3.5. Тext

3.5. Classification of Military Helicopters

Hels are a separate group of acft and have now begun to displace mil fixed-wing acft in many roles. They are classified as atk, obsn, utility, cbt assault transport, electronic warfare and target acquisition, antiarmor, etc.

3.6. Exercises

1. Ответьте на вопросы.

1. What is a helicopter?

2. What is the origin of the word helicopter?

3. What are the general characteristics of modern helicopters?

4. What are the principal structural elements of the helicopter?

5. What does the airframe consist of?

6. What does the fuselage house?

1. What does the undercarriage consists of?

7. What are the general components of the propulsion system?

8. Which type of engines is currently used in helicopters?

9. What is the purpose of the tail rotor in single-rotor helicopters?

10. Where does the helicopter derive lift from?

11. In which way does the pilot achieve horizontal flight?

12. What is the purpose of the swash-plate?

13. By means of what can the pilot control the helicopter's flight?

14. How can hovering over one point be achieved?

15. How are military helicopters classified?

2. Переведите предложения.

1. Вертолет - ЛА тяжелее воздуха, у которого подъемная сила и поступательное движение обеспечивается одним или несколькими несущими винтами.

2. The airframe includes a fuselage with a cabin, cargo compartment and tail boom, and undercarriage with main and nose landing gears and tail support.

3. Вертолет способен совершать вертикальный взлет и посадку, полет в различных направлениях, а также висеть над заданной точкой и на заданной высоте.

4. According to their mission helicopters are classified as atk, obsn, utility, cbt assault transport, electronic warfare and target acquisition, antiarmor, etc.

5. Одновинтовой вертолет состоит из следующих основных частей: фюзеляжа с хвостовой балкой, силовой установки, трансмиссии, несущего винта, рулевого винта, органов управления и шасси.

6. An axial-flow turboshaft engine having a high power-to-weight ratio is comprised of a compressor, combustion chamber, turbines, and main gear box.

7. Трансмиссия вертолета служит для передачи мощности от двигателя к несущему и рулевому винтам.

8. By the swash-plate the pitch angle of the main rotor can be varied simultaneously on all blades to change the lift and vertical movement of the helicopter.

9. Или же он может варьироваться циклически - для изменения наклона несущего винта и осуществления поступательного движения и управления вертолетом.

3. Переведите с опорой на текст. Helicopter operation

In a helicopter flight characteristics are determined by the rotational speed and pitch variations of the rotor blades. Since its flight characteristics are independent of forward speed, a helicopter is able to move in any direction at a controlled low speed and still remains safely airborne.

Many factors determine the amount of lift available in helicopter operation. Generally speaking, the pilot has control of two of these. One is the pitch angle of the rotor blades; the other is the power delivered to the rotor. By controlling the pitch angle of the rotor blades, the pilot can establish the vertical flight of the helicopter. By manipulating the engine speed, the pilot maintains the desired amount of lift of the aircraft regardless of the increase or decrease in blade pitch.

The cyclic pitch control is similar to the control stick of a conventional aircraft. It acts through a mechanical linkage to cause the pitch of each main rotor blade to change during a cycle of rotation. The rapidly rotating rotor blades create a disk area that can be tilted in any direction with respect to the supporting rotor mast. Horizontal flight is controlled by changing the direction of tilt of the rotor disk to produce a force in the desired direction.