Its flight features allow movement in all direction: upwards, downwards, sideways, forward as well as in reverse direction. This flexibility allows the helicopter to be flown in small and congested areas where it is not possible to land the airplanes. Since it can fly in any direction, it has a lot of parameters to take care of while flying. Therefore, the pilot needs to be very skilled and capable and must give full attention while flying.
Helicopters not only move in all three dimensions but can also rotate and hover at one point in air. These features, although, make it a unique mode of transport, also make it a very complex machine to understand as well as to pilot.
The main parts of helicopter are:
Main Rotor – The vertically mounted rotor in center
Fuselage – The main body of helicopter
Transmission system – Speed control mechanism of rotors
Tail boom – Rear portion on which the tail rotor is mounted
Tail rotor – Small horizontal axis rotor at the rear
Engine – Main engine used to spin the shaft
To understand the flight of a helicopter, we can begin from the simple vertically up and down motion. For a helicopter to move upwards, it needs wings that have air moving on its surface in one direction. In case of an airplane, the wings are fixed and the whole plane moves forward for the air to move on the surface of wings and generate lift. However, in case of helicopter we keep it on the same spot. Instead, the wings are rotated to generate the desired lift effect. Wings are shaped in such a manner that they deflect the air downwards and as a reaction, the helicopter is lifted. This shape of the wings is called airfoil. Two or more wings are mounted on a shaft and the shaft is made to rotate thereby, giving a continuous motion to the wings. This rotating wings and shaft are collectively called the main rotor. The main rotor is the most important part of any helicopter. It not only generates the lift force required for the helicopter to fly but also provides for the lateral movement, spinning and changing the altitude. The rotor has to be very strong as it supports all the forces on the helicopter and its weight. The wings have a swivel mechanism at the point where they connect to the rotor. This swivel functionality allows for changing the angle of blades, which changes the path of air. To affect lift, the angle of blades needs to be altered with respect to the oncoming wind. This is known as the angle of attack. The angle alteration mechanism for all wings is collectively called the hub. A device known as the swash plate assembly makes the adjustment of the angles of the rotor blades. The swash plate assembly has two plates, fixed swash plate and a rotating swash plate. The swash plate assembly has two main functions: Firstly, it changes the angle of all the blades simultaneously. It increases the overall lift, thereby gaining or losing altitude. Secondly, the swash plate can change the angle of individual blades while revolving. This gives the flexibility to a helicopter to move in any direction. This alteration of angle, called pitch, is carried out by means of the pitch control rods, which control the function of rotating swash pl