(DISCOVERY, July 1933, p. 220)

Steam Power for Aircraft

The Besler System

What is believed to be the first flight ever made in a steam-driven aeroplane has been achieved in California. By special arrangement "Discovery" is able to publish the first particulars of this interesting development.

Five years ago the residents of a quiet London street were startled one Sunday afternoon by the shriek of a steam whistle, as a powerful motor car accelerated to forty miles an hour and was then seen to reverse at the same speed. It was, in fact, the Besler steam car, developed by two young Americans, who had brought the machine to England in order to negotiate the European rights in the invention. One of their first visits was to Mr. John Benn, then Editor of Discovery, who had been a fellow student at Princeton with Mr. George Besler and his brother William in 1922. At the University the inventive bent of these two men was not suspected, but after graduating in engineering they were soon absorbed in the work on steam power, which has resulted in the development of the Besler system. Its chief applications are, naturally, to railway locomotion, buses, and marine power plants, but the steam car, followed this spring by the first steam-driven aeroplane, has shown in spectacular form the remarkable degree of efficiency attained by this particular system.

The successful flight of the aeroplane, believed to be the first ever made in a steam-driven machine, was accomplished in California on April 12th by Mr. William Besler and now his brother has again come to Europe in connexion with this latest development. Except for a photograph of the machine, no information has yet appeared in the English Press and by special arrangement with the inventors, Discovery is now able to give the first particulars.

The idea of using steam for aircraft dates, of course, from the early days of the steam engine, and about a century ago an English engineer named Henson projected a large aeroplane to be driven by steam. He under-estimated the power required, and his plan fell through, but one of his associates, Stringfellow, succeeded in flying a model steam aeroplane. Experiments were later made by Maxim, and Langley flew another model by steam in 1896.

An airship propelled by steam was flown with some success by Giffard in 1852, but not until this year was a flight carrying a passenger made in a steam-driven aeroplane. This spectacular achievement took place at the Municipal Airport at Oakland, California, in a biplane originally built for a Curtiss internal combustion engine, which was taken out and substituted by the Besler power unit for this experiment. There was found to be ample room, and while considerable ingenuity was required, no difficulty was experienced in making the steam plant compact enough to fit into the available space. The installation, however, included many parts taken from a Doble steam-car which were unnecessarily heavy and in some cases too large for the purpose. No attempt was made to develop either extraordinary power or to make it extremely light. The immediate objective was to build a power plant capable of flight.

The unit consists of a two-cylinder engine, which delivers approximately 150 h.p. at 1,625 r.p.m. The weight is about 180 lbs., and no serious attempt was made to make the engine lighter. The boiler consists of a single tube approximately 500 feet long, and is built according to a patented design, the chief improvement over previous boilers being that the temperature remains constant regardless of the pressure, and the control is entirely automatic. The efficiency is very high.

The engine is fitted with a steam feed water pump, the exhaust steam from this pump being used to preheat the feed water entering the boiler. The power plant condenses almost 99 per cent of the water used, so that very little water is lost, and ten gallons are sufficient for an ordinary flight under reasonably cool weather conditions. To start the boiler it is merely necessary to press a switch which starts an electric blower motor, causing air and fuel to be forced through the burner and into the boiler, where ignition is effected by spark. From then on the automatic controls operate all the necessary functions, and the pilot has only to move the throttle and reverse lever, there being one position for forward and one for reverse.

Several years of laboratory work preceded the actual flight, during which period several engines and steam generators were developed. When the power plant was finally installed in the aeroplane it had already run some thirty hours on the dynamometer and after installation in the fuselage it was operated for about twenty hours more. All of its characteristics were well known, and flight was to all practical purposes a foregone conclusion. Furthermore, prior to dismantling the original power plant, the aeroplane was carefully weighed and measured by students in the Boeing School of Aeronautics, the centre of gravity being exactly located for all conditions of loading, to insure that as close a comparison as possible could be obtained between the original Curtiss engine and the new steam installation. When the aeroplane was re-erected it was checked to determine its conformity to the previous figures, and the hub of the same propeller used with the petrol engine was modified to fit the new steam engine.

A report on Mr. Besler's pioneer flight was made for Aero Digest by Mr. A. F. Bonnalie, head of the Boeing School of Aeronautics, one of the largest flying services in the United States. He points out that the first flights, while short, were extremely impressive.

From the time the fires were started until the engine was run up, not more than five minutes elapsed. A little time was taken further to test out the reverse gear and to be sure that all apparatus was operating correctly; then the plane taxied down the field into position for the take-off. The take-off was normal in every respect except that the absence of noise was noticeable. In fact when the plane left the ground, it was the observer's impression that the machine was not getting up sufficient speed. It flew strongly, however, and circled overhead a couple of times. When under full power no more noise was noticeable than is apparent with an aeroplane gliding with the engine off - merely the swish of the air could be heard. Even when operating on the ground at full throttle, the propeller made very little noise.

While the first flights were made at low altitude, the climbing angle was noticeably steep and the aeroplane was obviously under full control of the pilot. As he approached for a landing and crossed the border of the field, the propeller rotation ceased, and backward rotation slowly started. After touching the ground the pilot gave it full reverse throttle, whiche, together with the brakes fitted to the particular aeroplane, brought it to a stop very quickly. Mr. Besler again took off and after a short flight simulated a forced landing, then took off once more round the field and landed again with a short run. Being satisfied with the preliminary tests, the proprietors propose to give more extensive demonstrations and to make quantitative tests.

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