Round-the-pole flying (RTP) is a form of flying model aircraft, in which the model is attached via a line from its wingtip or fuselage to a central support structure. Control signals can be passed to the model via wires alongside or integral with the attachment line. The operator can control the aircraft using a control console, situated outside the flying circle of the aircraft. Contrast this to control line flying where the pilot/operator stands at the centre of the flying circle and directly supports the aircraft.
RTP can be used indoors or outdoors, though usually requires calm wind conditions if used outdoors. The power source for the model is usually an electric motor, since the power can be supplied via the line and heavy batteries need not be carried. This makes it particularly quiet, clean and suitable for indoor flying. Conventional engines can be used outdoors.
The pole itself is usually a simple stand heavy enough to withstand the centrifugal forces on it. The head of the pole needs to provide a freely rotating hub, and usually incorporates a ball bearing race of some kind. In addition, where signals and power need to pass to the model, some form of slip ring arrangement is required.
Models for RTP can range from the very simple, usually converted from rubber-band powered models, to sophisticated true scale designs. The use of electric power can permit sophisticated control effects such as retracting undercarriage, operating flaps, etc. However the limited degree of freedom of the tethered model precludes the use of full aerodynamic control. Climb and descent are usually effected using variations in power to the motors.
The control console can be nothing more than a simple rheostat allowing the current supplied to the model to be varied. More sophisticated control consoles can be envisaged.
Typical RTP set-ups allow multiple models to fly simultaneously on the same pole. This allows such activities as formation flying and dogfights to take place. A kill in a dogfight is achieved by damaging the opponent's model with the propeller of the attacking model. Alternatively a paper streamer can be trailed behind each model and a kill is confirmed when the streamer has been successfully destroyed.
Other challenges such as flying under, over and between bars, popping balloons and loop the loop can also be attempted.
A yearly RTP Contest is held in Lake Tahoe, California. Called the Aaroone Cup, it requires 0.020 engines and is a speed and Concours d'Elegance contest. Record speeds exceed 60 mph on the 10-foot steel line.
There is another concept of RTP flying. This concept is with throttle and elevator control. This was invented by the model building club " kottenpark modelbouw club (in Dutch). This is done by using a normal RC-controller. In the pole is a RC-receiver including a RC-servo for controlling the elevator and a speed controller for regulation the electrical motor in the aircraft.
Elevator control and the electrical motor control is done with 2 electrical wires from the pole to the model aircraft. The elevator control is done by shortening one wire while simultaneously lengthening the other wire. This motion is converted in the model aircraft to control the elevator.
The whole idea behind this setup is to learn flying with remote control, because you have only 2 degrees of freedom.
An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor's shaft. Electric motors can be powered by direct current (DC) sources, such as from batteries, or rectifiers, or by alternating current (AC) sources, such as a power grid, inverters or electrical generators. An electric generator is mechanically identical to an electric motor, but operates with a reversed flow of power, converting mechanical energy into electrical energy.
A model aircraft is a small 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.
Radio-controlled cars are miniature model cars or trucks that can be controlled from a distance using a specialized transmitter or remote. The term "RC" has been used to mean both "remote controlled" and "radio controlled", where "remote controlled" includes vehicles that are controlled by radio, infrared or a physical wire connection. Common use of "RC" today usually refers only to vehicles controlled by radio, and this article focuses on radio-controlled vehicles only.
A radio-controlled model is a model that is steerable with the use of radio control. All types of model vehicles have had RC systems installed in them, including cars, boats, planes, and even helicopters and scale railway locomotives.
Radio control is the use of control signals transmitted by radio to remotely control a device. Examples of simple radio control systems are garage door openers and keyless entry systems for vehicles, in which a small handheld radio transmitter unlocks or opens doors. Radio control is also used for control of model vehicles from a hand-held radio transmitter. Industrial, military, and scientific research organizations make use of radio-controlled vehicles as well. A rapidly growing application is control of unmanned aerial vehicles for both civilian and military uses, although these have more sophisticated control systems than traditional applications.
