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The Besler Steam Plane
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George & William Beasler
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William Besler in front of the Airspeed 2000.
Besler steam plane in flight.
A very rare shot of the steam powered Airspeed 2000.
Approaching under steam!
Engine layout as published in "Luftwissen"/Germany 1941.
Concept of the Besler steam plane demonstrator.
Besler steam aero engine. The Besler brothers proudly posing in front of their design.
A Travel Air 2000 biplane made the world's first piloted flight under steam power over Oakland, California, on 12 April 1933.
The strangest feature of the flight was its relative silence; spectators on the ground could hear the pilot when he called to them from mid-air.
The aircraft, piloted by William Besler, had been fitted with a two-cylinder, 150 hp reciprocating engine.
An important contribution to its design was made by Nathan C. Price, a former Doble Steam Motors engineer.
Price was working on high pressure compact engines for rail and road transport; the purpose of the flight was to obtain publicity for this work. Following its unexpectedly favourable reception Price went to Boeing and worked on various aviation projects, but Boeing dropped the idea of a steam aeroengine in 1936. Price later worked for Lockheed where his experience with developing compact burners for steam boilers helped to design Lockheed's first jet engine.
The advantages of the "Besler System" that were claimed at the time included the elimination of audible noise and destructive vibration; greater efficiency at low engine speeds and also at high altitudes where lower air temperatures assisted condensation; reduced likelihood f engine failure; reduced maintenance costs; reduced fuel costs, since fuel oil was used in place of petrol; reduced fire hazard since the fuel was less volatile and operating temperatures were lower; and a lack of need for radio shielding.
For capacities in excess of 1000 horse power a turbine captures the energy released by the expansion of steam more efficiently than a piston. Thus, the steam reciprocating engine turned out to be unsuitable for scaling up to the needs of large aircraft.
World’s First Steam-Driven Airplane
Popular Science Monthly (July 1933) Vol 123, No. 1
H J Fitzgerald
Successful Flights with Long-Sought Craft Crown Many Similar Attempts by Early Aviation Engineers
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Over the Oakland, CA Airport, a few days ago, a silent planet slanted across the sky trailing a thin ribbon of white vapor. Spectators heard the pilot shout a greeting from the air. They saw him flash past, skimming the ground at 100 miles an hour. They watched him bank into a turn, slide to a landing, and, with the propeller spinning backward, roll to a stop in less than 100 feet. They had seen, for the first time in history, a man fly on wings powered by steam!
Two brothers, George and William Besler, the former a geologist 31 years old, and the latter a mechanical engineer, two years younger, have achieved the dream of Maxim, Langley, and other pioneers of flight. Through their work, the steam-driven airplane, long talked about, long planned, has become a reality.
This spectacular development in the field of aeronautics is the result of three years of secret experiment. The inventors began their work in 1930, in a machine shop at Emeryville CA. A few weeks ago, they brought the product of their researches, a 180-pound engine developing 150 horsepower, to the Oakland Airport and installed it at the nose of a conventional Travel Air biplane.
This blue machine, with William Besler at the controls, sped down the runway and climbed into the air without a sound except the low whine of the propeller and the hum of wind through the wires. Swinging back over the field at 200 feet, the pilot shouted ‘Hello!’ and heard the answering calls from spectators below. Conversation in the craft, the two inventors told me when I interviewed them a few hours after their historic demonstrations, was as easy as conversation in an open automobile.
Three times, the blue plane blazed a steam trail into the air, taking off, landing, circling about, remaining aloft for 5 minutes at a time. The constant, wearing vibration of the gas engine was gone; the smooth push and pull of steam power had supplanted it. Each time, as the machine swooped down and the wheels touched, Besler pulled back a small lever at the side of the cockpit and the steam engine at the nose of the ship instantly raced in reverse, whirling the propeller backward to act as a powerful brake and reduce the landing run to a minimum.
This method of slowing down, possible only with steam power plants, applies the braking effect above the center of gravity and thus prevents nosing over in a quick stop. When wheel brakes are jammed on suddenly, a plane nose over or somersaults in a ground crash. Coming in at 50 miles an hour, the Beslers told me, the new steam plane can sit down and come to a stop in a field hardly 100 feet square.
The engine is a 2-cylinder, compound, double-acting, V-type power plant. Its high-pressure cylinder has a 3-inch bore and a 3-inch stroke; its low-pressure cylinder has 5 and a quarter inch bore and a 3-inch stroke.
