The Goose was Grumman's first monoplane to fly, its first twin-engined aircraft, and its first aircraft to enter commercial airline service. During World War II, the Goose became an effective transport for the US military (including the United States Coast Guard), as well as serving with many other air forces. During hostilities, the Goose took on an increasing number of combat and training roles.

In 1936, a group of wealthy residents of Long Island, including E. Roland Harriman, approached Grumman and commissioned an aircraft that they could use to fly to New York City. In response, the Grumman Model G-21 was designed as a light amphibious transport. Grumman produced a high-wing monoplane of almost all-metal construction—the trailing half of the main wing and all of the flight control surfaces except for the flaps were fabric-covered. It was powered by two 450 horsepower (340 kW) Pratt & Whitney R-985 Wasp Junior nine-cylinder, air-cooled, radial engines mounted on the leading edges of the wings. The deep fuselage served also as a hull and was equipped with hand-cranked retractable landing gear. First flight of the prototype took place on May 29, 1937.

The fuselage also proved versatile, as it provided generous interior space that allowed fitting for either a transport or luxury airliner role. Having an amphibious configuration also allowed the G-21 to go just about anywhere, and plans were made to market it as an amphibian airliner. More than 345 have been built.

A number of modifications were made for the Goose, but the most numerous are those by McKinnon Enterprises of Sandy, Oregon, which holds 21 supplemental type certificates (STCs) for modifying G-21-series aircraft and which also manufactured four different conversions that were recertified under a separate FAA type certificate (TC no. 4A24) as brand-new "McKinnon" airplanes.

For more details on the operational history, modifications and numerous variants, click here.

The Grumman G-73 Mallard is a medium, twin-engined amphibious aircraft. Many have been modified by replacing the original Pratt & Whitney Wasp H radial engines with modern turboprop engines. Manufactured from 1946 to 1951, production ended when Grumman's larger SA-16 Albatross was introduced.

Building on the success of the Goose and Widgeon, Grumman Aircraft developed larger G-73 Mallard for commercial use. Retaining many of the features of the smaller aircraft, such as twin radial engines, high wings with underwing floats, retractable landing gear and a large straight tail, the company built 59 Mallards between 1946 and 1951. Unlike the smaller aircraft, the Mallard featured tricycle gear, stressed skin, a two-step hull and wingtip fuel tanks.

The Mallard prototype first flew on 30 April 1946, with the first production aircraft entering service in September of that year. While the Mallard was designed for regional airline operations with two pilots and ten passengers, especially aimed at harbor-based, city-to-city hops on the eastern seaboard, postwar surplus aircraft sales and the availability of smaller airports limited market potential. A number of smaller air carriers did use the Mallard in its intended role, notably Tahiti-Hawaii Airlines and Pacific Western Airlines (Canada). However, most of the 59 Mallards delivered were for corporate use. A prominent user in the United States was Roy Fruehauf and the Fruehauf Trailer Corporation. Fruehauf owned and operated a fishing camp, Killarney Lodge at Georgian Bay, Canada, and ferried customers there from Detroit. Another Detroiter, William Packer of General Motors, also owned a Mallard, which he often flew to Killarney.[1] another Mallard was purchased in the early 1950s by the Aga Khan.

The Toronto Globe & Mail newspaper owned one for use as a "flying newsroom".

The Royal Egyptian Air Force used a Mallard as part of their Royal Flight; it was reportedly King Farouk's favourite aircraft.

The Mallard received a new lease on life in the 1970s when a number of airframes were refitted by Frakes Aviation with Pratt & Whitney Canada PT6A turbines and upgraded for 17 passengers, to become "Turbo Mallards." Today, through attrition, only 32 Mallards remain registered in the United States. Many of the rest are in use around the globe.

A similar program has been undertaken by Paspaley Pearling in combination with Aeronautical Engineers Australia to fit new engines and modernize its Mallard fleet, which is used to support its pearling operations in Northern Australia. The fleet has been extensively rebuilt and also refitted with PT6A turbines, and is currently undergoing a life extension program.

TAA flew a Grumman Mallard on the Great Barrier Reef.

Originally designated as the SA-16 for the USAF and the JR2F-1 and UF-1 for the USN and USCG, it was redesignated as the HU-16 in 1962.

An improvement of the design of the Grumman Mallard, the Albatross was developed to land in open ocean situations to accomplish rescues. Its deep-V hull cross-section and keel length enable it to land in the open sea. The Albatross was designed for optimal 4-foot (1.2 m) seas, and could land in more severe conditions, but required JATO (jet-assisted take off, or simply booster rockets) for takeoff in 8–10-foot (2.4–3.0 m) seas or greater.

The Royal Canadian Air Force operated Grumman Albatrosses with the designation "CSR-110".

In 1970, Conroy Aircraft marketed a remanufactured HU-16A with Rolls-Royce Dart turboprop engines as the Conroy Turbo Albatross, but only one prototype was ever built.

For details of operational history and variants, click here.

Specifications below are for the UH-16B variant.

Albatross

One prototype and six production aircraft have been built.

Research to build a seaplane capable of replacing Beriev Be-6s in service was initiated by the PLANAF (People's Liberation Army Naval Air Force) in 1968, with designers reassigned from "Objective 3/17", a supersonic canard-wing fighter project. The first prototype flew in 1976; further units were delivered between 1986 and 1990.

