Flight, July 1920

The Olympia Aero Show 1920

The machines

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

   The "Sea-King" is a small single-seater fighting scout, fitted with a 160 h.p. Beardmore engine. In general design this machine is similar to the "Baby," and the Schneider Cup models of last year. The hull is practically of circular cross-section, with a V-bottom from stem to step, which is situated under the main planes. Between the first step and the stern a second step "grows" out of the hull. The pilot is seated well forward. Upper and lower planes are each in three sections, and the interplane struts, of which there are four pairs, slope outwards. The two innermost pairs are located at the centre sections, the lower one of which is of considerably smaller span than the upper; this lower section is supported on the hull by two pairs of struts, forming continuations of the centre-section interplane struts. The engine is mounted, in a streamline housing, midway between the planes on the lower centre section by six struts. The tail plane is of the monoplane inverted camber type, mounted on the top of a vertical fin above the stern of the hull. Wing-tip floats are mounted below the outer interplane struts. The speed range of the "Sea-King" is 51 to 96 knots (58-7 to 1105 m.p.h.).


A Flying Boat Exhibit

   The "Sea King" is very similar in general design to the Channel type, but is a small fast single-seater, capable of a speed of over 100 m.p.h. with a 160 h.p. Beardmore engine. The chief difference between the two boats, apart from size, is that the "Sea King" has a monoplane tail, and the rudder is extended down to the heel of the hull, forming a water rudder. This part of the rudder is covered with three-ply wood. As the machine is of such small overall dimensions, its wings are not made to fold as are those of the Channel type.

Flight, April 1922

THE SUPERMARINE SINGLE-SEATER FIGHTING SCOUT "SEA KING," MARK II.
An Interesting Amphibian Flying Boat, with Hispano Engine

