Although attacked and strongly criticized in the past, the Farnborough centre still conducts valuable research
FOR STUDYING AIRFLOW over the wings of an aircraft at different speeds and different attitudes, this Parnali monoplane was provided with tufts of wool on the main plane. A cinematograph camera on the tail of the aeroplane photographed the movements of the wool tufts. The films could then be studied at leisure in relation to the speed of the aircraft and the positions of its controls.
FARNBOROUGH has played a prominent part in British aircraft progress since the earliest days of practical aviation. Situated in Hampshire, about thirty-five miles from London, it has been, since before the war of 1914-18, a centre of official research work and testing.
To provide the correct background to the development of Farnborough to its present position as one of the world’s leading aeronautical research and experiment stations, it is necessary to go back as far as 1878. In that year the Balloon Equipment Store was formed at Woolwich, London. It was this unit that moved to Farnborough, in 1890.
Balloons were the aircraft for which the station originally came into existence and they left their permanent mark in the large balloon shed at Farnborough. This shed, however, was not built until later, for the Balloon Equipment Store temporarily moved to Aldershot. It returned to Farnborough in 1905 as the Royal Balloon Factory. After that there came the stormiest period in the
existence of the station. The storm centred in the question whether the highest efficiency in the design and production of military aircraft could be secured by an official factory, coming directly under Government control, or by independent commercial organizations building and selling aircraft for profit. The beginning of this controversy tended in favour of the official factory and, when war broke out in 1914, Farnborough was the Royal Aircraft Factory.
So much of future history of the Royal Aircraft Factory depended upon what may be called the first fully developed type of aeroplane it produced, that some account of the aircraft must be given. The B.E.2 was designed in 1912 by Geoffrey de Havilland and was intended to be a paragon of all the military aircraft virtues. It had originally a 60 horse-power Renault engine, ancestor to the 70 horse-power Renault, which was certainly one of the finest engines produced in the war period. Lateral control was by warping the wings and the machine had an undercarriage which included two skids projecting in front of the wheels to prevent the machine from turning over if a bad landing was made. With the 70 horse-power Renault engine the top speed was 70 miles an hour; the landing speed was 40 miles an hour. The machine was put through all the tests of the 1912 military aircraft competition without taking part in it (see the chapter on “Geoffrey de Havilland”).
The B.E.2 completed these tests well and was adopted for the Royal Flying Corps. It was the first British military aeroplane to land in France in the war of 1914-18. But its success was looked upon with suspicion in some quarters. When, in 1912, the famous official ban on monoplanes was issued, the B.E.2 was regarded in some measure as the cause and the culprit.
It was, however, the best known of all machines produced bj’ Farnborough, with the S.E.5 second (see the chapter “Evolution of the Fighter”). The S.E.5 was probably the most renowned aeroplane produced by the Royal Aircraft Factory. It did not, however, justify the faith some people placed in Farnborough as the supreme centre of all good military aircraft design and it did not prevent the idea of Government construction of aircraft from being abandoned.
As the construction of aircraft was taken out of its hands and transferred more and more to the individual constructors, Farnborough concentrated more and more upon research and experiment. Its early work with wing sections was of great importance and it was from the sections developed at Farnborough that the majority of British manufacturers took the designs for their machines.
Another notable Farnborough product was the F.E.8 (see the chapter “Evolution of the Fighter”), which was really a development of the D.H.2 and differed from it mainly in the high aspect ratio control surfaces. At this time Farnborough had developed a theory that control surfaces should be of extremely high aspect ratio to give the maximum effect. That is to say, they were to have large span and narrow chord, to be long and narrow. In the F.E.8 the ailerons, for instance, were unusually long and narrow, much more so than the ailerons of the D.H.2. Similarly the rudder of the F.E.8 — and the same can be said of other Factory productions such as the S.E.5 — was exceptionally high and narrow.
The theory seemed to work and the high aspect ratio controls did appear to give more power, though sometimes they tended to be heavy in operation. At any rate Farnborough pressed this theory to the limit.