Variants

SH-5B Firefighter
One SH-5 was rebuilt for firefighting duties.
However, by Chinese source, there were total of 7 SH-5 were produced: 3 SH-5X Prototype, 3 Maritime patrol aircraft, and 1 SH-B Firefighter.

The Heinkel He 115 was a three-seat World War II Luftwaffe seaplane. It was used as a torpedo bomber and performed general seaplane duties, such as reconnaissance and minelaying. The aircraft was powered by two 960 PS (947 hp, 720 kW) BMW 132K nine-cylinder air-cooled radial engines. Some later models could seat four, had different engines or used different weapon arrangements.

In 1935, the German Reich Air Ministry (RLM, Reichsluftfahrtministerium) produced a requirement for a twin engined general purpose floatplane, suitable for patrol and for anti-shipping strikes with bombs and torpedoes. Proposals were received from Heinkel Flugzeugwerke and from the Blohm & Voss aircraft subsidiary Hamburger Flugzeugbau. On 1 November 1935, orders were placed with Heinkel and Hamburger Flugzeugbau for three prototypes each of their prospective designs, the He 115 and the Ha 140.

The first prototype Heinkel flew in August 1937, testing was successful and the He 115 design was selected over the Ha 140 early in 1938, leading to an order for another prototype and 10 pre-production aircraft. The first prototype was used to set a series of international records for floatplanes over 1,000 km (620 mi) and 2,000 km (1,200 mi) closed circuits at a speed of 328 km/h (204 mph). A total of 138 units were produced.

Armament initially consisted of two 7.92 mm (.312 in) MG 15 machine guns, one in the nose and one in the dorsal position. Later He 115s were fitted with a fixed forward-firing 15 mm or 20 mm MG 151 cannon and two rearward-firing 7.92 mm (.312 in) MG 17 machine guns in the engine nacelles. He 115 variants carried LTF 5 or LTF 6b torpedoes and SD 500 500 kg (1,100 lb) or SC 250 250 kg (550 lb) bombs. Some also carried LMB III or LMA mines.

For details of operational history in five airforces, and 18 variants, click here.

Intended as a transatlantic flight transport for use during World War II, it was not completed in time to be used in the war. The aircraft made only one brief flight on November 2, 1947, and the project never advanced beyond the single example produced.

Built from wood because of wartime restrictions on the use of aluminum and concerns about weight, the aircraft was nicknamed the Spruce Goose by critics, although it was made almost entirely of birch. The Hercules is the largest flying boat ever built, and it had the largest wingspan of any aircraft that had ever flown until the Scaled Composites Stratolaunch first flew on April 13, 2019. The aircraft remains in good condition. After having been displayed to the public in Long Beach, California, from 1980 to 1991, it is now on display at the Evergreen Aviation & Space Museum in McMinnville, Oregon, United States.

In 1942, the U.S. War Department needed to transport war materiel and personnel to Britain. Allied shipping in the Atlantic Ocean was suffering heavy losses to German U-boats, so a requirement was issued for an aircraft that could cross the Atlantic with a large payload. Wartime priorities meant the aircraft could not be made of strategic materials (e.g., aluminum).

The aircraft was the brainchild of Henry J. Kaiser, a leading Liberty ship builder and manufacturer. Kaiser teamed with aircraft designer Howard Hughes to create what would become the largest aircraft yet built. It was designed to carry 150,000 pounds (68,000 kg), 750 fully equipped troops or two 30-ton M4 Sherman tanks. The original designation "HK-1" reflected the Hughes and Kaiser collaboration.

The HK-1 aircraft contract was issued in 1942 as a development contract and called for three aircraft to be constructed in two years for the war effort. Seven configurations were considered, including twin-hull and single-hull designs with combinations of four, six, and eight wing-mounted engines. The final design chosen was a behemoth, eclipsing any large transport then built. It would be built mostly of wood to conserve metal (its elevators and rudder were fabric-covered), and was nicknamed the Spruce Goose (a name Hughes disliked) or the Flying Lumberyard.

For more information on this unique aircraft, click here.

The Latécoère 521 was a French six-engined double deck flying boat designed and manufactured by Pierre-Georges Latécoère. At the time of its completion, it held the distinction of being the largest aircraft to be built in France as well as one of the first large passenger aircraft capable of flying trans-Atlantic routes.

First flown on 10 January 1935, the Laté 521 achieved several world records relating to payload and endurance. It was introduced to passenger service by national operator Air France, who was able to launch several previously-unattainable long distance passenger routes. As a civilian aircraft, the Laté 521 was outfitted as a luxurious airliner, providing a high level of comfort for up to 72 passengers. Shortly after the outbreak of the Second World War, the Laté 521 were taken over by the French Navy, who typically operated the type as a long distance maritime patrol aircraft. None survived the conflict due to intentional sabotage by the retreating German forces. The Laté 521 was the basis of the single Laté 522 "Ville de Saint Pierre" civil airliner, and the three Laté 523 navalized variants.

During the early 1930s, French aircraft manufacturer Groupe Latécoère set about designing a new large flying boat, which was intended to perform long range flights, carrying both passengers and air mail. Around this era, France, Germany, the United Kingdom, the Soviet Union, and the United States, were endeavouring to launch ever-larger aircraft that would exceed the scale and payload capabilities of preceding aircraft and ultimately displace the ocean liner as the principal means of passenger travel. The development of such aircraft was a matter of national prestige and Latécoère quickly found support for their endeavour.

