Supermarine Channel

Основателем компании, с 1916 года называвшейся "Supermarine Aviation Works", был Ноэль Пембертон-Биллинг. Одним из первых самолетов, построенных этой фирмой в заметном количестве, стала летающая лодка A.D. Boat, ведущая свое происхождение от проекта Авиационного департамента британского Адмиралтейства. Ее основу составлял легкий корпус с тандемными кабинами для пилота и наблюдателя, к которому крепились крылья бипланной коробки и бипланное хвостовое оперение. Двигатель с толкающим винтом был установлен под верхним крылом.
   В общей сложности построили 29 самолетов, включая два прототипа, оснащенных различными двигателями. Большая часть из них сразу была поставлена на хранение по завершении постройки. В 1919 году "Supermarine" выкупила 10 машин у Адмиралтейства для переделки в гражданский вариант. Их оснастили 160-сильными (119 кВт) двигателями Beardmore, присвоив обозначение Supermarine Channel I. Самолет, рассчитанный на перевозку трех пассажиров в открытых кабинах, вначале использовался для увеселительных полетов, местных авиалиний и недолго на перевозках через Ла-Манш. Эти и другие переделанные машины были проданы на Бермуды (пять), в Японию (три), Новую Зеландию (одна), Норвегию (девять) и Швецию (одна). Некоторые из них оснастили 240-сильными (179 кВт) двигателями Siddeley Puma, присвоив обозначение Channel II.

Flight, July 1920

The Olympia Aero Show 1920

The machines

Supermarine Aviation Works, Ltd. (STAND 45) Southampton.

   The "Channel Type" flying boat is a commercial machine providing accommodation for pilot and three passengers. It can, however, also be converted into a reconnaissance machine for war work in the following ways :- (a) With pilot and gunner, machine gun, W.T., and two 50 lb. bombs. Range, 350 miles, (b) With pilot and observer, machine gun and two 100 lb. bombs. Range, 350 miles, (c) With pilot and observer, machine gun, and 43 gals, of extra petrol giving the machine a range of 600 miles.
   This machine can very easily be converted into a school machine, carrying two pupils and pilot, by fitting a second set of controls built in one complete unit for the purpose. Fifteen minutes to half-an-hour is sufficient time to make this change, and when required the extra control can be supplied as an addition to the standard machine.
   In the commercial model one passenger is located forward in a separate cockpit, behind which is another seating two passengers side by side, the pilot's cockpit being behind this, level with the leading edge of the lower plane. If required, a cabin may be fitted for use in rough weather, which completely protects the passengers from rain, etc. The hull, of mahogany, cedar and rock elm, is of circular construction with "built-on" fore and aft "V" steps, either of which can be replaced in case of damage. The planes are made to fold forward to facilitate housing. The tail is of the biplane type, the top surface having a negative camber. A small water rudder is fitted which controls the machine at all speeds on the water. Several novel features are embodied in the control. Immediately above the pilot's cockpit is a crank handle, by means of which, through special control of switches and starting magneto, the engine may easily be started. The engine is a 160 h.p. Beardmore mounted on ash and steel supports midway between the planes and driving a pusher screw. The radiator is in front. By sacrificing one passenger the machine can be fitted out with Amphibian landing gear. This gear lifts well clear of the water and can be lowered and raised into position by the pilot during the flight.


