747 Questions

[cudgy_funt]

Just a few general interest questions, just to satisfy my own curiosity really

1) what is the small hatch in the roof of the 747 (all models i think) aft of the flight deck?

2) what do the winglest actually do on the -400?

3) in the first class section at the front of the plane, can you see forward, i.e. where you are going?

4)why do the main wing wheels hang down? is this for shock absorbing? ive noticed this no other aircraft (A330/340, TSR2 to name a few)

Many thanks

CF

[Bally Heck]

Fudgy

1) Escape hatch from the flight deck.

2) Reduce the lateral airflow over the wingtips thus reducing vortex and drag.

3) No.

4) The main wing wheels have a thing called a truck to carry them. The truck has four or more wheels on it two abreast. If they didn't hang down then the stress on them during take off and landing when the aircraft body angle changes would cause them to break off. Also when the truck isn't hanging down, it tells the aircraft systems that the aircraft is on the ground. The truck hanging down logic allows the interlocks on such systems as speedbrakes, thrust reversers and wheelbrakes to operate. :D

[Cornish Jack]

C F
Just a little additional info on the 747 gear. The tilt angle on the gear is to allow them to fit into their respective wheel wells on retraction. Although the gear wells look to be huge, the actual space available when the gear is retracted is limited. To ensure that they fit correctly, the wing gear is tilted to 53 degrees and the body gear to 8 degrees. The movement of the gear to the tilted position is used as one of the signals that the aircraft is airborne - and vice versa.

[Bally Heck]

Quite so Cornish.

On the 757 the gear hangs to the back and on the 767 to the front (rather like myself) for this very reason :)

[126.9]

Q3. You can actually see forward ie. where you are going: but only as far as the closet in the nosecone. :D :D :D