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European Seaplanes and Flying Boats

The idea of using the water for take-off and landing is very old indeed, having been suggested by Leonardo da Vinci. In 1869, Emmanuel Farcot, a Frenchman, was granted a patent for various improvements to ships, consisting of a series of inclined planes along the sides of the ships with variable angles. In 1878, John Stanfield and Josiah Clark of London proposed a new method of raising vessels or other moving bodies out of the water in order as to increase their speed. In 1895, Clement Ader, one of the most controversial figures in early French aviation, constructed a model craft with adjustable foils, two foils in the front, and adjustable from the inside to any desirable angle, a single adjustable foil in the rear, forming the tail.

In the year 1912, the big monoplane Guidoni was built and flown in Italy. It was 50 feet long and had a wing span of 66 feet. It was propelled by two 200-HP Gnome engines and was able to lift 9400 pounds of gross weight. It made history by dropping the first torpedo, two years after it was built. In the following year, in Britain, the Sopwith Bat Boat, an amphibious aircraft, was produced, whose hull resembled a conventional boat hull in configuration, with a sharp bow, in contrast to the Curtiss hulls of this date.

By 26 October 1913, Winston Churchill formulated the types of aeroplanes he considered to be most suitable for the Royal Navy, recommending an "overseas" fighting seaplane to operate from a ship as base. Indeed, the first cite in the OED for the word "seaplane" one is by Winston Churchill, the first lord of the Admiralty at the time: We have decided to call the naval hydroplane a seaplane, and the ordinary aeroplane or school machine, which we use in the Navy, simply a plane.

The value of Churchill's foresight was to be emphasized by 1914 when the peace between Great Britain and Germany was broken. After the outbreak of war, the Royal Naval Air Service could muster 52 seaplanes and 39 aeroplanes, flown or maintained by a hundred officers and some seven hundred non-commissioned officers and men. The British 1914 Pemberton-Billing PBl, otherwise known as the Supermarine PBl, was aesthetically very appealing. It was powered by a 50-HP Gnome rotary engine that was able to propel it through the air at 40-mph (80.5 Km/h).

In 1915, the first full year of the war, several improvements were made on the existing seaplanes, mainly concerning the use of torpedoes to be launched from the air. On 12 August, Flight Commander C. H. K. Edmonds, flying a Short 184 from the Gulf of Xeros, sighted a large Turkish merchant ship off Injeh Burnu and dived to a height of some 15 feet above the water, launching his torpedo at a range of 300 yards. The vessel was hit amidship, and Edmonds thus became the first man in history to torpedo an enemy ship from the air.

By 1916, the first aircraft type to use wing-folding in combat operation, the Short 184s, were embarked in seaplane carriers and participated with distinction in the Battle of Jutland on May 31. In Italy, in keeping with previous products and practice, the following year the Caproni company produced a giant triplane hydroplane, the Caproni 43, and a twinengine biplane hydro Model 47.

By 1917, in England, the First Lord of the Admiralty, Sir Winston Churchill, defined in a directive the correct designation for the flying water-craft and the term seaplane was to apply to float-equipped aircraft. The term flying boat was to apply to aircraft whose fuselage was in fact a boat-like hull. Simultaneously, there began a change in the structure of these water-craft.

In the 1920 and 1921 Schneider races, seaplanes were barely in the running as flying boats dominated the races and the US Services had entered air racing as a means of developing improved technology for application to service aircraft. The Schneider Cup, properly recorded as La Coupe D'Aviation Maritime Jacques Schneider, was to become the major incentive for the development of float-type hydroplanes. The Caproni Ca 60, built between 1919 and 1921, a triple-hydro-triplane flying boat with eight 400-HP Liberty engines developed a total of 3,000-HP and was designed to carry 100 passengers. However, in the second test flight on 4 March it had a bad landing with major damage forcing the cancellation of the project.

The Fairey Type III emerged to become one of the most successful designs of this period and a special version, the FIII Transatlantic, was fitted out to become the first to attempt the crossing of the South Atlantic in 1922. Captain Saccadura Cabral and Captain Gago Coutinho of the Portuguese navy succeeded in flying from Lisbon, leaving on 30 March, 1922 to St. Johns Rocks off the South American coast on the Equator. Unfortunately, a bad landing put an end to the aircraft.

