Rigging grease recommendations for long-term-rigged gliders

[Jim Hogue]

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

[Jim Hogue]

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

https://www.partzilla.com/product/yamaha/ACC-MOLDM-GS-10

Cheers,
Jim

[uncl...@ix.netcom.com]

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

[MNLou]

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

[rj]

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.

[chuck...@aol.com]

What does your maintenance manual recommend?

[Craig Funston]

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

[Jim Hogue]

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

[Jim Hogue]

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

[chuck...@aol.com]

Email Schleicher, tell them your concerns and ask for their recommendation. They have always been responsive to my queries in the past.
I would stay away from moly-based grease.
Chuck

[Eric Greenwell]

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/motorgliders/publications/download-the-guide-1

[jfitch]

Super Lube comes in an EP version, about twice the resistance to extreme pressures than their normal version:

https://www.amazon.com/gp/product/B001VXXJ5I/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

You could use molyD on the lift and drag pins as they aren't brass, and the main pins never wear (except through ham fisted assembly). But that seems fiddly. I've never seen a glider with more than a few hundred hours that didn't have some fretting on the pins, so it may be inevitable.

[Ed Downham]

I’ve used Lithium grease (a brown variety) with a wide temperature range and “high pressure” rating on a glider that flies a lot but is rigged 2-3 times a season. So far so good and there is still a film of grease on the pins and connectors when derigged. Can’t remember the name/spec but plenty comes up if you search for high or extreme pressure grease...

[uncl...@ix.netcom.com]

On Saturday, February 1, 2020 at 6:43:01 PM UTC-5, Jim Hogue wrote:

Another thought:
If you have a one man rigger, which almost all of us do,it isn't that hard to put a wing stand on one side , and the rigger on the other, like you are taking it apart, then pull the pins and slide the wings out enough(maybe 2 inches)to give the pins a fresh smear, and put it back together. You already have the alignment. I'll bet to could be done in less than 15 minutes. Cost is the price of wing root tape.
FWIW
UH

[Burt Compton - Marfa Gliders, west Texas]

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

Try "Flamingo Grease." Nasty, Sticky and Pink!
Made for boat trailer wheel bearings that dip into salt water in the Florida Keys.
Used it on my Blaink L-23 fittings when I had Miami Gliders and now at Marfa Gliders in southwest Texas since 2001 (where I traded rust for dust.)
Find something similar - nasty and sticky (and pink) - perhaps in a marine supply store.

Note the Blank L-23 horizontal T-tail stabilizer is very hard to remove after an outlanding or approaching storm if the pins have not been cleaned and greased every 3 months. Changed to "Flamingo Grease" and it slid off (forward) without using the expletive deleted words, a rubber mallet and wooden dowel. Mallets and hammers on aircraft are not recommended!

[jpg...@gmail.com]

The Schempp-Hirth manual just specifies "acid free grease". Which types of grease are not acid free?

[kinsell]

I believe our national dealer has recommended Master Pro Multi Purpose
Lithium Grease. If you're looking a a nasty messy gooey black grease
suitable for wheel bearings, this one fills the bill perfectly.

I've always been happy with the white lithium stuff in a tube myself.

-Dave

[Eric Greenwell]

I had the lift pins replaced on my ASH 26 E at 3000 hours, due to pitting and
wear. The wings weren't loose or making any noise, but Rex Mayes was doing the
3000 hour inspection, and said it was a good idea.

I rigged it for about half it's flights, the other half it remained assembled,
primarily at glider camps. I used various grease, but primarily the grease that
came with the glider in a little unmarked - thick amber axle grease is the look of
it. I was not very diligent with greasing the pins.

The pitting is something that proceeds slowly, so you have years to order
replacement lift pins (or rotate them 180 deg, as some pilots do).

[krasw]

Hard to think there is any techincal requirement for special grease with glider main and lift pins. The enviroment is not that extreme. Just put some clean vaseline on pins and clean old dirty vaseline off every time you rig. This has been done succesfully for close to 100 years now. Some pin wear is pretty normal during 3000 hrs no matter what grease you use.

[Jim White]

I have been using WD40 spray grease for a couple of seasons. Easy to apply
an non messy. They do two variants including a lithium based grease which
is good for high loads -25C to 130C

Any reason not to?

Jim

[Tango Whisky]

Le mardi 4 février 2020 09:08:00 UTC+1, krasw a écrit :
> Hard to think there is any techincal requirement for special grease with glider main and lift pins. The enviroment is not that extreme. Just put some clean vaseline on pins and clean old dirty vaseline off every time you rig. This has been done succesfully for close to 100 years now. Some pin wear is pretty normal during 3000 hrs no matter what grease you use.

Absolutely. I have been using plain automotive grease for the last 20+ years on my gliders and can't imagine why I should give it any more thought.

[6PK]

On Tuesday, February 4, 2020 at 12:08:00 AM UTC-8, krasw wrote:
> Hard to think there is any techincal requirement for special grease with glider main and lift pins. The enviroment is not that extreme. Just put some clean vaseline on pins and clean old dirty vaseline off every time you rig. This has been done succesfully for close to 100 years now. Some pin wear is pretty normal during 3000 hrs no matter what grease you use.

Super Lube- has the same consistency and appearance as Vaseline just not as messy and goes on thin.