Seaplane, Part V

An amphibious aircraft or amphibian

 

An amphibious aircraft or amphibian is an aircraft that can take off and land on either land or water. All Amphibian aircraft are thus classified both as seaplanes and make up the rarest subclass of seaplanes. Like all seaplanes, Amphibious aircraft are typically flying boats and floatplanes  — but while their major physical attributes are those placing them within those broad classes, amphibians are also engineered with retractable wheels making them amphibious — at the expense of extra weight and complexity, plus diminished range and fuel economy factors comparative to planes specialized for land or water only.

While floatplanes sometimes have floats that are interchangeable with wheeled landing gear (thereby producing a conventional land-based aircraft), it is rare for a floatplane to successfully incorporate retractable wheels whilst retaining its floats; the Grumman J2F Duck would be a notable example of one exception which does. Some amphibian floatplanes, such as the amphibian version of the Cessna Caravan, incorporate retractable wheels within their floats.

The majority of amphibian aircraft are of the flying boat type. These aircraft, and those designed as floatplanes with a single main float under the fuselage centerline (such as the J2F Duck), require small outrigger floats to be fitted underneath the wings: while these impose additional drag and weight on all seaplanes of this type, amphibious aircraft also face the possibility that these floats would hit the runway during wheeled landings.

A solution would be to have the aircraft fitted with wing-mounted retractable floats such as those found on the Grumman Mallard, a flying boat type of seaplane designed and built in the mid 1940s with dozens still employed today in regular small volume commercial (ferry service) air taxi roles.

The class which has retractable floats which also act as extra fuel tanks since fuel liquids weigh less than water of equal volume; these floats are removable for extended land/snow operations if and when use of extra fuel tanks is undesired but the plane type and class serves as an example of a true amphibious aircraft since they also retract up off the ground.

Amphibious aircraft are heavier and slower, more complex and more expensive to purchase and operate than comparable landplanes but are also more versatile.

They do compete favorably, however, with helicopters that compete for the same types of jobs, if not quite as versatile.

Amphibious aircraft have longer range than comparable helicopters, and can indeed achieve nearly the range of land-only airplanes, as an airplane's wing is more efficient than a helicopter's lifting rotor.

This makes an amphibious aircraft, such as the Grumman Albatross and the ShinMaywa US-1, ideal for long-range air-sea rescue tasks. In addition, amphibious aircraft are particularly useful as "bush" aircraft engaging in light transport in remote areas, where they are required to operate not only from airstrips, but also from lakes and rivers.

Amphibious aircraft have been built in various nations since the early 1920s, but it was not until World War II that saw their widespread service.

The Grumman Corporation, a United States-based pioneer of amphibious aircraft, introduced a family of light utility amphibious aircraft - the Goose, the Widgeon and the Mallard - during the 1930s and the 1940s, originally intended for civilian market. However, the military potential of these very capable aircraft could not be ignored, and large numbers of these versatile aircraft were ordered by the Military of the United States and their allies during World War II, for service in air-sea rescue, anti-submarine patrol, and a host of other tasks. The concept of military amphibious aircraft was so successful that the PBY Catalina, which began life as a pure flying boat, introduced an amphibian variant during the war.

In the United Kingdom, Supermarine Aircraft produced the Walrus and the Sea Otter single-engined biplane amphibians which were widely used for observation and air-sea rescue duties before and during World War Two.

After the war, the United States military ordered hundreds of the HU-16 Albatross and its variants for use in open ocean rescue, for the United States Air Force, Coast Guard and Navy.

The capabilities of these amphibious aircraft were found to be particularly useful in the unforgiving terrains of Alaska and northern Canada, where some remained in civilian service long after the war, providing remote communities in these regions with vital links to the outside world.

Nonetheless, with the increased availability of airstrips and amenities in remote communities, fewer amphibious aircraft are manufactured today than in the past, although a handful of manufacturers around the world still produce amphibious aircraft (flying boats or floatplanes with retractable landing gear), such as the Bombardier 415, the Grumman Albatross and the amphibian version of the Cessna Caravan.

The largest amphibious aircraft currently in service is the Beriev A-40 of the Russian Navy, with a wingspan of 41.62 meter and a takeoff weight of 86 metric tons. The Beriev Be-200 is a smaller model for civil applications and had its first flight in 2004. It can carry 72 passengers and is also built in a version for fire fight.

