Wing Loading Failure

Pretty cool!

I noticed it was a steady pull. I wonder how much less force it would take if it was done with a single jolt...
 
That was a great test but keep in mind, over-stress on an airframe is a cumulative effect just like normal fatigue and cycles of operation. For this reason, planes formerly used as trainers are often not the best purchase. At least I can honestly state that for a few I've seen. I wouldn't buy one without a very thorough inspection of the inner airframe and the wing structure.
 
KennyFlys said:
That was a great test but keep in mind, over-stress on an airframe is a cumulative effect just like normal fatigue and cycles of operation. For this reason, planes formerly used as trainers are often not the best purchase. At least I can honestly state that for a few I've seen. I wouldn't buy one without a very thorough inspection of the inner airframe and the wing structure.
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Peter Garrison has an overview article on metal fatigue in Flying.

The American Bonanza Society has an interesting report on spar cracks here.

In the report the author mentions an A36 with 21,000 hours TT that had no cracks.

It's also interesting to note that a Utility Category light airplane is rated to 4.4 Gs (such as a C172 or a Model 35 Bonanza), while an Air transport category airplane (such as a 777) must only meet 2.5 Gs (CFR 25.337)
 
That is an impressive video. Not being an engineer I wonder however how a wing that had been in service for say 20+ years such as the one on the MD-80s I flew this past week would react to that stress.
 
AdamZ said:
That is an impressive video. Not being an engineer I wonder however how a wing that had been in service for say 20+ years such as the one on the MD-80s I flew this past week would react to that stress.
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Not an engineer here as well but I'd think as long as there was no overstress on the airframe during the years and simply normal fatigue, it would hold up. But, they get pretty good inspections... I hope, given recent events.
 
AdamZ said:
That is an impressive video. Not being an engineer I wonder however how a wing that had been in service for say 20+ years such as the one on the MD-80s I flew this past week would react to that stress.
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Week before last we were in a 1995 model plane that had 28,000 hrs on it and 36,000 landings when we hit severe CAT. We overspeed by almost 40 kts and set off the ELT. Mechanics were flown up that night to do a full spar/frame/flight control inspection before the plane could fly again. Long story short, we flew the plane again the next afternoon. Some engineers must know what they're doing.
 
Teller1900 said:
Week before last we were in a 1995 model plane that had 28,000 hrs on it and 36,000 landings when we hit severe CAT. We overspeed by almost 40 kts and set off the ELT. Mechanics were flown up that night to do a full spar/frame/flight control inspection before the plane could fly again. Long story short, we flew the plane again the next afternoon. Some engineers must know what they're doing.
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...the ones at Beech sure do! :yes:
 
Teller1900 said:
Week before last we were in a 1995 model plane that had 28,000 hrs on it and 36,000 landings when we hit severe CAT. We overspeed by almost 40 kts and set off the ELT.
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Where? Altitude at the time? Airspeed? How much altitude did you lose? How long were you in it? Injuries to passengers or FA?
 
Lance F said:
Where? Altitude at the time? Airspeed? How much altitude did you lose? How long were you in it? Injuries to passengers or FA?
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Yeah... I'd love to hear about it. In the past year I haven't been in anything but mild CAT (all transatlantic)... never even been in severe CAT.

Cheers,

-Andrew
 
Lance F said:
Where? Altitude at the time? Airspeed? How much altitude did you lose? How long were you in it? Injuries to passengers or FA?
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3,000 feet (not CAT, by definition, but we were in the clear and it was severe by definition) between RKD and AUG. We gained 350 feet; started at 230kts, hit a max of just over 275 (Vmo=248) in less than 2-3 seconds. There were three heavy bumps lasting no more than 5-7 seconds (that was the severe part), then about 1-1.5 minutes of continuous moderate turb, then back into smooth air. No pax on board (thankfully...we dropped everyone in RKD, and the two that we were supposed to have going to AUG never made the connection in BOS, and we're not equipped with an FA. I wrote more about it here, if you're really interested :). We did a lot of paper work on this one!
 
Flyfishingpilot said:
Pretty cool!

I noticed it was a steady pull. I wonder how much less force it would take if it was done with a single jolt...
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AFaIK aluminum, unlike most plastics, is not rate sensitive. That essentially means that (ignoring inertia) the yield point will be the same whether the load is applied rapidly or slowly. And yes the video was quite impressive.

-lance
 
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