A Flying Boat Exhibit

   There is a healthy sea atmosphere on the stand of the Supermarine Aviation Works of Southampton, and there is that delightful yacht builder's touch about the machines which is so pleasing to everyone interested in and fond of marine craft. Everything on board is very shipshape and carefully thought out, and it is not in the design of the machines alone but also in their details and accessories that one can trace the expert boat builder's hand. The two machines shown, the Channel type and the "Sea King" single-seater, are built along similar general lines, although differing in several details. The Supermarine hulls are of elliptical or oval section, with a single-skin planking put on longitudinally, the butt joints of the planking occurring opposite thin longitudinal stringers. The whole is then covered with fabric. One of the advantages of this form of hull construction is that the boat possesses a great amount of flexibility, acting in fact as a huge shock-absorber. With the older type of flat-sided hulls this elasticity was not present, and consequently the shocks transmitted were much more evident Also the hulls had to be built considerably heavier, and even then they were more difficult to keep watertight. In alighting with a supermarine flying boat in a rough sea one can see the bottom part of the boat flexing quite perceptibly, but so sound is the construction that the boats never spring a leak. One of the Channel type boats was deliberately stalled from a height of nearly 100 ft. and struck the sea sideways. The blow on the side of the starboard wing tip float was so great that the spar in the outer bay buckled upwards, in the inner bay downwards, and the boat got a fair amount of water in through the cockpit. When the machine was hauled ashore it was found that the hull was absolutely watertight. A new pair of bottom planes was put on during the night, and the same boat has, since then, flown several thousand miles. In order to test the seaworthiness of the hulls Supermarine pilots have repeatedly made landings in the Channel in winds of 40 m.p.h., and it has been found to be possible to take off or alight in the sea accompanying such wind without shipping any water. These two tests prove, we think, both the quality of the Supermarine hull construction and the efficiency of the lines of the hulls.
   The steps, of which there are two, are separate structures and are divided by the keel. Each half-step is divided by two watertight bulkheads into three compartments, so that there are in all six watertight compartments in the step. This should ensure that in the event of a step being damaged by striking a hard object in the sea on starting or alighting there will be ample buoyancy left to keep the machine afloat.
   The Channel type, although fitted with a Beardmore engine, carries three passengers in addition to the pilot. It will thus be seen that the boat is very efficient, the maximum speed with this load being about 70 knots. The pilot's cockpit is just forward of the wings. In front of him is another cockpit accommodating two passengers side by side, while a third passenger is placed near the nose of the hull. It has already been mentioned that the Supermarine hulls are very flexible. In order not to destroy this flexibility all the internal fitments, such as thwarts for the seats, supports for the controls, etc., are given a loose fit which allows the hull a very considerable amount of "play." In order to effect this as regards the controls, these are mounted on a species of three-point-suspension. The platform carrying the controls has two supports at the rear and one in front. The two rear corners rest m crutches that allow of a certain amount of twisting. No matter, therefore, how the hull flexes, the control platform is always true in comparison with the control lever, etc., and there is no fear of the controls getting jammed.
   The Channel type has a biplane tail, with the top tail plane inverted, so to speak. That is to say, it has a negative camber. A small water rudder is fitted, which allows of steering the machine at very low speeds. This is naturally a great advantage for navigating in and out among the moving craft of a congested harbour, and should add to the general utility of the machine. The manner of interconnecting the air rudders and the water rudder is interesting, and is shown in one of the accompanying sketches.
   Mention has already been made of the neatness of many of the accessories carried on the Supermarine flying boats As an instance we may take the boathook. This implement has an automatic catch boathook which greatly facilitates picking up moorings, forming in reality an extension of the pilot's arm, and enabling him to make fast to a buoy in the shortest possible time. The action of the hook will be clear from the accompanying sketch. Another point which has received careful attention, and which shows the practical commonsense way of the designers, is the attachment of the anchor and mooring rope. This, as will be seen from the sketch, is coiled up on the side of the hull, thus avoiding getting water and mud inside the cockpits. The line is passed around to the nose, where there is a towing cleat of special design, enabling the pilot to do all handling of the anchor rope from his cockpit.

Flight, September 1920

THE AIR MINISTRY SEAPLANE (AMPHIBIAN) COMPETITION

The Supermarine Amphibian, 360 h.p. Rolls-Royce "Eagle."

