125 votes
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Why are fuel tanks located in wings?

Several advantages: Wing structures are hollow and voluminous in order to provide structural rigidity against flutter and carry flight loads. This provides the space needed to store fuel. On a ...
Romeo_4808N's user avatar
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84 votes

Why are fuel tanks located in wings?

I see what you're saying, but there's something you're overlooking in your logic. You're looking at an airplane sitting on the ground, where the wheels are near the fuselage and most of the wings are ...
Harper - Reinstate Monica's user avatar
57 votes
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Why does the second floor of the Boeing 747 occupy only part of the plane?

The basic design of the Boeing 747 was originally developed to for the US military's CX-HLS program for a large cargo aircraft. One of the main requirements of the program was for cargo to be loaded ...
fooot's user avatar
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50 votes
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Do aircraft have accelerometers?

Most modern aircraft, which includes long range airliners since around 1970, all airliners since not much later, and basically anything with glass cockpit, do have very accurate accelerometers for all ...
Jan Hudec's user avatar
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48 votes
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Why are commercial aircraft windows typically oval instead of circular?

It's done mainly for the passengers' viewing benefit in making structural trade offs over total opening area. For a given area, a round window has less "meat" of fuselage structure between ...
John K's user avatar
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45 votes
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Is there a common name for ailerons, elevators and rudder?

Primary control surfaces is the typical name for ailerons, elevators, rudders, etc. Auxiliary flight controls include things like flaps, slats, slots, spoilers, leading edge devices, etc. Secondary ...
Wyatt's user avatar
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36 votes
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How strong is aircraft-grade spruce?

My recollection of the Modulus of Rupture is about 6000 psi for aircraft graded sitka, based on the maximum allowed grain runout, and a maximum of around 10000 for straight grain. But you should be ...
John K's user avatar
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34 votes

Why aren't aircraft built with carbon fiber tubes?

If you're going to build from carbon fibre, you generally aren't going to bother with a very "old fashioned" structural method like tube and fabric; you're going to go with the natural ...
John K's user avatar
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32 votes
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Why are empty pylons weighed down?

Your reason 1 is correct. Without the ballast the aircraft would become a taildragger. Why not pallets? This would produce the same center of gravity location, but a different mass distribution. ...
Peter Kämpf's user avatar
31 votes
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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
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30 votes

Why do T- tail airplanes have a shorter vertical stabilizer?

Two reasons: T-tail design is often imposed on designs with twin engines mounted at the aft fuselage. This means they have a small moment arm in the yaw direction, the vertical tail is dimensioned to ...
Koyovis's user avatar
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28 votes

Why are fuel tanks located in wings?

added weight increases the structural load applied to the wings different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-...
motosubatsu's user avatar
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27 votes

Why are empty pylons weighed down?

You're correct- it is to maintain the center of gravity within limits and to prevent the possibility of tipping over. As for why weights in pylons and not ballast, this method is quite simple. You ...
aeroalias's user avatar
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26 votes

Why are commercial aircraft windows typically oval instead of circular?

Speaking in ship terms (from which airplane structure has evolved), modern passenger airliners use longitudinal framing, which relies on a lot of small tightly spaced longitudinal members (stringers) ...
Therac's user avatar
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26 votes
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Why aren't aircraft built with carbon fiber tubes?

They sometimes are. The Carbon Corsair is an ultralight built with a fabric-covered frame of CFRP tubes for the fuselage. This is an all-new design. Using CFRP tubes allowed it to have a +6/-4 g ...
Therac's user avatar
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25 votes
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Why are Stratolaunch's engines so far forward?

The forward location has two benefits: Wing upwash is smaller, so the flow direction at the intake varies less with speed and altitude. This makes the intake more efficient and requires less ...
Peter Kämpf's user avatar
24 votes
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Why does the Pilatus PC-24 have such a large "Airplane Support"?

To add to the other answer... The Pilatus PC-24 is billed as a business jet that can operate out of rough airfields. Comparing the pictures of the PC-24 to the Phenom 300 or CJ4, you can see that ...
Ron Beyer's user avatar
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22 votes
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Why do windowless cargo Metroliners still have overwing-exit hatches?

The window openings are still there, they are just filled with aluminum panels replacing the acrylic ones, and the joints are fine enough they don't show up in pictures unless the light is coming at ...
John K's user avatar
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18 votes

How do GFRP and CFRP compare?

The reason for using glassfiber on radome coverings is simple: Electromagnetic transparency. Carbon fiber conducts electricity, so it will absorb much of what the antenna radiates away or "listens" ...
Peter Kämpf's user avatar
18 votes

Why do windowless cargo Metroliners still have overwing-exit hatches?

Adapting an airframe for a new mission requires a series of cost-benefit decisions. Removing the exits from the fuselage would require a complete set of structural testing to gain certification, which ...
GdD's user avatar
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17 votes

How are engines mounted onto wings?

Engine mounts and thrust links How are engines mounted onto wings? Modern engines are hanged to the pylon struts fixed to the wings, at two mounts, using an attachment device named hanger ...
mins's user avatar
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17 votes
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What is the purpose of a wing Yehudi?

Mitteneffekt The pressure fields of the left and right part of a swept wing interfere at the center, causing a drop in lift. The Horten brothers called this "Mitteneffekt", and it was never ...
Peter Kämpf's user avatar
17 votes

Why do cargo aircraft still have floors?

Because the overwhelming amount of cargo is fairly small and floors allow easy loading of both decks at the same time which is more important than the ability to load big cargo on occasion. By having ...
Dave's user avatar
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17 votes

Why does the Pilatus PC-24 have such a large "Airplane Support"?

The huge support, or bulge, is a fairing, designed for reduction of wing root drag. So many people talk about wing tip vortex drag, but much more is created at the wing/fuselage interface, especially ...
Robert DiGiovanni's user avatar
17 votes
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What is the piece that covers the top part of tires?

Those are called speed fairings. They make the shape over the tire more aerodynamic and reduce drag, thus increasing airspeed and fuel efficiency. This is a page in a Cessna 172R information ...
Ryan Mortensen's user avatar
16 votes
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What is the function of the leading edge strip?

A wing's leading edge is a place where you really want to have a particular shape and a nice, smooth surface. Stretched coverings (I've done this a fair amount with monokote and other heat-shrink ...
Marius's user avatar
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15 votes

Why do airliners have "pressure bulkheads"?

You can think of an airliner (or any other pressurized airplane, or a submarine) as a pressurized container with control surfaces and a nosecone stuck to it. Rather like a submarine, an airliner has ...
Rostol's user avatar
  • 251
15 votes

Why are fuel tanks located in wings?

Quite simply: there's a lot of empty space in those wings, and there's a lot of empty space needed for fuel. Creating space elsewhere for fuel would make the entire aircraft larger and heavier, so ...
jwenting's user avatar
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14 votes

Why are fuel tanks located in wings?

Along with the other answers, I'll point out most of the recent the cases where an aircraft fuel tank exploded, the center tank, which is in the fuselage, was implicated. There are two reasons: First,...
user71659's user avatar
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