Control line is a simple and light way of controlling a flying model aircraft. The aircraft is connected to the operator by a pair of lines, attached to a handle, that work the elevator of the model. This allows the model to be controlled in the pitch axis. It is constrained to fly on the surface of a hemisphere by the control lines.
Free flight is the segment of model aviation involving aircraft with no active external control after launch. Free Flight is the original form of hobby aeromodeling, with the competitive objective being to build and launch a self controlling aircraft that will consistently achieve the longest flight duration over multiple competition rounds, within various class parameters.
In control engineering a servomechanism, sometimes shortened to servo, is an automatic device that uses error-sensing negative feedback to correct the action of a mechanism. On displacement-controlled applications, it usually includes a built-in encoder or other position feedback mechanism to ensure the output is achieving the desired effect.
A motor controller is a device or group of devices that can coordinate in a predetermined manner the performance of an electric motor. A motor controller might include a manual or automatic means for starting and stopping the motor, selecting forward or reverse rotation, selecting and regulating the speed, regulating or limiting the torque, and protecting against overloads and electrical faults.
A brushless DC electric motor, also known as electronically commutated motor and synchronous DC motors, are synchronous motors powered by direct current (DC) electricity via an inverter or switching power supply which produces electricity in the form of alternating current (AC) to drive each phase of the motor via a closed loop controller. The controller provides pulses of current to the motor windings that control the speed and torque of the motor. This control system replaces the commutator (brushes) used in many conventional electric motors.
A DC motor is any of a class of rotary electrical motors that converts direct current electrical energy into mechanical energy. The most common types rely on the forces produced by magnetic fields. Nearly all types of DC motors have some internal mechanism, either electromechanical or electronic, to periodically change the direction of current in part of the motor.
A radio-controlled aircraft is a small flying machine that is controlled remotely by an operator on the ground using a hand-held radio transmitter. The transmitter communicates with a receiver within the craft that sends signals to servomechanisms (servos) which move the control surfaces based on the position of joysticks on the transmitter. The control surfaces, in turn, affect the orientation of the plane.
A radio-controlled helicopter is model aircraft which is distinct from a RC airplane because of the differences in construction, aerodynamics, and flight training. Several basic designs of RC helicopters exist, of which some are more maneuverable than others. The more maneuverable designs are often harder to fly, but benefit from greater aerobatic capabilities.
An electronic speed control (ESC) is an electronic circuit that controls and regulates the speed of an electric motor. It may also provide reversing of the motor and dynamic braking. Miniature electronic speed controls are used in electrically powered radio controlled models. Full-size electric vehicles also have systems to control the speed of their drive motors.
A servomotor is a rotary actuator or linear actuator that allows for precise control of angular or linear position, velocity and acceleration. It consists of a suitable motor coupled to a sensor for position feedback. It also requires a relatively sophisticated controller, often a dedicated module designed specifically for use with servomotors.
An electric multiple unit or EMU is a multiple-unit train consisting of self-propelled carriages using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a number of the carriages. An EMU is usually formed of two or more semi-permanently coupled carriages, but electrically powered single-unit railcars are also generally classed as EMUs. The great majority of EMUs are passenger trains, but versions also exist for carrying mail.
An AC motor is an electric motor driven by an alternating current (AC). The AC motor commonly consists of two basic parts, an outside stator having coils supplied with alternating current to produce a rotating magnetic field, and an inside rotor attached to the output shaft producing a second rotating magnetic field. The rotor magnetic field may be produced by permanent magnets, reluctance saliency, or DC or AC electrical windings.
Remote control fishing is a fishing technique accomplished by using a remote control boat. The remote control fishing boats are almost exclusively battery operated, since batteries provide several benefits when compared with glow engines: less noise during operation, consume no power during idle time, requires no oxygen, easier to maintain, finer power and speed control, etc.
3D Aerobatics or 3D flying is a form of flying using flying aircraft to perform specific aerial maneuvers. They are usually performed when the aircraft had been intentionally placed in a stalled position.
Servos are small, cheap, mass-produced servomotors or other actuators used for radio control and small-scale robotics.