An introduction to remote controlled helicopters
Remote Controlled Helicopters
The unique invention of the last century, the helicopter has amazing flexibility to fly almost anywhere. Unlike an aircraft, which can move in five directions, the helicopterĎs ability to go up and down, fly backwards and hover motionless adds a new dimension its versatility.
Usually, toy remote control helicopters have two motors: one controls the main rotor, while the other controls the tail rotor. The throttle stick controls power supply to the main rotor and the rudder stick controls the tail rotor. As a toy RC helicopterís directional control capability is a bit different compared to a proper model helicopter given the fact that the latterís mechanism that connects operations of the main rotor and the tail rotor is slightly complex.
Contra-rotating or co-axial remote controlled toy helicopters do not have a conventional tail rotor. Since the main rotors spin in opposite directions to one another, they cancel the torque effect. Therefore, they do not require a tail rotor. Manoeuvres are achieved by slight variation of speed between the main motors, which changes the torque balance, thereby spinning the fuselage round to the desired direction. Co-axial helicopters fly more accurately than the toy single-rotor helicopters. Remote controlled helicopters use radio waves, which can be controlled using a remote control device.
In order to rotate the propellers of a toy helicopter at a high speed, a small engine or battery-powered motor is used. By changing the angle of the rotating propellers, desired manoeuvres can be achieved. If you want to move the helicopter upwards, then you should rotate the propellers and angle them downwards. As a result, an air pressure gap is generated on top and bottom of the propellers, moving the helicopter upwards.
Slanted Blades for Lift
Similar to a passenger helicopter a toy model has a combination of slanted blades to help produce lift and directional movement. For lifting it upwards, its lightweight electrical motor spins the overhead main rotor. Since the blades are designed at an angle, the rotor pushes air downward lifting the helicopter. A toy helicopterís main rotor may incorporate two, three or even four blades. Certain models may include multiple rotor assemblies with three or four blades each. Technically, more blades can help move larger amounts of air and hence produce highly powerful lift.
The secondary rotor at the rear of the toy helicopter also incorporates slanted blades to help it take a turn. When the rear secondary rotor spins, the slanted blades force air to the left or right, dependent on the rotorís clockwise or anti-clockwise spin, directing the machine to manoeuvre. Main Rotors for Thrust When the toy helicopter is airborne and moves in a particular direction, the main rotor moves in a slightly forward angle to produce thrust. By tilting slightly forward, the main rotor redirects the flow of air from straight down to down and slightly backward. It is the push of this rotor that moves the helicopter forward.
Some toy helicopters use highly accurate contra-rotation technique. Instead of relying on a tail rotor to spin the helicopter, these models use two main rotors. These rotors spin in opposite directions in order to control the toy's heading through variations in rotor speed. These models, which incorporate contra-rotation mechanism, are more accurate than the traditional tail rotor spin.
All remote controlled toy helicopters are made of durable materials to withstand crashes, vibrations, heat and hard-landings. But these machines have to be lightly built, so that they can fly and manoeuvre easily. Since smaller helicopters are not designed to do stunts, they are built of less durable materials. On the other hand, durable materials are used for bigger helicopters to protect them from damage.
Polypropylene foam is used in the construction of micro/mini remote controlled helicopters, which make them safe for indoor flying. In order to withstand high temperature and vibrations, plastics are mixed with acrylonitrile-butadiene-styrene. Another commonly used material is polycarbonate, which is resistant to high temperature and impact. Although aluminium is a light material, it is not sufficiently light for small toy helicopters. Fibre-glass is found to be useful for making toy helicopters, since it can withstand vibrations, besides being resistant to heat. Remote controlled helicopters may be divided into the following categories based on their design, functionality and features:
Guidelines for Buying Toy Helicopters
Remote controlled toy helicopters cannot be flown easily. It is necessary to learn how to operate them. Here are a few guidelines to help you buy a good model:
Usually, ready-to-fly toy helicopters can be flown by a bit of training and practice. Every model has some distinct features. Those with basic functions are easier to fly, while others are a bit complex. Many of the models are not complicated and maintenance-free, besides being inexpensive. Built of durable materials these delightful flying machines are almost indestructible.
Toy remote controlled helicopters excite both children and adults alike. Many who have taken to flying simple models initially have opted gradually for better and larger radio-controlled helicopters for the sheer delight of flying them. Being inexpensive and entertaining, toy remote controlled models are becoming increasingly popular.