Rigging grease recommendations for long-term-rigged gliders

So, I have been using white lithium grease for decades for all my glider fittings. This has worked out fine, no problems ever, all my fittings have stayed nice, with no damage of any kind.

However, now that I have an 18 meter motorglider and am retired and blessed with time to go soar, my rigging habits have changed. I now typically keep my glider rigged for weeks at a time when flying at soaring safari or contest sites. When based at my home 'drome off season, I have a hangar so I am typically rigged for months at a time off season.

A person knowledgeable about such things recently told me that white lithium grease for the main high stress attach points (wing pins and lift pins) is not good, it dries out and/or cannot stand up to or stay in place due to the high stresses on those components, and the result is scoring. This makes sense to me, and I am thinking about changing to a better grease for long-term rigging. He suggested molybdenum disulfide grease.

I would like to invite comments on this. Are there other options for grease for long-term rigged gliders? What are the best sources (USA) for such greases?

Thanks in advance,
Cheers,
Jim J6

Sorry, I forgot to include this link as a possible source of the molybdenum disulfide grease:

https://www.partzilla.com/product/ya...CC-MOLDM-GS-10

Cheers,
Jim

On Saturday, 1 February 2020 17:43:01 UTC-6, Jim Hogue wrote:
So, I have been using white lithium grease for decades for all my glider fittings. This has worked out fine, no problems ever, all my fittings have stayed nice, with no damage of any kind.

However, now that I have an 18 meter motorglider and am retired and blessed with time to go soar, my rigging habits have changed. I now typically keep my glider rigged for weeks at a time when flying at soaring safari or contest sites. When based at my home 'drome off season, I have a hangar so I am typically rigged for months at a time off season.

A person knowledgeable about such things recently told me that white lithium grease for the main high stress attach points (wing pins and lift pins) is not good, it dries out and/or cannot stand up to or stay in place due to the high stresses on those components, and the result is scoring. This makes sense to me, and I am thinking about changing to a better grease for long-term rigging. He suggested molybdenum disulfide grease.

I would like to invite comments on this. Are there other options for grease for long-term rigged gliders? What are the best sources (USA) for such greases?

Thanks in advance,
Cheers,
Jim J6

On Saturday, February 1, 2020 at 6:43:01 PM UTC-5, Jim Hogue wrote:
So, I have been using white lithium grease for decades for all my glider fittings. This has worked out fine, no problems ever, all my fittings have stayed nice, with no damage of any kind.

However, now that I have an 18 meter motorglider and am retired and blessed with time to go soar, my rigging habits have changed. I now typically keep my glider rigged for weeks at a time when flying at soaring safari or contest sites. When based at my home 'drome off season, I have a hangar so I am typically rigged for months at a time off season.

A person knowledgeable about such things recently told me that white lithium grease for the main high stress attach points (wing pins and lift pins) is not good, it dries out and/or cannot stand up to or stay in place due to the high stresses on those components, and the result is scoring. This makes sense to me, and I am thinking about changing to a better grease for long-term rigging. He suggested molybdenum disulfide grease.

I would like to invite comments on this. Are there other options for grease for long-term rigged gliders? What are the best sources (USA) for such greases?

Thanks in advance,
Cheers,
Jim J6

I would suggest a good quality wheel bearing grease. The nastier and stickier the better.
UH

Hi Jim -

When I got my glider, an engineer, CFIG, and motor glider owner recommended Super Lube Synthetic Grease. About $8 a tube available all over.

It seems to work great.

Lou

My sailplane manual says use a Molybdenum grease. All the people around me say White Lithium is just fine for daily assembly. The local A&P says use graphite if you keep the glider assembled for a long time.

I don't know. I just do what I'm told.

What does your maintenance manual recommend?

I used Superlube for awhile, but felt like I was getting too much fretting wear. Switched to Lucas Red n Tacky. Good wear and anti corrosion properties. https://lucasoil.com/products/grease/red-n-tacky-grease

The Schleicher manuals for my ASH-26E do not specify any grease types. The only mention of grease types is to not use molybdenum disulfide on any bearings with brass parts.

One correction to my original post, I said "scoring" I meant to say "fretting".

Also, FYI my knowledgeable person noted that white lithium grease is good long term for the other lube points (control connections).

Cheers,
Jim J6



On Saturday, 1 February 2020 20:16:16 UTC-6, wrote:
What does your maintenance manual recommend?

My knowledgeable person also mentioned graphite as good for long term rigged. What form is this, the powdery stuff, or is there a pasty type "graphite grease"? Not familiar with it....

Cheers,
Jim J6



On Saturday, 1 February 2020 19:08:14 UTC-6, rj wrote:
My sailplane manual says use a Molybdenum grease. All the people around me say White Lithium is just fine for daily assembly. The local A&P says use graphite if you keep the glider assembled for a long time.

I don't know. I just do what I'm told.

Jim Hogue wrote on 2/1/2020 3:42 PM:
So, I have been using white lithium grease for decades for all my glider
fittings. This has worked out fine, no problems ever, all my fittings have
stayed nice, with no damage of any kind.

However, now that I have an 18 meter motorglider and am retired and blessed
with time to go soar, my rigging habits have changed. I now typically keep my
glider rigged for weeks at a time when flying at soaring safari or contest
sites. When based at my home 'drome off season, I have a hangar so I am
typically rigged for months at a time off season.

A person knowledgeable about such things recently told me that white lithium
grease for the main high stress attach points (wing pins and lift pins) is not
good, it dries out and/or cannot stand up to or stay in place due to the high
stresses on those components, and the result is scoring. This makes sense to
me, and I am thinking about changing to a better grease for long-term rigging.
He suggested molybdenum disulfide grease.

I would like to invite comments on this. Are there other options for grease
for long-term rigged gliders? What are the best sources (USA) for such
greases?

My ASH 26 E came with a small can of what looks like an amber colored wheel
bearing grease. I've been using mostly that for 25 years. I'm not sure the exact
grease is important. What may be happening to lift pins that wear is "false
brinelling". From the full article under 'False Brinelling' in Wikipedia:

-------------
The basic cause of false brinelling is that lubricant is pushed out of a loaded
region. Without lubricant, wear is increased. It is possible for the resulting
wear debris to oxidize and form an abrasive compound which further accelerates wear.

In normal operation, bearings remain lubricated. However, if a bearing is
stationary but subject to a very small oscillating or vibrating load, lubricant
may be pushed out of the loaded area. Since the bearing is rolling only small
distances (less than roller spacing), there is no action or movement that replaces
the displaced lubricant.
-------------

Derigging/Rigging probably reestablishes the lubricant film, regardless of the
grease. Perhaps there is a lubricant that prevents the push-out; failing that,
periodically pulling each wing panel out about 3 inches, greasing the lift pins,
and sliding it back in would also do it.

Note the problem can affect wear bearings on cars shipped by rail from the one
coast to the other, or bell crank bearings in the wing of a glider that is
trailered long distances over many years (that's how I encountered the problem).

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1