Monday, December 5, 2016

The Sopwith Aeroplanes, Part I -- December 5, 2016


The 15-September-1919 issue of Aerial Age Weekly featured the first of two parts of "The Sopwith Aeroplanes," an article about the products of the Sopwith Aviation Company.

THE SOPWITH AEROPLANES

The Sopwith "Tabloid" biplane although built in 1913, has had such an extraordinary effect on aeroplane design in general, and in particular was certainly the beginning of the greatness of the House of Sopwith, that it undoubtedly merits inclusion in this series of article reproduced through the courtesy of "Flight."



The Sopwith "Tabloid"
 
In its original form the Sopwith "Tabloid" was built as a side-by-side two-seater, with an 80 h.p. Gnome engine. It was built for Mr. Hawker, the famous Sopwith pilot, to be taken out to Australia in 1914, but very soon after its triumphant appearance a number of single-seaters of similar type were ordered by and built for the Army. This machine, as shown in the accompanying illustrations, had a skid type under carriage and a balanced rudder, while there was no fixed vertical fin. The pilot and passenger sat side by side, the pilot on the left. Lateral control was by means of wing warping. When this machine paid its first visit to Hendon it left everyone agape, as such speed as it developed had certainly never been seen, nor probably been believed possible, with a biplane type of machine. In those days the general opinion was that for speed one must have a monoplane, and it was not until the advent of the "Tabloid" that this fallacy was effectively cleared up. After that the small fast single-seater biplane received a great impetus, and the type began to become general all over the world. It will, therefore, be seen that the world at large, and British aviation in particular, owes a debt of gratitude to the Sopwith firm for having demonstrated the possibilities of the small biplane. In addition to its great maximum speed--92 m.p.h.--the "Tabloid" was remarkable in those days for its great speed range, as it would fly as slowly as 36 m.p.h. This was a range of speeds which none of the contemporary monoplanes were capable of.

In its single-seater form the "Tabloid" underwent various minor alterations. Thus one form was with skid undercarriage, but with the front struts slightly more raked than they were in the original machine. Another slight alteration was the addition of a vertical fin in front of the rudder, which latter was not balanced. The next step in the evolution of the "Tabloid" was seen when the late Mr. Harold Barnwell flew a "Tabloid" in the aerial Derby. This machine, although similar to its prototype, was fitted with a Vee-type undercarriage. Finally, the "Tabloid" entered the last stage of its development by being fitted with ailerons instead of warping wings, and in this form it was a most successful single-seater scout.

The Gun 'Bus

As a result of their experience with Sopwith school pushers, the Sopwith firm were given an order by the Greek Government for a number of somewhat similar machines, carrying a pilot and gunner, but not fitted with dual controls. A gun was mounted in the nose of the nacelle. This order was nearing completion when war broke out, and the machines were commandeered by the Admiralty. From August, 1914, they were immediately put into service, being among the first aeroplanes to be armed, and were equipped with land undercarriages instead of the original float chassis. The earlier batches were equipped with 100 h.p. Gnomes, but later water-cooled Sunbeams were fitted. The scale drawings and photograph show one of these machines fitted with a 150 h.p. Sunbeam.



The Torpedo Seaplane

In 1915 the Sopwith Co. built for the Admiralty a torpedo-carrying aeroplane. This machine was of an experimental character, but is notable as having been the forerunner of the famous Sopwith "Cuckoo." It was fitted with a 200 h.p. Canton-Unne engine.

The Tractor Seaplane

In the matter of tractor seaplanes the Sopwith Co. had already done good work in connection with, for instance, the circuit of Britain, and they were therefore in a position to undertake the design and construction of machines of this type when, early in the War, the Admiralty ordered some seaplanes. It was designed for reconnaissance work and was unarmed. The engine fitted was a 100 h.p. Gnome monosoupape. From the illustration it will be seen that this machine was fitted with folding wings. A somewhat similar machine of the land type was built also. The land machine differed, however, in several respects from the seaplane, apart from the difference in undercarriage. Thus the span of the two planes was equal. Machines of this type caused curiosity briefly on account of the bomb racks fitted on the struts of the undercarriage, a feature that was somewhat unusual in those days.

