Hot answers tagged

117

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 ...


111

Those wings are from an ERCO Ercoupe. The diagonal ribs are very distinctive.


79

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 ...


71

They are Anti-shock bodies. In the transsonic speed range (above about Mach 0.7), aircraft drag is governed by Whitcomb area rule, which basically says that to minimize drag, the aircraft cross-sectional area must change as smoothly as possible, independent of its actual shape. It is somewhat counter-intuitive, but well established. Compare this Junkers ...


70

Some earlier prototypes of spinning-wing aircraft were produced but none were successful. The design has some very serious disadvantages. One of the main issues appears to be undesirable gyroscopic effects. Production ... why it was never produced? Several full-scale prototype aircraft with rotating Magnus-effect wings seem to have been produced: 921-V ...


61

The wing shape in the F4U Corsair is called the inverted gull wing. The main reasons for use of this is the large propeller used in the aircraft. The Corsair design was in response to the US Navy RFP (Request for Proposal) in 1938, which mandated the following things: It should have maximum attainable speed The stall speed should be 70 mph Minimum range of ...


57

Roll control is provided by 2 flaperons, 2 ailerons, and 14 spoilers. Spoiler panels 4 and 11 are controlled mechanically rather than electrically. They are driven directly from control wheel deflections via a control cable. In case of compete electrical loss, limited roll control is available until the electrical system is restored. This probably ...


52

Flow separation happens when the pressure gradient of the airflow along the flow path becomes too steep. In subsonic flow, the oncoming air is first decelerated ahead of the wing, then swiftly accelerated when it flows around the strongly curved nose section of a wing. This acceleration is the consequence of the wing's curvature. See it this way: If the ...


51

Anhedral wings will induce roll instability and improve roll maneuverability. In a large/heavy airplane with a high-wing configuration there is usually excess roll stability, so this type of wings can be pretty common. Both the high wing configuration and wing sweep contribute a negative sideslip-induced rolling moment, and anhedral is necessary to limit ...


49

Interesting question. Purely empirically, it is the lift-to-drag ratio you are looking for. If you take this value as given for any particular aircraft, you have a direct answer for how much more effective wings are. It is the ratio of the lift to the total drag. The engine only needs to overcome the drag. With L/D equal to unity you would need the same ...


46

Yes, otherwise airplanes would be unable to go upwards into the sky.


45

The wing planform (which is the shape and layout of wing) for each aircraft is mainly based on the aerodynamic requirements. There are other considerations like stealth, controllability etc. The basic terminology in the wing geometry is given in the figure below. Source: grc.nasa.gov Most of the wing platforms in use (or have been used) fall under one of ...


44

The main purpose of the wing fence is to prevent the boundary layer thickening in the wing due to the spanwise flow observed in swept wing, as can be seen below. Image from fuckyeahfluiddynamics.tumblr.com This is the reason for having wing fence in aircraft such as Mig-25- to avert stall and improve stability. In case of highly swept wing like the ...


42

Yes, a wing can (given sufficient forward speed and angle of attack) generate lift greater than the weight of the aircraft. As with any "unbalanced" force, this will result in an acceleration of the airplane in the direction of the lift, according to Newton's Second law. $$\mathbf F=m~\mathbf a$$ Please note, the entities in bold face are vector quantities....


41

To get to the bottom of it, it might help to look at lift at a molecular level: Every air molecule is in a dynamic equilibrium between inertial, pressure and viscous effects: Inertial means that the mass of the particle wants to travel on as before and needs force to be convinced otherwise. Pressure means that air particles oscillate all the time and ...


41

Early aircraft designs used gravity feed to supply the engines with fuel. All those designs had their tanks located above the wing, and in biplanes in the center of the upper wing. The picture below (source) shows an Etrich Taube with the cylindric fuel tank mounted above the fuselage. The next application of overwing tanks were "Doppelreiter" fuel tanks (...


