Radio-controlled Model aircraft

Info and trivia

Model aircraft are flying or non flying models of existing or imaginary aircraft, using materials such as balsa wood, foam and fiberglass. A vast array of designs are possible, from very simple gliders, to highly accurate scale models, some of which can be very large.

Models can be built either as static non flying models, or as flying models. Construction techniques differ

Flying models are usually what is meant by the term aeromodelling. Most flying model aircraft can be placed in one of three groups:

Free flight (F/F) model aircraft are designed and built in a manner that allows the craft to fly without any attachment to the ground.
This type of model pre dates the efforts of the Wright Brothers and other pioneers.
Control line (C/L) model aircraft are designed and built to be flown using cables leading from the wing to pilot. A variation of this system is the Round-the-pole flying (RTP) model.
Radio controlled aircraft have a transmitter operated by the pilot on the ground, sending signals to a receiver in the craft.
Some flying models resemble scaled down versions of piloted aircraft as much as static models do, while others are built without intention of looking like piloted aircraft. There are also models of birds and flying dinosaurs.

Radio-controlled aircraft (RC aircraft) are small model aircraft controlled remotely. They use radio control with a hand held transmitter and receiver in the craft. The receiver controls the corresponding servomechanisms to move the control surfaces based on the position of joysticks on the transmitter, which in turn maneuvers the plane.

RC planes as a hobby has been internationally growing due to the availability of smaller, relatively inexpensive parts and advancing technologies.

Scientific, government and military organizations are utilizing RC aircraft for experiments, gathering weather readings, aerodynamic modeling and testing, as drones or spy planes.

Most sport aircraft are capable to some degree of performing aerobatics. Many giant-scale aircraft can perform complex aerobatics, ranging from loops and rolls to multiple snap rolls and tailslides. Giant Scale aircraft are flown in world class competition.

Other sport aircraft are designated for scale-like flying referred to as "Scale." Scale is a very demanding but very rewarding aspect of the hobby.

Pattern Planes
Pattern Planes are RC models specifically designed to perform precision aerobatics in graceful and flowing manner. Pattern models are traditionally powered by glow engines and for the last couple of years by electric motors as well.

Sailplanes and gliders
Gliders are planes that do not usually have any form of propulsion. As most gliders are unpowered, flight must be sustained through exploitation of the natural lift produced from thermals and wind hitting a slope. Slope soaring, is a technique to maintain altitude in a full size glider or with a radio-controlled glider by flying it in the updraft produced by wind blowing up the face of a steep slope.
Jets
Jets tend to be very expensive and commonly use a turbine or ducted fan to power them. These aircraft can often reach speeds in excess of 200 mph.
Pylon racers
Racers are small propeller aircraft that race around a 2, 3, or 4 pylon track. They tend to be hard to see and can often go over 150 MPH, though some people do pylon races with much slower aircraft. Although several different types of aircraft are raced across the world, those flown primarily in the US are; Q500 (424 or ARPRA, and 428), and Q40. 424 is designed as a starting point into the world of pylon racing. Inexpensive (under $200 for the airframe) kits with wing areas of 500 square inches are flown with .40 size engines that can be purchased for less than $100. The goal is for the planes to be not only inexpensive, but closely matched in performance.
Autogyros
The autogyro is driven by a propeller, just like an airplane. It has an un powered rotor that provides lift. These models are challenging to design and build, and they provide a unique spectacle when flying in the air.
Helicopters
Radio controlled helicopters, although often grouped with RC aircraft, are in a class of their own because of the vast differences in construction, aerodynamics and flight training. Hobbyists will often venture from planes, to jets and to helicopters as they enjoy challenges, excitement and satisfaction of flying.
Flying Bird Models
Some RC models take their inspiration from nature. These may be gliders made to look like a real bird, but more often they actually fly by flapping wings. Spectators are often surprised to see that such a model can really fly.
3D flight
3D flight is a type of flying in which model aircraft have a thrust-to-weight ratio of more than 1:1 (typically 1.5:1 or more), large control surfaces with extreme throws, and relatively low wing loadings.

An RC flight simulator is a computer program that allows pilots of radio-controlled aircraft to practice on a computer, without the risk and expense of a damaging a real model. Besides the obvious use of training beginners, they are also used for practicing new aerobatics and evaluating a model before buying it, and of course for flying when it's dark and raining!

Wing location

High wing
The easiest planes to fly are typically ones that have a high wing, or a wing on top or above the plane's fuselage. Wing dihedrals or polyhedrals are also common. Most trainers and park flyers have this configuration.These planes hold most of their weight under the canopy of the wing structure and tend to react more like a glider.

Low wing
Low wing planes offer a higher level of flying difficulty because the weight of the plane sits on top of the wing structure, making the balance a bit top heavy. Most wing configurations provide a slight dihedral to provide a bit more balance during flight.

Low wings are typical of World War II war planes and many newer passenger planes and commercial jets.