 

 

A floatplane (or pontoon plane)

 

A floatplane (or pontoon plane) is a type of seaplane, with slender pontoons (known as "floats") mounted under the fuselage; only the floats of a floatplane normally come into contact with water, with the fuselage remaining above water. By contrast a flying boat uses its fuselage for buoyancy like a ship's hull.

A floatplane is essentially a straightforward development of land-based aircraft, with floats mounted under the fuselage instead of wheeled landing gear.

Floatplanes are traditionally more popular than flying boats for small aircraft designs, since it permits a single piston engine to be installed in the conventional manner, that is at the nose of the fuselage (this could be done on flying boats only by mounting the engine high above the fuselage).

Moreover, the fuselages of floatplanes are typically more aerodynamic than flying boats; while the large floats underneath the fuselages inevitably impose extra drag and weight to floatplanes, rendering them less manoeuvrable during flight than their land-based counterparts.

Historically it did little to affect their speed, as the contestants in the Schneider Trophy demonstrated. However, there is loss of speed, slower rate of climb and increased empty weight.

There are two basic arrangements for floats on floatplanes. One is the single float design, in which a single large float is mounted directly underneath the fuselage, with smaller stabilizing floats underneath the wings. The other is the twin float design, with a pair of floats mounted beneath the wing roots, in place of wheeled landing gear.

The main advantage of the single float design is its rough sea landing capability: the large central float is directly attached to the fuselage, this being the strongest part of the aircraft structure, while the small floats under the outer wings provide the aircraft with good lateral stability.

Dual floats on aircraft limit wave handling to minimal levels, often to an average of one foot in height. However the twin float design facilitates mooring and boarding, and in the case of a military floatplane, leaves the belly free to carry a torpedo or a heavy bombload.

Whatever the float layout, a floatplane tends to be much less stable on water than flying boats.

Floatplanes first appeared during World War I, and remained in widespread naval use until World War II.

Most larger warships of that era carried floatplanes - typically four for each battleship, and one to two for each cruiser - to be launched by catapults; their main task was to spot targets over the horizon for the big guns.

Other floatplanes, sometimes carried on seaplane tenders, were used for bombings, reconnaissance, air-sea rescue, and even as fighters.

During the interwar period, civilian use of floatplanes were rather rare, given the larger fuselage (hence greater payload) of flying boats; however floatplane racing aircraft were very popular, as exemplified by those which participated in the Schneider Trophy.

 

After World War II, the advent of radar and helicopters, and the advanced development of aircraft carriers and land-based aircraft, saw the demise of military seaplanes.

This, coupled with the increased availability of civilian airstrips, have greatly reduced the number of flying boats being built. However, numerous modern civilian aircraft have floatplane variants, most of these are offered as third-party modifications under a supplemental type certificate (STC), although there are several aircraft manufacturers that build floatplanes from scratch.

These floatplanes have found their niche as one type of bush plane, for light duty transportation to lakes and other remote areas, as well as to small/hilly islands without proper airstrips.

They may operate on a charter basis (including, but not limited to, pleasure flights), provide scheduled service, or be operated by residents of the area for private, personal use.

 

 

Tigerfish Aviation

 

Tigerfish Aviation is an aerospace research and development company based in Norwood, South Australia. Since the late 1990s, the company has been developing a retractable pontoon system for the float plane industry, which has been patented as Retractable Amphibious Pontoon Technology or RAPT.

The retractable float concept aims to reduce aerodynamic drag by folding the floats into a streamlined pannier under the fuselage of the aircraft.

The reduction in drag improves performance of the aircraft and reduces its operating cost, such as fuel consumption. Reduction in drag also increases the range, payload, speed, and productivity of the aircraft.

The drag reduction occurs due to the reduction of surface area exposed to the airstream and concealing the hydrodynamic features of the floats. It is designed as a retrofit, and is potentially capable of application to any existing aircraft.

The technology has been applied on a one-sixth scale Cessna Caravan for concept-proving.

As of 2010, Dornier 228 NG is the first proposed aircraft to be retrofitted for the RAPT system, besides the small-scale Cessna.

The retractable float system can be used in a wide range of aircraft including regional aircraft, utility aircraft, executive aircraft, military transports, VLJs, and UAVs.

The University of Adelaide, with assistance of the South Australian Government, has performed CFD analysis and other studies on the DHC-6 Twin Otter showing that the RAPT system would result in a significant cost benefit. Unlike traditional floats, RAPT pontoons are made of lightweight composite materials, but suffer additional mass penalties due to the electric, hydraulic and structural systems required to retract the pontoons. Total mass penalty has been estimated at 1,420 pounds (640 kg) for a Dornier 228 NG variant (comparable to existing Wipline floats).

