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Aileron Bellcrank Grease

Mudfly

Well Known Member
I'm ready to install the aileron bellcranks in the wings (RV14). Not sure about other models, but the bellcrank design for -14 has a brass bushing that is inserted into the steel housing of the bellcrank. The assembly is placed in position and secured using a AN4-32A. When the bolt is properly torqued, the bolt and brass bushing are to remain stationary with the rotation occurring between the bushing and the steel bellcrank. There is no mention in the plans of lubricating this rotation point, but I was thinking it may be a good idea. My question is what would be the better lubrication. LPS-2 and Lubriplate 630-AA are two products that I'm considering. It seems both may have pros and cons.
The pros for the Lubriplate would seem to be longer lasting. However, the con would be when it is time to replace, the bellcrank assembly would need to be disassembled. Also, will this lubriplate break down during the heat of the summer and drip out the bottom? That's what happens to grease in my grease guns out in the garage during summer. The pro for the LPS-2 would seem that when time to re-lube, it would just require opening the access panel on the bottom wing skin and applying fresh lube using a flexible tube. The con for LPS-2 would seem that it would need to be re-applied at shorter intervals.
I realize I'm overthinking this, but was just curious what others have used, and actual lubrication requirements for this part once in service.

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Check plans

The plans should say to use grease duringg assembly. I used Modil 1 synthetic wheel bearing grease from autozone.
 
Just a thought . . . .

I made a bell crank for a different function and drilled a hole in the center of the tube with a deep chamfer so a small grease gun could be used to inject some lube. One would need some path for it to flow internally though.
 
I tumbled the brass bushings for my bellcranks in a vibratory tumbler. I also ran a little 400 grit sand paper through the bellcrank and deburred the ends. Then, I assembled with just a little bit of Aeroshell 22 on the outside of the bushing.
 
The plans should say to use grease duringg assembly. I used Modil 1 synthetic wheel bearing grease from autozone.

The plans purposely don't say to use grease because you would have to disassemble it every year to re-lubricate it.

The oldest of Van's demonstrators with this style bellcrank are 20+ years old. They have all been maintained by regularly lubricating with LPS2 at each yearly condition (or 100 hr if that comes first.... the certification on all the demonstrators requires an inspection every 100 hrs if it is flown more than 100 per year) inspection.

None of the parts have ever been replaced and there is no appreciable wear so far.
 
The plans purposely don't say to use grease because you would have to disassemble it every year to re-lubricate it.

The oldest of Van's demonstrators with this style bellcrank are 20+ years old. They have all been maintained by regularly lubricating with LPS2 at each yearly condition (or 100 hr if that comes first.... the certification on all the demonstrators requires an inspection every 100 hrs if it is flown more than 100 per year) inspection.

None of the parts have ever been replaced and there is no appreciable wear so far.

I am curious what the recommendation is for the steel bushings on the front gear leg.

Larry
 
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Thanks

The plans purposely don't say to use grease because you would have to disassemble it every year to re-lubricate it.

The oldest of Van's demonstrators with this style bellcrank are 20+ years old. They have all been maintained by regularly lubricating with LPS2 at each yearly condition (or 100 hr if that comes first.... the certification on all the demonstrators requires an inspection every 100 hrs if it is flown more than 100 per year) inspection.

None of the parts have ever been replaced and there is no appreciable wear so far.

Thanks Scott. I'll go with the LPS2 and add to my yearly condition inspection checklist to re-lubricate.
 
Glad to have found this thread! I was wondering about lubricating these during installation too. Has anyone else polished the inside of the bellcrank and the brass bushing as noted below? I think the tumbler idea is a good one. Maybe just a little bit of fine grit sandpaper on a dowel rod for the bellcrank as well. Then lube with LPS-2 as Scott says...

I tumbled the brass bushings for my bellcranks in a vibratory tumbler. I also ran a little 400 grit sand paper through the bellcrank and deburred the ends. ...
 
I am curious what the recommendation is for the steel bushings on the front gear leg.

Larry

I just did mine Larry... the instructions say to use wheel bearing grease. So does this mean I need to take the nose gear off every year?
 
RV-7 instructions tell us to use grease on aileron bellcrank

This may be a slight diversion, but this thread prompted me to check the RV-7 instructions since I recalled being told to use grease on the aileron bellcrank bushing and have recently done so. Note that the brackets in the RV-7 are steel so possibly that's the reason for the difference?

