airliner wings

[wingboy]

with all the weight and stress that airliner wings must bear,they don't snap off.How are they attached to the fuselage? I mean,are they simply screwed on or riveted in place?

[boristhemini]

You would be amazed at how few bolts hold the things onto the fuselage my friend. If you are a nervous flyer, then its best not to know!! Totally safe tho. A prime example is the B52 wing when full/empty of fuel. The flex is ridiculous.

[barit1]

Wingboy -

You should be aware that the "wings" are not two separate pieces attached left & right. In fact it's a single wing assembly tip to tip (or nearly so) with a huge spar(s) running right through the belly, with the fuselage resting on the spar. Thus the fuselage-to-wing attachment can be pretty light in weight.

Aircraft designers go to a LOT of trouble making the whole structure strong and light. :ok:

[Intruder]

Not true in all cases...

At least for the Boeing 747 and 777 (and maybe others), the center wing box is assembled as a single unit, as are each of the external wing sections. The wings are then bolted onto the center box.

The last airplane I saw that had the wing built as a single unit was the A-4 Skyhawk. I'm sure there are others, but I haven't seen them disassembled...

[barit1]

Intruder has a point, but it doesn't change the fact that the wing-to-fuselage joint need not be too heavy. It's the spar and joint(s) holding the wings to each other that's the heavy-duty structure.

I have seen:

One-piece wing, tip to tip, such as the A-4 and I believe A-6

Two-piece, joined at the centerline, example P-51 Mustang

Three-piece, with a center-section, example DC-3/C-47 Dakota

[wingboy]

Thanks for shedding some light on the matter.I don't think I'm gonna worry about these structures coming apart at the seams!

[Intruder]

One-piece wing, tip to tip, such as the A-4 and I believe A-6
For the A-6, maybe from wingfold to wingfold, but not from tip to tip... ;)

[barit1]

But of course! :)

[CV880]

DC8 (and I think DC9 also) had wings built as left and right units each including half the centre section, which were then joined in the middle to make a complete wing and the fuselage was lifted over the wing and lowered on to it and then permanently joined. This is not the norm however. The 707 wing was also a one piece separate structure attached to the fuselage by 4 bottle pins (large hollow pins). Most aircraft and probably all modern designs, have the wing centre section made integral with the fuselage with the wings being made as separate units which are then spliced to the centre section. A cruciform shaped fitting is often embodied in the centre section top and bottom joints and the wing skins slide into it. Typically there are only a couple of rows of fasteners, albeit high strength one's, that attach the wing to the centre section at the exterior splice.

[chornedsnorkack]

So, when incomplete planes are transported from one factory to another, what does a plane look like before it is put together? Is it one whole wing, and fuselage with a hole for the wingbox, or an entire fuselage with wingbox and two wings?

Also, are wings attached to fuselage only once or repeatedly? That is, when a plane survives emergency landing somewhere where it is hard to take off again, does it have to be removed on ground in one piece, or can it be taken apart, be put back together again and return to flight?

[barit1]

If a plane lands successfully with a payload on board, it won't have any trouble (in general) taking off with no payload and minimum fuel. It's happened many times.

De-mating the wing on a large aircraft is a major maintenance task and would be done only in a well-equipped shop with special fixtures etc.

[411A]

And then there are others.
Take the four engine Douglas DC-6.
This airplane has an arrangement whereby the center (inner) wing sections are bolted onto a wing box fuselage structure, then the outer wings (outboard of each outboard engine) are bolted onto the center wing sections.

A model of the DC-6 series, the DC-6B also has another distinction...it was the least expensive, by the measurement of costs per seat/mile, to operate than any other piston airliner.
Its remarkable engines are the primary reason...Pratt&Whitney R-2800CB16's.

[CV880]

The A330/340 centre fuselage section is transported with the wing centre section installed which I expect is the norm. The wings, fwd and aft fuselage (with nose and tail added enroute to Toulouse) and stabilisers are transported to Toulouse as separate parts. First step in assembly is to mate the wings to the centre fuselage. Then the fwd and aft fuselage sections are added to the centre section (with wings already attached) and the stabilisers attached.
I think the DC10/MD11 was handled in a broadly similar manner.
The L1011 fuselage was assembled by Lockheed at their Palmdale plant with panels made at Burbank but the wings were transported by rail across the USA (from Tennessee I think) to Pamdale for mating to the fuselage.
With the exception of the 737 Boeing have tended to fabricate and assemble everything on site only transporting sub assemblies such as fuselage panels but not complete sections.

[GuppyEng.com]

There was a documentry on discovery several years ago about the 777 and how it was designed and assembled. They showed testing the wings to destruction. I think the tips got to over 60 degrees before the inboard part of the wing (inboard of the engines) failed.

[glhcarl]

CV880, You are correct that the L-1011 was assembed in Palmdale with the fuselage panels built in Burbank and the wings built in Nashville, by Avco. However, the center wing box was built in Palmdale and was the first part to be assembled. The wing box and fuselage section over the wing box started the fuselage down the production line. With the seactons fore and aft installed as it moved down the line until it was completly assembled, less the aft body, aft of the pressure bulkhead. The fuselage was then taken to the paint hanger where it was painted in the customers livery. Then the fuselage was brought back to the main building, where the wings and aft body where installed and final assembly completed. By the way the wings on the L-1011 were attached with approximately 400 3/8 inch Hi-Tigue fasteners.

[CV880]

Hi Guppyeng. I also saw Boeing's video about the 777 wing ultimate load test. Amazing stuff. I used to have a hand out from Airbus about the A330/340 wing test and it stated the tips were bent up more than 7 metres before rupture occured. There were photographs of the 747-400 doing stall tests that showed the end of the wings (not the winglet tips) raised well above the top of the fuselage probably just before stall.
GLHCARL, thanks for the extra details. I did my L1011 training at Palmdale and walked the assembly line many times but it was back in 1974 and some of the details have faded from memory. I recall watching a guy drilling the holes for the wing attachment one day. He was basically using a commercial electric drill with a hydraulic jack under it to apply upward pressure and a jig to align it. Not very high tech but it worked.

[glhcarl]

CV880,The L-1011 wing joint holes were drilled using "spacematic" automatic drills. These drills controlled the speed and feed of the drilled hole to insure the they had the proper fit for for the Hi-Tigue fasteners. "Spacematic" drills were state of art in 1970. The only way to see these drills in action was from inside the cabin where you could see the upper surface holes being drilled or to crawl under the wing mate jig to see the lower surface holes being drilled. The only electric drills allowed on the production floor were those used by the facilities maintenance crew.

[Ms Spurtle]

http://www.youtube.com/watch?v=6Uo0C01Fwb8

[darrenstaxis]

http://www.youtube.com/watch?v=6Uo0C01Fwb8