Inherent Stability Theory
Even more controversial than the work on the aeroplanes was the work on the engines. When the Royal Aircraft Factory at Farnborough brought out the famous R.A.F. engine (see the chapter “Aero Engines of the Great War”) there were two schools of thought about it. The first was that it was an almost perfect synthesis of the good points of numerous air-cooled engines and that it was probably better than any other engine. The second was that it was a frank imitation of the famous Renault and not nearly as good as the Renault.
Such aeroplanes and engines as the B.E., the S.E., the R.E. and the R.A.F. were the practical production work of the Royal Aircraft Factory. But all the time the factory was engaged on experimental work, some of a remarkable kind in the investigation of theories. The inherent stability theory was first fully exemplified in the B.E. and later developed in the R.E. This called for both lateral and longitudinal dihedral angles (between tail and wings). A great deal was made of the inherent stability of the Factory-produced machines, but pilots in France tended to belittle the scheme and to find machines like the Spad, which had no lateral dihedral, quicker on the controls.
Then there was the pusher theory. The F.E.8 has already been mentioned; but there was also the two-seater F.E. series, extending from the machines with the Beardmore engines to those with the Rolls-Royce engines. The F.E.s were also inherently stable and they did a great deal of useful work in France. But again the theory of the pusher seems to have been overdone, and it was found eventually that increased air performance was of more value than improved outlook and forward field of fire. Farnborough was, however, difficult to move on such points, and therefore came in for a great deal of criticism.
When the Factory brought out the B.E.12 (see the chapter “Evolution of the Fighter”), after the B.E.2 had been developed into the B.E.2c and the B.E.2e (the latter with big extensions on the top plane), Farnborough began to lose ground. The B.E.12, with an R.A.F. engine of 150 horse-power, was intended to give high performance. It did not, however, compare favourably as a fighting aircraft with machines such as the Sopwith Pup with the relatively small 80 horsepower Le Rhone engine and it was rapidly withdrawn.
THE HAWKER HORSLEY and later the Vickers Wellesley aircraft, which were used by the Royal Air Force for long-range flights, were the subjects of considerable work at the R.A.E. A great deal of preliminary investigation for these flights was undertaken at Farnborough and successfully completed in time for those engaged in the flights to take advantage of the information obtained.
These were some of the products of the Factory which made the name of the Factory known in the Royal Flying Corps and the Royal Naval Air Service. But they represented only a small fraction of the work done there. All the time research and experimental work were in progress on a big scale, and eventually this side of the Factory prevailed over the aircraft construction side. The criticisms of Government-run aircraft factories had had their effect, and it was determined in the end that the Royal Aircraft Factory should be a factory no longer. On April 1, 1918, the change was signalized by a change of name. The Royal Aircraft Factory became the Royal Aircraft Establishment.
A Flight of Royal Air Force officers was attached to the Establishment for “testing experimental designs in the air”, as the official explanation described their duties. In the work of the station, however, there was no great difference except that construction gave way to experiment and research.
Some idea of how the Establishment has developed may be gathered from the strength of its staff. At present there are a Chief Superintendent, with a Personal Technical Assistant, a Superintendent of Technical Development, a Superintendent of Scientific Research, two Assistant Superintendents (Development), one Assistant Superintendent (Research), eight Principal Scientific Officers, five Principal Technical Officers, fifteen Senior Scientific Officers, twenty-eight Senior Technical Officers, and about 140 Technical Officers. These are all in addition to the staff of pilots, who come under a Wing Commander in charge of the experimental flying department. There are normally also half a dozen Royal Air Force officers attached for special duty.
The equipment at Farnborough has been continuously improved. One of the first aerodynamic test instruments was the whirling arm, on which aerofoils could be mounted in such a way that their performance in controlled conditions of speed and angle of incidence could be studied.
Experiments in spinning were made with models dropped in the great balloon shed, and it may have been the consideration of these spinning tests in free flight that led to the free spinning vertical wind tunnel being looked upon as so important a piece of research equipment. In this the model is suspended on an upward stream of air while it autorotates. Its behaviour can then be studied in favourable conditions.
The equipment at the Royal Aircraft Establishment is most elaborate. It includes the seaplane testing tank, which was installed in 1938, and the giant 24-feet wind tunnel, which was opened in 1935 by Lord Londonderry, who was then Secretary of State for Air. The seaplane testing tank is used for studying the behaviour of seaplane hulls and floats during taking off and alighting, and when riding at moorings.
