I have installed my aleron bellcranks in both of my wings of my RV7a and noticed that one is very free takes no effort to rotate and the other is not as free. I would characterize it as being "tight" it does not bind and I have full movement with aprox. 1/32 of bushing showing. No burrs on the bushing or bell crank. It seems to get tighter when I torque the nut. Any thoughts on what to check? Something that just came to mind while typing is I should check the powdercoating but again it isn't binding. Thanks for any help
Van's Air Force
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Aleron Bellcranks
- Thread starter marvk
- Start date
rzbill
Well Known Member
Memory says the plans specify 1/64 to 1/32 total gap between bellcrank and mounting angles after tightening the pivot bolt. If the belcrank has no slop as specified then the relative length of the bushing and belcrank tube weldments need to be adjusted. Easiest adjustment is to shorten the weldment tube.
Don
Well Known Member
Okay, it slides in freely but does it also rotate freely? I found my bushings would fit better in one direction than the other and this was after extensive polishing of both the bushings and the tube they rotated in.
What I eventually found was where the three plates were welded to the tube, they were ever so slightly tighter. As near as I could tell the difference was <0.002" but it caused some noticeable tightness in part of the rotation but not the entire rotation. The way I found this was by chucking the bushing in a drill press and running it for about 30 seconds in the bellcrank tube. I could see the shiny spots on the bushing where there was contact. They lined up with welds perfectly.
I took the easy out and hand polished the outside of the bushing where they rubbed (not every where) on the Scotch Bright wheel. About 2-3 minutes of buffing and testing and they both inserted easily, and spun freely - as long as I inserted them correctly.
Now a question back to you. I called the builder's help desk and was discussing the drawing and part numbers and Joe at Van's was insistent that I ream the insides of bushing out with a reamer, not a drill bit. He must have said it three times. Since the bushing and the bolt turn together (and are pinched together with washers and a nut to make a tight connection, I don't understand the need for a reamer. If I thought anything needed a reamer it would be the bell crank tube for the 32A bolt.
rzbill
Well Known Member
Now that you fellows mention it, I do remember the tighter spots in the belcrank weldments. My wing construction was a long time ago but a dim image of me working the insides of the belcrank with a fine tooth round file (chainsaw file) is coming to mind. Would have used a ream if it was easily available.
MauiLvrs
Well Known Member
treat the inside of the bell crank?
In the same vein as this thread should the inside of the aileron bellcrank tubes be treated in some way? Primer, grease, etc. The directions don't say to do anything but I think we might be expected to know at this point...and I really don't
In the same vein as this thread should the inside of the aileron bellcrank tubes be treated in some way? Primer, grease, etc. The directions don't say to do anything but I think we might be expected to know at this point...and I really don't
In the same vein as this thread should the inside of the aileron bellcrank tubes be treated in some way? Primer, grease, etc. The directions don't say to do anything but I think we might be expected to know at this point...and I really don't
Yes, I beieve that oil is recommended and what I used. Be sure to re-lube at annual time. Some use grease, but it will dry up over time with no easy way to disassemble to clean and re-grease.
Larry
