61 votes
Accepted

What is the offset in a seaplane's hull?

That's called the step. Without it, you'd have to fight against the buoyancy of the rear end of the hull when you rotate for takeoff. However, a seaplane float or hull must be designed to permit the ...
Hobbes's user avatar
  • 10.2k
56 votes

Can cameras and LCD screens replace cabin windows?

Note that the windows are a safety feature: You need to see outside in case of emergency, e.g. to know which side of the plane is surrounded by flames, or how deep in the water you are. This is ...
yo''s user avatar
  • 1,154
50 votes
Accepted

What is this line found above the door on many aircraft?

These are rain gutters. They are designed to catch rain that runs off the upper surface of the aircraft fuselage and channel it away from the open aircraft door so that the water does not enter the ...
J W's user avatar
  • 16.6k
43 votes
Accepted

Why was the SR-71 made of titanium?

Because the specific strength of titanium at higher temperatures is better than that of steel (both are much better than that of aluminium). Specific strength vs. temperature is shown on the above ...
Koyovis's user avatar
  • 61.7k
37 votes

Can cameras and LCD screens replace cabin windows?

Problem #1: What gets displayed on the screen? While I'm aware of Emirates' recent 'virtual windows,' there is a big problem with this idea in general: what should actually be displayed there depends ...
reirab's user avatar
  • 19.5k
37 votes

Why don't Airbus planes have perfectly smooth front sections?

It is not about Boeing versus Airbus, but rather about old versus new. Your representative image for Airbus is an A320, whose technological competitor by Boeing is the 777. Juxtaposing the two, we ...
Aditya Sharma's user avatar
35 votes

Why is the A380's fuselage designed with a flat bottom?

There are 2 main reasons: The wing spars run through that area. If you wanted to keep the wing spar within the oval cross-section, you'd have to install the wing much higher on the fuselage which ...
Hobbes's user avatar
  • 10.2k
34 votes
Accepted

Can cameras and LCD screens replace cabin windows?

Emirates Airlines have recently launched their new First Class with a similar concept. It is only available in First Class and I doubt it has much to do with the structural implications as of now, ...
mbglobetrotter's user avatar
33 votes

Why use an airplane with non-retractable landing gear for aerobatics?

As you mentioned, drag is one of the reasons why retractable landing gears are used in the first place. But in order to use it, there are way more considerations than just drag. Scale: Size of the ...
tegginamaniss's user avatar
31 votes
Accepted

Why do airliners have "pressure bulkheads"?

What part aft of the bulkhead would leak pressure? That's a partial misunderstanding of what a bulkhead is there for. You could build the aft cone section to keep the pressure, but it would be a ...
Federico's user avatar
  • 32.6k
27 votes
Accepted

Why doesn’t lightning punch a hole in the fuselage?

Potentially, yes, but this would be a very rare event. The principal reason that lightning does not create damage to an aircraft is that the airframe, particularly aluminum airframes, are electrically ...
Romeo_4808N's user avatar
  • 73.7k
25 votes
Accepted

What are these elements on the back of a Boeing 737?

① Main outflow valve door (Source) A valve used for controlling the pressure in the cabin. Air is pushed into the cabin by the air conditioning packs, and exits by this hole. The flow can be ...
mins's user avatar
  • 73.2k
24 votes
Accepted

What are these lines on the fuselage of a 747?

No, they are just the boundaries between skin panels. See below for a picture of the 747-8 fuselage during assembly. [ Boeing 747-8 front from side (picture source) And this is how the panels for ...
Peter Kämpf's user avatar
24 votes

Why don't airliner vertical tails extend to the very aft of the fuselage?

Spin resistance and area ruling Locating the vertical a bit ahead of the horizontal tail brings it out of the probable wake of the horizontal at high angle of attack, so it still is effective in ...
Peter Kämpf's user avatar
22 votes

What are these "winglets" on the roof of the 737?

In general, those are called blade antennas. They consist of a monopole antenna (a single rod sticking out of the fuselage) with an aerodynamic fairing around it.
Hobbes's user avatar
  • 10.2k
22 votes

Why don't Airbus planes have perfectly smooth front sections?

The pinched-nose airplane has its (flat) frontmost windshield panels almost touching and raked back, which forces the vertical crease. The corresponding panels on the other airplane are farther apart, ...
Camille Goudeseune's user avatar
21 votes
Accepted

Why did water come into USAirways Flight 1549 if an airplane is sealed and pressurized?

Two reasons: Airplanes are not completely, perfectly hermetically sealed. They are pressurized using positive air pressure from the engine bleed air and packs. If there is a failure in the system, ...
Dean F.'s user avatar
  • 16.5k
21 votes

Why was the SR-71 made of titanium?

There is a great article here that breaks it down in depth but its combination of factors made it the best choice, not a single factor (i.e. heat resistance). But, in reality, the strongest titanium ...
Dave's user avatar
  • 101k
19 votes
Accepted

Why didn't the Boeing 757 share the 767 fuselage?

Boeing had already a fuselage for the 757 that fit the bill. It came originally from the 707 via the 727. To accommodate more baggage, the rear fuselage was deeper, as on the 737. During development ...
Peter Kämpf's user avatar
18 votes

What are these "winglets" on the roof of the 737?

It looks like a VHF and ELT antenna. References: Boeing 737NG Radio Equipment Communications
Deepak-MSFT's user avatar
18 votes
Accepted

What are the random, differently-coloured rectangular patches on the top of this Boeing 737's fuselage?

They aren't "repair patches" themselves, they are repainted areas where some sort inspection and/or repair was done to the underlying structure, that required removal of the paint in the ...
John K's user avatar
  • 131k
18 votes

Why doesn’t lightning punch a hole in the fuselage?

The other answers mention aircraft have a high electrical conductivity. However, air has a much lower electrical conductivity and does get hot, as you mentioned. The hot air causes little damage ...
Anonymous Physicist's user avatar
17 votes

What is this line found above the door on many aircraft?

It's for the passengers on a rainy day. If this strip would not be diverting the rainwater flowing from the upper fuselage, a curtain of water would soak the passengers upon entering or leaving the ...
Peter Kämpf's user avatar
17 votes

Why doesn’t lightning punch a hole in the fuselage?

Why doesn't it punch holes in the fuselage? It can. Can it ignite fuel in wings? Yes, lightning creates sparks that can potentially ignite fuel vapors. The liquid fuel itself does not ignite, but the ...
Chris's user avatar
  • 15.5k
16 votes

Why use an airplane with non-retractable landing gear for aerobatics?

Strictly speaking, a 'pure' aerobatic aircraft doesn't need a retractable landing gear. For such an aircraft maneuverability is much more important than speed. In fact, the aircraft can't fly too ...
aeroalias's user avatar
  • 100k

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