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dickwolff
PostPosted: Sun Feb 07, 2016 5:16 pm 
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Took my gear off again yesterday to make the repair. Got it back this afternoon. tHe patches aren't quite placed the way James Ball did it, but close enough.


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dickwolff
PostPosted: Tue Feb 09, 2016 4:11 pm 
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Another picture.


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Bill Williams
PostPosted: Wed Feb 10, 2016 5:47 am 
Wait and see,but my guess it will still crack at the crotch


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dickwolff
PostPosted: Fri Feb 12, 2016 7:26 am 
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I'm more optimistic, Bill.

The way I see it is that the original weld design could have been better. The cracks initiate at the inboard end of the weld bead... a spot where the bead is spanning a relatively large gap between the round gear leg and the thin flat reinforcing plate. As has already been discussed, the bead is also across the line of stress. One a crack initiates, it will propagate easily.

This patch design does three things:
1 It rounds out the inside corner, which is much more resistant to fatigue.
2 It adds a lot of material section to the problem area, which lowers stress, which is also better for fatigue.
3 It turns the transverse weld into a longitudinal weld, which is a better way to weld something under stress.

Personally, I think if the reinforcement plate design had originally incorporated a shape like this, we wouldn't see gear cracks in the fleet.

Time will tell.

D


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James Grahn
PostPosted: Fri Feb 12, 2016 11:04 am 
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Dick,
You need to make sure that surface is flat enough to handle the accompanying hardware. Side loaded bolts in that area would not be a good idea.
Cubes


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dickwolff
PostPosted: Tue Feb 23, 2016 6:30 am 
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Not a factor, Jim.

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SHIPCHIEF
PostPosted: Wed Jun 01, 2016 10:00 pm 
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I understand the doubler plate on the front, this area is under tension when landing etc.
I don't understand the need for the plate on the back, this area is under compression and does not have a history of cracking?

_________________
Scott Emery
EAA Chapter 326
T-18 N18TE


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dickwolff
PostPosted: Thu Jun 02, 2016 5:14 am 
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Yeah, I thought the same thing, but trust me, they crack on the back too. It'd just a poor weld design.

In theory, theory and practice are the same, but in practice they're not.

DW


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