Air Plane Photos 2013: R.C Airplane

R.C Airplane

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A Model aircraft is a small sized replica of an existing or imaginary aircraft. It may be flying or non-flying (static), and may be an accurate scale model of a full-size design.

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 or fibreglass. some can be very large, especially when used to research the flight properties of a proposed real design.

Static models range from mass-produced toys in white metal or plastic to highly accurate and detailed models produced for display and requiring thousands of hours of work. Many models are available in kit form, typically made of injection-moulded polystyrene.

Aircraft manufacturers also produce wind tunnel models not capable of free flight, used for testing and development of new designs. Sometimes only part of the aircraft is modelled.

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Fokker F28

Static model aircraft (i.e. those not intended to fly) are scale models built using plastic, wood, metal, or paper. Some static models are scaled for use in wind tunnels, where the data acquired is used to aid the design of full scale aircraft.

Models are available that have already been built and painted; models that require construction, painting and gluing; or models that have been painted but need to be snapped together.

Promotional use[edit]

Most of the world's airlines allow their fleet aircraft to be modeled as a form of publicity.[1] In the early days, airlines would order large models of their aircraft and supply them to travel agencies as a promotional item.

Scale[edit]

Static model aircraft are primarily available commercially in a variety of scales from as large as 1:18 scale to as small as 1:1250 scale. Plastic model kits requiring assembly and painting are primarily available in 1:200, 1:144, 1:72, 1:50, 1:48, 1:32 and 1:24 scale, often depending on the size of the original subject. Die-cast metal models (pre-assembled and factory painted) are primarily available in 1:400, 1:200, 1:72, and 1:600, 1:500, 1:300, 1:250, 1:48. A variety of odd scales (e.g. 1:239) are also available but less common.

The scales are not random but are based on easy divisions of imperial measuring systems so that 1:48 scale is 1" to 4 feet, 1:72 is 1" to 6 feet. Even numbered scales are similarly based on metric systems. 1:72 scale was first introduced in the Skybirds wood and metal model aircraft kits in 1932. Skybirds was followed closely by Frog which produced 1:72 scale aircraft in 1936 under the "Frog Penguin" name. According to Fine Scale Modeler magazine, 1:72 was also popularized by the US War Department (renamed the Department of Defense) when it requested models of single seat aircraft at that scale. The War Department also requested models of multi-engine aircraft at a scale of 1:144. The War Department was hoping to educate Americans in the proper identification of aircraft. These scales provided the best compromise between size and detail. After WWII, the toy manufactures continued to favor these scales. More detailed models are available at 1:32 and 1:24. Some manufacturers introduced 1:50 scale and 1:30 scale. Japan offers 1:100. The French firm Heller SA is the only manufacturer to offer models in the scale of 1:125. Herpa and others produce promotional models for airlines in scales including 1:200, 1:400, 1:500, 1:600, 1:1000 and more. A few First World War aircraft were offered at 1:28 by Revell, such as the Fokker Dr.I and Sopwith Camel.

A number of manufacturers have made 1:18th scale aircraft to go with cars of the same scale. Aircraft scales have commonly been different from the scales used for military vehicles, figures, cars and trains – the armour equivalent of 1:72 was 1:76 and the rail version was 1:87 scale however the difference between the scales can be noticeable and so a small number of kits have been offered over the years that match these alternate scales, while there has been a growing tendency in recent years for smaller military vehicle kits to use aircraft scales. This has resulted in a substantial amount of duplication of the more famous subjects in a large variety of sizes, which while useful for forced perspective box dioramas has limited the number of possible subjects to those that are more well known.

Other less popular scales are 1:50, 1:64, 1:96, and 1:128; however, old models are often revived in these scales. Many older plastic models, such as those built by Revell do not conform to any established scale as they were sized to fit inside standard commercially available boxes. These kits are often called "box-scale" and are often reissued in their original, unusual scales.[2] Some helicopters used to be offered in 1:32 scale, similar to some fixed-wing aircraft models. The trend is to issue helicopters in 1:35 scale, similar to most land vehicle models.

Materials[edit]

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. 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.[3] 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.[4]

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.[5] 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, model airplanes were built from light weight balsa wood and often covered with tissue paper. This was a difficult, time consuming procedure that mirrored the actual construction of airplanes through the end of World War II. The Cleveland Model and Supply Corporation made the most challenging kits, while Guillow's made relatively easy kits. Many model makers soon became adept at creating models from actual aircraft drawings.[6]

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 and plastic.[7] Snap Fit plastic plane models are manufactured[when?] by Wooster, Long Prosper, and Flight Miniatures.[citation needed]

Flying model aircraft[edit]

Main article: Radio-controlled aircraft

A free-flight hand-launched glider.

