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Encyclopedia > Wing loading

In aerodynamics, wing loading is the loaded weight of the aircraft divided by the area of the wing. It is broadly reflective of the aircraft's lift-to-mass ratio, which affects its rate of climb, load-carrying ability, and turn performance. This article is about the branch of Physics. ... Lift consists of the sum of all the fluid dynamic forces on a body perpendicular to the direction of the external flow approaching that body. ...

Typical wing loadings range from 20 lb/ft² (100 kg/m²) for general aviation aircraft, to 80 to 120 lb/ft² (390 to 585 kg/m²) for high-speed designs like modern fighter aircraft. General aviation (abbr. ... An A-10 Thunderbolt II, F-86 Sabre, P-38 Lightning and P-51 Mustang fly in formation during an air show at Langley Air Force Base, Virginia. ...

Wings generate lift owing to the motion of air over the wing surface. Larger wings move more air, so an aircraft with a large wing area relative to its mass (i.e., low wing loading) will have more lift at any given speed. Therefore, an aircraft with lower wing loading will be able to take off and land at a lower speed (or be able to take off with a greater load). It will also tend to have a superior rate of climb because less additional forward speed is necessary to generate the additional lift to increase altitude. It may also be capable of more efficient cruising performance because less thrust is required to maintain the lift for sustained flight.

Wing loading is also a useful measure of the general maneuvering performance of an aircraft. To turn, an aircraft must roll in the direction of the turn (i.e., in a right turn the pilot rolls to right wing low, left wing high), increasing the aircraft's bank angle. Banks lower the wing's lift against gravity and the nose moves toward the earth, so a control must be moved into the air stream (often the rudder) to keep the nose level. This increases drag. Also, turning is 'climbing around a circle' (wing lift is diverted to turning the aircraft) so the increase in wing angle of attack creates even more drag. The harder the turn attempted, the more drag. All this requires that power (thrust) be added to overcome the drag. The maximum rate of turn possible for a given aircraft design is limited by its wing size and available engine power: the maximum turn the aircraft can achieve and hold is its sustained turn performance. Aircraft with low wing loading tend to have superior sustained turn performance because they can generate more lift for a given quantity of engine thrust. Conversely, however, a large, lightly loaded wing will tend to have greater mass and inertia and create greater induced drag when the bank angle or angle of attack increases. The immediate turn position an aircraft can get into before drag seriously bleeds off speed is its instantaneous turn performance, its ability to rapidly change direction. An aircraft with a small, highly loaded wing may have superior instantaneous turn performance, but poor sustained turn performance: it reacts quickly to control input, but its ability to sustain a tight turn is limited. (A classic example is the F-104 Starfighter, which has a very small wing.) The principle of inertia is one of the fundamental laws of classical physics which are used to describe the motion of matter and how it is affected by applied forces. ... In aerodynamics, lift-induced drag, or more simply, induced drag, is a drag force arising from the generation of lift by wings or a lifting body during flight. ... In this diagram, the black arrow represents the direction of the wind. ... The Lockheed F-104 Starfighter was a high-performance supersonic interceptor aircraft, capable of high speeds and climb rates. ...

All else being equal, a larger wing generates more drag than a small one. The construction of a large wing also tends to be thicker, which further increases drag. This drag reduces the aircraft's acceleration, particularly at supersonic speeds. A smaller, thinner wing will (all else being equal) have less drag, making it more suitable for high-speed flight (albeit at the cost of higher take-off speeds and reduced turning performance). An object falling through a gas or liquid experiences a force in direction opposite to its motion. ...

Wing loading also affects gust response, the degree to which the aircraft is affected by turbulence and variations in air density. A highly loaded wing has more inertia and a small wing has less area on which a gust can act, both of which serve to smooth the ride. For high-speed, low-level flight (such as a fast low-level bombing run in an attack aircraft), a small, thin, highly loaded wing is preferable: aircraft with low wing loading are often subject to a rough, punishing ride in this flight regimeĿ. The F-15E ("Strike Eagle") has been criticized for its ride quality, as have most delta wing aircraft (such as the Dassault Mirage III), which tend to have large wings and low wing loading. A ground attack aircraft is an aircraft that is designed to operate very close to the ground, supporting infantry and tanks directly in battle. ... The Boeing (formerly McDonnell Douglas) F-15 Eagle is an American-built all-weather tactical fighter designed to gain and maintain air superiority in aerial combat. ... The delta-wing is a wing planform in the form of a triangle. ... The Mirage III is a supersonic fighter aircraft designed in France by Dassault Aviation during the 1950s, and manufactured both in France and a number of other countries. ...

A further complication with wing loading is that it is difficult to substantially alter the wing area of an existing aircraft design (although modest improvements are possible). As aircraft are developed they are prone to "weight growth" -- the addition of equipment and features that substantially increase the operating mass of the aircraft. An aircraft whose wing loading is moderate in its original design may end up with very heavy wing loading as new gear is added. Although engines can be replaced or upgraded for additional thrust, the effects on turning and takeoff performance resulting from higher wing loading are not so easily reconciled. This was a major reason for the well-known disparity between the World War II-vintage Supermarine Spitfire and Messerschmitt Bf 109. Earlier marks of the Messerschmitt design were significantly lighter than later ones as armament, armor, and equipment increased, and while improved engine power maintained the power-to-weight ratio, later models had such heavily loaded wings that their maneuverability suffered badly, eventually tilting the balance in favor of the Spitfire. Combatants Allies: Poland, British Commonwealth, France/Free France, Soviet Union, United States, China, and others Axis Powers: Germany, Italy, Japan, and others Casualties Military dead: 17 million Civilian dead: 33 million Total dead: 50 million Military dead: 8 million Civilian dead: 4 million Total dead: 12 million World War II... The Supermarine Spitfire was a single-seat fighter used by the RAF and many Allied countries in World War II. Produced by Supermarine, the Spitfire was designed by R.J. Mitchell, who continued to refine it until his death in 1937. ... The Messerschmitt Bf 109 was a World War II fighter aircraft designed by Willy Messerschmitt in the early 1930s. ... Alternative meanings: vehicle armour, Armor (novel) A hoplite wearing a helmet, a breastplate and greaves (and nothing else). ... Power-to-weight ratio is a measure commonly used when comparing various vehicles (or engines), including automobiles, motorcycles and aircraft. ...

  Results from FactBites:
Airfield Models - How to Calculate Wing Loading of a Flying Model Aircraft (469 words)
The wing loading of an aircraft is the measure of weight carried by each given unit of area.
Wing loading is the only indicator of how "heavy" an aircraft is. The actual weight of an aircraft is meaningless.
A larger model can have a higher wing loading and fly comparably to a smaller aircraft having a lower wing loading due to differences in the aerodynamics of different size aircraft.
Wing loadings are figured by dividing the wing area of your plane by 144 to convert square inches to square feet.
The charts below provide a shortcut to figuring wing loading for those competition events that require a minimum wing loading such as those flown in SAM (Society of Antique Modelers).
Multiply wing area in square feet by minimum weight in ounces per square feet desired which equals target minimum weight.
  More results at FactBites »



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