In this same year the Dornier J or Wal (Whale) made its first appearance. This was to be one of the workhorse designs of the 1920s. Its lines were teutonic and its performance, with a variety of engines, was always to be admired. Its descendant, the Dornier Do 18, saw service as recently as World War II. Designed in the period of the prohibition of aircraft construction by Germany, under the terms of the Armistice, the Wal was produced under licence in Italy, reaching at least 300 units, and was used by the military services of Italy, Spain and the Netherlands, while commercial use of this type was made by Lufthansa and Aero Lloyd, Aero Expresso in Italy, Varig in Brazil, SCATADA in Columbia and Nikon Koku in Japan.

Early in 1926, Major Ramon Franco, a brother of General Francisco Franco, became a national hero when made the first east-west crossing of the South Atlantic to Buenos Aires, Argentina, from Palos de Megues, Spain, in a Dornier Wal. In August 1930, Wolfgang Von Gronau successfully crossed the North Atlantic from Germany via Iceland, Greenland and New York on to Chicago, in a Dornier Wal. The Dornier Do X, which suffered from a number of mechanical problems and minor disasters during its service, has the distinction of being the first aircraft to carry 169 passengers as far back as 1929. In 1930, the Dornier Do X went on a world trip which took it to New York via South America.

The distinctive German designs of the mid-20s period bore the Junkers name who continued to produce a line of all-metal aircraft whose seaplane version is the Ju 52W, the standard work-horse of the Luftwaffe in World War II. In its early development, the Ju 52 was a single-engine aricraft, powered by an engine of 700-1000-HP. Two variations were powered by the Junkers 188 or BMW VII, both liquid-cooled engines, or the 700-HP Armstrong Siddeley Leopard aircooled engine. The better known World War II version was, of course, the trimotor, the ubiquitous Ju 52/3m, which was developed in 1932.

In France, in 1935, Farman produced the F271, a monster twin-engine biplane torpedo/reconnaissance seaplane, featuring very square lines of fuselage, wing and empennage. In the same year the Latecoere 521 flying boat made its first flight. Powered by six 860 HP Hispano-Suiza twelve-cylinder V engines, it was a very large plane, seating 70 passengers on trans-Mediterranean and 30 on transatlantic flights. The French Navy flew three such planes, another three were used commercially. The maximum endurance was an impressive 33 hours. In 1938 the Latecoere 631 was produced. It was capable of carrying 60 passengers over 3728 miles. After the war six such planes were used by Air France on the transatlantic service.

The Empire boats were built by Short Bros, from the design of Sir Arthur Gouge, the designer of the Princess. They were in use for some time by Imperial Airways before that company was dissolved into B.O.A.C. These boats came into service in 1937 and were taken over when B.O.A.C. was formed in 1940. The first of the Empire boats was delivered in 1936 and subsequent boats were delivered at the rate of two a month. The whole fleet of twenty-eight boats was in use in 1937. From these boats a larger type was developed, and all gave a very fine account of themselves. They were the main carriers in the British Empire air transport system. The maximum number of flying boats at any one time in service with Imperial Airways, and later in the B.O.A.C., was some thirty.

In 1936, the Short Sunderlands were being built. Their design was based on the C class Empire flying boats which formed the backbone of Britain's Imperial Airways. As war approached in Europe, several flying boat designs emerged, probably in anticipation of a military conflict. The first of these was the Blohm und Voss BV 138 B-1, the "Flying Shoe" as it was known, whose geometry reverted back to the short hull/tail boom configuration of the Curtiss NC boats of World war I.

An interesting design was the Short-Mayo Composite, one single aircraft, christened Mayo, had a large planing bottom with a wide flare at the bow, to lift the increased weight and area of both the wing and the tail surfaces. In addition, the outboard engines were more widely spaced to accommodate the Mercury, a twin-float, four engined aircraft which was mounted on a frame above the center of the wing of the Maia. Operationally, the Maia served to lift the Mercury to cruising altitude, at which time they would separate after the Mercury showed a positive lift capability, allowing the Mercury to proceed to its destination fully laden.

In Germany, the Blohm and Voss BV 138A-1 was first flown in April of 1940. In this version some structural weaknesses became apparent necessitating a return to the drawing board. The resulting BV 138 B-1, with improved armament, became the configuration to which all preceding production aircraft were modified. After all this redesign and modification, the aircraft were grounded during the winter of 1940-41 due to problems with the propellers and the Junkers Jumo 205C Diesel engines. For those not familiar with aircraft powerplants, it is worth relating that these engines were technically unique. They had six cylinders and 12 pistons. Two crankshafts at the upper and lower ends of the engine were paired to a common propeller shaft and two pistons converged at the center of the cylinder. The Jumo 205s were the most successful and the most widely produced of the very few diesel aircraft engine designs.