Just behind the engine, the inventors showed me the barrel-shaped metal boiler which, with its super-efficient burner, explains why they have succeeded where others have failed in attempting to drive planes with a steam engine.
Using vaporized fuel oil, the patented burner releases as much as 3 million BTU per cubic foot of firebox space. This, they told me, is far in excess of anything hitherto attained. An electric blower drives this tremendous heat down among the flat spirals of a single 500-foot pipe coiled within the boiler. Three-eights of an inch thick, inside measurement, at the bottom, the pipe gradually increases in size until it has an inside diameter of five-eights of an inch at the top. The water supply to the coiled pipe is thermostatically controlled to keep the temperature constant regardless of pressure.
Under the fuselage nose is the condenser which looks like an ordinary radiator for a water-cooled motor and which is said to recover more than 90 percent of the water from the used steam. By using a steam-fed water pump, the inventors employ the exhaust vapor to preheat the feed water entering the boiler and thus decrease the time required to build up pressure within the coils.
The operation of the power plant, once it is started, is practically automatic. At the start of a flight, William Besler climbs into the cockpit and flips over a small switch. Instantly the electric blower goes into action, driving air mixed with oil spray through the burner. Here, an electric spark ignites the mixture and send a blowtorch of flame roaring downward around the coils of pipe. A few minutes later, steam pressure is high enough for the take-off. All the pilot has to do, from then on, is to operate the throttle and reverse lever.
At 800 degrees F, the steam pressure built up within the coils reaches 1500 lbs. With a 1200 lb pressure, the engine will deliver 150 horsepower, whirling the propeller at 1625 rpm. Tests have shown that 10 gallons of water is sufficient for a flight of 400 miles. By increasing the size and efficiency of the condenser, the experimenters told me, they believe they can make this amount of water last indefinitely.
As news of their sensational flights flashed to all parts of the country, eager interest was aroused among aeronautical authorities. The prospect of steam planes on the skyways opens up fascinating possibilities.
Burning fuel oil so non-explosive that it merely smolders if struck by the flame of a blowtorch, the new power plant eliminates the menace of fire. In addition, the Beslers told me, enough fuel oil for a 100-mile trip can be bought for 40 cents.
Because, above 1000 feet, steam-driven planes would be as silent as soaring birds, they would have particular value in military work. Noiseless warplanes have long been sought. But muffling gasoline engines reduces their power to such an extent that the plan is impractical. The new power plant, silent by nature, would permit long-distance raids above the clouds by ghost ships giving off no telltale drone of motors to warn the enemy or to aid in directing anti-aircraft fire.
Most spectacular of all are the possibilities of steam on the airways of the stratosphere. In the thin atmosphere of this region, 10 miles or more above the surface of the earth, experts agree, the high-speed transport ships of the future will fly. Here there are no clouds, no storms, and the steady trade winds of the upper blue will increase the speed of long distance passenger, mail, and freight machines…
A Steam Driven Airplane Engine
Scientific American ( September 1933 )
By A. K.
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Controlled Balance Flow of Parallel Boiler Circuits
Boiler Control System
Two brothers, William J and George Besler recently installed a reciprocating steam engine in a conventional Travelair biplane, and a number of successful flights have been made at the Oakland, CA airport. The power plant is illustrated in these columns by photographs and a diagram. As the engine was really an old automobile engine, the airplane came out 300 lbs overweight, but it is expected that savings in weight will be readily made later.
The Besler brothers’ steam engine is a two-cylinder double-acting, compound 90-degree V engine, with a cut off at about 50 percent of the stroke. The high pressure cylinder has a bore of 4-1/4 inches and a stroke of 3 inches. The low pressure cylinder has the same stroke, but a 5 inch bore. The ordinary working pressure is 950 psi, and the temperature of the steam is 750 degrees F. The engine not only drives the propeller but also drives a blower through an over-running clutch. The blower (an electric motor used when starting) supplies air to a Venturi in which the fuel lines terminate. The Venturi leads the mixture to a fire box, where an ignition plug sets the mixture aflame. Once ignition has been started, the process of combustion is continuous.
The steam generator is of a modified flash type. The tubing is continuous in length, about 500 ft in total length; the coils are covered with metallic wool insulation and sheet aluminum. A pop valve is set to give relief at 1500 psi. A thermostatic normalizer device injects water into the superheater whenever the temperature goes over 750 degrees F. From the boiler the steam passes through a throttle to the engine proper, and then to two condensers --- one mounted at the top of the fuselage and one below. From the two radiators or condensers, the steam passes into the water tank, which is provided with a steam dome. From the water tank, a pump passes the water through a primary heater and then to a secondary heater. By preheating the water, some of the energy of the exhaust steam is put back into the system, ad thus the overall efficiency is improved. After passing through the heaters the water again goes back to the boiler, and the process is repeated over and over again.
