QANTAS747-438 From United States of America, joined Jan 2001, 1964 posts, RR: 2 Posted (13 years 7 months 1 week 5 hours ago) and read 896 times:
Hey! 2 questions:
1) On the nose gear of the 757, what is that box above the tires? I see it had headlamps above it and the tires below it. In a book, I saw a picture of a pilot standing in front of it, and it appeared as if he was typing someting into it! I have NO idea what it is though.
2) How is it that the outboard engines of a 747 stay on the wing?! To me, it looks like they'd fall right off, but of course, there is a reason behind it. Also, how does it not snap the wing in half with full fuel? Dont the engines weigh a few tons?
My posts/replies are strictly my opinion and not that of any company, organization, or Southwest Airlines.
Sammyk From United States of America, joined Oct 1999, 1690 posts, RR: 0
Reply 2, posted (13 years 7 months 6 days 12 hours ago) and read 823 times:
I don't know the answer to the first, but the answer to the second seems to show common logic. If you hold something in your hand, why doesn't your arm break? In the same manner, the wing is designed to be strong enough to hold two engines, fuel, and all other related equipment. It may not "look" strong enough, but obviously it is.
Mason From United States of America, joined Jun 1999, 748 posts, RR: 1
Reply 3, posted (13 years 7 months 6 days 12 hours ago) and read 822 times:
Actually, a wing with more weight doesn't need to be as strong as a wing with less weight. Let me explain. When in flight, gravity is acting on the fusalage, pulling it down (obviously). The wings create lift, and as a result, the wings appear to 'bend' upward, as you may have seen during a heavy takeoff. The fusalage is actually sagging between the wings. The 777 and 747 are famous for this effect, although just not as visible on other aircraft. Now then, when in flight, the wings want to bend upward (as explained above), so the engines, fuel, and weight of the wing itself 'push' it down. Therefore the more weight (in the form of engines) helps keep the wing down, whereas a wing with two engines doesn't have as much weight, so it needs to be stronger to keep the wings from ripping right off. If you have the chance, look at a 747 center section when being assembled. It is the strongest part of the aircraft, and can handle the weight of the engines and fuel with no problem. Also, the wings have braces that run parallel to the fusalage, to facilitate the 'bending' by making the wing more flexable. Seeing that this is not my area of speciality, I did the best I could to explain it. I hope this helps. Perhaps someone who is more articulate and educated on this topic could fill in the gaps. As for the 757 question, I have no clue. Sorry.