How Helicopter Flies

Although my focus is on avionics and electrical systems, I do need to have some knowledge on other systems. As one of the module covered in the blog is EASA part 66 module 12, which is about rotorcraft systems, some knowledge of helicopter aerodynamics is necessary.

For my shared learning, I enclose a video on how helicopter flies.



 The concept of directional control
There are only two set control surfaces that dictate the flying direction of the helicopter.
- The main rotor
- the tail rotor.
By changing the effective forces of the main rotors, determines the direction of the helicopter.

The effective forces on the main rotor can be changed by following factors:
1. The speed of the rotor
2. the angle of attack
3. the gyroscopic effect
4. the differential forces between the blades.

If both of the rotor provide equal force, then the helicopter will just move vertically up. This is done by the collective control lever.

Let say the lift is more at 3 o'clock. It appear that the helicopter would lean to the left and bank to the left. But gyroscope property will shift the lift by 90 degrees, thus the helicopter will pitch down.