In the tests the rapidity with which the boiler got up steam was remarkable. In 5 minutes the plane was ready to take the air. In the air, the absence of noise was remarkable. On landing a very interesting possibility of the steam engine was in evidence. As soon as the pilot landed he reversed the engine (reversing the engine is a simple matter on a reciprocating steam engine). With the propeller driven in the opposite direction, a powerful braking effect was obtained. Perfect control and smoothness of operation was noted throughout the test flights.
A great deal of the technical work on the Besler steam engine was done at the Boeing School of Aeronautics, and we are indebted to Mr Welwood Beall of this school for a first-hand account of the design.
The Besler Steam-Driven Aeroplane.
This is probably the best-known of the steam aeroplanes. The extracts here are once more from Steam Car Developments and Steam Aviation for June 1934.
Steam Car Developments and Steam Aviation
VOL. III. JUNE, 1934 NO. 28.
At the Oakland Airport, California, U.S.A. a short time ago a silent ’plane slanted across the sky, showing a thin trail of white vapour. It was so silent in operation that spectators heard the pilot shout a greeting to those on the ground. He banked into a turn, and was watched sliding to a landing, and, with the propeller spinning backwards – roll to a stop in less than a hundred feet. This was Mr. William Besler giving his first demonstration flight, and it was, we think, for the first time in history that a man had flown in a steam-driven aeroplane.
This steam driven machine is the achievement of two brothers—Messrs. George and William Besler, and is the result of experimental pioneer work carried out by them during the past three years. Through their endeavours— undertaken with a good deal of secrecy—the steam-driven aeroplane, the possibilities of which have long been discussed, as become an accomplished fact. Our American correspondent, to whom we are indebted for the following particulars, tells us that passengers on the stem ’plane in full flight are able to carry on a conversation as easily as when riding in an open motor car. The pilot, when flying at 200 ft. altitude, called to the spectators below, and heard their answering calls.
During the demonstration Mr. Besler made three flights, taking off, circling about, and landing, to show the ease of control. What was generally remarked upon was the almost complete silence. The constant, wearing vibration of the internal combustion engine was gone; the elastic pull and push of the steam engine had supplanted it. Each time as the machine swooped down and the landing wheels touched ground, the pilot pulled back a small lever at the side of the cockpit and the steam engine at the nose of the ’plane instantly reversed, whirling the propeller backwards, creating a powerful braking effect which reduced the landing runs to a very short distance.
This is one of the fundamental characteristics of a reversing steam engine and that which can never be imitated by an explosion motor. There is, moreover, the fact that the reversed propeller applies its braking effect above the centre of gravity of the machine, and thus prevents it nosing over in a quick stop. Brakes applied to the landing wheels of a steam-driven ’plane are not necessary. On an I.C. ’plane landing wheel brakes—suddenly applied—have been a cause of somersaulting, and a ground crash. It is said that the Besler ’plane, coming in at 50 m.p.h., can sit down, and come to a stop, in a field scarcely 100 feet square.
Turning now to the power-plant, this, of course, is of Doble Steam Motors and Besler’s design and manufacture; and its main details are already familiar to many of our readers. The production of steam automatically, at a practically constant pressure and degree of superheat, from the forced-feed or flash steam generator, and the patented electric controls, by which it is accomplished; are fully described in the Doble-Besler Patent Specification, which we reproduce on another page.
The steam generator is fed with water by a steam donkey pump, the exhaust from which is first taken through a Feed-water heater, before finally passing into the condenser. The burner is similar to that described in our May 1931 issue of “S.C.D.” The whole of the power plant is installed at the nose of the aeroplane, with the engine forward of the steam generator. The engine is a 2-cylindered compound, double-acting of a V-design, with the cylinders H.P. 3 inches and L.P. 5¼ inches bore, by 3 inches stroke. It develops 150 B.H.P. at 1,200 lbs. (temperature 800 degrees Fahr.) steam pressure, and abut 1,650 revolutions per minute. The engine was not built particularly for lightness—it weighs 180 lbs.—and by using special aircraft materials, its weight could be lessened.