Generally known collectively in all its forms as the sport and pastime of aeromodeling, some flying models resemble scaled down versions of piloted aircraft, while others are built with no intention of looking like piloted aircraft. There are also models of birds and flying dinosaurs. The reduced size affects the model's Reynolds number which determines how the air reacts when flowing past the model, and compared to a full sized aircraft the size of control surfaces needed, the stability and the effectiveness of specific airfoil sections may differ considerably requiring subtle changes to the design.

Flying model aircraft used in the range of different aeromodeling activities can be placed in one of three groups:

Free flight (F/F) model aircraft fly without external control from the ground. This type of model pre-dates manned flight.[8]

Control line (C/L) model aircraft use cables (usually two) leading from one wing to the controller. A variation of this system is the Round-the-pole flying (RTP) model.

Radio-controlled aircraft have a transmitter operated by the controller, sending radio 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.

Construction[edit]

The construction of flying models differs from that of most static models as both weight and strength are major considerations. Flying models borrow construction techniques from full-sized aircraft although the use of metal is limited. These might consist of forming a frame using thin planks of a light wood such as balsa to duplicate the formers, longerons, spars and ribs of a vintage full sized aircraft, or on larger (usually powered) models where weight is less of a factor, sheets of wood, expanded polystyrene and wood veneers may be employed. Regardless of the underlying structure, it is then skinned and subsequently doped to provide a smooth sealed surface. For light models, tissue paper is used. After it is applied, the paper is sprayed with a mist of water, which causes the paper to shrink when it dries. For larger models (usually powered and radio controlled) heat-curing or heat shrink covering plastic films or heat-shrinkable synthetic fabrics are applied to the model then heated using a hand held laundry iron or heat gun to tighten the material and adhere to the frame. Microfilm covering is used for the very lightest models and is made by bringing the model up through water to pick up a thin plastic film on the surface made from a few drops of lacquer spread out over several square feet. For a more mass market approach, "foamies," or aircraft injection-molded from lightweight foam (sometimes reinforced) have made indoor flight more accessible to hobbyists. Many require little more than attachment of the wing and landing gear.

ParkZone P-51D Mustang

Flying models can be built from scratch using plans, or assembled from kits. Plans are intended for the more experienced modeller, since the builder must make or find all the parts themselves. A kit contains the necessary raw material, some molded parts, plans, assembly instructions and has usually been tested. Assembling a model either way can be labour-intensive. To increase the hobby's accessibility to the inexperienced, vendors of model aircraft have introduced Almost Ready to Fly (ARF) designs which reduce the time and skills required. A typical ARF aircraft can be built in under 4 hours, versus 10–20 or more for a traditional kit. More recently, Ready To Fly (RTF) radio control aircraft have been offered however among traditional hobbyists, RTF models are controversial as many consider model building integral to the hobby.

Gliders[edit]

Glider aircraft do not have an attached powerplant. Larger outdoor model gliders are usually radio-controlled gliders and hand-winched against the wind by a line attached to a hook under the fuselage with a ring, so that the line will drop when the model is overhead. Other methods include catapult-launching, using an elastic bungee cord. The newer "discus" style of wingtip handlaunching has largely supplanted the earlier "javelin" type of launch. Also using ground based power winches, hand-towing, and towing aloft using a second powered aircraft.

As gliders are unpowered, flight must be sustained through exploitation of the wind in the environment. A hill or slope will often produce updrafts of air which will sustain the flight of a glider. This is called slope soaring, and when piloted skillfully, radio controlled gliders can remain airborne for as long as the updraft remains. Another means of attaining height in a glider is exploitation of thermals, which are bubbles or columns of warm rising air created by hot spots on the ground. As with a powered aircraft, lift is obtained by the action of the wings as the aircraft moves through the air, but in a glider, height can only be gained by flying through air that is rising faster than the aircraft is sinking relative to the airflow.

Sailplanes are flown using thermal lift. As thermals can only be indirectly observed through the reaction of the aircraft to the invisible rising air currents, sailplane flying can be challenging.

Hang gliders are composed of rigid & material delta wings with a harness (payload) suspended from the airframe. Control is exercised through the movement of the harness in opposition to a control frame,

Paragliders are aircraft consisting of its parts: wing, strings, and a falling mass. Usually the wing of a paraglider is flexible, fabric wings, whose shape is formed by its suspension lines made taut by the paragliders falling payload and the pressure of air inflating either a single-skin or double-layered wing. Some wings are ram-air where air enters vents in the front of the wing. Control is exercised through lines that deform the trailing edge of the airfoil or the wing's end regions.

Walkalong gliders are lightweight model airplanes flown in the ridge lift produced by the pilot following in close proximity. In other words, the glider is slope soaring in the updraft of the moving pilot (see also Controllable slope soaring).