A SEAPLANE TESTING TANK is used for studying the behaviour of seaplane hulls and floats. The tank simulates the conditions experienced by a float or hull during the take-off, when the aircraft is alighting, and when it is riding at moorings. The tank was installed at the Royal Aircraft Establishment in 1938.
The giant wind tunnel is used for research with full-scale aeroplanes. One of the first machines to be tested in it was a Royal Air Force single-seater fighting aeroplane which had puzzled even its own designer by showing in the air a greater speed than had been predicted, or than ordinary computations had suggested would be possible with the amount of power available.
As the 24-feet tunnel is the most elaborate piece of research apparatus at the Royal Aircraft Establishment, a description of it is justified. It is built of steel and reinforced concrete, and is designed for making tests on aeroplanes and large-scale models.
The air stream issues from the 24-feet diameter nozzle, crosses the working section and enters the 40-feet diameter mouth of the collector. The collector narrows to 30 feet, and at the throat is a six-bladed wooden fan driven by a 2,000 horse-power electric motor. In the floor of the working section there is a pit to accommodate the main balance. This is of the weighbridge type, and measures lift and drag simultaneously. It will measure up to 8,000-lb. lift and plus or minus 4.000-lb. drag.
Aeroplanes can be tested in this tunnel with their engines running, petrol being fed to the carburettors from a tank located outside the building. There is also provision in the tunnel for making measurements on large-scale models slung from an overhead balance.
Apart from research and experiment with aeroplanes, there is an immense amount of work on components. Single-cylinder aero-engine research is in constant progress at Farnborough. A great many aero-engine developments undergo their first really exacting tests in a single-cylinder engine at the Royal Aircraft Establishment. Radiators have been made the subject of extensive work at Farnborough. The ducted type of radiator was developed to some extent by workers at Farnborough, although much work was also done by an individual constructing company. This type of radiator (see the chapter on “Fighter Design”) is found in modern fighting and bombing aeroplanes; in it drag is reduced to a minimum by controlling the pressure and speed of the air flow past the radiator elements.
Helicopter experiment has been carried out at Farnborough, and the Brennan helicopter was built and made to do a brief “hop” in the balloon shed there. Work on the “Autogiro” aircraft and the Hafner gyroplane (see the chapter “Moving Wing Flight”) has also been done at Farnborough, and is continuing there.
Blind flying and blind landing experiments have been made at Farnborough. A method was devised for landing on days when visibility was nil. The method made use of a balloon anchored at a predetermined height above the fog. The aeroplane about to land took its height and position from this balloon, and then was set in a steady and straight glide on a definite course. From that moment on the pilot never looked outside the cockpit. He was warned to make the landing motions by the flashing of a light in the cockpit. The light was worked by a weight suspended below the machine.
Ice accretion has more recently been the subject of extensive research work at Farnborough. One pilot has flown in ice-forming conditions until his machine was covered in ice, and his cockpit cover jammed up with ice so that he could not have escaped by parachute even if he had wanted to do so. He was able, however, to thaw out the machine by making an appropriate change of height. Partly as a result of this kind of work, a form of chemical de-icing apparatus was developed successfully at Farnborough.
Much work has been done there on instruments, and most of the instruments in the Royal Air Force show some evidence of Farnborough’s constant watch over this sort of development. The side of Farnborough’s work that appeals most to the imagination, however, is undoubtedly the work of the experimental pilots who are called upon to test the theories that are advanced by the technical officers, or to try new designs.
This work demands high skill in the piloting of the machine and also — what is rare — the faculty of constructive criticism. The pilot must not only be able to fly well, but he must be able to analyse his impressions when flying and to record them afterwards clearly so that the technical men may interpret them accurately.
One of the earliest and one of the most prolonged researches ever undertaken by Farnborough was into spinning. The spinning nose dive, when the machine falls nose first, turning round and round on a steep corkscrew course, was in the early days a fruitful cause of accidents. It was also thought to bear some close relation to the flying qualities of the machine. Work on elucidating the spin has involved hundreds of flying hours at Farnborough and thousands of calculations and theoretical discussions.
