Text 3.

Read and translate the following text into Ukrainian.

Categories of aircraft are: airplane, rotorcraft, glider, lighter-than-air, powered lift, powered parachute, weight-shift-control. Most aircraft categories are further broken down into classes. The airplane category is divided into single-engine land, multi-engine land, single-engine sea, and multi-engine sea classes. The rotorcraft category is divided into helicopter and gyroplane classes. The lighter-than-air category is divided into airship and balloon classes. The powered parachute category is divided into powered parachute land and powered parachute sea. The weight-shift-control category is divided into weight-shift-control land and weight-shift-control sea. Aircraft type is the classification based on what the aircraft does: fighter, bomber, cargo plane, passenger plane, etc. Aircraft model denotes the particular design of an aircraft: F-14 Tomcat, B-52 Stratofortress, C-5 Galaxy, 747 Jumbo Jet. It can be confusing because types have many models, and some models are designed or modified to fulfill multiple types.

Types of Aircraft

In order to fly man must have aircraft, i.e. weight-carrying device capable of creating the lift. Three principles of creating the lift are known: aerostatic, aerodynamic and reactive. Accordingly, aircraft may be divided into two main groups: aircraft, the lift of which is created on the base of aerostatic principle, and aircraft capable of creating the lift on the base of aerodynamic or reactive principle. The former are called lighter-than-air craft or aerostats, and the latter heavier-than-air craft or aerodyne.

Aerostats are subdivided into airships and balloons, the difference being that a balloon is an aerostat without a propelling system, while an airship is an aerostat provided with the propelling system and with means of controlling the direction of motion.

Heavier-than-air craft may be subdivided into aeroplanes, helicopters, autogyroes, ornithopters and gliders according to the means of creation of the lift.

The aeroplane is a mechanically driven fixed-wing aircraft, heavier than air, which is supported by the dynamic reaction of the air over its wing surfaces.

The principal features of the helicopter are two rotating airscrews mounted on a vertical driving shaft, revolving in opposite directions. These provide the lift required to support the machine. By having two airscrews rotating in opposite directions, the tendency for the machine to turn about the vertical axis, which could exist if there were only one airscrew, is eliminated: a gyroscopic effect is also produced by tilting the axis of the vertical propellers, or by other means.

The principal feature of autogyro is a rotor having a number of blades which autorotate under the action of the relative wind, and which are also free to rise and fall with the pressure of the air; these blades provide the necessary lift for supporting the weight of the machine and therefore take the place of the wings or main planes of the orthodox aeroplane. As distinct from the helicopter, forward motion is obtained by means of an airscrew, as in the normal aeroplane.

Ornithopter derives its chief support and propelling force from flapping wings. Glider is similar to an aeroplane but without a power plant.

Aircraft may be divided according to the purpose for which they are used into civil machines and military machines. Civil or commercial machines are employed not only for the conveyance of mail, passengers, and freight, but for aerial photography, for aerial survey, and for such work as the protection of crops by the spraying of chemicals, and for many other purposes.

The aeroplane is usually qualified by the number and position of its main planes. There is the monoplane, which has only one wing, or, as it is sometimes considered preferable to say, one pair of wings. In some monoplanes the wing is set at the top of the body, in others at the bottom, and in still others it occupies an intermediate position; these are referred to respectively as high-wing, low-wing, and mid-wing machines.

Then there is the biplane, which has two pairs of wings, one set above the other. There are also machines which possess more than two supporting surfaces, notably the triplane and the quadruplane; but machines with more than two main planes have not so far met with much success.

According to the number of engines installed in aircraft it may be divided into single-engined, two-engined and, in general, multi- engined aircraft.

Aeroplanes may be also divided into four types as follows:

1. The landplane.

2. The float seaplane.

3. The boat seaplane.

4. The amphibian.

The landplane, as the name implies is restricted to use from land; the second and third types use water only as their take-off and landing "grounds"; and the last, the amphibian, is so constructed that it may take-off from or alight on either land or water.

Exercise 1. Transcribe the following words.

Aerostatic, aerodynamic, reactive, autogyro, ornithopter, glider, surface, machine, axis, propel, propeller, survey, biplane, triplane, quadruplane, float, amphibian.

Exercise 2. Using a monolingual dictionary of aviation or encyclopedia, please, find the definition of the following words and word combinations.

High-wing airplane, low-wing airplane, mid-wing airplane, aerostat, aerodyne, aerial survey, a gyroscopic effect, fixed-wing aircraft.

Exercise 3. Fill in the blanks with a suitable word or phrase.

1. Aerostats are subdivided into … and ...

2. Three principles of creating the lift are known: …

3. Heavier-than-air craft may be subdivided into …

4. Ornithopter derives its chief support and propelling force from …

5. Glider is similar to … but without ...

6. According to the number of engines installed in aircraft it may be divided into...

Exercise 4. Answer the questions:

1. What’s the difference between airships and balloons?

2. What are three principles of creating the lift?

3. How many groups aircraft may be divided into?

4. What are the principle features of the helicopter?

5. What is the principle feature of autogyro?

6. What is the aeroplane usually qualified by?