Power sources[edit]

Powered models contain an onboard powerplant to propel the aircraft through the air. Electric motor and internal combustion are the most common propulsion systems, but other types include rocket, small turbine, pulsejet, compressed gas and tension-loaded (twisted) rubber band.

Rubber and gas propulsion[edit]

An old method of powering free flight models is Alphonse Pénaud's elastic motor, essentially a long rubber band that is wound up prior to flight. It is the most widely used powerplant for model aircraft, found on everything from children's toys to serious competition models. The elastic motor offers extreme simplicity and survivability, but suffers from limited running time, and the fact that the initial high torque of a fully wound motor drops sharply before 'plateauing' to a more steady output, until finally declining as the final turns are run off. Using this torque curve efficiently is one of the challenges of competitive free-flight rubber flying, and variable pitch propellers, differential wing and tailplane incidence and rudder settings, controlled by an on-board timeswitch, are among the means of managing this varying torque and there is usually a motor weight restriction in contest classes. Even so, a competitive model can achieve flights of nearly 1 hour.[9][10]

Stored compressed gas (CO2), similar to filling a balloon and then releasing it, also powers simple models.

A more sophisticated use of compressed CO2 is to power a piston expansion engine, which can turn a large, high pitch prop. These engines can incorporate speed controls and multiple cylinders, and are capable of powering lightweight scale radio-controlled aircraft. Gasparin and Modella are two recent makers of CO2 engines. CO2, like rubber, is known as "cold" power because it becomes cooler when running, rather than hotter as combustion engines and batteries do.

Steam, which is even older than rubber power, and like rubber, contributed much to aviation history, is now rarely used. In 1848, John Stringfellow flew a steam-powered model, in Chard, Somerset, England. Hiram Stevens Maxim later showed that steam can even lift a man into the air. Samuel Pierpont Langley built steam as well as internal combustion models that made long flights.)

Baronet Sir George Cayley built, and perhaps flew, internal and external combustion gunpowder-fueled model aircraft engines in 1807, 1819 and 1850. These had no crank, working ornithopter-like flappers instead of a propeller. He speculated that the fuel might be too dangerous for manned aircraft.

Internal combustion[edit]

An internal combustion powered model aircraft.

Main article: Model engine

All internal combustion engines generate substantial noise (and engine exhaust) and require routine maintenance. In the 'scale-R/C' community, glow-engines have long been the mainstay until recently.

For larger and heavier models, the most popular powerplant is the glow engine. Glow engines are fueled by a mixture of slow burning methanol, nitromethane, and lubricant (castor oil or synthetic oil, which is sold pre-mixed as glow-fuel). Glow-engines require an external starting mechanism; the glow plug must be electrically heated until its temperature can trigger fuel-ignition, upon which the engine's combustion-cycle becomes self-sustaining. The reciprocating action of the cylinders applies torque to a rotating crankshaft, which is the engine's primary power-output. (Some power is lost in the form of waste-heat.)

Model Aircraft Engines

Vendors of model engines rate size in terms of engine displacement. Common sizes range from as small as 0.01 cubic inch (in3) to over 1.0 in3 (0.16 cc–16 cc). Under ideal conditions, the smallest .01 engines can turn a 3.5" (9 cm) propeller at speeds over 30,000 rpm, while the typical larger (.40-.60 cubic inch) engine will turn at 10–14,000 rpm.

The simplest glow-engines operate on the two-stroke cycle. These engines are inexpensive, yet offer the highest power-to-weight ratio of all glow-engines. Glow engines which operate on the four-stroke cycle, whether using ordinary poppet valves or occasionally rotary valves offer superior fuel-efficiency (power-output per fuel-consumption), but deliver less power than two-stroke engines of the same displacement – yet, often because the power they deliver is more suited to turning somewhat larger diameter propellers for lighter weight, more drag-producing airframe designs such as biplanes and scale aircraft models of pre-World War II full-scale subjects, four-stroke model engines, fueled either with methanol or gasoline fuels are slowly increasing in popularity from their generally lower noise output.

A very large "giant scale" US Coast Guard C-130J Hercules radio control flying model. The wingspan is 18 feet 6 inches (5.6 m). The crew of five who fly and maintain it are in the background.

Internal combustion (IC) engines are also available in upscale (and up-price) configurations. Variations include engines with multiple-cylinders, spark-ignited gasoline operation, and carbureted diesel operation. Diesel-combustion operates by compression-ignition. The compression-ratio is controlled by an adjustable threaded T screw on the cylinder head, bearing onto a contra piston within the cylinder bore. Diesels are preferred for endurance competition, because of their fuel's higher energy content, a mixture of ether and kerosene (with lubricating oil).