787's flexable flappers

[TimothyFarrar]

"Boeing has completed static testing of a three-quarter wingbox, but engineers are still considering whether to limit testing of the full wing to a 150% load limit held for 3 sec. of to continue bending it to see when it breaks. "There's a raging debate within the engineering team to see if we should break it or not," says [787 General Manager Mike] Bair.

Breaking it isn't necessary for certification, but Bair says the wing is so strong and flexible that there's been talk that maybe it could be bend far enough for the wingtips to touch above the fuselage—or come quite close."

link to article

Raging debate? Engineers not wanting to do destruction testing? Perhaps they were going to deduct the price of the wing from the engineering teams combind sallary.

[kach22i]

Cool.


http://blog.wired.com/wiredscience/materials_science/index.html

After my post yesterday on the carbon-fiber wings on Boeing's new 787 jet, reader Craig Steffen pinged to alert me to a mistake I made. He points out that while the 787 is certainly an ambitious deployment of carbon-fiber composite, it ain't the first commercial attempt. That honor seems to go to the Beech Starship. "Even though only 53 were ever made, [it] was certainly a production aircraft," Craig writes. "It was made entirely, wings and all, of carbon fiber."

[arcsine]

I cannot accept engineers not wanting to blow stuff up. Why not do both tests? Do the 150% load test for certification then bust out the popcorn and keep bending. You gotta find out when she is going to give.

[kach22i]

Originally posted by arcsine
I cannot accept engineers not wanting to blow stuff up. Why not do both tests? Do the 150% load test for certification then bust out the popcorn and keep bending. You gotta find out when she is going to give.

I know of a commercial hovercraft outfit having some C.F. testing done. Problem is the parts exceed what the test equipment can put out.

[TimothyFarrar]

Good point! I bet it would be an expensive endevor to build a rig to test the wing's load cycles to failure also...

[masraum]

I'd like to see pics of wings that flexible.

[kstar]

I posted this in the other 787 thread - there's a video there of a 777 wing test where they bend the wings until they break:

787 photos

Best,

Kurt

[TimothyFarrar]

Thanks Kurt, don't know how I missed that thread!

[Jeff Higgins]

I witnessed both the 767 and 777 wings break. Does that date me or what? I'm not on the 787 program per se, but I am in Everett. I was looking forward to this one...