...I was pushing plane back into hanger and bumped a inch and a quarter door lip to roll into the hanger...
I've tested firsthand a chromoly T joint in tension that didn't fail until @ 7200 psi.
It does look like a Bell tail wheel fork. But the swivel is probably Van's. Bell builds the forks but suggests you install it on the Van's swivel, which it fits perfectly so there is no need to redrill the assembly to the tail spring.
Agreed.Poor weld and they likely used the wrong filler rod. Easy to fix.
I agree, that's what I would do too.I'm with Bob and Brad.
Clean up the parts, prep the parts and (properly) reweld.
Then you won't have to drill new bolt holes in alignment with the existing holes in the spring.
Is there reason to or any possible way to non distructively test tailwheel knuckles out there today? Can a bad weld be noticed visually?
Here is a possible future replacement.
In the photos the area that failed in this instance look identical to the construction of the part that you're referencing.
Dave
Many of us do a dye penetrant check on the lower engine mount/gear leg area. Perhaps checking the tailwheel mounting socket would be a good area to inspect once in a while?
Here's one from Grainger that should work:
dye penetrant test kit
You might also take a look at your tailwheel mounting socket welds. As Dan Horton pointed out, these are thick walled steel parts. The weld beads should be substantial. Here's a good example:
If your welds look puny, it is a very easy thing to fix by re-welding, or even adding a triangular gusset for "belt and suspenders" protection. I don't think the gusset is necessary if the weld is beefy though.
If you decide to re-weld, try not to overheat your bronze bushing. Stuff a hot dog into the hole to soak up the heat. When you're done welding, the hot dog will be cooked. Lunch is ready. Enjoy.
I the only time I have done a die penetrant it has been on bare metal. Would it not require you to strip any coatings off before using this kit?
Well, I hope to see the crack through the paint before it fails, if it ever does, as I am not going to strip off the paint and repaint my tail post to do a die penetrant check.Correct Jay, for best results the weld area neds to be cleaned and clear of paint, coatings, etc. Keep in mind that you are only going to discover surface irregularities/cracks and not penetration information...but the crack information is obviously useful for eventual failure.
David.
Metallurgist, destructive and non-destructive material testing engineer, forensic failure analyst and American Welding Society QC1 certified welding inspector.
It would be interesting to see some well focused, close up photos of the failed weld areas...
I definitely agree. But I would also like to see a free-body diagram that analyzes the stresses within the weld that prevail as the tailwheel passes backwards over a 1.25" obstuction. My suspicion is that this loading case gets close to the yield stress even for a properly-done weld.
Rewelding will shrink the ID by a considerable amount. Usually when welding stuff like this if it can't fit back in the jaws of my lathe I set my mill up with a boring head/bar and shave a few thousandths off the ID to true the hole again.
The bushing should be pressed out to reweld. If its an oillite bushing have fun welding if its still in there, they tend to catch on fire readily.
Just being a proficient welder doesn't insure that the finished weld will be satisfactory. A well designed welding process based on the materials and anticipated loads expected is necessary. If the loads are cyclic in nature like those experienced by this weld it is extremely important that the process developed insures that fatigue failures are prevented.
David
Metallurgist, destructive and non-destructive material testing engineer, forensic failure analyst and American Welding Society QC1 certified welding inspector.