A quadcopter, also known as a headship or squadron, is an electrically-powered small helicopter with four spinning blades. It was first developed by the United States Army during the 1950s as a military surveillance and reconnaissance tool. These machines were used to deliver U.S. Army Troops to remote locations and for various military maneuvers. Today, the basic quadcopter is still used in the same capacities for both military and civilian operations. However, with the advance in technology and design, the quad copter has also become an excellent hobby for many individuals. The basic quadcopter comes with two seats and can be flown indoors (if batteries are present) or outdoors (in an enclosed case).
A typical quadcopter contains two main components: a controller (or computer) and the radio transmitter. The controller and transmitter usually communicate with each other over a radio channel. The radio transmitter sends radio waves out into the greater than world area that the quadcopter is flying in. The transmitted radio waves are picked up by the receiver on the end of the craft, and the radio channels are transformed into laser signals that can be read by the quadcopter’s four motors. When the crafts’ propellers turn, the motor rotates the blades and creates lift which adds to the thrust of the craft.
The two major types of these machines are the electric or “brushless” quadcopters, which use their own battery to power the four motors and transmit the radio waves. The electric quadcopter is the most popular type, since it is much easier to fly and more efficient than the previous brushless designs. Unfortunately, brushless machines are prone to “phantom performance failure”, which means the controller won’t receive any radio signal for several seconds after the transmitter sent one. This renders the quadcopter useless while it is transmitting. In addition, this type of machine usually does not have a fail safe mechanism to protect against engine failure.
The third type of quadcopter is the “Kv” model. The kv quadcopter (sometimes spelled as “kg” or “kv” models) is very similar to the electric quadcopter – it uses its own battery to power the four motors. Because of this, the batteries used in these machines are typically of a much larger size than those used in the other types of quadcopters, and they are also heavier and more cumbersome. This also makes them far less portable and easier to use, but they are far more expensive and less user-friendly. As with the brushless model, a successful flight requires the propeller to turn at a rapid rate of speed, making the battery incredibly weak at times.
Most Kv quadcopters use a variation of the continuous-speed control (CSC) technique. The way this works is that the copter pushes itself ahead of the desired altitude/time in a counter-clockwise (counter-clockwise) motion, and it must return to the starting altitude/time by reversing the propeller action. As is often the case with modern engineering, there are drawbacks to this style of control. For one thing, if the propeller is moved too far in a turn, it can damage the propellers themselves. Also, a slow rotation into a deadlock (where there is no forward motion) can easily spin the engine out of shape, making it necessary to reverse the direction in which the propellers are moving in to get the plane back on course.
A “stall zone” is often found on some Kv models, where the copter will halt flying after it has reached the maximum lift or thrust level for that particular weight class. This is caused by the rotor becoming deformed because of metal filings and heat from the exhaust fan. Removing this can be difficult; you can try cleaning the intake vents, cleaning the exhaust vents, or using a blower or fan to remove the metal filings from the rotor. It may be best to leave this type of condition untreated until the fan can remove the metal filings completely. This will prevent this problem from returning if the fan is later removed.
The four rotor (or counter-rotating) quadcopter is the fastest of the configurations, with the maximum lift and thrust being achieved at nearly a constant flight rate. It requires the most maintenance because of the nature of the actuators being used and the fast change in speed that are required. Quadcopter with two motors (two forward and two backward) produce the slowest speed changes from a forward angle of attack, while still maintaining good forward momentum over a full turn.
In summary, quadcopters have come a long way. They are typically more affordable and are more easily controlled than either a radio controlled or remote controlled vehicle, and they have become an extremely popular method for hobbyists and professionals alike. As with any model aircraft, you should expect to pay a bit more for a quadcopter of higher quality. Still, there are options available for low cost models that offer the same performance and stability as much more expensive quadcopters. When considering the purchase of a quadcopter, you will need to consider the level of complexity of your quadcopter will require, the space you have available for it to be stored, and how often you will be using it.