 

 

Flying boat

 

A flying boat is a fixed-winged seaplane with a hull, allowing it to land on water. It differs from a float plane as it uses a purpose-designed fuselage which can both float, granting the aircraft buoyancy, and give aerodynamic sheath.

Flying boats may be stabilized by under-wing floats or by wing-like projections (called sponsons) from the fuselage.

Flying boats were some of the largest aircraft of the first half of the 20th century, superseded in size only by bombers developed during World War II. Their advantage lay in using water instead of expensive land-based runways, making them the basis for international airlines in the interwar period. They were also commonly used for maritime patrol and air-sea rescue.

The craft class or type came about after The Daily Mail offered a large monetary prize for an aircraft with transoceanic range in 1914. This prompted a collaboration between British and American air pioneers, resulting in the Curtiss Model H.

Following World War II, their use gradually tailed off, partially because of the investments in airports during the war. In the 21st century, flying boats maintain a few niche uses, such as for dropping water on forest fires, air transport around archipelagos, and access to undeveloped or roadless areas.

Many modern seaplane variants, whether float or flying boat types are convertible amphibians—planes where either landing gear or flotation modes may be used to land and take off.

Henri Fabre, a French aviator, invented and successfully flight tested a seaplane which he named Le Canard; it is acknowledged as the first seaplane in history. It was a 'landmark' invention that inspired other aviators.

Over the next few years, Fabre designed "Fabre floats" for several other flyers. American pioneer aviator Glenn Curtiss had built experimental floatplanes before 1910, without proceeding to flight testing. But after Fabre's successful seaplane flights, Curtiss focused mainly on land-based aircraft. He made only small experimental models of floatplanes, and slowly improved upon his earlier work.

In 1911 Curtiss unveiled a development of his floatplane experiments married to a larger version of his successful Curtiss Model D land plane, but with a larger engine and a rudimentary hull and fuselage, designated as the Model E. The was the first air plane with a hull, and arguably the creation of the "flying boat" type that dominated long distance air travel for the next four to five decades.

Consequently he soon became acquainted with others interested in both seaplane based and long range commercial aviation development  — two aspects which were hopelessly interrelated in those days when airports were yet to be built throughout most of the world. The design also brought him in contact with Lieutenant Commander John Cyril Porte RN, an influential British aviation pioneer.

In February 1911, the United States Navy took delivery of its very first airplane, a Curtiss Model E, and soon tested landing and take-offs from ships using the Curtiss Model D.

In 1913, London's Daily Mail newspaper put up a ¤10,000 prize for the first non-stop aerial crossing of the Atlantic which was soon "'enhanced by a further sum"' from the "Women's Aerial League of Great Britain".

American businessman Rodman Wanamaker became determined that the prize should go to an American aircraft and commissioned the Curtiss Aeroplane and Motor Company to design and build two aircraft capable of making the flight. In Great Britain in 1913, similarly, the boat building firm J. Samuel White of Cowes on the Isle of Wight set up a new aircraft division and produced a flying boat in the United Kingdom.

This was displayed at the London Air Show at Olympia in 1913. In that same year, a collaboration between the S. E. Saunders boatyard of East Cowes and the Sopwith Aviation Company produced the "Bat Boat", an aircraft with a consuta laminated hull that could operate from land or on water, which today we call amphibious aircraft.

The "Bat Boat" completed several landings on sea and on land and was duly awarded the Mortimer Singer Prize. It was the first all-British aeroplane capable of making six return flights over five miles within five hours.

In America, Wanamaker's commission built on Glen Curtiss' previous development and experience with the Model E for the U.S. Navy and soon resulted in the Model H. The H series began as a conventional biplane design with two-bay, unstaggered wings of unequal span with two tractor (pulling, not pushing) inline engines mounted side-by-side above the fuselage in the interplane gap. Wingtip pontoons were attached directly below the lower wings near their tips.

The Model H resembled Curtiss' earlier flying boat designs, but was built considerably larger so it could carry enough fuel to cover 1,100 mi (1,800 km).

The three crew members were accommodated in a fully-enclosed cabin.

Trials of the Model H (christened America) began in June 1914, with Lt. Cmdr. Porte as test pilot. Testing soon revealed a serious shortcoming in the design; especially the tendency for the nose of the aircraft to try to submerge as engine power increased while taxiing on water.

