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Lift Strut Threaded Rod Ends

28 posts in this topic

Posted

TJay asked about this on another forum recently and I happened across the following info in my files tonight. Source was Steve Winder from [old] Airdale.

On the Avids, the threaded rod sticking out of the lift strut is a AN490 weldable/rivet threaded rod end. It is part number AN490HT11P carried by Aircraft Spruce. The adjustable rod end bearing on the lift strut is a Heim F45–19. They were chosen by Dean Wilson for their significant safety factor ratings, 125,000 psi Tensile and 3,723 lbs. Radial load ratings respectively, plus the ball bearing does not have an aluminum outer. (FYI, the threaded rod and on the elevator push pull tube is part number AN490HT8P)

If you've wondered why you could never find them, they're listed under 'Cable Assemblies – Studs' at Aircraft Spruce?!

HTHs

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Posted

WOW!

I hope you "oldtimers" have your drives mirrored somewhere. If not, us "newbies" will probably crash and burn. Thanks for sharing!

Lou

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Posted

Mr Holly is our resident librarian.. if we ever loose him we are all screwed!  :lol:

 

:BC:

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Posted

I used the Aurora equivlent on mine to replace the Heim that was frozen solid.  GMW-4M-595 is the Aurora part number.   3,359 lbs radial load capacity.

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Posted

Thanks guys with all this Info tonight I ordered all the material that I need to make new struts.

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Posted (edited)

Thanks guys with all this Info tonight I ordered all the material that I need to make new struts.

So, here I am, a $$ short, and too late to help again - Just got some KF3 struts with 4 rod ends and one little dent in one tube - oh well...They would be too long for your KF1 anyway.

EDMO

Edited by EDMO

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Posted

Its OK ED, it would probably cost more to ship them than my total bill in materials.

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Posted (edited)

Its OK ED, it would probably cost more to ship them than my total bill in materials.

I planned on you flying down to get them!  Ha!

BTW:  Where do you find the new (Letters/numbers) Airport locations, like Festus, Missouri - I am old school.

EDMO

Edited by EDMO

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Posted

Thanks JIm,

EDMO

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Posted (edited)

'Just a little bit more about those AN 490 rod ends:  Yes, the material used is 4130 steel, heat treated to 125.000 psi strength.  But that doesn't tell you the whole story..  To see what the threaded rod will carry, you have to multiply the 125,000 lb/sq in tensile strength by the smallest area (in square inches) of the section taking the load.  In the case of a 1/4 by 28 thread, the minor diameter of the threaded section.

In many cases a fitting or part will carry the intended load but may also have to be "over designed" to take into consideration the sometime rough handling that the part may be exposed to.  A 5/16 inch threaded section is considerably more damage tolerant than a 1/4 inch one.

Remember that those strut ends are a single load path primary structure.  Handle with care.

Edited by Avid90
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Posted

I don't get it?

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Posted (edited)

I don't get it?

I believe his point is that the material is rated at 125,000 lbs/sq inch, but to remember that is per square inch, and the point where the load is spread over the fewest square inches is where it will fail.  That would likely be at the threaded fastener if the load is carried by that fastener (as opposed to a fastener that just holds a part in position, but the load is not carried by the fastener - like the nut on the end of an axle).

Sounds like an engineer, and you have to make allowances for them - they forget how to speak english after a period of time :P

Edited by marksires
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Posted

pls, do someone have the Aspruce ref for the rodend of stab control column?

:BC:

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Posted

All my parts showed up the other day and im questioning the rod ends yet. they are the part number GMM-4M-675 https://www.aircraftspruce.com/catalog/appages/aurorabearings.php they look plenty heavy but the threaded portion is not solid on the inside. Ill take a picture later on to show you all. I figures for 20 bucks a piece they should work.

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Posted

Per the drawing, in the "specification chart" portion of the ACS page, all of these larger than 1/4" diameter are bored.

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Posted

Are you modifying the strut ends to take a male rod end?  I thought the first post in this thread mentioned a female threaded rod end threaded onto an AN 490 fitting welded into the lift strut.

 

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Posted

you are correct that was my first thought, then I decided to go this direction and use the male threads better or not who knows, Do you guys know why they are all bored, is it a way to allow them to flex without breaking.

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Posted

pls, do someone have the Aspruce ref for the rodend of stab control column?

:BC:

I think something is lost in the translation .  Do you have a part number for your kit or can you post a picture of the area you are referring to?

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Posted

I don't know why they drill the hole, but the Heim equivalent has the hole drilled the same way.  Both the Aurora and Heim bearings are magnafluxed and traceable.  The limiting factor of the bearing is the radial strength.  That 3/8-24 shank is much stronger than needed for the 3200 lb load.

Are you making your own threaded inserts for the strut end?

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Posted

pls, do someone have the Aspruce ref for the rodend of stab control column?

:BC:

I think something is lost in the translation .  Do you have a part number for your kit or can you post a picture of the area you are referring to?

hemm this is the connection between elevator and push tube

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Posted

My mistake.  AN486-4P.   'Haven't had much success editing the posts lately.

 

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