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Topic: Flight Balance With One Wing Lost.
Username: Poadrim
Posted 2012-10-25 11:57:38 and read 4317 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

Topic: RE: Flight Balance With One Wing Lost.
Username: wingscrubber
Posted 2012-10-25 13:18:25 and read 4276 times.

If a wing seperates, the remaining wing will have no opposing moment on the opposite side of the airplane, so it will roll up and over the top...

Topic: RE: Flight Balance With One Wing Lost.
Username: Roseflyer
Posted 2012-10-25 13:40:55 and read 4258 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.

http://www.youtube.com/watch?v=V6cMK9LUnzI

Topic: RE: Flight Balance With One Wing Lost.
Username: Poadrim
Posted 2012-10-25 13:55:34 and read 4248 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

Topic: RE: Flight Balance With One Wing Lost.
Username: mrocktor
Posted 2012-10-25 14:47:42 and read 4205 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.

Topic: RE: Flight Balance With One Wing Lost.
Username: Roseflyer
Posted 2012-10-25 14:54:47 and read 4195 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.

Topic: RE: Flight Balance With One Wing Lost.
Username: Poadrim
Posted 2012-10-25 15:42:21 and read 4165 times.

Well then, thank you guys! Much appreciated help   

Topic: RE: Flight Balance With One Wing Lost.
Username: Roseflyer
Posted 2012-10-25 16:02:26 and read 4145 times.

Quoting Poadrim (Reply 6):
Well then, thank you guys! Much appreciated help

No problem. Just think of the wing as a helium balloon.

Topic: RE: Flight Balance With One Wing Lost.
Username: moose135
Posted 2012-10-25 18:08:07 and read 4081 times.

Quoting Roseflyer (Reply 7):
Just think of the wing as a helium balloon.

On a conveyor belt...
 Big grin

[Edited 2012-10-25 18:08:35]

Topic: RE: Flight Balance With One Wing Lost.
Username: saafnav
Posted 2012-10-25 20:30:47 and read 4015 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?

Topic: RE: Flight Balance With One Wing Lost.
Username: Larshjort
Posted 2012-10-25 23:22:52 and read 3966 times.

Quoting moose135 (Reply 8):
Quoting Roseflyer (Reply 7):Just think of the wing as a helium balloon.
On a conveyor belt...
[Edited 2012-10-25 18:08:35]
Quoting saafnav (Reply 9):
If the weight of the wing would outweigh the lift, then there is really no point in having a wing?

How fast would a helium balloon without wings have to move on a conveyor in order to takeoff   

And what if it has one wing on the RH side 

/Lars

Topic: RE: Flight Balance With One Wing Lost.
Username: Poadrim
Posted 2012-10-26 05:07:08 and read 3868 times.

Quoting saafnav (Reply 9):
If the weight of the wing would outweigh the lift, then there is really no point in having a wing?

Point taken, I should have known that.

Quoting Roseflyer (Reply 7):

No problem. Just think of the wing as a helium balloon.
Quoting moose135 (Reply 8):
On a conveyor belt...
Big grin
Quoting Larshjort (Reply 10):
How fast would a helium balloon without wings have to move on a conveyor in order to takeoff

And what if it has one wing on the RH side

/Lars

I LOL'd, really. Thanks!  

Topic: RE: Flight Balance With One Wing Lost.
Username: DocLightning
Posted 2012-10-27 00:10:26 and read 3547 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?
http://www.youtube.com/watch?v=hedLTEbhjJ0

Evidently, it will flip up and then rapidly assume a negative AOA and then stall.

Topic: RE: Flight Balance With One Wing Lost.
Username: HAWK21M
Posted 2012-10-27 03:15:26 and read 3502 times.

Flip up and over before gravity takes over.

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.....

Topic: RE: Flight Balance With One Wing Lost.
Username: DocLightning
Posted 2012-10-27 09:06:56 and read 3449 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.

Topic: RE: Flight Balance With One Wing Lost.
Username: tdscanuck
Posted 2012-10-27 10:35:10 and read 3428 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.

Tom.

Topic: RE: Flight Balance With One Wing Lost.
Username: DocLightning
Posted 2012-10-27 12:20:29 and read 3396 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.

Topic: RE: Flight Balance With One Wing Lost.
Username: HAWK21M
Posted 2012-10-28 02:41:44 and read 3251 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  

Topic: RE: Flight Balance With One Wing Lost.
Username: HaveBlue
Posted 2012-10-28 03:48:02 and read 3230 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.

Topic: RE: Flight Balance With One Wing Lost.
Username: HAWK21M
Posted 2012-10-29 00:54:20 and read 3076 times.

Quoting HaveBlue (Reply 18):
he wasn't aware the wing was gone. He has said that had he knew the extent of the damage, he would've bailed.

I'm sure such a situation would never have been simulated before too on the type ever.....

Topic: RE: Flight Balance With One Wing Lost.
Username: DocLightning
Posted 2012-10-29 17:14:38 and read 2922 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.

Topic: RE: Flight Balance With One Wing Lost.
Username: flyingturtle
Posted 2012-10-30 02:58:04 and read 2855 times.

Quoting DocLightning (Reply 20):

Wind tunnel?


Perhaps it could work with a really slow aircraft (a glider?) and a ludicrous amount of sideslip...

Never mind maneuverability.



David

Topic: RE: Flight Balance With One Wing Lost.
Username: Fabo
Posted 2012-10-30 07:37:00 and read 2800 times.

Quoting flyingturtle (Reply 21):
Perhaps it could work with a really slow aircraft (a glider?) and a ludicrous amount of sideslip...

I would not think so. You still have all weight on one side and all lift on the other. Sideslip wont help you with that.

Topic: RE: Flight Balance With One Wing Lost.
Username: flyingturtle
Posted 2012-10-30 11:02:35 and read 2765 times.

Quoting Fabo (Reply 22):

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

Topic: RE: Flight Balance With One Wing Lost.
Username: mrocktor
Posted 2012-10-30 15:43:38 and read 2687 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.

Topic: RE: Flight Balance With One Wing Lost.
Username: Larshjort
Posted 2012-10-30 15:59:32 and read 2734 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.

/Lars

Topic: RE: Flight Balance With One Wing Lost.
Username: MD-90
Posted 2012-11-03 23:43:31 and read 2334 times.

Quoting DocLightning (Reply 20):
Also an option that no airliner has...

Well there were a few SSTs back in the day...

Topic: RE: Flight Balance With One Wing Lost.
Username: sprout5199
Posted 2012-11-05 13:43:09 and read 2167 times.

http://www.youtube.com/watch?v=dsQcdTBwgKU

Watch what happens to the Skyhawk. This shows what happens when you lose a wing.

Dan in Jupiter


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