The steam generator tubing is coiled into flat spirals, and totals abut 500 feet in length. The lower coils, into which the feed-water is introduced, are of tube about 3/8 of an inch bore, and the upper coils from which the superheated steam is drawn off, are about 5/8 of an inch bore. The water supply to the coils is thermostatically controlled to keep the steam temperature constant irrespective of the steam pressure.
Under the fuselage nose is the condenser—which is simply a section of an ordinary petrol car radiator, and this is said to be sufficient to recover more than ninety per cent. of the water from the exhaust steam At the start of a flight, the pilot climbs into the cockpit and flips over a small switch. The electric blower immediately goes into action, driving air mixed with oil spray into the combustion chamber. Here, an electric spark ignites the mixture and sends a sheet of flame roaring downwards among the spiral boiler coils.. A minute or so later, steam pressure is high enough for takeoff. All the pilot has to do from then on, (as regards the power unit) is to operate the throttle and the reverse lever.
The tests have shown that ten gallons of water is sufficient for a flight of 400 miles. By increasing the size and efficiency of the condenser, the Besler Brothers believe they can make this amount of water last indefinitely.
The prospect of steam ’planes on the skyways opens up fascinating possibilities. Burning, as they do, ordinary furnace oil of so high a flash point that it merely smolders if struck by the flame of a blowtorch, steam power plants have little to fear from the menace of fire. Moreover, fuel oil is cheap, sufficient for a hundred-mile trip can be bought for 1s. 8d.
At any height above a thousand feet a steam-driven ’plane is quite inaudible from below, this would give it particular value for military work. Noiseless war ’planes have long been sought; but attempting to muffle the noise of an I.C. aerial engine reduces its power to such an extent that the plan is impracticable. A steam power plant, silent by nature, would permit of long-distance raids above the clouds by ’planes giving off no tell-tale drone of motors to warn the enemy, or to aid in directing anti-aircraft fire.
It is interesting to speculate upon the possibilities of steam on the airways of the stratosphere. In the thin atmosphere of this region, ten miles, or more, above the surface of the earth, experts predict, the high speed transport ships of the future will fly. The chief stumbling block at present is the internal combustion motor. It steadily loses power as it ascends, and it has been said that a motor, which delivers 150 H.P. at seal level, will only give about half that power when it has climbed to 20,000 feet altitude. At 30,000 feet the sea level horse power of 150, will probably have dwindled to about 45 horse power. And you are then only half way to the stratosphere!
Superchargers, driving a blast of air into the carburetor to make up for the reduced pressure in rarefied atmospheres, help these internal combustion motors, but they never completely prevent loss of power at high altitudes. On the other hand, a steam engine loses no power at all with altitude, and it gains in efficiency the higher it climbs—partly because the exhaust back-pressure is less in thin air than at sea level. Thus it seems that the perfecting of steam power aerial units will be an important step towards conquering the stratosphere.
There are several other engineering firms actively engaged in developing stem aviation, and we give some brief details herewith. These may perhaps, be of interest to our readers. In the first place, we are indebted to the “Daily Telegraph” of April 16, 1934, for the following extract:
Details are now available of the steam-driven aeroplane which has been under secret construction on the outskirts of Berlin for many months. The inventor is Herr Huettner, chief engineer of the Klingenberg electricity works.
The machine is not yet finished, but the plans, according to the “Berliner Tageblatt” have been submitted to experts and found to be theoretically satisfactory. They have been elaborated down to the smallest detail, and give rise to the following expectations:
Range: 60 to 70 hours non-stop flight.
Speed: 230 m.p.h. on starting, rising to a maximum of 260 m.p.h. when the “ceiling” is reached.
Maximum height: 43,000 ft.
Load: One ton for a non-stop flight of 60 hours.
Engine Power: 2,500 h.p.
Length: 6 ft. Breadth: 108 ft.
If practice agrees with theory, a non-stop flight will be possible to Japan, Capetown, San Francisco, Rio-de-janeiro, or Singapore, of more than one third of the circumference of the earth.
The secret of these claims is said to lie in the fact that for the first time Herr Huettner has succeeded in solving the problem of a satisfactory ratio of weight to power.
Herr Huettner’s solution consists of a revolving boiler combined with a steam turbine. If successful it will, of course, also be applied to motorcars. The fuel used is oil gas, and in view of the great power developed, Herr Huettner has adopted twin propellers, revolving in opposite directions.
In March last the Daily Telegraph Prague Correspondent reported that an article in the Czechoslovak newspaper “Prager Tagblatt,” giving details of Herr Huettner’s invention, has led to the arrest of the Berlin correspondent of that paper.
