I lied, ANOTHER stupid question... Landing gear tie rod

[citabrickr]

Ok, have some rust issues to deal with...so, why is the landing gear tie rod bolted to the axle end of the gear leg but welded to the upper end? With the upper ends in the exhaust path and with neglect over the years I have a lot issues to deal with and seeing the bolt was encouraged that it would be a simple matter of unbolting the strut....but, nope.

[mikerice]

Re: I lied, ANOTHER stupid question... Landing gear tie rod

This is a good question. I have the same problem with my landing gear tube, except it is bent. I guess we both need to find some one who can replace the tube.

All I could figure regarding the bolted vs. a welded connection is that the bolt "pins" one connection, which from my engineering statics classes was easier to calculate loads. Bridges often set on huge pin connections rather than rigid welded connections, because you cannot transfer a moment or rotational force through a pin or bolted connection. Welded connections on the other hand, resist rotation and that causes fatigue if the connection is taking a rotational load.

[Hank Jarrett]

Re: I lied, ANOTHER stupid question... Landing gear tie rod

You got it Mike. Welded on both ends would be Statically Indeterminate and would be prone to fatigue in bending at the ends. Engineers love pinned joints because the loads stay in line with the structural member.
Unfortunately, pins don't help much with corrosion.
If the tube on the gear has to be replaced you will need to fixture the gear before you cut the tube out. A crooked gear can cause some really exciting landings! Get it straight and check it on the plane before you fly!
Hank

[Robert Lees]

Re: I lied, ANOTHER stupid question... Landing gear tie rod

If I were designing that diagonal strut today, I would have it as a welded tube both ends.

Unfortunately, that would give no opportunity to attach wheel pant attach brackets at the lower end.

But I would still have it as a sealed strut.

[Hank Jarrett]

Re: I lied, ANOTHER stupid question... Landing gear tie rod

I think SEALED is a good idea. Welded closed on both ends, but with a pin (bolt) at both ends and some form of adjustment. It wouldn't take a lot of adjustment to really screw it up. You would NOT want it welded on both ends to the rest of the strut.
Hank

[mikeg]

Re: I lied, ANOTHER stupid question... Landing gear tie rod

The only stupid question is the one that does not get asked. Ref. the gear leg. Check with John at Aero Fabricators (Wag-Aero) about repair. I had one repaired last summer (replaced the drag tube and it was "sprung"). They did an excellent job and the gear fits perfectly now. BTW-the streamlined tube they used is the original dimension.
Mikeg
NC29804
NC27451