Coaxial radio controlled model helicopters are an ideal introduction to rc helicopter flying gue to their stability and slow responsiveness. This makes them far easier to master than the traditional single rotor/tail rotor counterparts. With a bit of practice they are stable enough to be flow indoors in a confined space so you can practice anywhere.
A conventional rc helicopter has a single rotor and a tail rotor to control yaw ie the direction in which the helicopter is pointing. A coaxial helicopter however has two rotors on top of the helicopter and no tail rotor. These rotors rotate in opposite directions and the torque generated by each rotor cancels the other one. This results in extremely stable hovering. Yaw is controlled by adjusting the speed of one of the two rotors. Coaxial helicopters are available in 2, 3 and 4 channel versions. We would recommend a 4 channel coaxial helicopter as this provides for controls pitch, bank, throttle, and yaw.
Coaxial helicopters have a number of advantages and disadvantages.
- easier setup due to them requiring no gyro.
- Cheaper since less electronics are required.
- Very stable in the hover making them ideal for orientation practice.
- Most are available ready to fly requiring no building or setup.
- Generally they are very tough and can survive crashes well.
- the motors need to be evenly matched so the torque generated by each rotor is similar.
- Very slow and unresponsive. Getting them to move from the hover can require quite violent stick movements!
- at extreme cyclic throws the rotors can clash causing a crash
Generally coaxial radio controlled helicopters are small in size ranging from 3 inch rotor spans up to about 15 inch. Whilst some coaxial helicopters can be considered nothing more than toys some of the better 4 channel models from companies such as ESky and E-Flite are an excellent introduction to the world of radio controlled model helicopter flying.