The following steam-aviation items have also been received from various sources:
In Akron, Ohio, last autumn, a local inventor, Harold C. Johnson, announced the completion of a steam engine with two opposed cylinders, weighing, complete with boiler, only 146 pounds. Some months earlier, it
became known that the Great Lakes Aircraft Company, at Cleveland, Ohio, was working upon an experimental steam-driven biplane. Recent dispatches from France reported that a Paris mechanic had perfected a light steam power plant for aeroplanes. Another news item, coming from Sweden, told of steam turbine engineers who are working on a new-type turbine for aircraft use; while a third—from Italy—carried the information that G. A. Raffaelli, an aeronautical engineer, had announced a steam engine for stratosphere machines. But we think, it was the two California inventors—the Besler Brothers—who first achieved steam-driven flight.
Well the plane may be long gone, but it appears that the Besler aircraft engine has survived, and may be seen either at the Warner Robins Air Force Museum in Warner Robins, Georgia USA, or at the Savannah Science Museum (from where it was loaned). According to the museum sign, the engine is a three cylinder single-acting radial design, putting out 70HP at 300PSI steam pressure. Bore and stroke: 3.125″ x 4.125″, displacing 165.38 inches and the whole unit weighed 100lb including pumps and propeller.
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Note: The size of the propeller listed on the sign is not correct. The actual size measures approx. 60 1/2 inches.
Flight by Steam
TIME Magazine Monday, April 24, 1933
Two young men climbed into the open cockpit of a Travelair biplane one day last week at Oakland Municipal Airport. After a minute or so the propeller began to turn. The plane started down the runway, gathered speed, soared into the air, its propeller beating a loud tattoo but without any noise of engine exhaust. After circling the airport at 1,000 ft. for about 15 minutes the plane glided to a landing and out jumped the two young men, grinning broadly. Thus unpretentiously, aeronautic history was made. For the first time, a steam-powered airplane had flown.
The Engine consists of two cylinders developing 90 h.p. in the air, 150 h.p. in block tests. It weighs 500 Ib.—considerably more per horsepower than gasoline airplane engines. Steam is generated from water (not from any special chemical) by burning cheap crude-oil. Sealed condensers return the steam from the cylinders to the boiler with only 1% loss. Constant pressure in the boilers is maintained by electric gauges which automatically ignite the burners when pressure begins to fall. Take-off pressure can be generated in one minute. The engine is reversible in flight, effecting a short, slow landing.
The Inventors are George D. Besler, 31, and his brother William J., 29, sons of Board Chairman George William Besler of Central Railroad of New Jersey. Associated with them was their Princeton classmate (class of 1926) Clement Bates Ellery Harts, son of Brigadier-General null Wright Harts, onetime military attache of the U. S. Embassy in Paris.
As youngsters at Hun School in Princeton, N. J. the Besler boys were usually mistaken for twins. (Now William is dark, slender; George is blond, stocky, has a mustache.) As Princeton undergraduates they played polo, learned to fly, owned planes. As graduates they became steam-engine conscious, as are all Beslers because of the family's substantial interest in Davenport Locomotive Works. They went to California and got control of Doble Steam Motor Corp., which had been in difficulties, began producing steam automobiles, steam trucks and busses. About three years ago the Beslers and their friend Clement Harts began experiments on the steam airplane engine, simply to prove it could be done.
Significance. Aeronauts began 100 years ago to try to make steam engines fly, because no other motive power existed. The first successful dirigible, flown by Henri Giffard in 1852, was steam-propelled. Ten years before, W. H. Phillips had sent aloft a small model helicopter with a steam engine in it. Langley's first successful flying model, in 1896, was steam driven. Maxim worked on the idea. But no full size airplane flew. And before one did, Charles M. Manly had built a gasoline engine lighter per horsepower than any steam plant produced so far. When it was proven that gas engines would fly, there remained no reason for early aeronauts to bother with steam.
Reasons for a renaissance of interest in steam are the same as motivated the development of Diesel engines for airplanes: elimination of fire hazard by use of crude oil; elimination of ignition and hence of radio interference; simplification of mechanism; economy. Also the steam engine offers reduction of noise, of vibration, of complicated lubrication.
While the Besler flight was regarded as a significant as well as an historic experiment, few observers were prepared to guess whether the steam-engine idea will get farther than the Diesel, which has yet to be accepted by aviation.
Steam Power for Aircraft
DISCOVERY, July 1933, p. 220
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 connation 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, which, 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.