stunthanger.com
General control line discussion => Open Forum => Topic started by: Trostle on February 23, 2019, 03:57:49 PM
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There has been some discussion in an on-going thread and in threads in the past regarding ball links binding up. I have seen this on other peoples airplanes and have not heard a good explanation of what causes this problem. When I was in Tucson, some thought that the hot weather or temperature extremes had something to do with it. Other thoughts are that lubricating material was incompatible with the ball cap or a combination of temperature extremes and improper lubricating materials. Whatever the cause, the problem is real.
For my flap/elevator horns, I have used nothing but the ball links and caps from the race car counter of the hobby shop. These have no play, are totally free as in no friction. I have used these on a number of airplanes over a large number of flights over a period of a large number of years and have never had a problem with them binding up or showing any kind of wear. I do not use any kind of lubricants on these ball links.
Keith
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Although I like to use ball links for ease of alignment, I remember buying one kind which were stiff right out of the package. Oil didn't help, and close inspection didn't reveal any obvious defect. Therefore, it's a good idea to test these products before sealed up in the structure.
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at toro lawn mowers they changed to a diff nylon bushing material on one of their mowers and after about a month the shaft would seize up ..they went back to the org material and the problem went away
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I've used Great Planes ball links and occasional Dubro HD links on the bellcrank. They are screwed down tightly. One plane has 5 seasons in 40° - 100°F, drizzle to dry, and stored in an unheated garage. No problems, and on a profile I have access except the bell crank. From what I read, I've been lucky.
https://www.hobbytown.com/great-planes-swivel-ball-links-440-4-gpmq3864/p608477
https://www.hobbytown.com/dubro-632-heavy-duty-ball-link-black-2-dub2266/p92022
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Yes, I bought some of those Great Planes ball links. They were not as free as I would like either. And, they look wimpy to me.
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I'v been using Dubro Monster ball links on a 60" size ship with great success. Yes, they are too tight when new, so I remove a thin nickel layer off a ball link and then it works fine.
Vitalis
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I have bought a few Dubro heavy duty ball links (the ones with the brass ball) for my very first .60 size stunter about a decade ago, and find them inconsistent from one to another on tightness, as there were some that are too tight and needs to be worked in a bit with a drill and polishing compound. and there were some that are too loose with play. so I never used them. Then I got some Rocket city ones from Control line Central, both heavy duty and super heavy duty, and they all seems to be very free and no play. and I have used them ever since. I also got some just recently from Tom Morris /SH Hobby and they are all good no problem. :)
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I have bought a few Dubro heavy duty ball links (the ones with the brass ball) for my very first .60 size stunter about a decade ago, and find them inconsistent from one to another on tightness, as there were some that are too tight and needs to be worked in a bit with a drill and polishing compound. and there were some that are too loose with play. so I never used them. Then I got some Rocket city ones from Control line Central, both heavy duty and super heavy duty, and they all seems to be very free and no play. and I have used them ever since. I also got some just recently from Tom Morris /SH Hobby and they are all good no problem. :)
Just as every one I put in one of my planes. But, over time they all have tended to tighten up.
They need the race inside opened up to make them loose again. If you have some that are loose, great. But be prepared as they may tighten up!
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Nylon is one of the most hygroscopic plastics that we use. When a piece of nylon with a hole in it swells the hole gets smaller.