In 1940 a new approach to flying boat design was launched by Blackburn Aircraft Ltd. combining features of flying boats and single-float hydroplanes on a large scale. The B.20 was a design in which the propellers were kept clear of the water while mounted on engines that were installed in the leading edge of the wing, providing a better aerodynamic combination. To accomplish this, the lower portion of the hull was constructed of a self-contained central float or hull. In flight, this float was tucked up against the fuselage producing a neat, low air resistance airframe. During take-off, landing and while at rest, this large central float was lowered simultaneously with the retractable wing-tip floats. This unusual design feature also placed the wing at its most advantageous angle of incidence for take-off and landings.

With World War II underway a number of aircraft in development, which were anticipating such an eventuality, began to emerge. Among these was the gigantic Blohm und Voss BV 222 Wiking which made its first flight on 07 September 1940, and was used as Luftwaffe transports instead of service with Lufthansa, for whom the design was begun.

Anticipating the end of the war, Short Brothers set out to produce a completely civilian transport aircraft, the S.25 Sandringham, which appeared in 1945. All armament positions were neatly faired, producing a fine looking aircraft which would be ready at the end of the war. At the same time developments were underway on the Short Seaford, which resulted in the Short S.45 Sonolent, a more powerful and much heavier replacement of the Sunderland, which would gross at 75,000 lb (34 000 Kg), instead of the 65,000 lb (29 500 Kg) of the original war model. This seaplane proved to be very popular with passengers flying the Empire routes to South Africa until November 1950. The first jet-powered flying boat, the Saunders-Roe SR/Al, flew on 15 July 1947.

The three prototypes of the giant Saro SR.45 Princess flying-boat, ordered in May 1946, were intended for non-stop transatlantic service by BOAC, but early post-war appreciation that landplanes could operate on this route just as safely and more economically killed all interest. Instead, the boats were to be completed as long-range military transports for the RAF, but the lack of a suitable powerplant brought even these optimistic hopes to an end.

Apart from the Saunders-Roe Princess, by 1949 there were no British commercial flying boats in process of design. The Short Solent was in service on B.O.A.C.'s African routes. With an all-up weight of 78,000 lb. it had four Bristol Hercules engines. The latest version had accommodation for up to 40 day passengers; payload 10,000 lb. over a still air range of 2,300 miles; cruising speed 200 m.p.h. And the Short Sandringham, a civil conversion of the R.A.F. Sunderland, had four Pratt and Whitney engines. with an all-up weight 60,000 lb. it could carry 30 passengers for 2,100 still air miles at a cruising speed of 170 m.p.h.

The value of the flying boat for military operations was proved during the war. The Sunderlands were very effectively used for anti-submarine operations. They were also used for the evacuation of civilians in conditions in which land planes could not have been used. In the Far Eastern theatre of warfare in the Second World War flying boats were of considerable value as they could be operated where there were no aerodromes or where the aerodrame was subjected to heavy enemy bombardment.

The Korean war emphasised the importance of flying boats. The main contribution of the R.A.F., apart from transport work, has been carried out by squadrons of Sunderlands. Very little is known of the valuable work done by these units, but they did a tremendous job in the Korean war in transporting personnel and equipment to places where landplanes could not be navigated. In fact, no landplane of comparable size could have carried out the same work at all, due to the lack of airfields.

But by that time neither the Royal Air Force nor civil aviation, nor the Royal Navy, which might be suspected of having a predilection in favour of flying-boats, were developing flying-boats. There is one obvious difficulty in having flying-boats as bombers. We cannot drop the bombs through the hull, or, if we did, it would be a very complicated operation, and that would seem to rule them out as bombers, at any rate, for the moment. Superficially fighters seem more attractive, but the practical difficulties of operating fighters off the sea were impossible to overcome.

From the military point of view, it looked as if the development of transport would be in the tail or nose loading aircraft. This is not an easy thing to carry out on water, so the present state of development required aerodromes on land, and when we aircraft carried tanks and lorries they had to be big aerodromes on land.

The Princess (passenger transport), SARO SR-A1 (military jet), Convair SeaDart (supersonic flight) and Martin P6M SeaMaster (anti-submarine warfare/mine warfare)demonstrated that jet-engine and turbo-prop aircraft seaplanes could be effective in a variety of roles. But Europe abandoned the flying boat after the failure of the Princess.



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