SST


Also found in: Dictionary, Thesaurus, Medical, Acronyms, Wikipedia.

airplane

airplane, aeroplane, or aircraft, heavier-than-air vehicle, mechanically driven and fitted with fixed wings that support it in flight through the dynamic action of the air.

Parts of an Airplane

The airplane has six main parts—fuselage, wings, stabilizer (or tail plane), rudder, one or more engines, and landing gear. The fuselage is the main body of the machine, customarily streamlined in form. It usually contains control equipment, and space for passengers and cargo. The wings are the main supporting surfaces. Modern airplanes are monoplanes (airplanes with one wing) and may be high-wing, mid-wing, or low-wing (relative to the bottom of the fuselage). At the trailing edge of the wings are auxiliary hinged surfaces known as ailerons that are used to gain lateral control and to turn the airplane.

The lift of an airplane, or the force that supports it in flight, is basically the result of the direct action of the air against the surfaces of the wings, which causes air to be accelerated downward. The lift varies with the speed, there being a minimum speed at which flight can be maintained. This is known as the stall speed. Because speed is so important to maintain lift, objects such as fuel tanks and engines, that are carried outside the fuselage are enclosed in structures called nacelles, or pods, to reduce air drag (the retarding force of the air as the airplane moves through it).

Directional stability is provided by the tail fin, a fixed vertical airfoil at the rear of the plane. The stabilizer, or tail plane, is a fixed horizontal airfoil at the rear of the airplane used to suppress undesired pitching motions. To the rear of the stabilizer are usually hinged the elevators, movable auxiliary surfaces that are used to produce controlled pitching. The rudder, generally at the rear of the tail fin, is a movable auxiliary airfoil that gives the craft a yawing (turning about a vertical axis) movement in normal flight. The rear array of airfoils is called the empennage, or tail assembly. Some aircraft have additional flaps near the ailerons that can be lowered during takeoff and landing to augment lift at the cost of increased drag. On some airplanes hinged controls are replaced or assisted by spoilers, which are ridges that can be made to project from airfoils.

Airplane engines may be classified as driven by propeller, jet, turbojet, or rocket. Most engines originally were of the internal-combustion, piston-operated type, which may be air- or liquid-cooled. During and after World War II, duct-type and gas-turbine engines became increasingly important, and since then jet propulsion has become the main form of power in most commercial and military aircraft. The landing gear is the understructure that supports the weight of the craft when on the ground or on the water and that reduces the shock on landing. There are five common types—the wheel, float, boat, skid, and ski types.

Developments in Airplane Design

Early attempts were made to build flying machines according to the principle of bird flight, but these failed; it was not until the beginning of the 20th cent. that flight in heavier-than-air craft was achieved. On Dec. 17, 1903, the Wright brothers produced the first manned, power-driven, heavier-than-air flying machine near Kitty Hawk, N.C. The first flight lasted 12 sec, but later flights on the same day were a little longer; a safe landing was made after each attempt. The machine was a biplane (an airplane with two main supporting surfaces, or wings) with two propellers chain-driven by a gasoline motor.

The evolution of the airplane engine has had a major effect upon aircraft design, which is closely associated with the ratio between power load (horsepower) and weight. The Wright brothers' first engine weighed about 12 lb (5.4 kg) per horsepower. The modern piston engine weighs about 1 lb (0.4 kg) or less per horsepower, and jet and gas-turbine engines are much lighter. With the use of jet engines and the resulting higher speeds, airplanes have become less dependent on large values of lift from the wings. Consequently, wings have been shortened and swept back so as to produce less drag, especially at supersonic speeds. In some cases these radically backswept wings have evolved into a single triangular lifting surface, known as a delta wing, that is bisected by the fuselage of the plane. Similar alterations have been made in the vertical and horizontal surfaces of the tail, again with the aim of decreasing drag.

For certain applications, e.g., short-haul traffic between small airports, it is desirable to have airplanes capable of operating from a runway of minimum length. Two approaches to the problem have been tried. One, the vertical takeoff and landing (VTOL) approach, seeks to produce craft that take off and land like helicopters, but that can fly much faster. The other approach, short takeoff and landing (STOL), seeks to design more conventional aircraft that have reduced runway requirements. The lessened lift associated with swept-back wing designs increases the length of runway needed for takeoffs and landings. To keep runway lengths within reasonable limits the variable-sweep, or swing, wing has been developed. A plane of this type can extend its wings for maximum lift in taking off and landing, and swing them back for travel at high speeds.

A proposed variant of the swing wing, in which one wing sweeps to the rear and another forward, produces an arrangement that causes a minimum shock wave at supersonic speeds. It is thought that if this modification were applied to supersonic transport (SST) designs it would somewhat lessen their objectionable noise levels. No solution has been proposed to lessen their high fuel consumption, however. Recent developments in fan-jet engines, in which a turbine powers a set of vanes that drive air rearward to augment thrust, have made supersonic flight possible at low altitude. Much research has also gone into reducing the noise and air pollution caused by jet engines.

See aerodynamics; airport; aviation; autogiro; glider; seaplane.

Bibliography

See bibliography under aviation.

The Columbia Electronic Encyclopedia™ Copyright © 2022, Columbia University Press. Licensed from Columbia University Press. All rights reserved.

SST

(aerospace engineering)
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

SST

On drawings, abbr. for stainless steel.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
Pituitary tumors are generally benign slow-growing neoplasms, and different adenomas show a typical pattern of SST receptor expression [74] according to the secreting cells from which they originate: GH-secreting pituitary adenomas mostly express sst2 and sst5 [147], ACTH-secreting lesions predominantly coexpress sst5 and sst2 [148] while in prolactinomas sst1 and sst5 are the predominant receptors [149].
A convenience sample of ED nurses (N = 8) was recruited to participate in semistructured interviews to obtain feedback on barriers and facilitators to implementing an SST with water swallow in the ED.
The researchers explained that the local weather and marine environmental factors changed around Oman in recent years making it imperative to investigate the SST dynamics of the seas around Oman.
Requests for SST support have also been increasing monthly as word of the program spreads in the Army's G6/S6 community.
The configuration can also be stored on a USB memory stick and then plugged into the SST module so it can be booted using the new configuration.
There was a greater mean percentage decrease in methadone concentration before compared with after pegylated interferon [alpha]-2b administration in both glass SST [28.0 (12.4)% vs 20.1 (6.8)%] and plastic SST X28.0 (7.1)% vs 23.2 (5.2)%], but this effect was only statistically significant in glass SST (P = 0 .03).
Within "SST for Africa", refrigerated trucks and containers that transport beef from the interior of Namibia have been secured with battery-powered RFID sensor bolt seals.
SST might spend $300 for an ad, while the police department would only get $120 of that money.
SST believes that its embedded SuperFlash technology is the best candidate for future generations of smart card IC applications that require much higher density of embedded memory because the SuperFlash cell size is much smaller and the thicker oxide used in the SuperFlash technology has proven to have excellent data retention reliability in high-volume production.
The Concorde began with a 1958 report on the possibilities of SST by British aircraft designers and with the 1959 commitment to SST by Harold M.
We took the necessary precautions to minimize the effects of the latter four problems (see above), but our sample size is small relative to the number of paths in the structural model, and two of our predictor (independent) variables, SST length and SST number, are significantly negatively correlated when we do not control for phylogeny (Table 1).