I didn't get so far as to know which shipper they were using. My
experience has been DHL is the preferred transporter from china. I
verified ceramic balls with 100c2 races. This is the company just
purchased by a Japanese bearing manufacturer to produce large thin
section wheel bearings for hybrid wheel hubs with the motor built in.

They appear to have the standard quality certs. We did not discuss
payment method.

Ed Carver

Good news and bad news. The good news is this verifies our design as
a wheel bearing application at this RPM and load is far more severe
than the load on a prop shaft. Here we are... out on the bleeding
edge again with these guys :) What a relief for me that somebody else
had the same idea.

The bad news is their bearing is a bit too large at 4.134 inches
in diameter ID. I have not got the material back yet but I think our
shaft material is only 4 inches in diameter.

Paul Lamar


The 7075 material is 4.25" id. That is what is lost in Mike's shop.  I
ordered that size because the planet diameter is more than 4.25 and with
4" material, I felt the bolt threads came to close to the edge. We can
always turn the Dia. down if we want. I just did'nt want to be too
small. The 4.134  bearing id will leave about .113" to rest the bearing
on. More than we had with 4" which would have been only .063 with the
100mm id bearing. The 4" id presented even grater issues.

We can actually use a 100x140x18mm which has larger balls. This will
give us a better seat area, and a stronger bearing for about the same
money. I have room for it in the casting. I don't know if you noticed,
but the bearing prices I received from Lily, are for the 105mm id size,
not the 100mm.

Louyang bearing was a referral from a slewing bearing companies that I
contacted. Slewing bearings can have really big diameters. I believe
they advertised a 400 inch id being available. They told me they did
not make a bearing as small as I needed as they only went down to
6"id., so they referred me to Louyang precision, in the same city.

Ed Carver

Ok Ed. 4.25" in dia.. I am going to a make a concerted effort this
week to get the stock back from Mike. Sorry about the one week
computer delay.

Paul Lamar


Right now I am looking at angular contact bearings. The load ratings for
radial deep groove bearings when loaded axially are approx 1/2 the
stated dynamic radial load limit.

Common limits for bearings our size are about 5000lbs radially, so axial
loads should be considered 1/2 this force for radial deep groove
bearings, but remain nearly the same for angular contact bearings.

The design change means we would need to use two angular contact
bearings in a back to back arrangement somewhere in the thrust line to
accommodate reverse loading, as single row angular contact bearings can
work only in one direction of axial force.

It all depends on a couple issues, is the max thrust load substantially
less than the limit of the radial bearing thrust limit? Do we need one
bearing to sort of float on the shaft line to accommodate expansion
differences between the shaft and the housing, as deep groove radial
bearings are sensitive to misalignment.

Having a floating bearing on the planet end, with two opposed angular
contact bearings on the prop end, might increase the thrust capacity of
the bearing assembly while not threatening the radial limits under gyro
loads.

Ed Carver


The max thrust is only 1000 pounds. One non deep groove bearing can
handle it.

Max thrust is seen only briefly during climb out. As speed
increases the thrust falls off.

HP is thrust in pounds times speed in FPS.

One HP is 550 ft lb/sec
200 HP is 110,000 ft lb/sec

Lets say it is 200 Net HP out of the prop at 200 MPH or
300 feet per second

So 110,000 ft lb/sec  = Thrust in pounds X 300 FPS

Thrust is only 366 pounds.

Cross check. Dynamic pressure at 200 MPH is 100 pounds per
square foot. Flat plate drag equivalent is therefore 3.66 square
feet about right for most airplanes.

It's the LAW!!!!!

I got the material back. I need a sketch with dimensions of the casting
pattern so I can do a final dwg on the prop shafts.
Then we can get them in the NC shop.

Paul Lamar

I'm a bit ancient when it comes to math. Have a friend, mathematician,
sandy pilot in Viet Nam, teased me cause as far as I got in math was
pythagoris. "thats all I need though Lou!" a squared + b squared = and
besides, who needs to know about string theory anyway? super strings?

I've been reading too much on the bearings, they got me worried. You
probably covered it 6 months ago.

I'll get you a sketch in the morning along with a photo of the prop
housing made from the 6061 t6 @ 5"id x 6"od tube.

Ed Carver

The math is simeple. It is the physics you need to know :)


Paul Lamar