Sarj idea

Hmm, I wonder if something got into that bearing from the launch locks or
the affixing bolts?

It presumably only needed to jam one trundle bearing to start the damage of
the race ring.
Brian

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On Tue, 18 Dec 2007 13:52:37 GMT, "Brian Gaff" wrote:

Hmm, I wonder if something got into that bearing from the launch locks or
the affixing bolts?

It presumably only needed to jam one trundle bearing to start the damage of
the race ring.
Brian
It is most curious that it is only the one ring of the three being used.
I wonder if it is a manufacturing defect. Maybe a bad nitride surfacing
on that one ring.

Sir Frederick wrote:
On Tue, 18 Dec 2007 13:52:37 GMT, "Brian Gaff" wrote:

Hmm, I wonder if something got into that bearing from the launch locks or
the affixing bolts?

It presumably only needed to jam one trundle bearing to start the damage of
the race ring.
Brian
It is most curious that it is only the one ring of the three being used.
I wonder if it is a manufacturing defect. Maybe a bad nitride surfacing
on that one ring.

I'm not sure where you get "three" from. There are two SARJs, each of
which has two race rings, only one of each being active.

It was clearly stated that there were three surfaces, only one of which was
affected in the coverage yesterday I thought I understood the mechanics.
Being in zero g, you have to stabilise the mass in all directions, as you do
not have gravity to help. Also, a lot was said about pre loading of
bearings, which I suppose has to be done to stop play in the system causing
vibrations given the gyro effects moving, or attempting to move the arrays
as they rotate. It may well be a small force, but anyplay on such a large
system is not a good thing.

Brian

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"Jorge R. Frank" wrote in message
...
Sir Frederick wrote:
On Tue, 18 Dec 2007 13:52:37 GMT, "Brian Gaff"
wrote:

Hmm, I wonder if something got into that bearing from the launch locks
or the affixing bolts?

It presumably only needed to jam one trundle bearing to start the damage
of the race ring.
Brian
It is most curious that it is only the one ring of the three being used.
I wonder if it is a manufacturing defect. Maybe a bad nitride surfacing
on that one ring.

I'm not sure where you get "three" from. There are two SARJs, each of
which has two race rings, only one of each being active.

Jorge R. Frank wrote:

Sir Frederick wrote:
It is most curious that it is only the one ring of the three being used.

I'm not sure where you get "three" from. There are two SARJs, each of
which has two race rings, only one of each being active.

Not sure "one ring of the three being used" is right, but I got three
from:

The 10-foot-wide toothed gear at the heart of the SARJ is gripped by
the trundle bearing assemblies, which each feature three rollers
pressed against three race surfaces with 1,000 pounds of force. Going
into today's spacewalk, engineers knew the surface layer of one race
was damaged and one was not. Using a mirror to peer at the third race
surface today, Tani reported it, too, was free of damage. The motor
drive gears appeared properly engaged and there were no other signs of trouble.

http://spaceflightnow.com/shuttle/st...ng/index4.html

Does "surface" mean the three non-geared surfaces (I guess you'd call
them top/bottom/back) of the ring here?
http://www.nasa.gov/images/content/1...g_and_gear.jpg

A search found a few diagrams/photos, but I think they'd help more if
I knew what I was looking for:
http://www.nasa.gov/images/content/1...h_callouts.jpg
http://www.nasa.gov/images/content/1...Race_Rings.jpg

Jim Kingdon wrote:
Jorge R. Frank wrote:

Sir Frederick wrote:
It is most curious that it is only the one ring of the three being used.
I'm not sure where you get "three" from. There are two SARJs, each of
which has two race rings, only one of each being active.

Not sure "one ring of the three being used" is right, but I got three
from:

The 10-foot-wide toothed gear at the heart of the SARJ is gripped by
the trundle bearing assemblies, which each feature three rollers
pressed against three race surfaces with 1,000 pounds of force. Going
into today's spacewalk, engineers knew the surface layer of one race
was damaged and one was not. Using a mirror to peer at the third race
surface today, Tani reported it, too, was free of damage. The motor
drive gears appeared properly engaged and there were no other signs of trouble.

http://spaceflightnow.com/shuttle/st...ng/index4.html

Does "surface" mean the three non-geared surfaces (I guess you'd call
them top/bottom/back) of the ring here?
http://www.nasa.gov/images/content/1...g_and_gear.jpg

That explains the confusion. Each race ring has three race surfaces. The
cross-section of the end of a race ring is triangular and the trundle
bearing assemblies wrap around that.

So... one more time:

Two SARJs
Each SARJ has two race rings, only one of which is active at a time
Each race ring has three race surfaces

On Tue, 18 Dec 2007 22:45:02 -0600, "Jorge R. Frank"
wrote:



I'm not sure where you get "three" from. There are two SARJs, each of
which has two race rings, only one of each being active.
I am reticent to correct you Jorge, knowing you are much more
knowledgeable than I. But in the briefing Mike S. referred to 3 race
rings with rollers which exerted 1000 pounds of force on each race. So
there are 3 races.
Could someone please direct me to an exploded drawing of the SARJ for
I have no idea as to what they are talking about. I don't understand
the construction of the motor at all. Also the same for the BGA.
Thanks in advance.
Regards,
Jim in Houston.

Contrary to popular opinion RN does not mean Real Nerd!
Teddy Roosevelt's mother said: "Fill what is empty,
empty what is full, and scratch where it itches"

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If that were true, since they have some samples and test samples from the
manufacture, added to the fact that the other side is fine, then one would
have thought we would have heard if it were true by now.

Did they lose anything when un fixing the launch latches.

Brian

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"Sir Frederick" wrote in message
...
On Tue, 18 Dec 2007 13:52:37 GMT, "Brian Gaff"
wrote:

Hmm, I wonder if something got into that bearing from the launch locks or
the affixing bolts?

It presumably only needed to jam one trundle bearing to start the damage
of
the race ring.
Brian
It is most curious that it is only the one ring of the three being used.
I wonder if it is a manufacturing defect. Maybe a bad nitride surfacing
on that one ring.