The design, designated the Laté 520, was a large sesquiplane, comprising a central double-decked hull and a pair of stub wings, somewhat resembling the smaller Latécoère 300. Weighing roughly 37 tonnes when loaded and 17 tonnes empty, it was the largest aircraft to be manufactured by French industry at that time. It offered a maximum range of 2,800 miles between refuelling stops. The four inboard water cooled engines, which were mounted as tandem push-pull pairs and intended to be capable of generating up to 1,000 hp, enabled the aircraft to attain a maximum design speed of 160 mph. It was named Lieutenant de vaisseau Paris, after a highly accomplished French naval officer and record-breaking pilot of the era.

In its civilian service configuration, the Laté 521 would transport a maximum of 72 passengers in luxurious conditions. However, typical trans-Atlantic services would normally only carry around 26 passengers, all of which would be upon the lower deck. Larger passenger complements could be carried on the shorter trans-Mediterranean routes for which the design had originally been envisioned to serve. On the lower level, there was a salon occupied by 20 armchairs and tables, along with six deluxe double cabins, each with its own bathroom, and seating for a further 22 passengers, a kitchen, a bar, a lavatory, and a baggage hold. Separate compartments for the wireless operator and navigator are also present on the lower deck. The more compact and narrower upper level of the hull featured seating for 18 passengers, along with a storage compartment, a second kitchen and bar, and another lavatory.

For more details of development, design, operational history and variants, click here.

The Latécoère 631 was a civil transatlantic flying boat built by Latécoère, the largest ever built up to its time. The type was not a success, being unreliable and uneconomic to operate. Five of the eleven aircraft built were written off in accidents and one was lost during World War II.

The Latécoère 631 was the result of a specification issued in 1936 by the Direction Générale de l'Aviation Civile for a 40-passenger airliner with a range of 4,000 kilometres (2,500 mi). The aircraft was ordered in 1938. It was intended that it would be powered by six Gnome et Rhône P.18 engines of 1,650 horsepower (1,230 kW) each. A competitor for this specification was the SNCASE SE.200 Amphitrite.

Construction of the aircraft was stopped due to the outbreak of World War II and was not resumed until after the signing of the Franco-German Armistice. The prototype, registered F-BAHG, first flew on 11 November 1942. It was subsequently confiscated by the Germans, and passed to the Luftwaffe, who allocated the codes 61+11. The aircraft was flown to Lake Constance, where it was destroyed in an attack by two Royal Air Force de Havilland Mosquito aircraft on 17 April 1944. SNCASE SE.200 Amphitrite 20+01 was destroyed in the same attack.

For details of the history and accidents of the 631, click here.

The Latham HB.5 was a French biplane flying boat with four engines in push-pull configuration pairs. Ten were used by the French Navy.

Despite its military designation as an HB.5 or five-crew flying boat bomber, this four-engine aircraft was designed as a civil version of the Latham Trimoteur of 1919. The main design change was to move from three engines to four whilst retaining a total power of about 750 kW (1,000 hp). Its original Latham type number is not known.

It was a large biplane, with unequal span wings of high aspect ratio for the day. In plan the wings, mounted with very slight stagger, were rectangular out to straight-angled tips. There were three parts, a central section attached to the upper hull which contained the engines and had no dihedral and outer sections with about 2° of dihedral. Each outer section was divided into two bays with three vertical pairs of interplane struts, the innermost at the junction with the central section. Outboard, the overhangs of the upper wing were supported by outward-leaning pairs of struts from the feet of the outer interplane pairs; below these points flat-bottomed floats which provided lateral stability on water were mounted on short struts. The upper centre section was supported over the fuselage with a pair of transverse pair of inverted V-struts. Balanced, short-span, broad-chord ailerons were mounted at the tips of the upper wing only.

The HB.5's four water-cooled, nine-cylinder Salmson 9Z radial engines were mounted as push-pill pairs, with each pair sharing a single nacelle placed midway between the centre section wings on a frame of horizontal members and diagonal struts, tied to the inner interplane struts and the centre section V-struts. The 3.40 m (11.2 ft) interplane gap allowed the rear propellers to turn between the wings; the tractor pairs were just ahead of the wing leading edge. 1,000 l (220 imp gal; 260 US gal) of fuel was equally distributed between four fuselage tanks.

For more details of the design and the operational history of the HB.5, click here.

The Lioré et Olivier LeO H.242 was a French-manufactured flying boat that was used for European passenger air services in the 1930s. Several were operated by Air France.

One LeO H.242 features at the end of Hergé's The Adventures of Tintin comic King Ottokar's Sceptre.