The Sopwith Bat Boat

Although not included in the drawings, the Sopwith Bat Boat merits brief mention here on account of the good work done by this type of machine before the War. Thus it may be remembered that the Sopwith Bat Boat, which was first exhibited at the Olympia Aero Show of 1913 and which had a 100 h.p. Green engine, won the Mortimer Singer Trophy by starting off the sea, coming down on land, and starting from the land alighting on the sea again. This was accomplished by fitting it, in addition to the boat, with a collapsible wheel undercarriage. Probably this was the first flying boat to be built in Great Britain. A later type of bat boat was fitted with a 200 h.p. Salmson engine and differed from the previous type in various details. Thus, for instance, it had a straight top plane, while the bottom plane had a pronounced dihedral. Also it had a single rudder instead of the twin rudders of the previous model. Also the tail booms were so arranged as to form a Vee when seen in plan view. Boats of this type were ordered by Germany before the War, and from photographs later published in German aviation papers it would appear that the Germans made several copies of this machine, imitating the original down to the smallest details.

The Baby Seaplane

The Baby Seaplane was an immediate development of the "Tabloid," from which it differed principally in the fitting of floats instead of wheels. One of these machines made history by winning the Schneider Trophy at Monaco, and the Baby Seaplane is very similar to the famous Sopwith "Schneider." In this machine wing warping had given way to ailerons. The floats were of the plain, non-stepped type, and a tail float of considerable size was fitted under the stern. The engine originally fitted was a 100 h.p. Gnome monosoupape, but later on 110 and 130 h.p. Clergets were also used.

It is of interest to note that, although this seaplane performed highly successfully at its first appearance, it was more or less put on one side at the outbreak of the War, and it was not until November, 1914, that the demand arose for a fast single-seater seaplane. It was then immediately put into production, and from that distant date until the signing of the Armistice the Sopwith Baby Seaplane has been continually in service.

The 1 1/2-Strutters

The Sopwith 1 1/2-Strutter has claims to great historical distinction, not only for its great capabilities for use as a fighter, but because, indirectly, it set a new fashion in aerial fighting, being the first British aeroplane to carry a synchronized gun firing through the propeller. The Sopwith-Kauper synchronization gear which made this possible was developed at the Sopwith works, and was as much a product of this firm as was the machine in which it was installed. It was also fitted with the Scarfe gun ring for the gunner, which has since become such a well-established feature on all fighters. The 1 1/2-Strutter was originally designed as a high-performance two-seater fighter, with a 100 h.p. Clerget engine. At the time of its introduction it was justly regarded as an extraordinarily good 'bus, having an excellent performance and a good manoeuvrability. Incidentally it established a world's altitude record for an altitude of 23,980 ft. In view of its good performance, coupled with its (for the times) excellent armament, the 1 1/2-Strutter had a tremendous success, and it is not surprising that many machines were built to the order of the Governments of Roumania, Russia, America and Belgium. In addition, it might be mentioned that the French Government has manufactured under license no less than 4,500 machines of this model. In addition to the novel points connected with the mounting and firing of the guns carried, the 1 1/2-Strutter was interesting in several other respects. Thus the wing bracing—which gave it its name —was very unusual, and in a modified form set a new fashion, so to speak. The top plane was in two halves, bolted to the top of a central cabane, while the spars were provided with an extra support in the shape of shorter struts running from the top longerons to the top plane spars some distance out. In the single-seaters to follow this bracing of the top plane was generally adopted, with the exception that the central cabane was done away with, the outer struts of the W formation having a slightly less pronounced slope, and supporting a separate top plane centre section. Aerodynamically the l/2-Strutter is of interest in being fitted with an air brake in the form of adjustable flaps in the trailing edge of the lower plane adjacent to the fuselage. These flaps could be rotated by the pilot until they were normal to the wind, thus helping to pull the machine up when about to land.

A more successful innovation incorporated in this machine was the trimming gear, by means of which the angle of incidence of the tail plane could be altered during flight. In this manner the difference in weight of the passenger carried could be counteracted by the tail setting, and also the tail could be adjusted for high speed, climbing, etc. This feature has since become universal practice on passenger-carrying machines.