   Generally speaking, the Supermarine Amphibian entered for the Air Ministry Competition is similar to the well-known Supermarine "Channel type," although as regards actual dimensions the new machine is somewhat larger. Built for reliability in commercial work rather than for "stunt" performance in the actual competition, the machine is somewhat heavily loaded both per sq. ft. and per h.p., although her performance is by no means bad. One has always associated sturdy construction with the Supermarine boats, but the present one is, or at any rate gives the impression of being, extraordinarily strong, as an amphibian craft should be to be of any practical use. In fact, we understand that the machine is excessively strong, and that in future repetitions of the design a considerable amount of weight can be saved. It should be remembered that the machine was designed and built in a hurry, and many little refinements for which there was no time in the present machine will be incorporated in subsequent ones.
   The boat hull is similar in shape to previous types, that is to say the main hull structure is a shell of circular section, built up of two skins of mahogany, the inner of which is laid diagonally, the outer longitudinally, covered with fabric. By way of strengthening the aft portion of the hull against the severe shocks caused by alighting on land, this part has fabric strips wound around it circumferentially, pulled as tight as possible by hand and then doped, so that the pressure exerted by the fabric strips on the shell is enormous and strengthens this portion of the hull very materially.
   There are two steps, formed by a separate structure, of which the forward one is placed approximately under the centre of gravity and the aft one about half-way towards the stern. The planing surfaces appear to be considerably larger than those of the "Channel type," and the nose of the hull is more pointed, resembling that of the little "Sea King" exhibited at Olympia rather than the nose of the "Channel type." In the engine installation also one notices a departure from the previous model, in that the engine is a 360 h.p. Rolls-Royce "Eagle." It is mounted high in the gap to give clearance for the pusher airscrew, and supported on a very substantial structure of steel tubes. Unlike the "Channel type," the wings are not made to fold, as this would have complicated the fitting of the land undercarriage. A novel feature on this machine is the cambering gear, which is similar in principle to, although differing in detail from, that of the Fairey float seaplane.
   There is accommodation for two passengers in addition to the pilot, who occupies the aft cockpit just in front of the leading edge of the planes. The passengers are seated tandem fashion in front, and a hinged "conservatory" roof with windows is placed over their cockpit so as to protect them against wind and spray. The bolt which locks this hinged roof extends aft to the pilot's cockpit, but should it be necessary in an accident for the passengers to get out quickly, it will be an easy matter to knock a hole in the flimsily-built roof and thus get at the fastenings.
   The pilot's "office" is very well equipped, not forgetting a very efficient bilge pump connected to the different watertight compartments into which the hull is divided. Recently an onlooker at Martlesham made the acquaintance of the aforesaid bilge pump by a stream of bilge water squirted on him. When he wishes to make remarks about the machine this gentleman now does so from a safe distance, or else from the starboard side. The cockpit of the Supermarine bears the obvious traces of having been designed by practical boat builders. This is indicated by a dozen and one little things too numerous to mention, but one instance may serve to illustrate the point: A short tiller is provided in front of the pilot, by means of which he can steer the boat while standing up in his cockpit. This allows him to obtain a good view of the sea all around, and is a very great assistance when navigating on the sea in crowded waters or when picking up moorings. Only a little thing, it is true, but showing the practical considerations which have been studied by the designers.
   The land undercarriage consists of two wheels mounted on short, bent axles, and supported by a structure of steel tubes. For raising them out of the water, the wheels and their mounting structures are swung outwards and upwards by a series of cables and pulleys giving a great amount of purchase. In order to prevent the pilot from accidentally over-winding, stop cables incorporating short lengths of rubber cord are fitted. When the wheels are down, the inner end of the axle and the lower apex of the inner wheel Vee is locked by a hook as shown in one of our sketches. This locking is very positive, and at the same time the wheel-supporting structure is rigidly attached to the rest of the machine, the loads from all the heavy items such as engine, hull, etc., being transmitted direct to the land undercarriage Vees. Although somewhat heavy, the appearance of the land gear inspires confidence, and owing to the distribution of the load, one does not anticipate that the hull will be strained, even after repeated landings. This is one of the difficulties of the amphibian machine, that unless very carefully designed a few rough alightings on land are almost sure to result in a strained and probably leaking hull.
   The combined water rudder and tail skid is mounted some distance aft of the rear step. The rudder has a folding portion which can move into a slot in the main portion, and is provided at the heel with a steel shoe which takes the wear. This steel shoe is simply bolted on, and can be renewed in a few minutes should excessive wear render a renewal necessary. The method of springing is ingenious. From the front of the rudder two cables pass aft to the stern of the hull, to which they are anchored via rubber cords. In this manner the rudder itself is left free of protuberances which might interfere with the flow of the water around it, and at the same time the shocks are turned into an end load on the hull, which is well able to withstand them in this direction.
   The tail plane is of the monoplane negatively cambered type, and the rudder is balanced by a forward projection working in a cut-out portion of the fixed vertical fin.