Variants

H-24.01
First prototype. Powered by two 373 kW (500 hp) Renault 12Jb engines. One built.
H-241
The initial four-engined long-range heavy-weight variant of the H-24. The hull was almost exclusively made of anodised Duralumin, for corrosion resistance. Although construction began before the H.242, the sole H.241 was completed later, but did not enter production.
H-242
Initial production. Powered by four Gnome-Rhône 7Kd Titan Major radial engines. Two were built for Air France and delivered in December 1933 and February 1934. They could carry ten passengers.
H-242/1
Revised production version, with a modified engine installation. Twelve were built for Air France and delivered between March 1935 and May 1937, carrying twelve passengers. Most H.242/1s were fitted with wide chord NACA cowlings over the front engine only, but some aircraft were fitted with narrow chord Townend rings around the front engine.
H-243
an un-built projected version for the French navy with enlarged hull.
H-244
A projected high-speed inter-continental flying boat for Air Union, abandoned when Air Union was absorbed by Air France.
H-24.01
First prototype. Powered by two 373 kW (500 hp) Renault 12Jb engines. One built.
H-241
The initial four-engined long-range heavy-weight variant of the H-24. The hull was almost exclusively made of anodised Duralumin, for corrosion resistance. Although construction began before the H.242, the sole H.241 was completed later, but did not enter production.
H-242
Initial production. Powered by four Gnome-Rhône 7Kd Titan Major radial engines. Two were built for Air France and delivered in December 1933 and February 1934. They could carry ten passengers.
H-242/1
Revised production version, with a modified engine installation. Twelve were built for Air France and delivered between March 1935 and May 1937, carrying twelve passengers. Most H.242/1s were fitted with wide chord NACA cowlings over the front engine only, but some aircraft were fitted with narrow chord Townend rings around the front engine.
H-243
an un-built projected version for the French navy with enlarged hull.
H-244
A projected high-speed inter-continental flying boat for Air Union, abandoned when Air Union was absorbed by Air France.
H-246
A major redesign, the four engines now all in tractor configuration.

 

The Sud-Est LeO H-246 was a large four-engined flying boat from the late 1930s.

The LeO H-246 was designed by the French aircraft manufacturer Lioré-et-Olivier to meet a 1935 specification for a commercial flying boat for use on the Mediterranean routes of Air France.[1] It was a four-engined parasol monoplane of mixed construction and powered by four 720 hp (537 kW) Hispano-Suiza 12Xir liquid cooled V12 engines. All four engines were mounted in streamlined nacelles ahead of the leading edge of the wing. It had a duralumin hull which was of similar layout to that of Lioré et Olivier's H-47; it had seats for 26 passengers, and a crew of four.

The prototype H-246.01 (Lioré et Olivier's factories had been nationalised at the end of 1936, so the aircraft was built by Sud-Est) made its maiden flight from the Étang de Berre on 30 September 1937.[1][4] Air France placed an order for six H-246.1 aircraft in January 1938, with the prototype also being brought up to production standard for commercial service.

The refurbished prototype and the first production aircraft were being readied for commercial service when the Second World War broke out in September 1939. The French Navy drew up plans to requisition the H-246s as maritime patrol aircraft, but Air France still needed them, and the Navy agreed to take over only four of the aircraft. This allowed Air France to commence operations with the prototype on the Marseille–Algiers route on 14 October 1939.

The third production aircraft was completed for the Navy in June 1940, with a glazed position in the nose for a bombardier/navigator, bomb racks below the wings and four 7.5 mm Darne machine guns as defensive armament. It entered service with Escadrille 9E on 25 August 1940, the only aircraft of the type actually to be operated by the French Navy, with the remaining aircraft going to Air France.

In November 1942, the Allies landed in French North Africa and, in response, German forces occupied Vichy France. They seized the single French Navy H-246, along with three Air France aircraft. Two more Air France aircraft were at Algiers at the time and so escaped seizure by the Germans. (The prototype H.246 had been withdrawn from use in 1941).

The German Luftwaffe took over the three seized ex-Air France aircraft, fitting them with five MG 15 machine guns as defensive armament and carrying up to 21 soldiers or 14 stretchers. The aircraft were used for various tasks, including transport in Finland. The ex-French Navy H-246 was destroyed at Lyon by Allied attacks in the spring of 1944. After the war, the two surviving H-246s were used by Air France to restart the Marseille–Algiers service, continuing in use until September 1946.

The Lioré et Olivier LeO H-47 was a flying boat airliner built in France in 1936. It was designed to operate passenger services over the South Atlantic, but the outbreak of the Second World War caused the type to be used by the French Navy as a maritime patrol aircraft.

In 1934, the French air ministry issued a specification for a long-range flying boat to be used by Air France on services over the South Atlantic between Dakar in Senegal and Natal in Brazil. As such, the specification required that the new transport be capable of flying 3,000 km (1,900 mi) at a speed of 250 km/h (160 mph) while carrying a payload of 1,000 kg (2,200 lb). Lioré et Olivier received an order for a prototype of its design to meet this specification, the LeO H-47 on 10 August 1935.

The H-47 was a cantilever high-wing monoplane, with a streamlined hull. A flight deck, which accommodated a crew of five (two pilots, a navigator, a radio operator and a mechanic) and a cabin for four to eight passengers were fully enclosed within the aircraft's hull. The four 660 kW (880 hp) Hispano Suiza 12Y engines were mounted in two tractor-pusher pairs above the wing.

The prototype H-47 first flew from Antibes on 25 July 1936, and was destroyed in a crash in May 1937 that was attributed to a wingtip float breaking away whilst the aircraft was in flight. Nevertheless, Air France went ahead with the purchase of five similar (though strengthened) machines, designated H-470, which were put into service as mail planes. These machines were impressed into the French Navy at the outbreak of the Second World War.

