Poadrim From Norway, joined Oct 2008, 173 posts, RR: 0 Posted (7 months 2 hours ago) and read 3219 times:
Hi guys and gals,
Did a search and found nada so there for this thread.
I watching NGC's Air Crash Investigation about Chalk's Ocean Airways Flight 101, and yeah, I know, you need both wings to fly (except the Israeli F-15 in '94?). But what happens when a wing breaks off? Does the wing, that is still attached, flip upward due to the increased lift on the side with the wing or down due to the increase weight?
//Poadrim
Good judgment comes from experience. Good experience comes from someone else's bad judgment.
Roseflyer From United States of America, joined Feb 2004, 8746 posts, RR: 52 Reply 2, posted (7 months ago) and read 3160 times:
Quoting Poadrim (Thread starter): But what happens when a wing breaks off? Does the wing, that is still attached, flip upward due to the increased lift on the side with the wing or down due to the increase weight?
If you'd like to see a visual of this happening, take a look at the crash videos of the FedEx MD-11 in NRT or the United DC-10 in Sioux City. In both crashes, the landing gear failed, which caused the spar to break. This separated one wing from the airplane, which caused the rest of the airplane to roll over until the other wing contacted the ground and was upside down.
In this video you can clearly see what happens when the left main landing gear fails and the wing spar breaks. The other wing which is still achieving lifts causes the airplane to roll until it is upside down.
Poadrim From Norway, joined Oct 2008, 173 posts, RR: 0 Reply 3, posted (7 months ago) and read 3150 times:
Aight, thank you. But some how it's seams more logic that the weight of the remaining wing vs. the life momentum should in best case stay level(I know it don't, but still)
//Poadrim
Good judgment comes from experience. Good experience comes from someone else's bad judgment.
mrocktor From United States of America, joined Jan 2005, 1645 posts, RR: 51 Reply 4, posted (6 months 4 weeks 1 day 23 hours ago) and read 3107 times:
Quoting Poadrim (Reply 3): But some how it's seams more logic that the weight of the remaining wing vs. the life momentum should in best case stay level(I know it don't, but still)
Maybe this will help you visualize it:
At the moment immediately prior to your wing separation, each wing is lifting its own weight, plus half the weight of the rest of the airplane (opposite wing excluded). When the wing separates, the opposite wing is now lifting its own weight, plus trying to lift the full weight of the rest of the airplane (minus the separated wing). Since the lift is horribly off center, the plane flips over.
Roseflyer From United States of America, joined Feb 2004, 8746 posts, RR: 52 Reply 5, posted (6 months 4 weeks 1 day 23 hours ago) and read 3097 times:
Quoting Poadrim (Reply 3): Aight, thank you. But some how it's seams more logic that the weight of the remaining wing vs. the life momentum should in best case stay level(I know it don't, but still)
If you remember free body diagrams from physics class, the wing is creating a net force up, while the fuselage is a net force down. So while the airplane as a whole would fall out of the sky and go down, relative to the fuselage, the intact wing is going to go up and roll the airplane over.
If you have never designed an airplane part before, let the real designers do the work!
Roseflyer From United States of America, joined Feb 2004, 8746 posts, RR: 52 Reply 7, posted (6 months 4 weeks 1 day 22 hours ago) and read 3047 times:
Quoting Poadrim (Reply 6): Well then, thank you guys! Much appreciated help
No problem. Just think of the wing as a helium balloon.
If you have never designed an airplane part before, let the real designers do the work!
saafnav From South Africa, joined Mar 2010, 204 posts, RR: 0 Reply 9, posted (6 months 4 weeks 1 day 17 hours ago) and read 2917 times:
Quoting Poadrim (Reply 3): Aight, thank you. But some how it's seams more logic that the weight of the remaining wing vs. the life momentum should in best case stay level(I know it don't, but still)
If the weight of the wing would outweigh the lift, then there is really no point in having a wing?
DocLightning From United States of America, joined Nov 2005, 16824 posts, RR: 57 Reply 12, posted (6 months 4 weeks 14 hours ago) and read 2449 times:
Quoting Poadrim (Thread starter): Does the wing, that is still attached, flip upward due to the increased lift on the side with the wing or down due to the increase weight?
DocLightning From United States of America, joined Nov 2005, 16824 posts, RR: 57 Reply 14, posted (6 months 4 weeks 5 hours ago) and read 2351 times:
Quoting HAWK21M (Reply 13): On the IAF F15 story.....was the loss of wing imbalance countered by the skill of the pilot using thrust as a compensation....amazing feat.....
