sent you an IGES or DXF.
What dwg program are you using? The dims are in the IGES or DXF files.
Paul Lamar
These alloy steel screws are 135,000 PSI and the diameter at the root
of the
thread is at least .2 inches. So the area is 0.031. Times 10 for ten
screws
is .31 square inches. Times 135,000 PSI = 42,000 pounds shear.
The bolt circle radius is roughly 1 inch so that is
42,000 inch pounds of torque in theory. Divided by 12 for foot pounds or
3490 foot pounds.
The prop torque is 3.17 times 200 foot pounds engine torque or 635 at the
engine torque peak.
That is a factor of safety of 5.5 in theory.
Putting it another way the stress on the bolts is 24,000 PSI in theory.
They should be inspected for cracking at ten hours or so and then once a
year there after. Or just put new ones in.
Paul Lamar
----------------------------------------
Here is a trick to strengthen the joint about 20%.
Buy longer bolts than necessary so there is a straight section of bolt
inserted in the end of the cut down recycled Lycoming crank shaft.
Drill the end of the shaft for the length of the straight section.
Then cut them off at the desired thread depth.
This is a major improvement from a metal fatigue point of view as you are
not starting with a thread notch.
Paul Lamar
Paul I am sorry I did not read your instructions properly. We
received your
planet carrier drawing ok.
We do not have a drawing program. If we had one, I would not know how
to use it! I am very ignorant reference computers. When we have
drawings to do, the wife Wenjin does them, but she is at work every
day so it takes time for me to respond with a return drawing. milo
Does you wife use Catia?
If so she could try this IGS.
Paul Lamar
Send it in IGES. milo
OK here it is IGS and IGES are the same.
Paul Lamar
As someone stated on here previously, the joint will be held in
tension by the bolts and friction by the mating surfaces, therefore
no shear should be experienced by the bolts. I don't remember exactly
by whom, but I remember they were a reliable source of knowledge.
It is always a good idea to inspect the bolts regardless, and use
a thread locker.
Graeme Riley
That's in theory. Suppose the bolts back out just slightly? Or a
temperature changes the tension on the bolts?
I feel more comfortable calculating the shear stress.
Paul Lamar