121

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 conventional aircraft, placing fuel tanks in the wings places the fuel mass very close to, or on, the center of lift. This dramatically reduces Cg shift during ...


81

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 dead weight that creates strain on the structure. Think about one in flight. Now all the lift is coming from the wings, imagine the airplane suspended by ...


50

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 three axis, as part of the inertial reference system. They are important instruments for the autopilot, as they provide faster feedback on the effect of ...


35

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 able to find everything you need in the old Forest Products Laboratory study at this google search link. The key weakness in spruce (and wood in general) used ...


32

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. Clearing this configuration even for being loaded and pushed around is more effort than simply placing the ballast where the mass of the engines would go. Now all ...


31

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 much heavier solution. The shape of the final aft section is not well suited to resist pressurization stresses: the best shape is a sphere; the cylinder (with ...


29

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 compensate for engine failure. The further away form centreline the engine is mounted, the higher the yawing moment that the remaining engine exerts upon ...


27

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 can simply hang the weight of the engine on the pylon and the aircraft will behave as it there is an engine (weight and c.g. wise). In case you want to load ...


27

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-span As a result of the effects of lift (and the deceasing need for it as the plane lightens) the reverse is actually true see here higher risk of ...


22

Could winds of up to 150 km/h impact the structural loads on the B777-200LR? Not at all. The dynamic pressures on the plane depend on the plane's velocity with respect to the air, not the ground speed. Flying in 150 km/h tailwind is the same as flying with no wind, the plane's indicated and true airspeeds won't be affected. True airspeed is the plane's ...


22

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 there is quite a bit of extra ground clearance. You can also see that the rear landing gear on the PC-24 are much more robust (dual wheels, longer travel length) ...


18

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" for. Glassfibers are good insulators and transparent to radar waves. The reason for glassfiber on forward-facing surfaces is impact tolerance. Compared to carbon ...


17

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 floors you can load standard cargo containers quickly and efficiently. It also gives you the ability to standardize the containers with a reasonable degree of ...


17

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 manual that comments on the differences in performance when they are installed.


16

The lines start at zero load factor because with no speed there is no lift. If you move further right, the upper line is determined by the maximum lift, while the lower line is determined by the minimum lift. Both have the same value only for symmetric airfoils - regular airfoils are optimized for creating lift in only one direction. The upper and lower ...


16

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 in uncoordinated flight. This improvement, first seen in 1930s vintage gliders (where else!), improves the airflow around the aircraft, resulting in ...


15

The aircraft is the Indonesian Airforce Boeing 737-2X9 “Surveiller” aircraft, used for Maritime Patrol. The fairings house Side looking Airborne Radar for matitime surveillance. From b737.org: Fitted with Motorola AN/APS-135(V) Side Looking Airborne Modular Multi-Mission Radar (SLAMMR) The antenna of which was mounted in two 16ft housings on the upper ...


15

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 a floor with seats, a nose to make it aerodynamic, wings for lift, and a tail section for control (yes, I know I am way oversimplifying it, and that's the whole ...


15

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 coatings on model airplanes) suffer in this regard since, between ribs, the covering will bend inward and alter the shape of the leading edge (and, locally, the ...


15

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 makes little sense. And it's not just the wings, many aircraft carry fuel in the vertical stabiliser as well.


14

On Sunday 4 October 1992, El Al Flight 1862 crashed into a suburb of Amsterdam after the right inboard engine separated from the wing and took part of the wing and the right outboard engine with it. The separation was caused by fatigue fracture of the fuse-pins that connect the engine to the aircraft. The engines of the Boeing 747-200 are joined to the ...


14

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, a fuselage tank is located lower than the engines and requires pumps to raise the fuel. Electrical pump failures have caused explosions. This also means that ...


13

The wing folding mechanisms (in aircraft) and rotor folding mechanisms (in helicopters) are different. The V-22 Osprey falls somewhere in the middle. In case of aircraft, the wing folding mechanism is usually made of high grade steel (or titanium in some cases) and actuated either hydraulically (or in recent cases) electrically. The outer wing rotates about ...


12

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 properly translated into English, so the German term is used. The Hortens increased chord at the center trailing edge of the wing, reducing local sweep and increasing ...


12

Because most cargo aircraft are derived from passenger aircraft. All dedicated cargo designs have no extra floor: They carry the payload on the fuselage bottom structure. Comparison of transport aircraft cross sections aft of wing drawn to the same scale (picture source). The C-5 and C-17 are dedicated military cargo designs and their round bottom is not ...


12

Depends on the crack characteristics, number of striations (individual propagation events) etc., whether the cracks are from a small number of near-yield overloads or many small loads from regular cycles. This sort of thing happens quite a lot. You are designing parts at all times to be "just strong enough" for all the various requirements and goals, since ...


11

I suspect the reason for this has nothing do with aviation and better fits at our history or statistics stackexchange counterparts. Information about the production capacity of the enemy is of major strategic importance. Using the serial numbers of a relative few aircraft one can make a quite accurate estimate of the total number of aircraft produced. This ...


11

Yes, absolutely. The skin transfers shear stresses between the stringers or longerons which run lengthwise along the fuselage and transmit tensile or compressive stress. Cutouts and openings (for doors and windows) need special local reinforcements, so the reduced structure can still withstand the loads. Equally, the wing skin is the main element for the ...


11

The crew took 3 tonnes of taxi fuel of which they only burned 800kg and that put them at least a tonne above MTOW not taking the tailwind into consideration which the report states would have been negligible. I can't speak to operations in today's environment, but at the two 747 carriers I worked for in the late 1980s and the 1990s, it was quite common to ...


11

Raymer gives the following answer: The 'T-Tail' is also widely used. A T-tail is inherently heavier than a conventional tail because the vertical tail must be strengthened to support the horizontal tail, but the T -tail provides compensating advantages in many cases. Due to end-plate effect, the T -tail allows a smaller vertical tail. The T ...


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