Читать книгу The Rise of the Flying Machine - Hugo Byttebier - Страница 19

The Powerplant Takes Shape

In an article published towards the end of 1876, Pénaud stated his belief that sooner or later science would succeed “in creating the light engines that the solution of the problems related to aviation is clamouring for”. It was already 70 years after Cayley had similarly stated his belief that a light power plant could be developed, but there was a sense by 1876 that things were beginning to move towards an effective solution.

In Philadelphia, during the Exhibition held to celebrate the first centennial of the Independence of the United States, George Brayton showed his new hydrocarbon engine that used preliminary compression and liquid fuel. Brayton’s engine ran smoothly, started easily and seemed to be a great improvement over the old Lenoir engines.

The French engineer Eugène Farcot went to Philadelphia and wrote in a letter to Hureau de Villeneuve: “I have found an engine. Is it the engine of the future for aerial navigation? I don’t know but it is nearing the ideal you set out in 1868.”

As it happened, Brayton had come too late because the real “engine of the future” was already up and running.

From the outset of the use of lighting gas, engine builders had felt that a preliminary compression of the inflammable mixture would increase power ratings manifold, but the question of how to do this had remained unsolved? Brayton had cleverly solved the problem by his separate compressed-air reservoir, but he had been forced to introduce a second cylinder and piston to compress the air, adding weight and mechanical complication.

Around 1861, a French engineer, Alphonse Beau de Rochas had come up with on an ingenious idea. To lose a full cycle in the power-producing process by using the working cylinder during a complete revolution of the crankshaft solely for aspiration and compression of the mixture without doing any useful work. It was a clear case of one step back to take two steps forward.

Beau de Rochas never built an engine to test his speculations but the German Nikolaus Otto did, possibly unaware of the Frenchman’s ideas of 15 years before. He did so to such good effect that in May 1876 the first four-stroke internal combustion engine was running and Otto was granted a master patent (DRP No. 532).

Otto’s patent included a system for stratification of the explosive charge which proved to be useless, but the four-stroke cycle remained and earned him and his firm a fortune in royalties until 1882.

Brayton’s engine inspired George Selden, a clever patent attorney who became convinced that the Brayton-powered automobile was at hand. By deferring the definitive grant of his patent until the 1890s he obtained a master patent on the automobile that would also earn him a small fortune.

The year 1876 can be considered as the year of the great master patents. Pénaud’s aeroplane, Otto’s four-stroke cycle and Selden’s automobile. Selden’s deferments were eventually stymied because Brayton came too late with his new two-stroke system with the result that Selden was too early with his patent, which did not include the four-stroke cycle, leading to him being eventually defeated on that account. But one cannot anticipate everything.