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Old 04-23-2009, 07:44 PM
scsmith scsmith is offline
Join Date: Jan 2008
Location: Ashland, OR
Posts: 3,059
Default Conclusions? well that depends....

Well, I could analyze a typical, although hypothetical load case on the gear assembly to show what the loads are that the attachment hardware is expected to carry. I have not done that at this point.

I can not say that the current assembly is inadequate - from the ground-loop damage I have seen, the gear tower seems to tear out of the fuselage with the gear leg still bolted on. I have not examined any of those to see if there have been any failures of the nuts.

I can only say that from my engineering experience I was rather skeptical about the supplied nuts, which is why I did the tests. I can say that it is typical engineering practice to use hardware that allows you to develop the full tensile strength of the bolts, when possible. ( of course you would not bother to do that in a pure shear loaded situation). But in a situation where gear loads can go from normal levels to catastrophic levels easily in a ground loop or wheel falling in a squirrel hole on landing, I think I want all the strength I can get.

My OPINION is that I think it is better to use a higher strength nut, and I will. It may be that the existing nuts are fully adequate, I don't have any evidence that says otherwise. It is likely that there are other weak links in the assembly that would usually fail first. It is also possible that a particular scenario would lead to failure of the nut before any other part failed. I might as well go for all the strength I can just in case....
Steve Smith
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