Radio-controlled model
From Free net encyclopedia
Image:97rcsonn2.jpg A radio-controlled model (or RC model) is a model that is steerable with the use of radio control. All types of vehicles imaginable have had RC systems installed in them, including cars, boats, planes, and even helicopters.
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History
Radio control has been around since WWII. The Luftwaffe used controllable winged bombs for targeting Allied ships. However, it was impractical for civilian use due to the size and weight of transistors. In the 1980s, computer chips were widely available because of the wide production of personal and business computers. These chips made circuits small and light enough for installation on miniature model vehicles.
Before radio control circuits were widely available, scale models with internal combustion engines were available from around the early 1950s. Since remote control was not possible, they were tethered to control wires. Tether cars and tether airplanes using miniature internal combustion engines were produced up to early '80s. The models' owner had to pivot in one spot as miniature vehicles making circles around him. Alternatively the model was tethered to the ground or a post. These are commonly known as control line models.
Design
RC electronics have three essential elements. The transmitter is the controller. Transmitters have control sticks, triggers, switches and dials at the user's finger tips. The receiver is mounted on the model. It receives and processes the signal from the transmitter, translating it into signals to send to the servos. The number of servos in a model determines the number of channels the radio must provide.
In recent years, electronic speed controllers (ESCs) have been developed to replace the old variable resistors, which were extremely inefficient. They are entirely electronic, so they do not require any moving parts or servos.
In the 1980s, a Japanese electronics company, Futaba introduced wheeled steering for RC cars. It has been widely accepted along with a trigger control for throttle. It's often configured for right hand users, so the transmitter would look like a gun with a wheel attached on its right side. Pulling the trigger would accelerate the car forward, while pushing it would either stop the car or cause it to go into reverse. Steering wheels control steering.
Mass production
There are thousands of RC vehicles available. Most are toys suitable for children. What separates toy grade RC from hobby grade RC is generally, the modular characteristic of the standard RC equipment. RC toys generally have simplified circuits, often with the receiver and servos incorporated into one circuit. It's almost impossible to take that particular toy circuit and transplant it into other RCs.
Hobby grade RC
Hobby grade RC systems have modular designs. Many cars, boats and airplanes can accept equipment from various manufacturers, so it is possible to take RC equipment from a car and install it in a boat. Moving equipment to and from aircraft is impossible in most countries because of radio frequency laws controlling what can be used on the ground and in the air.
Hobby grade models can be fine tuned, unlike most toy grade models. For example, cars often allow toe-in, camber and caster angle changes, just like the real life counterpart.
Types
Airplanes
Template:Main Radio-controlled airplanes (also called RC airplanes) are small airplanes that can be controlled remotely. There are many different types, ranging from small park flyers to large jets and aerobatic models.
Cars
Template:Main A radio-controlled car is a powered model car driven from a distance. Both gas and electric cars exist, designed to be run both on and off-road. Building, driving, and modifying radio-controlled car kits is a hobby enjoyed by enthusiasts of all ages.
Helicopters
Template:Main Radio-controlled helicopters, although often grouped with RC airplanes, are unique because of the differences in construction, aerodynamics and flight training. Several designs of RC helicopters exist, some with limited maneuverability (and thus easier to learn to fly), and those with more maneuverability (and thus harder to learn to fly).
Boats
Template:Main Radio-controlled boats are small boats controlled remotely with radio control equipment. There are two main types of RC boat: the sailing boat and the power boat. The latter is the more popular amongst toy grade models. Radio controlled models were used for the childrens television program Theodore Tugboat.
Power
Internal combustion
Internal combustion engines for remote control models have typically been two stroke engines that run on specially blended fuel. Engine sizes are typically given in cm³ or cubic inches, ranging from tiny engines like these .02's to huge 1.60's or larger like this. For even larger sizes, many modelers turn to four stroke or gasoline engines (see below.) Glow plug engines have an ignition device that possesses a platinum wire coil in the glow plug, that catalytically glows in the presence of the methanol in glow engine fuel, providing the combustion source.
Since 1976, practical "glow" ignition four stroke model engines have been available on the market, ranging in size from 3.5 cm³ upwards to 35 cm³ in single cylinder designs. Various twin and multi-cylinder glow ignition four stroke model engines are also available, echoing the appearance of full sized radial, inline and opposed cylinder aircraft powerplants. The multi-cylinder models can become enormous, such as this Saito five cylinder radial. They tend to be quieter in operation than two stroke engines, using smaller mufflers, and also use less fuel.
Glow engines tend to produce large amounts of oily mess due to the oil in the fuel. They are also be much louder than electric engines.
Another alternative is the gasoline engine. While glow engines run on special and expensive hobby fuel, gasoline runs on the same fuel that powers cars, lawnmowers, etc. These typically run on a two-stroke cycle, but are radically different from glow two-stroke engines. They are typically much, much larger, like this 80 cm³ Zenoah. These engines can develop several horsepower, incredible for something that can be held in the palm of the hand.
Electrical
Electric power is often the chosen form of power for airplanes, cars and boats. Electric power in airplanes in particular has become incredibly popular recently, mainly due to the popularity of park flyers, and the development of technologies like brushless motors and lithium polymer batteries. These allow electric motors to produce much more energy, rivalling that of fuel powered engines. It is also relatively simple to increase the torque of an electric motor at the expense of speed, while it is much less common to do so with a fuel engine.
In cars and boats, electric power has been the most common form of power for a while. However glow and gas engines are still commonly used as well.
External links
- RCGroups - A popular forum for discussing RC models.
- Radio-Control-Model.com
- Radio Controlled Sailing Forum
- RC Warships
- Tournament Of Championsda:Radiostyret model