26
comprised of a compressor, combustion chamber, turbines, and main gear box. The
latter is of utmost importance as the safe operation of the entire system depends
on it.
Рис. 5. Principal structural units of the AH-64 Apache attack helicopter:
1
-
pilot’s cabin -
кабина экипажа;
2
-
main rotor blades -
лопасти несущего винта;
3 -
main rotor hub -
втулка несущего винта;
4
-
tail (anti-torque) rotor -
хвостовой винт;
5
-
vertical fin -
киль, вертикальный стабилизатор;
6
-
horizontal stabilizer -
горизонтальный стабилизатор;
7
-
tail boom -
хвостовая балка;
8
-
fuselage -
фюзеляж;
9
-
landing gear -
шасси
The rotation of the
main rotor
tends to cause the fuselage to rotate in the
opposite direction. To prevent this, the single-rotor helicopter is provided with a
tail
rotor
producing a counteracting thrust. Alternatively, the helicopter may have two
rotors which revolve in opposite directions and thus counterbalance each other. Such
helicopters can be
tandem-rotor
,
side-by-side
or
co-exial
.
3.4. ТEXT
Principle of Operation and Control
The helicopter derives lift from rotating an airfoil called the rotor. Usually it is
equipped with one or more power-driven rotors. When the angle of attack of rotating
rotor blades attains a certain value, the lift overcomes the weight of the aircraft and
then it takes off vertically.
To achieve horizontal flight, the pilot tilts the rotor forward at a certain angle.
This is done by what is known as cyclic pitch change, i.e. changing the pitch of each
blade once per revolution. More particularly, the angle of attack of each blade is
1
3
4
5
6
7
8
9
2