   IT is, unfortunately, an indisputable fact that, for some reason or other which is not at all clear, the seaplane type of machine has not received, in this country, the attention which it would appear to merit. In view of the fact that the different parts of our Empire are separated by leagues of ocean, it might have been thought that this type of machine would be the first to come to mind in attempting to visualise the advantages of air travel and air defence. Yet the fact remains, that the seaplane has had very little encouragement, both from the Government and from commercial users of aircraft. It is, therefore, all the more creditable that a few of our firms have, in spite of the severe handicaps imposed by a relative lack of incentive, "carried-on" with seaplane design and construction, in the certain knowledge that sooner or later this type is bound to gain the recognition which it deserves. One might fill columns in enumerating the various uses to which seaplanes can be put, both commercial and service, and yet not exhaust the subject, but this is not the place, nor have we the space here, to do so.
   If the seaplane pure and simple is of the very greatest potential value, its latest development, the amphibian, is still more so, owing to its capacity for taking off from, or alighting on, land and water with equal facility. In the case of a commercial machine, this means that a service can be run between two cities which are situated on the coast, or which have running through them rivers suitable for use as "aerodromes," but which are otherwise separated partly by the sea and partly by land. The London-Paris service is a case in point. It has already been demonstrated that it is possible to leave the Thames at Westminster, and to alight on the Seine in the centre of Paris, or vice versa, making the complete journey in about two hours, and saving the tedious run to and from the aerodromes to the business section of the respective cities.
   For service purposes, the amphibian scores also, as in the course of a war, it is often necessary for seaplanes to go inland for considerable distances, and for land machines to fly far out to sea. A machine which can, for instance, fly off the gun turrets of a battleship, scout over the sea and, if desired, far inland, returning either to the ship or alighting on the sea at any desired point, is obviously at a very great advantage as compared with a pure seaplane or a land machine.
   Among the firms who have, from the early days of flying, been believers in, and producers of, seaplanes are the Supermarine Aviation Works, Ltd., of Southampton, who have made a speciality of flying boats and amphibian flying boats. In designing a seaplane, it is possible to attack the problem from two entirely different points of view. One can produce an aeroplane which will get off from and alight on the sea, but which retains, in many respects, the characteristics of an aeroplane. Or one can start with a boat which is seaworthy in the first instance, and then proceed to make this boat fly. The Supermarine Works have always followed the latter procedure, and the hulls of their machines are boat-built structures on to which have been added the necessary wings, etc. Now it will be obvious that, in the initial stages of developments, the one type will probably have the better performance, but at the cost of seaworthiness, whereas the other will be substantial, seaworthy and, probably, somewhat heavy and consequently have an inferior performance. Thus at first, there will be a marked difference in the qualities of the two types, and the choice will depend upon the particular purpose for which a machine is wanted. There is, undoubtedly, room for both types. As time goes on, however, improvements will be made to both types, tending to improve the seaworthiness of the one and the performance of the other, and the time comes when the two types are practically on an equal footing. This would appear to be the logical development, and it is interesting to note that history is already beginning to prove that this is actually what is happening.
   In the case of the Supermarine amphibian flying boat "Sea King," which forms the subject of this article, and photographs of which were published in our issue of March 30, we have a craft which represents the development of a seaworthy hull, fitted with wings and an engine which give it a performance equal, or nearly so, to that of a land machine of the same power. This result has been attained by years of constant application to the problems involved, and always with this idea in view that a start must be made with the boat hull, the performance being a second consideration, although it should be as good as it is possible to make it. Viewed in this light, one is better able to appreciate what it is the "Sea King" represents.
   Designed as a single-seater fighting scout, for use with naval units or squadrons, the "Sea King," Mark II, possesses an unusual degree of manoeuvrability, being capable of all the stunts which one usually associates with land machines only. The machine can be, and has been repeatedly, looped, rolled, spun, and stunted in every conceivable way. It is thus an ideal machine for fighting, while combined with these qualities it possesses a great amount of inherent stability, a combination which is extremely difficult of attainment, more especially in a machine of the flying boat type. We are informed, by a pilot who has flown the machine extensively, that the "Sea King" is entirely free from that difference in trim, according to whether the engine is "on" or "off," which was at one time thought inseparable from machines of the flying boat type. Once in the air, the machine can be flown "hands off," with the greatest ease, its longitudinal trim being such as to require no force on the control stick.
   On the water, the "Sea King" handles remarkably well, showing no tendency to porpoising, and being very seaworthy for a machine of such small dimensions. We understand that she has been put through all sorts of manoeuvres on the sea, in a wind of 30 m.p.h., and has proved capable of riding out a fairly heavy sea. In getting off and alighting, machine is very dry and comfortable for the pilot, and the view from the cockpit is particularly unobstructed, another feature, which is of great importance in a machine intended for fighting.
