For quadcopters there are many names. They are also called quadrocopter, quadricopter, drone, multicopter or simply 'UFO'. This type of model construction is very young. It began early in the new millennium with commercial products for flying camera inspections. One sees quadcopters in all sizes and price ranges on the market. They start with the toy quadcopters, which are small and, despite their low price, often surprisingly robust. In this model division, a similar trend can be observed as with helicopter and airplane models. The smaller and cheaper systems are often built as 'ready to fly', while larger systems are often available as kits. Contents: Functionality Ready to fly quadcopters Components GPS, photo and film flight Flight mechanics Setting the controller Dimensioning of motors and propellers Special shapes, tri, hexa and octocopters Initial operation, sources of errors and flight