Mid wing
Mid wing planes are usually considered the most difficult to fly. The wings are usually located right in the vertical middle of the plane, near the bulk mass of the plane. Very little leverage is needed to turn, rotate the plane's weight.

Number of channels
The number of channels a plane requires is determined by the number of mechanical servos that have been installed. On smaller models, usually one servo per control surface is sufficient.

Ailerons - controls roll.
Elevator - controls pitch.
Throttle or, if electric, motor speed.
Rudder - controls yaw (left and right).
For more complex models and larger scale planes, multiple servos may be used on control surfaces. In such cases, more channels may be required to perform various functions such as opening cargo doors, dropping bombs, operating remote cameras, lights.

Powerplants
Most planes need a powerplant to drive them, the exception being gliders. The most popular types for radio controlled aircraft are internal combustion engines, electric motors, jet, and rocket engines.

Frequency
Frequency determines the line of communication between a receiver and transmitter. The transmitter and receiver must both be on the same frequency so the plane can be controlled.

Reserved frequencies
Many nations reserve specific frequencies on radio control. Due to the longer range and potentially worse consequences of radio interference, model aircraft have exclusive use of their own frequency allocation in some countries.

USA and Canada reserved frequencies

72 MHz: aircraft only (France also uses US/Canada channels 21 through 35).
75 MHz: surface vehicles.
27 MHz: general use, toys.
Europe reserved frequencies

35 MHz: aircraft only.
40 MHz: surface vehicles.
27 MHz: general use, toys, citizens band radio.
Australia reserved frequencies

36 MHz: aircraft and water-craft (odd channels for aircraft only)
29 MHz: general use
27 MHz: light electric aircraft, general use
Amateur Radio License reserved frequencies

50 and 53 MHz in the USA and Canada
433-434 MHz in Germany
Remarkably, there are specific bands in 35 MHz called A and B bands. Some European nations allows only use in A band, whereas others allow use in A and B band.

Sub channels
RC aircraft in the USA utilize a 72 MHz frequency band for communication. The transmitter radio broadcasts on AM, FM using PPM or PCM. Each aircraft needs a way to determine which transmitter to receive communications from, so a flight channel, or sub-channel (range of frequency), is necessary.

A crystal is put into the transmitter to allow it to communicate at a specific sub-channel to match the receiver in the aircraft. This is important so that two transmitters are not trying to control the same craft, resulting in an uncontrolled and potentially dangerous crash. For example, if a person is flying an aircraft on channel 35, and someone else turns their radio on the same channel, the aircraft's control will be compromised and the result is almost always a crash. For this reason, when flying at RC airfields, there is normally a board where hobbyists can post their sub channel flag, so everyone knows what channel they are using, avoiding such incidents.

A modern computer radio transmitter and receiver can be equipped with synthesizer technology, using a Phase Locked Loop (PLL), with the advantage of giving the pilot the opportunity to select any of the available channels with no need of changing a crystal. This is very popular in flying camps where a lot of pilots have to share a limited number of channels.

Some new controllers use spread spectrum technology. The most popular of these radio systems is made by a company called Spektrum, though other companies are working on their own versions. Spread spectrum allows multiple applications (pilots) to transmit using the same radio frequencies with little fear of conflicts.

Buddy box or buddy boxing is a colloquialism referring to two R/C aircraft radio systems joined together for pilot training purposes. This training system is universal among the five major R/C radio manufacturers (Futaba, JR, Hitec, Airtronics and KO Propo) which means that transmitters do not have to be the same brand in order to be joined via an umbilical cable. There are, however, two different types of DIN cable connectors used for the purpose and the two are incompatible. Therefore, both transmitters must have the same type of receptacle in order to operate together.

Jet power
In jet-powered model aircraft, the engine is a single-piece assembly with no user-changeable parts. The turbine-wheel spins at extremely high speed (>150,000 RPM), limiting most adjustments to the original factory.

Model aerodynamics
The flight behavior of an aircraft depends on the scale to which it is built. The Reynolds number depends on scale and speed. Drag is generally greater in proportion at low Reynolds number so flying scale models usually require larger than scale propellers.

The British Model Flying Association is the body elected by the Royal Aero Club to be responsible for all aspects of model aircraft in the UK. Many clubs in the UK are affiliated with it.

The Academy of Model Aeronautics, based in Muncie, Indiana USA, is a non-profit organization dedicated to the promotion of model aviation as a recognized sport as well as a recreational activity.

Interesting Trivia and factoid info that has been in the news about the devices

In 2004 may the Express joined the Times with talk of plans to celebrate the anniversary of D-Day at Winston Churchill's former home at Chartwell in Kent. But the RAF Memorial Flight was so overbooked the event was to be marked by 12 radio controlled model aircraft.

In 1998 an unmanned radio controlled plane with a wingspan of just three metres successfully flew the Atlantic, the first such aircraft to do so. The plane took off from the roof of a car in Newfoundland, Canada and - guided for most of its route by satellite - landed twenty-seven hours later on the Scottish island of South Uist.