   As already mentioned, the performance is extremely good, the top speed being 125 m.p.h. at sea level, and the ceiling 20,500 ft . The climb to 10,000 ft. only occupies 12 minutes, and the alighting speed is in the neighbourhood of 50 m.p.h. Sufficient fuel is carried for about two hours at top speed, and in this connection one cannot help wondering what would have been the result of the Jutland battle had our fleet been provided with a couple of squadrons of such machines.
   The general arrangement of the "Sea King" is well shown in the accompanying scale drawings and photographs, while some of the constructional details form the subject of our sketches. The boat hull is of the typical Supermarine type, boat-built and through-fastened, with copper or brass fixings throughout. The mahogany single-skin planking is riveted to the rock elm timbers and frames, and covered externally with fabric suitably treated with pigmented dope. The two steps are formed by entirely separate units, attached to the main hull, and can, therefore, be renewed in case of extensive damage. Should the hull itself, which is of approximately circular cross-section, be damaged, it is quite possible to repair it by scarphing in new planks where required.
   In order to reduce air resistance a metal fairing, provided with large holes for the easy filling and emptying of water, is fitted behind the main step. This fairing can be seen in several of our illustrations. The rear step is provided with a tube running through the hull, and admitting air to the step when the machine is taxying on the water, thus preventing the rear portion of the hull from being sucked under.
   The pilot's cockpit is in the nose of the hull, from which position the pilot has an excellent view, an important consideration not only for fighting, but also for landing on the deck of a ship. His controls are mounted on the triangular tubular frame so well known in all Supermarine boats, and whose function it is to allow the circular hull to flex and "give" in a seaway, without interfering with the smooth working of the controls. When the machine is used for fighting, a Lewis gun will be mounted in the nose of the hull, where it is very accessible by the pilot. A very complete set of instruments is provided, and all necessary mooring and towing tackle is conveniently arranged in and around the cockpit. For starting the engine, a starting handle is provided, and in order the better to reach this, the pilot's back rest is so arranged as to fold down and form a step, as shown in one of our sketches. In the fairing behind the pilot's head are housed, on one side, the starting magneto, and on the other the filler cap of the petrol tank, which latter is carried inside the hull, approximately on the e.g. of the machine.
   The undercarriage consists of two Palmer wheels, mounted on bent axles, hinged to the sides of the hull, and strutted to the hull and to the lower plane. A worm runs across the top of the hull and engages with metal claws running along a steel strip guide bolted to the front spar of the lower plane. The accompanying sketches will indicate the arrangement, which is very neat and simple, and yet sufficiently robust to withstand taxying, even on rough ground. When the worm is rotated, the claws are pulled inwards, bringing with them the stout tubes carrying the rubber shock absorbers, and raising the wheels upwards and outwards until clear of the water. It will be noticed that the strutting of the undercarriage is so arranged that landing shocks are not transmitted through the hull. At the stern is a small combined tail skid and water rudder, working in conjunction with the air rudder. We are told by the pilot who has flown the machine on all its tests that on the ground it handles remarkably well, and is as easy to steer as a motor-car.
   The engine, a 300 h.p. Hispano-Suiza, is mounted on a structure of steel tubes, which is entirely independent of the wing bracing, so that the engine can be removed without interfering with the wings, or, conversely, the wings may be taken off without interfering with the engine. It is neatly enclosed in an aluminium nacelle, and drives a small-diameter four-bladed pusher airscrew. The radiator, which is provided with shutters operated from the cockpit, is so mounted as to be unaffected by engine vibration, even in the case of a badly missing engine. It might also be mentioned that the complete wing structure, and, if desired, the engine unit, can be removed after undoing eight bolts.
   As already mentioned, the petrol tank is mounted in the hull, and the fuel is fed to the carburettor by pressure from a pump. This is the usual arrangement on seaplanes, and for some reason has not been found to give as much trouble as does a similar petrol system on a land machine. One would prefer gravity feed, but it is difficult to see how this could be attained, and practical experience appears to indicate that it is not really necessary on a machine of this type.
   The wings are of usual design, with one pair of inter-plane struts on each side. Bracing is by stream-line wires. Both upper and lower planes are provided with ailerons, controlled by cables in the usual way. Attention has already been called to the method of mounting the engine independently of the wings, and apart from this fact the wings do not possess any unusual features. The fittings are very robust, and treated to withstand the action of salt water. Also they are very accessible and easily renewed. The machine is steadied laterally, when on the water, by wing tip floats of the usual Supermarine type.
   Figures relating to the performance have already been given. The following are the main characteristics of the Supermarine "Sea King" :-
   Length of hull, 24 ft. g ins.; wing span, 32 ft.; chord 5 ft. 9 ins.; gap (maximum), 6 ft.; area of main planes, 352 sq. ft.; weight of machine (empty), 2,115 lbs. The useful load is composed as follows :- Pilot, 180 lbs.; Lewis gun and six double trays, 100 lbs.; instruments, 20 lbs.; equipment, 30 lbs.; petrol (50 gallons), 365 lbs.; oil (4 gallons), 40 lbs.; total useful load, 735 lbs. Weight of machine fully loaded, 2,850 lbs. Wing loading, 8.1 lbs, /sq. ft. Power loading, 8.4 lbs./h.p.