wings for excellent gliding ability. Suitable brushless motors are installed as the most common pushers to provide better flight performance and longer flight time. Pusher-propeller planes are preferred so that the propeller is not in view of the camera. Flying wing designs are also popular for FPV, as they provide a good combination of large wing surface area, speed, maneuverability, and gliding ability. In the United States, the Academy of Model Aeronautics' (AMA) Safety Code (which governs flying at AMA affiliated fields) allows FPV flight under the parameters of AMA Document #550, which requires that FPV aircraft be kept within visual line of sight with a spotter maintaining unaided visual contact with the model at all times. Similarly, in the United Kingdom, the Civil Aviation Authority (CAA) Air Navigation Order 2009 under General Exemption E 4185 requires small unmanned aircraft (SUA) be kept within visual line of sight with a competent observer maintaining direct unaided visual contact with the model at all times for the purpose of collision avoidance. Because these restrictions prohibit flying beyond the visual range of the pilot (an ability which many view as the most attractive aspect of FPV), most hobbyists that fly FPV do so outside of regular RC clubs and flying fields. Types of kits and construction There are various ways to construct and assemble an RC aeroplane. Various kits are available, requiring different amounts of assembly, different costs and varying levels of skill and experience. Some kits can be mostly foam or plastic, or may be all balsa and ply wood. Construction of wood kits typically consists of using formers and longerons for the fuselage and spars and ribs for the wing and tail surfaces. Many designs use solid sheets of balsa wood instead of longerons to form the fuselage sides and may also use expanded polystyrene for the wing core covered in a wood veneer, often balsa or obeche. Such designs tend to be slightly heavier but are typically easier to build. The lightest models are suitable for indoor flight, in a windless environment. Some of these are made by bringing frames of balsa wood and carbon fiber up through water to pick up thin plastic films, similar to rainbow colored oil films. The advent of "foamies," or craft injection-molded from lightweight foam and sometimes reinforced with carbon fiber, have made indoor flight more readily accessible to hobbyists. EPP (Expanded Polypropylene) foam