| Although experiments with rotary winged aircraft may | | | | and there by a reduction in pressure, over its upper |
| be traced back to Leonardo da Vinci, successful flights | | | | surface. At the same time, pressure increases across |
| were not achieved until the 1930s, and it was not until | | | | its under- surface of the wing. |
| 1941 that the first practical, full size helicopter was built | | | | The helicopter generates lift by the movement of its |
| by lgor Sikorsky. Model enthusiasts are notably quick | | | | main rotor blades through the air as its rotor turns. The |
| to emulate full-size aviation achievements, but were | | | | blades have to be moved at high speed and at a |
| not as successful with rotary wing aircraft, and it was | | | | comparatively high angle of attack in order to produce |
| not until 1968 that the first fully controllable R/C model | | | | sufficient lift to raise the model into the air. Weight is |
| helicopter appeared, built by Dr. Dieter Schluter of | | | | critical and experimenters who discovered that their |
| West Germany. | | | | chosen engine had insufficient power to produce the |
| Many modellers were convinced that the single rotor | | | | required lift were faced with a vicious circle. Fitting a |
| autogiro would be an easier subject to tackle than the | | | | larger engine to increase the available power also |
| helicopter and were conducting their experiments along | | | | meant an increase in the weight to be lifted. |
| these lines, but in fact the first really successful British | | | | Bigger engines require more fuel and more weight! |
| R/C autogiro, a semi-scale model of the Wallace | | | | Increasing the angle of the rotor blades in the airflow |
| Autogiro, was first flown in 1978, ten years after the | | | | produces more lift, up to a point but this also increases |
| first appearance of the R/C helicopter. Designers and | | | | the drag of the blade, which now requires more power |
| manufacturers the world over were quick to take | | | | to move it at the required speed. All problems were |
| advantage of Schluter's success and, In the early | | | | eventually overcome and the fully controllable R/C |
| 1970s, model helicopter kits were on sale in the model | | | | model helicopter had arrived. |
| shops. | | | | There were, however, no short cuts in its |
| In order to appreciate the reasons for the slow | | | | development: engines, drive gears, rotor blades, control |
| development of the model helicopter, at least a few of | | | | methods, etc all had to follow a similar design to |
| the problems which faced the pioneers must be | | | | full-size helicopter and be built to the same exacting |
| considered. These problems were many and complex, | | | | standards or perhaps closer to the mechanism design |
| for instance in order to achieve fight with any | | | | of the full-size helicopter. |
| heavier-than-air machine, the lift force generated by its | | | | So how difficult is the model helicopter to control in |
| airfoils must overcome the aircraft's weight. In the | | | | fight? Well, it has been described as similar to balancing |
| case of a conventional aircraft this is achieved by its | | | | a steel ball on a knife edge whale riding a bicycle! more |
| forward speed through the air which flows across its | | | | on that when you visit Model Aeronautics for Dodos |
| airfoil-sectioned wing, causing a speeding-up of the air, | | | | by following the link in my resource box. |