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VTU AEROMODELLING

                              AEROMODELLING

A model aircraft is a small sized unmanned aircraft or, in the case of a scale model, a replica of an existing or imaginary aircraft. Model aircraft are divided into two basic groups: flying and non-flying. Non-flying models are also termed static, display, or shelf models.
Flying models range from simple toy gliders made of card stock or foam polystyrene to powered scale models made from materials such as balsa wood, bamboo, plastic, styrofoam, carbon fiber or fibreglass and are skinned with tissue paper or mylar covering. Some can be very large, especially when used to research the flight properties of a proposed full scale design.
Static models range from mass-produced toys in white metal or plastic to highly accurate and detailed models produced for museum display and requiring thousands of hours of work. Many models are available in kit form, typically made of injection-moulded polystyrene.
Aircraft manufacturers and researchers also make wind tunnel models not capable of free flight, used for testing and development of new designs. Sometimes only part of the aircraft is modelled.

 MATERIALS USED

The most common form of manufacture for kits is injection molded polystyrene plastic, using carbon steel molds. Today, this takes place mostly in China, Taiwan, the Philippines, South Korea, and Eastern Europe. Injection molding allows a high degree of precision and automation not available in the other manufacturing processes used for models but the molds are expensive and require large production runs to cover the cost of making them. Smaller and cheaper runs can be done with cast copper molds, and some companies do even smaller runs using cast resin or rubber molds, but the durability is of a lower standard than carbon steel and labour costs are higher.
Specialized kits cast in resin are available from companies such as Anigrand, Collect Aire, CMK, CMR, and Unicraft, made in molds similar to those used for limited run plastic kits, but usually not as durable, hence the much smaller numbers of each kit that are made, and their higher price. Vacuum forming is another common alternative to injection molded kits but require more skill to assemble, and usually lack detail parts that must be supplied by the modeller.^[4] There is a handful of photo etched metal kits which allow a high level of detail but can be laborious to assemble, and lack the ability to replicate certain shapes.^[5]
Scale models can be made from paper (normal or heavy) or card stock. Commercial models are printed by publishers mainly based in Germany or Eastern Europe.^[6] Card models are also distributed through the internet, and several are offered this way for free. Card model kits are not limited to just aircraft, with kits being available for all types of vehicles, buildings, computers, firearms and animals.^{[citation needed]}
From World War I through the 1950s, flying model airplanes were built from light weight bamboo or balsa wood and covered with tissue paper. This was a difficult, time consuming process that mirrored the actual construction of airplanes through the beginning of World War II. The Cleveland Model and Supply Corporation made the most complex, challenging kits, while Guillow's made simpler, relatively easy kits. Many model makers became adept at creating models from drawings of the actual aircraft.^[7]
Ready-made models (desk-top models) include those produced in fibreglass for travel agents and aircraft manufacturers, as well as collectors models made from die-cast metal, mahogany, resin and plastic

CONTROLS 

Flying model aircraft are generally controlled through one of three methods

• Free flight (F/F) model aircraft fly without external control from the ground. The aircraft must be set up before flight so that its control surfaces, and weight allow stable flight. Most free flying models are either unpowered gliders or rubber powered. This type of model pre-dates manned flight.^[9]
• Control line (C/L) model aircraft use cables to tether a plane to a central point, either held by hand or to a pole. The aircraft is then flown around the point in circles. Usually two cables are used, one tethering the aircraft and one controlling the elevator.
• Radio-controlled aircraft have a transmitter operated by the controller, sending signals to a receiver in the model which in turn actuates servos which manipulate the model's flight controls in a similar manner to a full sized aircraft. In traditional aircraft, the radio has directly controlled the servos. However, modern aircraft often use flight controlling computers to stabilize an aircraft or even to fly the aircraft autonomously. This is particularly the case with quadcopters.

 POWER SOURCES

 Powered models contain an onboard powerplant, a mechanism powering propulsion of the aircraft through the air. Electric motors and internal combustion engines are the most common propulsion systems, but other types include rocket, small turbine, pulsejet, compressed gas, and tension-loaded (twisted) rubber band devices.