The four remaining aircraft remained in use with the Vichy French Navy following the French Armistice, serving as transports between France and Tunisia, before being transferred to Dakar in Senegal in June 1941. The last H-470 was scrapped in August 1943 when stocks of spares ran out.

The Loire 70 was a 1930s French long-range maritime reconnaissance flying boat produced by Loire Aviation.

The Loire 70 was designed to meet a 1932 French Navy requirement for a long-range flying boat for maritime reconnaissance and bombing. The prototype first flew on 28 December 1933. It was an all-metal monoplane, with a heavily braced high wing, with three radial engines mounted above the wing, two as tractors and one as a pusher. The original engines, three 500 hp (373 kW) Gnome et Rhône 9Kbr radials, were not powerful enough and were replaced with 740 hp (552 kW) Gnome-Rhône 9Kfr radials. Seven production aircraft were produced.

The seven production aircraft and the prototype were all delivered to the French Navy, serving with Escadrille E7 at Karouba in Tunisia. During the early days of World War II, the aircraft carried out patrols in the Mediterranean. In an Italian air raid on their base on 12 June 1940, three of the four surviving aircraft were destroyed. It is not known what happened to the last aircraft.

The Macchi M.C.94 was a 1930s Italian commercial flying boat built by Macchi.

The M.C.94 was designed by Mario Castoldi as a commercial passenger transport flying boat to replace the Ala Littoria airline's elderly CANT 10s. Constructed mainly of wood, it was a high-wing cantilever monoplane with a two-step hull and single fin and rudder. The prototype, which was an amphibian with a retractable wheeled undercarriage which swung forward into streamlined casings in the leading edges of the wings, was powered by two 574 kilowatts (770 hp) Wright SGR-1820-F Cyclone nine-cylinder air-cooled radial engines mounted above the wing, each driving a tractor propeller. It was followed by 11 production aircraft, which were all pure flying boats. From the seventh aircraft, 570 kilowatts (760 hp) Alfa Romeo 126 R.C.10 radial engines were fitted. The three-man crew was accommodated in a raised and enclosed cockpit and the main cabin could accommodate 12 passengers.

Ala Littoria purchased the prototype and first five production aircraft in 1936. The Regia Aeronautica (Italian Royal Air Force) declined purchase of the final six production aircraft, which Ala Littoria then also bought.

The M.C.94 entered service with Ala Littoria in 1936 on Adriatic routes, and a number were still in service during World War II. In 1939, Ala Italia sold three of its M.C.94s to its Argentinian partner, Corporación Sudamericana de Servicios Aéreos.

The prototype set a number of international world records for flying boats in 1937, including a new altitude record of 6,432 metres (21,102 ft) carrying a payload of 1,000 kilograms (2,200 lb), a speed record of 248.967 kilometres per hour (154.701 mph) over a 2,000 kilometres (1,200 mi) closed circuit, and a speed record of 257.138 kilometres per hour (159.778 mph) carrying a 1,000 kilograms (2,200 lb) payload over a 1,000 kilometres (620 mi) closed circuit.

Variants

M.C.94 Anfibio
Prototype amphibian version with Wright engines.
M.C.94
The first five production aircraft built as pure flying boats with Wright engines.
M.C.94
The final six production aircraft, also built as flying boats with Alfa Romeo 126 R.C.10 engines.

It was the largest Allied flying boat to enter production, although only seven were built. The United States Navy contracted the development of the XPB2M-1 Mars in 1938 as a long-range ocean patrol flying boat, which later entered production as the JRM Mars long-range transport.

Four of the surviving aircraft were later converted for civilian use to firefighting water bombers. Two of the aircraft still remain based at Sproat Lake just outside of Port Alberni, British Columbia, although neither are operational.

The Glenn L. Martin Company scaled up their PBM Mariner patrol bomber design to produce the prototype XPB2M-1 Mars.[1] The XPB2M-1 was launched on 8 November 1941. After a delay caused by an engine fire during ground runs, the aircraft first flew on 23 June 1942. After flight tests with the XPB2M between 1942 and 1943, she was passed on to the Navy. The original patrol bomber concept was considered obsolete by this time, and the Mars was converted into a transport aircraft designated the XPB2M-1R. The Navy was satisfied with the performance, and ordered 20 of the modified JRM-1 Mars.[1] The first, named Hawaii Mars, was delivered in June 1945, but with the end of World War II the Navy scaled back their order, buying only the five aircraft which were then on the production line.[2] Though the original Hawaii Mars was lost in an accident on Chesapeake Bay a few weeks after it first flew, the other five Mars were completed, and the last delivered in 1947.

For more information on the operational history and variants, click here.

The Martin M-130 was a commercial flying boat designed and built in 1935 by the Glenn L. Martin Company in Baltimore, Maryland, for Pan American Airways. Three were built: the China Clipper, the Philippine Clipper and the Hawaii Clipper. All three had crashed by 1945. A similar flying boat, (the Martin 156), named Russian Clipper, built for the Soviet Union, had a larger wing (giving it greater range) and twin vertical stabilizers.

Martin named them the Martin Ocean Transports, but to the public they were the "China Clippers", a name that became a generic term for Pan Am's large flying boats – the Martin M-130, Sikorsky S-42, and Boeing 314.

