I am really surprised this didn't kick up

retroron said
You're right, I don't know that for certain, I was generalizing, a foolish thing to do. Mine subframe connectors are welded full length, but I also have a lowered floor pan and I understand welding well. I was a welding engineer for more years than I'd like to recall. I ran a welder test qualification shop for number of years. I would disagree with you regarding MIG being more brittle, of course a lot of that depends on wire type, feed rate, amperage, shielding and the welder. I've seen MIG welds that bent like rubber, in fact the standard bend test for plate and pipe require the weld to bend over a prescribed radius, but I'll bet you know that ! And to be fair I've also seen MIG weld that cracked like glass.

Haha, yeah, you caught me generalizing too! It is a really long length of weld with those subframe connectors, and that definitely can have its own shortcomings. But of course there are a ton of variables just with the weld as you mentioned.

There are pros and cons to both styles, both from an engineering standpoint and a general installation standpoint. I certainly can't say which is better, and I've installed both. But I think either kind is better than nothing at all.

retroron said
I must have missed the part about wings breaking off. Aircraft are inspected for cyclic fatigue so as to preclude material failure. Airplanes normally crash because of terrain interference with the flight path or operator error, hardly ever for material failure.

That is the truth! That damn ground gets in the way!

Although some of aircraft materials engineering is making sure that when the materials DO fatigue you can catch it on the inspections. Because they do fatigue and parts do have to be replaced over the lifespan of the airframe. A notable exception was that Aloha Airlines flight that had the section of fuselage rip off- catastrophic failure due to rapid crack propagation. Turns out the cracks were being hidden behind the heads of the rivets of the panel, a materials problem because the metal could fracture small enough to be hidden behind the rivets but still achieve enough of a crack that it would propagate. Other part of that issue was all the short hops, the number of pressurizations became more important than the number of flight hours, and the hours were the inspection threshold.