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John Hauck
Joined: 09 Jan 2006 Posts: 4639 Location: Titus, Alabama (hauck's holler)
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Posted: Thu Sep 30, 2010 6:53 pm Post subject: new owner of an older kolb x kit |
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No, I didn't say that.
I did not have to change out aileron push/pull rod end bearings. I changed out aileron push/pull rod end bearings that showed any sign of play, 25 hours, 50 hours, whenever there was the slightest bit of play, in an effort to prevent aileron flutter. Not because the ball was going to pull out of the socket.
In my last post I shared I have aileron push/pull rod end bearings with over 3,000.00 hours, lots of play/slop, and no aileron flutter with aileron counterbalance weights installed.
I'm talking about 1/4" and 5/16" rod end bearings used on elevator and aileron controls on Kolbs, not tiny rod ends used on throttle linkages. There is a tremendous difference in durability and longevity between tiny ones and large ones.
I have never seen or read a report where a 1/4" or larger rod end bearing failed, especially on a Kolb.
First time I saw fender washers being used on rod end bearings was back in the early days of ultralights. Probably came from the same book as clear plastic fuel line so you can see your fuel.
john h
mkIII
[quote] Did you not recount awhile back how, before adding aileron counterweights you had to replace rod ends on a yearly basis as they wore? 60 cents worth of washers seems like awfully cheap insurance to me.
"For want of a nail....a kingdom was lost."
Rick
[b]
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_________________ John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama |
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Dana
Joined: 13 Dec 2007 Posts: 1047 Location: Connecticut, USA
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Posted: Thu Sep 30, 2010 8:13 pm Post subject: new owner of an older kolb x kit |
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I added the large washers to the controls on my UltraStar because it definitely looked like a failed bushing could allow the bolt could pull through the eye. Can't do any harm, and it adds peace of mind.
I recently replaced the larger (3/8") rod ends on my US engine mounts after finding them badly worn. On these (I know because I just did it) the bolt head and AN960 washer definitely could pass through the eye. I added AN970 washers there, too.
Does Kolb spec AN rod end bearings on the controls? On the US engine mounts, at least, the drawings call out a commercial part number, not an AN part, so the dimensions may be slightly different. I'm sure the Army choppers used AN parts, though.
-Dana
At 01:13 PM 9/30/2010, John Hauck wrote:
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BTW: I don't add fender washers to my rod end bearings. Haven't figured out how they could wear enough to separate. My MKIII rod end bearings have over 3,000.00 flight hours on them and they are quite serviceable. During my time flying Army helicopters, I do not remember fender washers being added to rod end bearings.
I wanted to refresh my memory, so I walked over to the hanger and took a close look at Larry Cottrell's FSII rod end bearings on his aileron push/pull tubes. Looks like it would be pretty difficult to get the small AN 1/4 inch washer through the hole if the bronze bearing totally disintegrated. |
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Work is underway on drafting a new constitution for Iraq. Why don't we send them ours? It worked for 200 years, and we don't use it any more. [quote][b]
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Dana
Joined: 13 Dec 2007 Posts: 1047 Location: Connecticut, USA
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Posted: Fri Oct 01, 2010 6:30 am Post subject: new owner of an older kolb x kit |
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At 10:50 PM 9/30/2010, John Hauck wrote:
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I'm talking about 1/4" and 5/16" rod end bearings used on elevator and aileron controls on Kolbs, not tiny rod ends used on throttle linkages. There is a tremendous difference in durability and longevity between tiny ones and large ones. |
I don't think it matters whether large or small, as long as the rod end is loaded according to its design limits. The problem in a throttle linkage, perhaps, is vibration, which probably causes a lot more wear than smoothly operating controls.
Quote: | I have never seen or read a report where a 1/4" or larger rod end bearing failed, especially on a Kolb. |
Well, the 3/8" ends in my engine mount didn't fail completely, but there was about 1/16" of play in them, so it might not have been too long. Of course a control rod end never would have gotten that bad, you'd catch it as you check the linkages during preflight, but with the weight of the engine always on the rod ends, you don't see the play unless you actually lift the engine up.
Again, here, it's vibration... the 3/8" size is rated over 3000# each. I have no idea how many hours were on these (or even on the plane) but my guess is the rod ends were original with the plane.
Quote: | First time I saw fender washers being used on rod end bearings was back in the early days of ultralights. Probably came from the same book as clear plastic fuel line so you can see your fuel. |
Must.... not.... go.... there....
-Dana
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"Gold cannot always get you good soldiers, but good soldiers can always get you gold"-- Niccolo Machiavelli [quote][b]
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John Hauck
Joined: 09 Jan 2006 Posts: 4639 Location: Titus, Alabama (hauck's holler)
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Posted: Fri Oct 01, 2010 6:50 am Post subject: new owner of an older kolb x kit |
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Dana/Gang:
I'd guess there was a lot more load and wear in an engine mount application than used as rod ends for ailerons.
Again, I am flying with rod ends on my aileron push/pull tubes with more than 3,000.00 hours that are serviceable.
john h
mkIII
[quote] Well, the 3/8" ends in my engine mount didn't fail completely, but there was about 1/16" of play in them, so it might not have been too long. -Dana
[b]
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_________________ John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama |
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