Question about the structure of planes

[Cyrus664]

I'm interested to know about the structure of large planes, such as the Boeing 747 or Airbus A380. How are they built, how does these incredible 'beasts' get up in the air, and stay there? How do they fly past turbulence without damage? And this might seem a bit silly, but what stops the wings from simply breaking off? They have often two massive engines hanging under them, and during strong wind, they really "bounce" up and down.

As you might have gathered, I'm a complete newbie when it comes to this issue. Hope to get some fruitful answers.


Cheers! :)

[TheOddOne]

Basically the body or fuselage is constructed of a series of hoops or frames which are joined together by thin strips or longerons which run down the length of the fueslage. These are covered in a skin which because it is closely attached to the longerons gives the whole structure its basic strength. Further strengthening is given by the floors of both the passenger cabin and the cargo/baggage holds underneath. The circular nature of the frames gives an unobstructed space inside the fuselage for passengers or freight.

The wings consist of a main strong component called a spar; there may be a main spar about one third in from the front or leading edge of the wing and another smaller spar towards the rear, on which are hinged various moving surfaces that change the shape of the wing for control and lift management. The basic shape of the wing is given by a series of structures called ribs, which ae attached to the spars. A skin is attached to these and, like the fuselage, this skin contributes to the strength of the structure. On large aircraft, the whole of this structure also forms the fuel tank. Most aircraft have the engines attached to pylons which are in turn attached to the main spar.

The wings are attached to a strengthened part of the fuselage by a few large bolts.

There are much smaller wings attached to the rear of the fuselage to provide stability and control in the up and down sense, or pitch . One of these wings is mounted vertically and is called the fin.

You have noticed that all these structures move about in relation to one another. If they were held rigidly then they would most likely snap off but they are designed to be quite flexible to absorb rapid changes in forces encountered in turbulence or simply when landing or taking off. Wing tips of large aircraft can flex up and down several metres in relation to the fuselage. If you take a steel ruler you will be able to flex it up and down quite easily, without damaging the ruler, unless you apply excessive force, when you will put a permanent distortion into it. However, you will find it impossible to bend fore and aft. The trick in designing an aircraft is to make is just flexible enough to withstand all the likely flexing it will get in its lifetime without making it too heavy to fly economically.

I suggest that you find out more by using a search engine on the Internet, such as Google.

The Odd One