Round-the-pole flying (RTP) is a form of flying
model aircraft
A model aircraft is a small unmanned aircraft. Many are replicas of real aircraft. Model aircraft are divided into two basic groups: flying and non-flying. Non-flying models are also termed static, display, or shelf models.
Aircraft manufactur ...
, 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
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 forc ...
, since the power can be supplied via the line and heavy
batteries
Battery most often refers to:
* Electric battery, a device that provides electrical power
* Battery (crime), a crime involving unlawful physical contact
Battery may also refer to:
Energy source
*Automotive battery, a device to provide power t ...
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 force
In Newtonian mechanics, the centrifugal force is an inertial force (also called a "fictitious" or "pseudo" force) that appears to act on all objects when viewed in a rotating frame of reference. It is directed away from an axis which is parallel ...
s on it. The head of the pole needs to provide a freely rotating hub, and usually incorporates a
ball bearing
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races.
The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this ...
race of some kind. In addition, where signals and power need to pass to the model, some form of
slip ring
A slip ring is an electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure. A slip ring can be used in any electromechanical system that requires rotation while transmitting p ...
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
A potentiometer is a three- terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.
The measuring instrum ...
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
dogfight
A dogfight, or dog fight, is an aerial battle between fighter aircraft conducted at close range. Dogfighting first occurred in Mexico in 1913, shortly after the invention of the airplane. Until at least 1992, it was a component in every maj ...
s to take place. A kill in a dogfight is achieved by damaging the opponent's model with the
propeller
A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...
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.
Round-the-pole flying with Radio Control
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.
External links
Model aircraft