Читать книгу The Rise of the Flying Machine - Hugo Byttebier - Страница 32

The First Powered Experiments

As mentioned above, in 1888 Léon Serpollet invented, or rather dramatically improved, the flash steam generator which permitted the construction of a very light and powerful engine, the light powerplant that had hitherto eluded the aviation pioneers’ efforts.

A precursor in the use of power in a full-sized aeroplane was the Frenchman Clément Ader, who was continually on the brink of success but never quite achieved it.

Born in 1841, Ader was from early youth attracted to the mechanical sciences. He worked for a time on the railways and was continually thinking of new inventions. There is a certain inevitability about his becoming interested in human flight.

He built a flapping-wing machine in 1873, but then turned his attention to a new wonder of applied science, an electric machine that could transmit sounds over great distances. By 1880, the telephone had made him rich and famous, having in 1878 improved on the telephone invented by Alexander Graham Bell, and then in 1880 he established the telephone network in Paris. So, in 1881 he returned to aviation. Mouillard had just published his book and it made a deep impression on Ader, who decided to dedicate his efforts to the achievement of flight by means of a soaring machine moved by mechanical power.

In 1881 he travelled to Strasbourg so as to observe the storks there, and the following year he visited North Africa with the purpose of watching the great vultures.

His investigations showed him that the soaring birds always took off against the wind, as Lilienthal had also observed, and that the birds never left their nests when there was no wind.

Continuing his investigations, Ader became spellbound by the perfection of the bat’s wings and decided to use this animal as a prototype for his flying machines, in spite of its questionable aesthetic appeal.

Around 1889, he was working on the creation of his first mechanical bat which would be able to carry a man and would be powered by a steam engine fed by a Serpollet-type generator. His machine was to fly with fixed wings and was to be driven by a propeller moved by an extremely light and ingenious two-cylinder compound steam engine of about 20 hp.

Details of the progress of his construction are scant because Ader worked in secrecy, having in mind the importance of his plans for national defence. Such secrecy does not help the historian who is trying to assess what was real and what was imaginary in the flight or flights Ader claimed to have made. During the next decade he spent a fortune on the construction and perfection of several flying machines. This will be related in a later chapter.

Another pioneer of mechanical flight was Hiram Maxim, who decided in 1889 to create a real-life or rather a larger-than-life flying machine, regardless of cost and effort. Born in 1840 in the US, Hiram Stevens Maxim made a fortune from several inventions, the most noteworthy being the lethal machine-gun which was to cause so many casualties during the First World War.

It was inevitable that Maxim was also to become attracted to human flight and in Great Britain, where he lived from 1881, Maxim began to study aviation in earnest in 1887. Maxim, who was sure of his own capabilities, said that he could solve the problem in five years if he was allowed to spend £100,000 ($500,000). The money, or a great part of it, was indeed spent but, although Maxim did become a true expert on aviation, he did not reach the definitive solution.

His plan was to dedicate three years to perfecting a suitable internal combustion engine along the lines of the system invented by Brayton or by Otto, but as neither type was at that moment adaptable as an aviation powerplant he did not go ahead with his plan. Meanwhile the technique of drawing steel tubes had become so perfected that it had become possible to build them with such a small inner diameter that, when heated, the water inside evaporated instantly.

This system was perfected by Serpollet in the flash steam generator, so Maxim, like Ader, was forced to turn to steam power for the great aeroplane flying machine he had in mind.

Maxim had already carried out experiments with a whirling arm and a wind tunnel, and in 1889 he decided to leave speculation and small-scale experiments and get down to the realization of man’s age-old dream. He applied for two master patents; then he engaged two first-rate craftsmen from the US and began the construction of a huge flying machine on his property of Baldwyn Park in Kent, in order, as he stated, to experiment with a real aeroplane instead of continuing to elaborate theories, as most of his predecessors had done. It was soon possible to evaluate the results he obtained.

The year 1889 was also remarkable for the great number of experiments with piston internal combustion engines as well as those driven by steam.

Daimler and Maybach, who had conceived the light internal combustion engine seven years before, built a V-twin cylinder engine during 1889. In this engine two pistons worked on a single crankshaft by means of forked connecting rods and this may be considered as the ancestor of the great number of V-8 and V-12 engines that were to be built thereafter.

Meanwhile progress was being made in the use of air compressed at very high pressure as a source of power. The development of the automobile torpedo for the Austrian Navy by Whitehead in Fiume had called for a compact and powerful prime mover and the firm of Peter Brotherhood Ltd. in London had designed and developed a successful three-cylinder radial engine, the Brotherhood engine, driven by compressed air from a separated container.

At the same time in Australia, Lawrence Hargrave, who was then experimenting with small flapping-wing planes, was on the lookout for a more suitable source of power than Pénaud’s system of twisted india rubber which Hargrave had used until 1889, when his last flapping-wing model was made.

In 1887 Hargrave wrote to London inquiring about engines suitable for experiments with model aeroplanes but received no reply until, at the end of that year, a Major of the Royal Engineers, who was stationed in Sydney, provided him with details about Brotherhood’s radial torpedo engine. So in 1888, Hargrave built the first of thirty-six aero engines of different types which he was to manufacture during his aeronautical experiments. The first was a single-cylinder engine moved by compressed air.

Then, in 1889, Hargrave built a three-cylinder radial engine after the Brotherhood pattern but with the peculiarity that its crankshaft was fixed and the cylinders revolved around it. The cylinders were attached to the blades of a propeller and thus the first rotary aero engine came into being. It started Hargrave on the road to research into fixed-wing propeller-driven aircraft, as he had already become acquainted with previous experiments along those lines, and also with Pénaud’s writings, and probably with Cayley’s as well.

During 1889, ideas around internal combustion engine construction for airships or aircraft were running wild in France. It all started with Fernand Forest, who had published a drawing in 1888 of an air-cooled engine which had thirty-two cylinders arranged radially around a four-throw crankshaft. Designed for 120 hp, nothing tangible ever came of it except fame for Forest later on. And in 1889 Count de Dion applied for two patents for internal combustion engines, one was a three-cylinder rotary and the other a big ten-cylinder radial with many original features.4 This flurry of activity was to lead to the creation of the first real aviation engines about ten years later.

The important pioneers of the following decade had started with their specific activities by 1889. Many of them were still around with advice and counsel when the era of real flying began, but at the turn of the century the heavier-than-air flying machine had not yet found its definitive shape, nor was there a clear-cut solution in sight.

4. Automobile Quarterly Vol. 15, No. 8, pp. 286-289.