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Dorsal
05-11-2010, 08:42 AM
Any ideas on what the maximum exposed threads on the lift struts can be? I am making some final adjustments and am running 1/4"-1/2" of exposed threads on one side. The dihedral on the wings was correct but off by ~.5 degree relative to the top rear cross tube so I took out a couple of turns on one side and added them to the other. The good news is now the tips line up when folded (a minor point but appeals to my sense of engineering harmony).

SkyPirate
05-11-2010, 09:35 AM
Dorsal ..ussually the "threaded" section of bolts under torque are rated for 75% of the shanks strength, if the width of the shank is the portion that is screwed in ie 1/2 inch shank diameter ..1/2 " of threaded in section of bolt,. so with a 5000 lb rated bolt ,..the threaded section equal to the shanks diameter would be 75% of that rating, in a torque'd condition. being that the strut barrels and hiem joints aren't really under torque,.but rather variable loads far below their strength capacity,.if it's a 1/2" wide threaded section,.. with 1/2" screwed in to the strut barrel, it's closer to 90% of the torque rating on the bolt..just for that warm and fuzzy feeling I'd opt for 5/8's to 3/4" of threaded in area for a 1/2" shank ,..I would not go less then the diameter of the shank even though this application is not in a torque'd condition.

just to clarify ..if your bolt has 1.5" of threaded area and a 1/2" diameter shank I would not let more then 1 inch of the threaded area be exposed to maintain 90% + of it's rating in an other then a torque'd condition,..I'd opt for 3/4" or less threaded area exposed on a 1.5" long bolt with 1/2" shank

Chase

SkyPirate
05-11-2010, 10:32 AM
An example ..the hiem joints I'm using on my struts are rated for 70,000 lbs they have 1.25" threaded area with 7/16" diameter shank,..as long as I have 7/16's of the thread into the strut barrel ..the rating will be at least 90% of the 70,000 lb rating,.. the concern is more for what part of the bolt is screwed in,.as long as at least 7/16" or more is screwed in ,..then I'm golden so I could have 0.8125 ~ 13/16's or less thread showing

Dorsal
05-11-2010, 10:55 AM
Thanks, just need to know how long the threaded sections is to begin with.

Av8r3400
05-11-2010, 03:47 PM
On "aircraft" female threaded rod ends there is a cross hole drilled in the fitting. This cross-hole is not for safety-wiring. The fastener must be threaded this far into the rod end to be correct and safe.

(From my E-LSA inspection course.)