The 1 1/2-Strutter Bomber

Originally designed as a two-seater fighter, the l 1/2-Strutter was later adopted as a single-seater bomber, and it is the machine which has been so successful in bombing, with good results, such towns as Essen, Munich and Frankfort. For bombing work the 1 1/2-Strutter was equipped with a 130 h.p. Clerget, which afterwards took the place of the 110 h.p. Clerget in the standard two-seater fighter model. It might also be mentioned that fairly recently the French Government converted a large number of two-seaters into school machines with dual controls. These machines are fitted with 80 h.p. Le Rhone engines.

The Sopwith "Pup"
The famous single-seater scout bears a strong family resemblance to the Sopwith "family," being reminiscent of both the 1 1/2-Strutter and of the original "Tabloid." The "Pup" was brought into existence principally with the object of tackling the Fokker monoplanes that were at one time doing far too well on the Western Front. In this object it succeeded admirably, and although judged by present standards it is of very low power—it was fitted with an 80 h.p. Le Rhone engine—its performance and ease of handling endeared it so much to its pilots that its merits are spoken of with much affection, tinged with a little regret that it has had to give way for higher-powered machines. A feature of the "Pup" are the window panels in the upper plane. The windows were rendered necessary by the fact that the pilot sat with his head below the level of the plane. A single machine gun firing through the propeller is mounted above the fuselage.

The "Pup" (Sea Type)

When starting from and alighting on the deck of a ship became the fashion, the Sopwith "Pup" was modified slightly for this purpose, and good work was done by this type on the North Sea patrols, for which work it proved very suitable. The "Pup" machine did not differ greatly from the standard type.



The Sopwith Triplane

Amongst all the Sopwith productions, nearly all of which have attained great fame, none is more characteristic than the triplane, affectionately known as the "Tripe" or "Tripehound." This machine was fitted with 130 h.p. Clerget engines. The principal objects aimed at in this notable design were, first, the attainment of a high degree of visibility, or, rather, the reduction to a minimum of the pilot's blind angle. With his head on a level with the intermediate plane, he enjoys a practically unrestricted arc of vision through about 120°, whilst sections cut out of the centre of the intermediate plane enable him to have a good view of the ground when landing, the position of the cockpit being such that the bottom plane has no restricting influence on the view. The narrowness of the chord made available by the use of three main planes also allowed the pilot an exceptional view upwards and to either side, an important consideration in a purely offensive machine. The second object aimed at was an increase in maneuverability, and the triplane principle was adopted to secure this purpose in consequence of the fact that, owing to the narrow chord, the shift of the center of pressure with varying angles of incidence is relatively smaller than in a biplane, and consequently demands a shorter length of fuselage to carry the tail. At the same time the small span reduces the moments of inertia in the horizontal plane, and a machine is thus obtained which is highly responsive to its controls and which can add the important ability to dodge to its other strategic advantages. The consideration of movement of the centre of pressure enabled single I-struts to be adopted in place of the usual pairs springing one from each spar. This construction also leads to a sensible simplification of the wiring system. Ailerons of the unbalanced type are fitted to all three planes.

The Sopwith "Camel"

Few aeroplanes have done more to repulse German attempts at aerial supremacy than the famous "Camel," so called from the hump which it carries on the forward top side of its fuselage by virtue of the fitting of two fixed machine guns, both firing through the propeller. Furnished with a 130 h.p. Clerget, and designed to achieve a very high performance both in climb and speed, the "Camel" showed itself a redoubtable fighter against antagonistic scouts, and also performed extraordinarily well as a Zeppelin catcher, in which latter connection its ability to climb with great rapidity was extremely valuable. A good angle of vision was obtained by keeping the pilot fairly well forward, and also by the positive stagger of the planes. In place of the large transparent panels fitted in the middle of the top plane in the "Pup," that of the "Camel" was provided with a faired-off slot. The remainder of the designed followed "Pup" lines pretty closely, but it is of interest to note that this machine was the first to be fitted with two machine guns, a practice that has since been extensively adopted in both Allied and enemy aeroplanes of a similar type.

The Sopwith "Camel" (Sea Type)

This design was almost identical with the above, except that the fuselage was made detachable at the rear of the pilot's seat, enabling the machine to be conveniently stowed aboard ship. It was used for flying from the deck of seaplane carriers, and, in addition to this, was also carried on some of our fast cruisers. The method of launching was off the Barbet guns. It will be appreciated that it required a machine of considerable efficiency to get off with certainty and satisfaction with so short a run.



{To be concluded)

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