AN AIRCRAFT IN THE WIND TUNNEL. This photograph was taken from the twenty-four-feet air nozzle. The air collector has a forty-feet mouth narrowing to thirty feet. At the throat of the collector is a six-bladed wooden fan driven by a 2,000-horse-power electric motor. Large-scale models or full-size aircraft can be tested in the tunnel.
It is impossible to be certain as to when and where the first deliberate spin was done; but it is positive that spins were being done deliberately at an early stage at Farnborough, long before they were included in the repertoire of the average pilot. Some obstinate spinning problems were there examined, not only with models in wind tunnels, but also with full-scale machines. The small pusher scouts of the war period were thought at one time to be dangerous in a spin and it was not until they were spun deliberately and extricated at will at Farnborough that this view was proved wrong.
Farnborough does not confine its attention to experimental flying and research. There are usually some Royal Air Force units on the aerodrome. During the early days of the war of 1914-18 Farnborough was the headquarters of the ferry pilots. These men were really the pioneers of the London-Continental airway, for they flew that route regularly long before it was flown regularly by any commercial company.
The duty of the ferry pilots was to take new aeroplanes over from England to the Expeditionary Force in France. At first the pilots landed at St. Omer (Pas de Calais), but later at other depots. The ferry pilots, by dint of frequent operation over the same route, became familiar with it and were therefore able to take aeroplanes across to France in poor visibility. They did not often make the trip direct, but usually went from Farnborough to Hawkinge, near Folkestone, and thence on to the depot in France to which their orders had instructed them to fly. More recently the Royal Aircraft Establishment has been called upon to play a big part in preparing for attempts on air records made by Great Britain and for officially sponsored participation in air racing. In this way the Royal Air Force entries for the Schneider Trophy races of 1927, 1929 and 1931 were backed by a great deal of technical work done at the National Physical Laboratory (Teddington, Middlesex), and at Farnborough. The special problems which the designers of the British machines wanted to have elucidated were tackled and in most instances positive replies were given in time for the designs to be influenced by them.
Preparations for Altitude Record
In addition, research was undertaken into such problems of piloting as making turns at very high speeds. Thus not only the designs of the machines were considered at Farnborough, but also the flying of them. Similarly for the long-range flights made by the Royal Air Force, both with the Hawker Horsley and later with the Vickers Wellesley aeroplanes, a great deal of preliminary investigation was undertaken by Farnborough and brought to a successful conclusion quickly enough to enable those engaged in the flights to take advantage of it.
Perhaps the most noteworthy of these instances of practical aid to high-performance work occurred in the Royal Air Force attempts on the international aeroplane height record. A good deal of preparation had been done by the manufacturer of the aeroplane and of the engine, but considerable work remained to be completed before the flight could take place. Much of this work was done by Farnborough. The pilots who made the flights were Farnborough pilots.
The second high-altitude flight from Farnborough was made by Flight Lieutenant M. J. Adam, on June 30, 1937, when he reached a height of 53,937 feet, thus improving on the first flight, made by Squadron Leader Francis R. D. Swain, who had reached a height of 49,944 feet in his attempt on September 28, 1936. For both these flights a pressure suit was used to enclose the pilot, and the adoption of this suit was to some extent the outcome of the recommendation of Farnborough.
Today when the use of the pressure cabin both for military and for civil purposes is being looked upon with steadily increasing favour, Farnborough’s work on this type of component should prove of value.
It has been frequently said that Farnborough’s work lacks practical value and that it takes too long to produce, so that designers are unable to obtain the full benefit from it. It is possible, however, to find within British aviation the opposite view that Farnborough is an establishment of great value and an asset to British design and construction.
THE PRESSURE SUIT USED BY FLIGHT LIEUTENANT M. J. ADAM when he established an aeroplane world height record of S3 93> feet in 1937, was recommended for use by the Royal Aircraft Establishment. Much of the preparatory work for the high-altitude flights from Farnborough in 1936 and 1937 was carried out by the R.A.E. Pilots attached to Farnborough for experimental flying were employed.