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INA, but that does not necessarily mean they are better quality. There are MANY ways to spec the bearing. Your book may have been giving a worst case number. L10 life spec is what I typically try to use unless the application just can't fit around those. Sometimes you have to give up 10,000 hour life for other considerations.
Tracy
On Mon, Jan 19, 2009 at 3:41 PM, George Lendich <lendich@optusnet.com.au> wrote:
Thanks Tracy,
These speeds are much higher than those in my
books, quite obviously a better quality product - can you tell me what brand
they are?
George ( down under)
----- Original Message -----
Sent: Tuesday, January 20, 2009 3:52
AM
Subject: [FlyRotary] Re: Thrust
bearings
I've learned it's rarely wise to debate these kind of things
but FWIW, needle bearing rpm capabilities are not simple to nail down.
You might notice that this same (or very close) sized bearing (a single stage
at that) is used in the 13B itself and of course it does not limit the engine
to 2800 rpm. Needle bearing ratings are also sensitive to lubrication
schemes. The thrust bearing in the RD-1 is pressure fed to insure the
best possible lubrication and cooling environment.
If it gives you any
comfort, check it out on www.Mcmaster.com website (pg 1135 of
catalog) and you will note that the 35mm x 52mm needle bearing at a dynamic
load of 4000 lbs is rated up to 6500 rpm in a single stack. In a double
stack, that gives you a good margin well over 10,000 rpm.
Hope this
puts your mind at ease.
Tracy
On Sun, Jan 18, 2009 at 6:23 PM, George Lendich <lendich@optusnet.com.au>
wrote:
Tracy.
On
another subject, I was looking at your web site and noticed the different
Sun gear thrust bearing stages and notice you went from Ball bearing (
failed) to roller bearing - to what appears to be 2 back to back
needle bearings with their end and intermediate washers.
Looking at
the bearing book, I notice a limit of about 2,800 rpm on needle bearings
which give only 5.600 rpm limit.
My question is, wouldn't 3 needle
thrust bearings be needed and could you use 2 thrust ball bearings back to
back which run at 5,600 rpm each?
I guess it would be way over kill
but NSK double direction angular contact thrust ball bearings, run to 9,500
rpm.
Did you consider any of these other options? or was space your
over riding factor
George (down under)
Steve:
Any reaction from the Dept of Homeland Security to that muffler?
:>)
Tracy
On Sun, Jan 18, 2009 at 4:01 PM, Steven
Boese <sboese@uwyo.edu> wrote:
Mike,
The
length of the cylindrical section is 24 inches. The conical
section is
9 inches long.
The dome was made from a Kmart
mixing bowl. Some of it is less than 0.032
inches thick
but has held up so far.
The cylindrical section was made by a
local sheet metal shop with a stove
pipe joint that also has been
tack welded in a few places.
I made the conical section, inside
parts, heat shield, and mount from the
same sheet material as the
cylindrical section. The joint in the conical
section is
similar to the stove pipe joint and is also tack
welded.
Steve Boese
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