2M views · Jul 7, 2010 · 3:17 · 2 HN recommenders · 10 mentions · discussed 2013–2023
A short video of a Boeing 777 wing being tested to destruction, finally breaking at 154 percent of its designed limit load. The wing is flexed upward until it fails.
Why Hacker News points people here: HN links it constantly as vivid evidence of how much margin aircraft structures have and that destructive testing is real.
“you might find this really interesting”HN comment, 2018
“Check out this video”
Modern aircraft structural engineering shown in wing test.
Planes come to mind. Basically, back in the age of the slide ruler, engineers "overcompensated" in durability. This is why older planes are much heavier (so more inefficient and costly to run) but also last forever. PS: Not to crap on the structural engineering of more modern planes, don't get me wrong! Check out this video: this video
“you might find this really interesting”
777 wing snaps at far more flex than turbulence causes.
Since you are posting on HN and I'm guessing you are technically minded, you might find this really interesting: this video - it's a video from a documentary about the development of the Boeing 777. Specifically, the video shows a test where they bend/stress the 777 wings to the point where they actually snap. Spoiler alert: they snap at orders of magnitude more flex than you've ever seen. Even for very severe turbulence (like you experienced), it's very comforting for me to know (via that video evidence) that even if I haven't seen turbulence this bad, the people that made the airplane definitely thought about it.
“video of boeing stress-testing 777 wings by deflecting them up with cables”
777 wings deflected with cables in stress test.
this video video of boeing stress-testing 777 wings by deflecting them up with cables, against a stationary fuselage first thing that came to mind after seeing the video of the crashed plane do a cartwheel on its wing.
“This Boeing 777 wing was tested to destruction, finally breaking at one fifty four percent (154%) of the designed limit load.”
777 wing tested to destruction at 154% limit load.
One of the wing tests: this video "This Boeing 777 wing was tested to destruction, finally breaking at one fifty four percent (154%) of the designed limit load."
“Actually, there is”
Evidence that destructive aircraft testing exists.
> There is no such thing as 'destructive aircraft testing' Actually, there is: this video "This Boeing 777 wing was tested to destruction, finally breaking at one fifty four percent of the designed limit load."
“Here is another video of a 777 wing test where it broke at 154%”
777 wing test breaking at 154% of load.
It's a stress test. You would expect things to break during a stress test. > "They loaded it up well beyond capacity and bent its wings in an extreme manner, in a way almost certain to never happen in the real world." Here is another video of a 777 wing test where it broke at 154% of the [s/normal/maximum theoretical/] load - a bit beyond what was expected by the engineering team. this video
“so it's 1.54 times the design limit.”
Source for 154% meaning 1.54 times the limit.
It's not a matter of interpretation or tricky language. The video says "of" [1] so it's 1.54 times the design limit. [1] this video
“Have you seen the wing failure test?”
Wing failure test broke slightly beyond design target.
This sounds fine. It's a catastrophic failure test. They push until it breaks, then it broke, and they were very close to their designed target (within 1%). If they had gone 1% past their designed target, they would have been upset, as they could have made the plane lighter. They were 1% short of design limit, they are upset because they'll have to add reinforcement. Have you seen the wing failure test? I worked for the company that did these tests (they did them before I worked there), and they still talk about how upset the engineers were that it went over spec in strength. this video
“look how the wing was tested”
Shows how wings are tested until they break.
there is no way to fail gracefully, because what this test does is to test the breaking point. when there is such a stress, there's no middle ground. for example, look how the wing was tested: this video
“The famous video is of a 777 wing.”
Famous 777 wing test video.
The famous video is of a 777 wing. I don't believe any similar footage exists for the 747 or if the test was even performed decades before. this video