That and the fact that most of the aircraft was actually part of the lifting surface.
tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80 Reply 15, posted (6 months 4 weeks 3 hours ago) and read 2330 times:
Quoting HAWK21M (Reply 13): On the IAF F15 story.....was the loss of wing imbalance countered by the skill of the pilot using thrust as a compensation....amazing feat.....
In addition to what DocLightning said (the aircraft was nowhere close to losing 50% of its lifting surfaces), the F-15 also has augmented stability in the flight controls. This helps to reject even very large disturbances, like significant asymmetric lift. At least annecdotally, the pilot in that case had no idea that the damage was as bad as it was until after he landed.
DocLightning From United States of America, joined Nov 2005, 16824 posts, RR: 57 Reply 16, posted (6 months 4 weeks 2 hours ago) and read 2298 times:
Quoting tdscanuck (Reply 15): In addition to what DocLightning said (the aircraft was nowhere close to losing 50% of its lifting surfaces), the F-15 also has augmented stability in the flight controls. This helps to reject even very large disturbances, like significant asymmetric lift. At least annecdotally, the pilot in that case had no idea that the damage was as bad as it was until after he landed.
That's what I heard. It wasn't until he got out of the cockpit that he saw what had happened.
HAWK21M From India, joined Jan 2001, 31201 posts, RR: 58 Reply 17, posted (6 months 3 weeks 6 days 11 hours ago) and read 2153 times:
Quoting tdscanuck (Reply 15): At least annecdotally, the pilot in that case had no idea that the damage was as bad as it was until after he landed.
Usully the case.....reminds me of a B732 lading back after a hydraulic failure only to realise on ground that the caue was a loss of a MW along with the brake, broken at the axle
HaveBlue From United States of America, joined Jan 2004, 2069 posts, RR: 1 Reply 18, posted (6 months 3 weeks 6 days 10 hours ago) and read 2132 times:
Quoting HAWK21M (Reply 13): On the IAF F15 story.....was the loss of wing imbalance countered by the skill of the pilot using thrust as a compensation....amazing feat.....
And he wasn't able to counter the loss of a wing until he used afterburner.. an option no airliner (anymore) has. So it was partly the fact that the F-15's flat underbelly contributes a good amount of lift, partly that he used afterburner to power thru it, and partly that he wasn't aware the wing was gone. He has said that had he knew the extent of the damage, he would've bailed.
DocLightning From United States of America, joined Nov 2005, 16824 posts, RR: 57 Reply 20, posted (6 months 3 weeks 4 days 21 hours ago) and read 1824 times:
Quoting HaveBlue (Reply 18): He has said that had he knew the extent of the damage, he would've bailed.
Also an option that no airliner has...
Quoting HAWK21M (Reply 19): I'm sure such a situation would never have been simulated before too on the type ever.....
I'm wondering how one would go about rendering such a simulation accurately.
Hm, and how about using full *upward* flaps deflection on the first few feet of the wing (measured from the glider's body), and normal downward deflection of the flaps on the rest of the wing? Though, you need to shift the pivot point into the wing, away from the fuselage...
...well, there has already been the Blohm & Voss 141...
David
Even a letdown, if it is thoroughly and final, is a step forward.
mrocktor From United States of America, joined Jan 2005, 1645 posts, RR: 51 Reply 24, posted (6 months 3 weeks 3 days 22 hours ago) and read 1589 times:
Quoting DocLightning (Reply 14): That and the fact that most of the aircraft was actually part of the lifting surface.
That and the fact that the missing wing exposed the ungodly huge elevator behind it to free airflow. Those things respond differentially to roll command (which would be at or near the stop...) - I'm sure he was getting a good bit of lift out of the elevator on the wingless side.
Larshjort From Denmark, joined Dec 2007, 1216 posts, RR: 0 Reply 25, posted (6 months 3 weeks 3 days 22 hours ago) and read 1634 times:
Quoting flyingturtle (Reply 23):
Hm, and how about using full *upward* flaps deflection on the first few feet of the wing (measured from the glider's body), and normal downward deflection of the flaps on the rest of the wing? Though, you need to shift the pivot point into the wing, away from the fuselage...
...well, there has already been the Blohm & Voss 141...
If your ailerons were big enough it could probably work. But they would need to be big. The outboard wing would have to creat the same negative lift as the fuselage provides with the inboard wing section having to create twice the amount of lift normally produced by two whole wings.
And the Bv 141 still had a wing on each side of the fuselages.
sprout5199 From United States of America, joined Feb 2005, 1779 posts, RR: 2 Reply 27, posted (6 months 2 weeks 4 days 23 hours ago) and read 1067 times:
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