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increased every time it sweeps over the tail of the machine, thereby temporarily
developing a greater amount of thrust than the other blades.
Additionally each blade can swivel about its longitudinal axis and its pitch is
changed cyclically, through a linkage system, by a so called swash-plate, which
performs a sort of wobbling rotary motion around the shaft and swivels the blades to
and fro as they rotate. The tilt of the swash-plate can be varied by the pilot, and the
tilt of the rotor follows the tilt of the plate.
So, by changing the pitch angle of the main rotor blades, by manipulating the
engine speed and by tilting the main rotor, the pilot controls the helicopter's flight in
any direction.
Hovering
over one point is done by selecting the correct speed and setting the
rotor blades so that their vertical lift is exactly equal to the weight of the helicopter.
3.5. ТEXT
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?
7.
What does the undercarriage consists of?
8.
What are the general components of the propulsion system?
9.
Which type of engines is currently used in helicopters?
10.What is the purpose of the tail rotor in single-rotor helicopters?
11.Where does the helicopter derive lift from?
12.In which way does the pilot achieve horizontal flight?
13.What is the purpose of the swash-plate?
14.By means of what can the pilot control the helicopter's flight?
15.How can hovering over one point be achieved?
16.How are military helicopters classified?
