Wing types

COMMENTARY

1. Акронимы VTOL и STOL читаются нетрадиционно: ['vJ" tOl] и ['es" tOl] соответственно.

2. Перечисляя тактико-технические характеристики (specifications, performance characteristics или performances) практически любой системы вооружений, нельзя обойтись без таких параметров, как вес - weight и высота - height. В английском языке эти термины пишутся почти одинаково, но произносятся совершенно по-разному: weight [w eI t] - height [h aI t].

Exercise 4. Listen to the tape, read and translate the text at sight:

TYPES OF AIRCRAFT

There are a number of ways to identify aircraft by type. The primary distinction is between those that are lighter than air and those that are heavier than air.

Lighter-than-air (LTA)

Aircraft such as balloons, airships or dirigibles are designed to contain within their structure a sufficient volume that, when filled with a gas lighter than air (heated air, hydrogen, or helium), displaces the surrounding ambient air and floats, just as a cork does on the water. Balloons are not steerable and drift with the wind.

Non-rigid airships, which have enjoyed a rebirth of use and interest, do not have a rigid structure but have a defined aerodynamic shape, which contains cells filled with the lifting agent. They have a source of propulsion and can be controlled in all three axes of flight.

Heavier-than-air (HTA)

This type of aircraft must have a power source to provide the thrust necessary to obtain lift. Simple heavier-than-air craft include kites.

Gliders are usually used for flight training and have the capability to fly reasonable distances when they are catapulted or towed into the air.

AIRCRAFT CONFIGURATIONS

Wing types

Aircraft can also be categorized by their configurations. One measure is the number of wings, and the styles include monoplanes, with a single wing (that is, on either side of the fuselage); and biplanes, with two wings, one atop the other.

The wing planform is the shape it forms when seen from above. Delta wings are formed in the shape of the Greek letter delta (∆) and are triangular wings lying at roughly a right angle to the fuselage. The supersonic Concorde features delta wings.

Swept wings are angled, usually to the rear and often at an angle of about 35°. Forward swept wings also are used on some research craft.

Some aircraft have wings that may be adjusted in flight to attach at various angles to the fuselages. Variable geometry (swing) wings can vary the sweep (i.e., the angle of a wing with respect to the plane perpendicular to the longitudinal axis of the craft) of their wings in flight. These two types have primarily military applications.

Another configuration limited to military craft is the so-called flying wing, a tailless craft having all its elements encompassed within the wing structure (as in the Northrop B-2 bomber).