On page 7-11 (my instructions dated 06/13/11) it says:

"Install the WD-421 bellcrank as shown on DWG 15A. The bushing in the WD-421 needs to be drilled to final size for the slip fit on the AN4 bolt. The bushing should be slightly longer than the WD-421 aileron bellcrank. It is held firmly between the bellcrank brackets with the bolt. The bellcrank rotates around the bushing, not the bolt. This is the same way that the stick assembly is done also. Lubricate the bushing with your favorite grease when assembling for the final time."

I used Lubriplate Mo-Lith No.2 grease. Hope I don't need to remove it or replace every year!
 
I just did mine Larry... the instructions say to use wheel bearing grease. So does this mean I need to take the nose gear off every year?
I like to re-grease through the Zerk fitting at annual, but disassemble/clean/re-grease every other year.
 
I like to re-grease through the Zerk fitting at annual, but disassemble/clean/re-grease every other year.

No Zerk's for the three steel bushings for nose gear pivot.

I would expect that grease to get hard and crusty after a few years and would seem they need to come apart. However, adding oil every annual to these should keep the grease from drying up.

Larry
 
my take

No Zerk's for the three steel bushings for nose gear pivot.

I would expect that grease to get hard and crusty after a few years and would seem they need to come apart. However, adding oil every annual to these should keep the grease from drying up.

Larry

I read the same thing in the manual about using grease. I realized it might be a while before they are taken apart again so I chose the synthetic grease that is not suppose to harden. If I feel the ailerons starting to stick, this will be the first thing I inspect, besides being done during condition inspection. I just don't feel right putting this together without some kind of lube, not unless the bushing is oil lite material, which it isn't.
 
No Zerk's for the three steel bushings for nose gear pivot.

I would expect that grease to get hard and crusty after a few years and would seem they need to come apart. However, adding oil every annual to these should keep the grease from drying up.

Larry

You can do that by just being sloppy changing the oil filter.........:D
 
You can do that by just being sloppy changing the oil filter.........:D

Now lots of us have a rational justification for spilling oil during the filter change. I sense lots of smiling as we tell onlookers that this is done on purpose. "See, the oil filter is strategically placed directly above the bushings."
 
The plans purposely don't say to use grease because you would have to disassemble it every year to re-lubricate it.

The oldest of Van's demonstrators with this style bellcrank are 20+ years old. They have all been maintained by regularly lubricating with LPS2 at each yearly condition (or 100 hr if that comes first.... the certification on all the demonstrators requires an inspection every 100 hrs if it is flown more than 100 per year) inspection.

None of the parts have ever been replaced and there is no appreciable wear so far.

Page 7-12 of the RV-8 plans say “ Lubricate the bushing with your favorite grease when assembling for the final time.” I read what Scott said that it purposely says do not use grease.

I’m confused
 
Use standard wheel bearing grease.

Anytime you have two metals together that have relative motion, or you want to ever take apart, add grease.

So reminder to always add grease to landing gear to weldment contact surfaces and such.

Carl
 
Page 7-12 of the RV-8 plans say “ Lubricate the bushing with your favorite grease when assembling for the final time.” I read what Scott said that it purposely says do not use grease.

I’m confused

I have never seen that construction manual entry in the RV 7/RV 8 wing build manual.
This happens every once in a while…. That what gets written in the manual doesn’t align with what is actually being done in the prototype part of engineering on the actual airplanes.
I don’t think any of the other models that use this style of bell crank specify the use of Grease. As I mentioned, previously, this is considered a movable part that requires regular maintenance lubrication. To regularly renew the grease, you would have to fully disassemble. The bell crank pivot point which would be annoying. That is why in the Proto shop we have always used a regular application of LPS2.
This is the same type of pivot joint that is on the bottom of the control stick on the majority of the different models and Grease has never been recommended there (I don’t think).
There is nothing wrong with using grease, but it just shouldn’t be considered a one time and forget it task.
 
Thank you Scott. LPS for me then.
Just for your reference I’m reading section 7 of the manual bottom left corner has “8s7-1r11 06/13/11” as the revision and date. Perhaps an update would be in order to align with LPS usage.
 
Scott's long term experience with LPS2 makes for a strong recommendation. Would anyone care to comment about LPS1 for the same applications?
 
Scott's long term experience with LPS2 makes for a strong recommendation. Would anyone care to comment about LPS1 for the same applications?

