Normally, the skids were raised off the ground by the wheels, upon which the biplane actually ran. But, in the case of a rather abrupt descent, the chassis was so designed that the wheels were forced up against their rubber bands, thus allowing the skids of the machine to come into contact with the ground. Then, when the force of the shock had been absorbed, the wheels came into play again. With this biplane, Farman achieved fine flights at Rheims.
Apart from its constructional excellence, the biplane was fitted with a motor which was destined to have a remarkable influence upon the development of flying—and upon military aviation in particular. This was the seven-cylinder, revolving "Gnome." To-day, the application of this wonderful engine is practically universal. In August, 1909, it was regarded quite as a freak, and was seen for the first time upon Henry Farman’s biplane.
Up to the time when this motor was introduced, makers had, in designing aeroplane engines, followed very largely upon motor-car design, constructing motors with fixed cylinders, either upright, or in "V" shape, and with their parts lightened wherever possible. Some were water-cooled; others air-cooled. But with both systems, and particularly with the latter, the tendency—owing to the high speeds at which the engines had to turn—was to overheat, and either lose power, or stop altogether.
The specially-lightened water-cooling systems which were devised gave a great deal of trouble; and, in the case of air-cooled engines, it was usually found almost impossible to prevent overheating, after the engines had been running for ten minutes or a quarter of an hour.
In the case of the "Gnome," the designer struck out in a new line. Instead of making his cylinders fixed, and his crank-shaft revolving, as was the method with other engines, he set his seven cylinders revolving around the crank-shaft. Petrol and oil he fed to the cylinders by way of the stationary hollow crank-shaft.
The internal complications of this engine, in the opinion of experts who first saw it, were such that it could not be expected to achieve reliability.
But it did, nevertheless; and it ran so well, in fact, that, at the Rheims meeting, Henry Farman remained in the air, while using it, for more than three hours, and won the prize for the longest flight.
The advantages of this remarkable engine proved to be many. In the first instance, its method of construction enabled it to be built remarkably light; and the fact that the seven cylinders revolved, generally at a speed of 1000 revolutions a minute, effectually disposed of cooling difficulties. In fact, the engine automatically cooled itself; and its fly-wheel effect, as it flew round, gave a smooth, even thrust to the propeller.
From the very day of its first introduction, the "Gnome" motor gained overwhelming success. It represented a piece of mechanism made specially for the work in hand, and not a motor-car engine adapted to aerial purposes. This fact was the secret of its success.
As rapidly as they could acquire them, other aeroplane makers fitted "Gnomes" to their machines. It proved all-conquering. Fixed-cylinder engines did not languish completely, however. Some of them were steadily improved, and performed reliable work. But the "Gnome" was then, and is now, regarded as the aeroplane engine.