Coaxial RC helicopter is one of the more popular images that come to mind when people think about electric RC helicopters. And for good reasons too; these double-bladed helicopters is accredited with bringing hordes of new enthusiast into the world of RC aviation. Their popularity stems from their unequivocal stability in the air - which makes them relatively easier to master when compared to their single rotor counter part.

They are also predictable enough to be flown within the compounds of one's home, securing its spot as one of the most loved indoor fliers. Being able to fly right out of the box because they are sold as RTF (Ready to Fly) kits adds to their appeal. So where did such stability come from? To answer that, the first step lies in understanding how helicopters work.

A single-rotor helicopter generates lift when their rotor rotates. As the main rotor turns, another force will also be generated - known as torque, which will in turn cause the entire fuselage to turn in the opposite direction. Since the days when helicopters were in their nascent stage, their pioneers have learnt to counter this effect by including another smaller perpendicular rotor in the tail. This rotor counters the any rotation generated by the torque as well as provides pilots a mean to control the direction in which the helicopter's nose is pointing at, more technically known as the yaw.

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Learn About Gas, Nitro Powered Helicopters

Nitro helicopters are at this time more common than any other types of RC helicopters. It uses a mixture of nitromethane and oil to keep it working. Nitro helicopters are available in various sizes - 15, 30, 50, 60 and 90 size. These refer to the engine size included in each type. The larger and more powerful the engine is, the bigger the main rotor blade that it can revolve thus the superior power to lift the aircraft.

On average, nearly all nitro helicopters can last up to 15 minutes. One thing that serious RC helicopter enthusiasts love about nitro-operated models is the thrilling experience they get similar to a real-life helicopter. The maneuver and the noise it produces sort of simulate a real flight thus a more amazing flying adventure.

There are a number of plus factors, such as: More flight time since tank can be refilled immediately, Steady power that is coming from the engine, Secured and easier direction, Provides more realistic and adventurous flying experience, No upgrade needed when moving to an ultra-light helicopter.

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Learn About Dual-Rotor RC Helicopters

Dual-rotor also known as coaxial rotors helicopters consist of a pair of rotor rotating in opposite directions. One rotor is positioned above the other. Coaxial helicopters are popular because of its clear stability while in flight making it easier to learn. It is also considered to be a favorite indoor activity compare to the single rotor model. Its maneuverability makes it ideal and safe even within one's home.

Underlying Theory: When a helicopter is not in motion its angular momentum is zero. Once the engine is started, it produces a significant amount of angular momentum that can cause the body of the helicopter to spin around in opposite direction of the rotors. To maintain flight stability, coaxial rotors are used by turning each rotor in opposite directions. This allows the fuselage to sustain a zero angular momentum.

How does it work?: Coaxial helicopters do not necessarily need a tail rotor. The torque created by the 2 rotors spinning in opposite directions cancels each other. This results to a more stable flight and hovering capabilities. Hovering is one of the main elements in flying a helicopter. When the pilot slows down or speeds up one of the 2 rotors, he can control the hover or direction of the helicopter.

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