Dan - I used to use LPS-1. However, I switched to LPS-2 as LPS-1 wasn't holding up well in exposed areas like hinge pins, etc.... There where also some reports of corrosion on joints when LPS-1 was being used, but you know how that goes....
LPS-1 might be as good inside the wing, or perhaps even a bit better as it seems to penetrate better as it isn't as thick. However LPS-2 is listed as a penetrant.

That said, I exclusively use LPS-2 now for everything. I reserve LPS-1 for cleaning things like rudder cable/horn bolts, or any joint that has gotten dirty. LPS-1 works sort of like a solvent for this application. I then apply LPS-2. I like this approach vs using a true solvent for compatibility. I don't have to disassemble, clean, and blow off parts to make sure the solvent is gone. I spray with LPS-1, blow it out, and repeat until clean, then apply LPS-2.
 
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Lubrication.....

Scott's long term experience with LPS2 makes for a strong recommendation. Would anyone care to comment about LPS1 for the same applications?

LPS 1 is lighter and may not stay in place as long or lubricate as well as -2.

Us bicyclists like things that are thicker and stay in place a little better. Boeshield T-9 (developed by Boeing) is a good general-purpose lubricant. Squirt is a thick lubricant used on bicycle chains but works well on other moving things. Both are wax-based (rather than oil) and don't attract dust/dirt/grime as much as some others might. They are sold in a small bottle. The T-9, I believe, also comes in a spray form..... Visit your local cycle shop and see the variety of lubricants they sell.....:)
 
LPS 1 is lighter and may not stay in place as long or lubricate as well as -2.

Us bicyclists like things that are thicker and stay in place a little better. Boeshield T-9 (developed by Boeing) is a good general-purpose lubricant. Squirt is a thick lubricant used on bicycle chains but works well on other moving things. Both are wax-based (rather than oil) and don't attract dust/dirt/grime as much as some others might. They are sold in a small bottle. The T-9, I believe, also comes in a spray form..... Visit your local cycle shop and see the variety of lubricants they sell.....:)

How would that differ from LPS 3?
 
My LPS ABCs

LPS-1 is essentially silicone, and does not have any load bearing properties, and will not perform long term.
LPS-2 is a mineral based oil that is very compatible with the carrier in Aeroshell #5 grease.
LPS-3 is a high content paraffin formulation intended to provide a moisture resistant coating.

I only use LPS-1 where there is minimal load, and no evidence of residue is desired, such as cowling hinge pins. LPS-2 covers about 90% of what gets lubed during an inspection. LPS-3 is, for me, limited to infrequent movement part connections where water exclusion is important.

I lube bushings with Aeroshell #5 during assembly, followed by LPS-2 thereafter.
 
Frustrating

I just greased and installed these WD-421 bellcranks yesterday per the 8 wing manual page 7-11, last paragraph, last sentence states "use your favorite grease when assembling for the last time". Does Vans recommend disassembling and removing the grease or just applying LPS-2 going forward?
 
LPS-1 is essentially silicone, and does not have any load bearing properties, and will not perform long term.

The safety data sheet suggests it's mostly kerosene? If so, it may indeed evaporate over time. Guess I should order some LPS2.

https://www.itwprobrands.com/files/branddocs/29/LPS_LPS1_Aerosol_US_English.pdf

LPS-2 is a mineral based oil that is very compatible with the carrier in Aeroshell #5 grease.

Kerosene with a light oil?

https://www.itwprobrands.com/files/branddocs/29/LPS_LPS2_Aerosol_US_English.pdf

LPS-3 is a high content paraffin formulation intended to provide a moisture resistant coating.

https://www.itwprobrands.com/files/branddocs/29/LPS_LPS3_Aerosol_US_English.pdf
 
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I just greased and installed these WD-421 bellcranks yesterday per the 8 wing manual page 7-11, last paragraph, last sentence states "use your favorite grease when assembling for the last time". Does Vans recommend disassembling and removing the grease or just applying LPS-2 going forward?

The important thing is that it is lubricated with something that is meant to be a friction and wear reducing lubricant. That is likely why it says "use your favorite grease" with nothing specifically mentioned.

In the future, if you don't want to disassemble and add more grease, just lube with a spray lube like LPS2 (just don't use something that it only meant for corrosion prevention or moisture displacement like WD40, etc.).
 
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