Designed to meet Pan American World Airways President Juan Trippe's desire for a trans-Pacific aircraft, the M-130 was an all-metal flying boat with streamlined aerodynamics and engines powerful enough to meet Pan Am's specified range and payload. They were sold at US$417,000. The first flight was on December 30, 1934. On November 22, 1935, the China Clipper, piloted by Captain Edwin C. Musick and First Officer R.O.D. Sullivan, flew the first trans-Pacific airmail route. A postage stamp, Scott Catalog C-20, was printed for use on the transpacific service. With extended service, two more denominations were later issued. All three have the same design showing the M-130 in flight.

Weekly passenger flights across the Pacific Ocean began in October 1936 when Hawaii Clipper left San Francisco for Manila, stopping overnight at Honolulu, Midway Island, Wake Island and Guam. An S-42 began flying the Manila-Hong Kong route in 1937, and the Martins replaced it in 1938.

In July 1938, Hawaii Clipper disappeared between Guam and Manila with the loss of nine crew and six passengers. No cause was determined.

Their range and capacity made them valuable for trans-ocean military flights during World War II. Beginning in 1942, the two remaining planes were pressed into transport roles for the United States Navy.

The Philippine Clipper was on a civilian flight when it encountered – and survived – the surprise Japanese attack on Wake Island in December 1941, following the attack on Pearl Harbor. It crashed in January 1943, between Ukiah and Boonville, California on a flight from Honolulu. ComSubPac Admiral Robert H. English and 18 others were killed.

In January 1945 the China Clipper left Miami on Pan Am's first scheduled flight to what is now Kinshasa in the Democratic Republic of the Congo. The route went via Brazil before crossing the South Atlantic Ocean, but the last surviving M-130 did not complete the flight. It broke up and sank during landing at Port of Spain, in the West Indies islands of British colonies of Trinidad and Tobago on January 8, killing 23 of those on board.

The Martin P5M Marlin (P-5 Marlin after 1962), built by the Glenn L. Martin Company of Middle River, Maryland, was a twin piston-engined flying boat that entered service in 1951, and served into the late 1960s with the United States Navy performing naval patrols. It also served with the United States Coast Guard and the French Navy. 285 were produced.

Built as a successor to the PBM Mariner, it had better engines, an improved hull, and a single vertical fin tail. The XP5M Marlin prototypes were based on the last PBM-5 Mariners, the company designation being Model 237. The type was heavily improved, again leading to the P5M-2 (Model 237B), which was redesignated SP-5B. A number of P5M-1 models were also used for training, designated TP-5A (after 1962).

The Marlin was designed as a gull-winged aircraft to place the engines and propellers high above the spray. Power was provided by two Wright R-3350 radial engines. The rear hull did not lift sharply from the water at the tail, instead rising up steadily, a Martin innovation; this gave the aircraft a longer base of flotation and reduced "porpoising" over waves.

The prototype had nose and tail turrets with twin 20 mm (0.79 in) cannon in each, as well as a dorsal turret with two 0.5 in (12.7 mm) M2 Browning machine guns. The cockpit area was the same as the Mariner's. It first flew on 30 May 1948.

For more details of the design, operational history and 15 variants, click here.

The Martin P6M SeaMaster was an experimental strategic bomber flying boat built by the Glenn L. Martin Company for the United States Navy that almost entered service; production aircraft were built and Navy crews were undergoing operational training, with service entry expected in about six months, when the program was cancelled on 21 August 1959. Envisioned as a strategic nuclear weapon delivery system for the Navy, the SeaMaster was eclipsed by the Polaris submarine-launched ballistic missile (SLBM). Due to the political situation at the Pentagon, the Navy promoted the P6M primarily as a high speed minelayer.

In the immediate postwar defense climate, the United States Air Force's Strategic Air Command was the linchpin of the United States' security as the sole means of delivery of the nation's nuclear arsenal. The Navy saw its strategic role being eclipsed by the Air Force and knew both its prestige and budgets were at stake.

Its first attempt to address this came in the form of the USS United States, a large supercarrier intended to launch Navy strategic bombers. This was cancelled in 1950 shortly after her keel was laid down, a victim of budget cuts and US Air Force interference. In response, the Navy chose to create a "Seaplane Striking Force", useful for both nuclear and conventional warfare, including reconnaissance and minelaying. Groups of these planes supported by seaplane tenders or special submarines could be located close to the enemy, and being mobile, they would be hard to neutralize.

The requirement issued in April 1951 was for a seaplane able to carry a 30,000 lb (14,000 kg) warload over a range of 1,500 mi (1,300 nmi; 2,400 km) from its aquatic base. The aircraft was to be capable of a low altitude dash at Mach 0.9 (1,100 km/h). Both Convair and Martin submitted proposals, and the Martin proposal was chosen as more promising. An order for two prototypes was issued which was projected to lead to six pre-production aircraft and a projected twenty-four production aircraft. Ultimately, 12 aircraft were buiilt.

Originally the plane was to have a Curtiss-Wright turbo-ramjet engine but this ran into problems and a more conventional Allison J71-A-4 turbojet was employed, fitted in pairs in overwing pods to keep the spray out of the intakes. Wings swept at 40° were used; they displayed a notable anhedral and were designed with tip tanks that doubled as floats on the water. Many features of Martin's XB-51 bomber prototype were used, including an all-flying "T" tail and a rotating bomb bay—pneumatically sealed against seawater in the P6M.

