RC helicopters fly by means of rotor movement – that is obvious. However, the closer that rotor movement is to real helicopter flight, the better RC electric helicopters will fly.
For this reason, many pilots – even beginners – opt for collective pitch RC helicopters - starting as they mean to go on.
To understand how collective pitch RC helicopters work, you have to understand what the term “pitch angle” means. This is the angle of the rotor blades relative to the air flowing over them. When the blades are moving, it is better known as the “angle of attack”. To keep the helicopter level and straight – or to perform manoeuvres - the pilot must vary the angle of attack depending on the air flow hitting the advancing blades.
When fixed pitch electric helicopters lift off, they have to do so by throttle speed alone. Although the swash plate allows for cyclic changes - i.e. tilting of the entire rotor disc, the individual blades are immovable. With collective pitch helicopters, the blades can be adjusted to provide the best angle of attack to the oncoming air flow. In addition, the swashplate lifts and lowers, thus increasing or decreasing the lift of the helicopter. Both fixed pitch and collective pitch electric helicopters have cyclic control in which the entire rotor disc is tilted to change the angle of attack. However, this tilting also changes the RC helicopter’s direction of travel - it is of little use when the aircraft is taking off, descending, hovering or performing small and intricate movements.
Therefore, any helicopter equipped with collective pitch has the manoeuvrability and adaptability of a full sized craft. All RC helicopters flown competitively are collective pitch.