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Aileron bellcrank

Posted: Mon Feb 03, 2020 1:58 pm
by 6843
HI All. I need some help. I didn't notice the bushings above and below the bellcrank and now I don't know how to reassemble. The bellcrank has a Torrington bearing (illustration #2-27). Inside the bearing is a bushing that is approx 0.090 longer then that thickness of the bellcrank. I had 2 "washers" that fill the gap between the bracket and the bearing, one on top of the bellcrank, one below. One is 0.030 think, the other is 0.060 thick. The parts manual only shows one "washer" (they call is a bushing) on top of the bellcrank, illustration 2-24 (part # 0422162). I can't find a reference to the thickness of the correct bushing so I don't know which of the ones I have is the correct part/deminision).

So my questions are: should there be a washer/bushing top and bottom to pad-out the bushing inside the Torrington bearing? Do you know which washer/bushing I should use. If I mix-up the washer/bushings, would the height of the bellcrank being off 0.030 make a difference?

This is hard to describe, I hope what I wrote makes sense.

Dave

Re: Aileron bellcrank

Posted: Sun Mar 15, 2020 3:41 pm
by 7130
I'm curious if you found the answer to your question. I don't see bushings above and below the bellcrank on my 1947 140, just the one bushing. I can move the bellcranks up/down about 1/8 to 1/4 inch and am wondering what I'm missing.

Re: Aileron bellcrank

Posted: Sat Mar 21, 2020 12:30 am
by 6843
7130,

I don’t have a definite answer, but I purchased a bellcrank from a salvage yard and it came with the same washer/spacer so I’m guessing they came from the factory. One is 0.030 thick, the other 0.060 thick. The bellcrank on my other wing had only an 0.030 washer/spacer. My, and my IA’s, best guess is they used spacers as necessary to have a snug fit between the bellcrank and the C-shaped fitting it mounts into. Since the C-shaped mount is assembled from several sheet metal pieces, there might have been inconsistencies and they used different thickness spacers as needed. Also, without the spacer, the (or at least my) bellcrank scraped the bottom of the C-mount. I don't think you want any vertical movement in the bellcrank and I think you want to space it off the bottom a bit to prevent scraping. I ended up putting the thicker spacer on the bottom to provide a little more clearance for the nut on the bolt holding the control cable to the bellcrank.

Re: Aileron bellcrank

Posted: Tue Mar 31, 2020 10:49 pm
by 7130
Thank yoy!