Round-the-pole flying

Lore & Background

Round-the-pole flying can be conducted indoors or outdoors, though outdoor use usually requires calm wind conditions. The power source is typically an electric motor, as power can be supplied via the line, eliminating the need for heavy batteries; this makes the setup quiet, clean, and suitable for indoor flying. Conventional engines can be used outdoors. The pole itself is a heavy stand that withstands centrifugal forces, with a freely rotating hub often incorporating a ball bearing race. Where signals and power pass to the model, a slip ring arrangement is used.

Models for RTP range from simple conversions of rubber-band powered models to sophisticated true scale designs. Electric power permits control effects such as retracting undercarriage and operating flaps, but the limited freedom of the tethered model precludes full aerodynamic control; climb and descent are usually effected by varying power to the motors. The control console can be a simple rheostat for varying current, or more sophisticated designs.

Typical RTP setups allow multiple models to fly simultaneously on the same pole, enabling formation flying and dogfights. A kill in a dogfight is achieved by damaging the opponent's model with the attacking model's propeller, or by destroying a paper streamer trailed behind each model. Other challenges include flying under, over, and between bars, popping balloons, and loop the loop. A yearly RTP contest called the Aaroone Cup is held in Lake Tahoe, California, requiring 0.020 engines and featuring speed and Concours d'Elegance events; record speeds exceed 60 mph on a 10-foot steel line.

There is another concept of RTP flying with throttle and elevator control, invented by the model building club 'kottenpark modelbouw club' (in Dutch). This uses a normal RC controller, with an RC receiver and servo in the pole for elevator control and a speed controller for the electric motor. Elevator control is achieved by shortening one wire while lengthening the other, converting that motion to elevator movement. The idea is to learn flying with remote control, as only two degrees of freedom are involved.

Reader's Guide

Round-the-pole flying occupies a distinct niche in model aviation, offering a controlled environment for both simple and sophisticated model operation. Its significance lies in enabling indoor and calm-weather outdoor flying with electric power, which is quiet and clean, and in allowing multiple models to fly simultaneously for formation flying and dogfighting. The Aaroone Cup in Lake Tahoe, California, demonstrates the competitive aspect, with speeds exceeding 60 mph on a 10-foot steel line. The development of a radio-controlled variant with throttle and elevator control, invented by the kottenpark modelbouw club, further extends RTP's utility as a training tool for learning remote control flying with reduced degrees of freedom. The legacy of RTP includes its adaptability for various challenges—such as popping balloons and loop the loop—and its role in fostering model aircraft building and flying skills in a structured, tethered format.

Did You Know?

• Round-the-pole flying can be used indoors or outdoors, but usually requires calm wind conditions outdoors.
• Multiple models can fly simultaneously on the same pole, allowing formation flying and dogfights.
• A radio-controlled variant with throttle and elevator control was invented by the kottenpark modelbouw club.