41

Their primary wing feathers have an unusual structure incorporating a fringed, comblike leading-edge, which reduces wind noise. The wing feathers also have an overall softness or flexibility. The trailing-edge of the wing is also dominated by soft, fringed edges. Even the underwing lining (covert) feathers have an unusual softness that plays a role in ...


40

You can get negative load factors (g forces) in different ways than just flying upside down: Change in pitch: When you push on the control column, the pitch will start to decrease. Depending on how fast you do this, the load factor can even become negative from this. Some aircraft do this intentionally to reduce the g force to exactly zero: (image source: ...


39

The FAA has decided/proposed (Nov 2017) that the folding mechanism must comply with certain standards, of which: The wingtips must have means to safeguard against unlocking from the extended, flight-deployed position in flight, as a result of failures, including the failure of any single structural element. All sources of airplane power that could ...


37

That is the visual effect produced by a shockwave. The air above the wing is accelerated and will reach Mach 1 (the speed of sound) locally. It is usually best visible when the sun is right behind you (from the viewers perspective, so on the 3 or 9 o'clock position from the aircraft) and high above the horizon. Here is a video of shockwave on an A320 on ...


37

In addition to quiet flyer's excellent answer: Owls have large wings in relation to their body size and weight. One might think that no, their bodies are quite large, but actually owls are kind of fluffy flying feather balls: what you percieve as their bodies, is mostly air. This leads to two things: Low wing loading. Their large wings do not need to ...


36

Yes, this is common in heavy cargo haulers. As you probably are aware, a dihedral wing configuration provides roll stability. Roll the plane, and it will naturally roll back to level. A center of mass well below the center of lift provides the same effect. Put a lot of weight down below the center of lift, and you'll get the roll-back effect again. While ...


35

Both the Typhoon and English Electric Lightning used over the wing fuel tanks as standard equipment for many years. There may have been others. English Electric Lightning Typhoon (with conforming tanks)


34

Fighter (combat) aircraft are designed to perform quick maneuvers in order to get into a position quickly to engage and shoot down an enemy aircraft or evade incoming threats (like missiles, etc.). Civil aircraft like airliners are designed with other things in mind like comfort, safety, reduced fuel consumption, etc. The wings are only a part of the story ...


33

There was one, and it did it to increase directional stability at supersonic speed. I am talking of the North American XB-70, of course. There were three benefits to this configuration: Improved directional stability. Without the effect of the folded-down wingtips, the XB-70 would had lost all directional stability upwards of Mach 2. The wingtips folded ...


32

Short answer: by exerting a downward force on the air around them. Long answer: Some outreach people at NASA's Glenn Research Center have written up a very good multi-page explanation, dealing individually with each contributing effect, as well as some discussion of why explanations you might have heard at school don't work. Since the navigation there is a ...


32

They are the overwing exit markings. You can see them in full in the following photo. Boeing 737 Max overwing exits. By Oleg V. Belyakov - http://spotters.net.ua/file/?id=110706&size=large, CC BY-SA 3.0, Linkec This is because as already noted in another answer, B737 does not have self inflating slides for its overwing exits and as such, the passengers ...


32

A wing can be tested in any orientation as long as the load is applied correctly. The classic wing test photo is the 787 in a fixture showing its extremely flexible wings. I thought it might be fun to add an ultimate load test, so here is the 777 tested to failure. Sorry for the early 1990s video quality. Boeing 777 wing fail at 154% design load


31

Actually, in aircraft construction tension is preferable to compression: aeroplanes are thin walled structures, and compression forces introduce buckling. In a low wing aircraft, the fuselage is pressing downwards on the top half of the wing, the bit that is under compression. In fact, quite complicated frame structure members are required for the fuselage/...


30

In the event of a water evacuation, there is a line associated with each overwing exit that is extended, and clips to that yellow bracket, as a guide to get everyone out on the wing. From Wikipedia, these are for overwing exits. The use of overwing exits in a ditching varies from airline to airline. On aircraft fitted with overwing exits, there is ...


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