Variants

XP6M-1
prototypes, two built (BuNos 138821, 138822). Both crashed.
YP6M-1
pre-production model, six built (BuNos 143822-143827). All six examples were scrapped when the program was cancelled.
P6M-2 (Specifications below)
production model, eight built (BuNos 145876-145899). 145877-145879 were completed and flown, 145876 and 145880-145883 were completed but not flown. Contracts for 145884-145899 were cancelled.

The Martin PBM Mariner was an American patrol bomber flying boat of World War II and the early Cold War era.

It was designed to complement the Consolidated PBY Catalina and PB2Y Coronado in service. A total of 1,366 were built, with the first example flying on 18 February 1939 and the type entering service in September 1940.

In 1937 the Glenn L. Martin Company designed a new twin-engined flying boat, the Model 162, to succeed its earlier Martin P3M and complement the PBY Catalina and PB2Y Coronado. It received an order for a single prototype XPBM-1 on 30 June 1937. This was followed by an initial production order for 21 PBM-1 aircraft on 28 December 1937.

To test the PBM's layout, Martin built a ⅜ scale flying model, the Martin 162A Tadpole Clipper with a crew of one and powered by a single 120 hp (89 kW) Chevrolet engine driving two airscrews via v-belts; this was flown in December 1937. The first genuine PBM, the XPBM-1, flew on 18 February 1939.

The aircraft had multiple gun positions including single mounts at each midship beam and stern above the tail cone. Additional guns were positioned in the nose and dorsal turrets, each fitted with two-gun turrets. The bomb bays were in the engine nacelles. The gull wing was of cantilever design, and featured clean aerodynamics with an unbraced twin tail. The PBM-1 was equipped with retractable wing landing floats that were hinged outboard, with single-strut supported floats that retracted inwards to rest beneath the wing, with the floats' keels just outboard of each of the engine nacelles. The PBM-3 had fixed floats, and the fuselage was three feet longer than that of the PBM-1.

Martin PBM Mariners were operated by RAAF Squadrons 40 and 41.

For details of the operational history, and the 17 variants, click here.

A number of modifications were made for the Goose, but the most numerous are those by McKinnon Enterprises of Sandy, Oregon, which holds 21 supplemental type certificates (STCs) for modifying G-21-series aircraft and which also manufactured four different conversions that were recertified under a separate FAA type certificate as brand-new "McKinnon" airplanes. The first was the McKinnon model G-21C which involved replacing the original R-985 radial engines with four Lycoming GSO-480-B2D6 piston engines. It was approved under TC 4A24 on November 7, 1958, and two examples were converted in 1958–1959.

In November 2007, Antilles Seaplanes of Gibsonville, North Carolina, announced it was restarting production of the turbine-powered McKinnon G-21G Turbo Goose variant, now identified as the Antilles G-21G Super Goose. Pratt & Whitney Canada PT6A-34 turboprops flat-rated to 680 shp (510 kW) would have replaced the original PT6A-27 engines, and the airframe systems and especially the avionics (aviation electronics – i.e. radios and navigation systems) would have been updated with state-of-the-art "glass panel" instrumentation and cockpit displays. However, as of 2009, Antilles Seaplanes' manufacturing center has been foreclosed and sold at auction. The fate of new Goose production is currently unknown.

The Potez-CAMS 141 was a French long range reconnaissance flying boat of the late 1930s. Intended to equip the French Navy, only a single prototype was completed before the German invasion of France stopped production. That prototype did, however serve operationally from bases in French North Africa until scrapped in 1943.

The Potez-CAMS 141 was designed by Chantiers Aéro-Maritimes de la Seine (or CAMS, which since 1933 had been part of Potez) to meet a 1935 French Navy specification for a long range marine reconnaissance flying boat to replace obsolete aircraft such as the Breguet Bizerte, competing against the Latécoère 611 and Breguet 730. The prototype first flew on 21 January 1938 at Caudebec-en-Caux, starting official trials in August 1938.

It was a four engined monoplane, powered by Hispano-Suiza 12Y engines, with a braced, high aspect ratio wing mounted above the fuselage and a twin tail. It was armed with a dorsal turret carrying two 7.5 mm Darne machine guns, with a further two machine guns in lateral "cheek" barbettes and two in waist positions. After evaluation, a production order for four aircraft was placed, with a further 15 being ordered before the start of the Second World War.

The prototype, named Antarès, entered service with Escadrille E8 of the French Navy in September 1939, flying its first patrol mission over the Atlantic on 20 September 1939. Additional large orders for Potez-CAMS 141s were placed shortly after the start of the war, with delivery expected from June 1940, but these orders were cut back owing to changing priorities and the realisation that the loss rate of long range flying boats was very low.

No production aircraft had been completed by the time of the Armistice in June 1940, with Antarès being evacuated to Port Lyautey in Morocco. It was operated by the Vichy French Navy, serving with Escadrille 4E at Dakar, continuing in service until the Allied Invasion of North Africa, when after brief fighting, the French armed forces in North Africa joined with the Free French. Antarès continued in service, carrying out patrols over the Central and South Atlantic. On 2 June 1943, Antarès sank the German submarine U-105 near Dakar. Antarès was retired and scrapped early in 1944.

Rohrbach Ro V was a seaplane manufactured by the Rohrbach Metall-Flugzeugbau company in Berlin, Germany. Only one was built, in 1927. It was delivered to Severa GmbH for comparison flights with the Dornier Do J "Superwal" and as a seaplane trainer. It was used for commercial flights in 1928 by the Deutsche Luft Hansa for the Travemünde to Oslo route.

The Saro A.21 Windhover was a British amphibious aircraft from the period between World War I and World War II, constructed by Saunders-Roe, or Saro. It was originally advertised as the A.19 Thermopylae after the famous clipper ship, being an enlarged version of the Saro Cutty Sark.

When tests to improve the power of the Saro A.17 Cutty Sark by adding a third de Havilland Gipsy II engine proved impractical (due to the additional weight on the small airframe), Saro designed a larger aircraft on similar lines that could indeed carry three Gipsy II engines. Although a technically successful aircraft and nearly viceless in service, it was a type with a very limited market and only two were built.

Production Aircraft

A.21/1

Prototype first flown at Cowes 16 October 1930, registered ZK-ABW for delivery to Dominion Airways of New Zealand. Aircraft sold in September 1931 to Matthews Aviation of Melbourne, Victoria and placed on the Australian register as VH-UPB. Between January 1933 and February 1934 operated a regular Bass Strait passenger service between Melbourne and Launceston, Tasmania via King Island. On 13 May 1936 it was damaged beyond repair when blown ashore at King Island while on a charter with a party of game hunters. The hull was salvaged and ended its days as an instructional airframe in Melbourne during the Second World War before being demolished.

A.21/2

 First and only production example, completed July 1931. After modifications (addition of auxiliary winglet over engines to improve air flow and lift), it was sold to Francis Francis as G-ABJP, who onsold it in September to Gibraltar Airways for the Gibraltar-Tangier route. In July 1932, it was sold to The Hon Mrs Victor Bruce and named City of Portsmouth. The undercarriage was temporarily removed, and during August 1932, it was used in three attempts to break the world flight-refuelled endurance record. That was not achieved, and in May 1935, the aircraft was sold to Jersey Airways, being taken out of service in 1938.

A21/1 VH-UPB over Melbourne

A21/1 as ZK-ABW

A21/2 G-ABJP

The Saunders Roe A.27 London was a British military biplane flying boat built by the Saunders Roe company. Only 31 were built, entering service with the Royal Air Force in 1936. Although due for replacement by the outbreak of World War II, they saw some active service pending the introduction of the ultimately unsuccessful Lerwick.

The A.27 London was designed in response to the Air Ministry Specification R.24/31 issued for a "General Purpose Open Sea Patrol Flying Boat" and was based on the Saro A.7 Severn. The London and its contemporary, the Supermarine Stranraer, were the last multi-engine, biplane flying-boats to see service with the RAF. The design utilized an all-metal corrugated hull and fabric-covered wing and tail surfaces, with two Bristol Pegasus II radial engines, mounted on the upper wing to keep them clear of spray while taking off and landing.

The first prototype first flew in March 1934 and then went on to serve until 1936 with 209 and 210 Squadrons RAF at RAF Felixstowe and Gibraltar respectively.

The first deliveries of production aircraft began in March 1936 with Pegasus III engines, and from the eleventh aircraft onwards the Pegasus X engine was fitted instead and the aircraft's designation changed to London Mk.II. Earlier Londons were retrofitted with the Pegasus X and were also given the "Mk.II" designation.

The London Mk.II model equipped 201 Squadron RAF at RAF Calshot beginning in 1936, replacing Supermarine Southamptons. Others later were delivered in October 1936 to 204 Squadron RAF at RAF Mount Batten, Plymouth, also replacing Southamptons. More were delivered to the same squadron in 1937 to replace Blackburn Perths, and to 202 Squadron RAF at Kalafrana, Malta, replacing Supermarine Scapas, and 228 Squadron RAF at Pembroke Dock.

In 1937–1938 204 Squadron RAF used five Londons equipped with auxiliary external fuel tanks for a long-distance training flight to Australia to celebrate the 150th anniversary of the founding of the Colony at Sydney, New South Wales. In this configuration, they had a range of 2,600 miles (4,180 km).

At the outbreak of World War II in September 1939, Londons equipped 201 Squadron RAF, which was by now stationed at Sullom Voe in Shetland, and 202 Squadron RAF at Gibraltar, as well as 240 Squadron RAF at Invergordon, which had re-equipped with Londons in July 1939. These aircraft carried out active patrols over the North Sea and the Mediterranean. Some were fitted with a dorsal fuel tank to increase operational radius. Armament in the form of bombs, depth charges, and naval mines up to a total weight of 2,000 lb (907 kg) could be carried beneath the lower wings.

Gradually, the Londons' duties were assumed by newer aircraft such as the Lockheed Hudson, while squadrons flying Atlantic and Mediterranean patrols were re-equipped with Short Sunderlands. Some Londons were transferred to the Royal Canadian Air Force. All were withdrawn from front-line duties by the middle of 1941.

Variants.

Prototype
One only
London Mk.I
10 built with two 820 hp Pegasus III engines and two-bladed propellers. Later converted to Mk II.
London Mk.II
20 built with two 915 hp Pegasus X engines and four-bladed propellers.