This phenomenon had not been encountered before, since Curtiss' earlier designs had not used such powerful engines nor large fuel/cargo loads and so were relatively much more buoyant. In order to counteract this effect, Curtiss fitted fins to the sides of the bow to add hydrodynamic lift, but soon replaced these with sponsons, a type of underwater pontoon mounted in pairs on either side of a hull, to add more buoyancy.

These sponsons (or their engineering equivalents) would remain a prominent feature of flying boat hull design in the decades to follow. With the problem resolved, preparations for the crossing resumed. While the craft was found to handle 'heavily' on take-off, and required rather longer take-off distances than expected, 5 August 1914 was selected as the trans-Atlantic flight date. Porte was to pilot the America.

Curtiss and Porte's plans were interrupted by the outbreak of World War I. Porte was recalled to service with the Royal Naval Air Service. He became commander of the Seaplane Experimental Station at Felixstowe in 1915.

Impressed by the capabilities he had witnessed, Porte persuaded the Admiralty to commandeer (and later, purchase) the America and her sister from Curtiss.

This was followed by an order for 12 more similar aircraft, one Model H-2 and the remaining as Model H-4's.

Four examples of the latter were actually assembled in the UK by Saunders. All of these were essentially identical to the design of the America, and indeed, were all referred to as Americas in Royal Navy service.

The initial batch was followed by an order for 50 more (totalling 64 Americas overall during the war).

Porte also acquired permission to modify and experiment with the Curtiss aircraft.

At Felixstowe, Porte advanced flying boat design and developed a practical hull design with the distinctive "Felixstowe notch". The notch could be added to Curtiss' airframe and engine design, creating the Atlantic or Type A flying boat (as it became known in Great Britain). After that initial mass upgrade Porte modified the H4 with a new hull with improved hydrodynamic qualities. This design was later designated the Felixstowe F.1, of which only four were built as they were deemed underpowered for arduous North Atlantic patrol conditions.

Consequently, Curtiss was asked to develop a larger flying boat, which was designated the "Large American" or Curtiss Model H8 when it became available in 1917. But when some H8s were tested at Felixstowe, they too were found to be under powered. Porte soon upgraded the H8s with 250 HP Rolls-Royce Eagle engines and replaced the hulls with a larger Felixstowe hull variant. These became the Felixstowe F.2 and F.2a variants and saw both wide use and long service.

The innovation of the "Felixstowe notch" enabled the craft to overcome suction from the water more quickly and break free for flight much more easily. This made operating the craft far safer and more reliable.

The "notch" break through would soon after evolve into a 'step', with the rear section of the lower hull sharply recessed above the forward lower hull section, and that characteristic became a feature of both flying boat hulls and seaplane floats. The resulting aircraft would be large enough to carry sufficient fuel to fly long distances and could berth alongside ships for refueling.

After several years of war development and upon getting negative reports on the H-8, Curtiss produced upscaled flying boats which by 1917 were designated as the Curtiss Model H12. Porte then designed a similar hull for the H12, designated the Felixstowe F.2a, which was greatly superior to the original Curtiss boat. This entered production and service with about 100 being completed by the end of the War. Another seventy were built later, and these were followed by two F.2c also built at Felixstowe.

In February 1917, the first prototype of the Felixstowe F.3 was flown. It was larger and heavier than the F.2, giving it greater range and heavier bomb load, but poorer agility. Approximately 100 Felixstowe F.3s were produced before the end of the war.

The Felixstowe F.5 was intended to combine the good qualities of the F.2 and F.3, with the prototype first flying in May 1918. The prototype showed superior qualities to its predecessors but, to ease production, the production version was modified to make extensive use of components from the F.3, which resulted in lower performance than the F.2A or F.5.

F.2, F.3, and F.5 flying boats were extensively employed by the Royal Navy for coastal patrols, and to search for German U-boats.

The Curtiss Aeroplane and Motor Company independently developed its designs into the small Model 'F', the larger Model 'K' (several of which were sold to the Russian Naval Air Service), and the Model 'C' for the US Navy. Curtiss among others also built the Felixstowe F.5 as the Curtiss F5L, based on the final Porte hull designs and powered by American Liberty engines.

Macchi L and M series flying boats. The original Macchi L.1 was a copy of the Austrian Lohner L flying boat of 1915.

A Curtiss NC-4 became the first aircraft to fly across the Atlantic Ocean in 1919, crossing via the Azores. Of the four that made the attempt, only one completed the flight.

In the 1930s, flying boats made it possible to have regular air transport between the US and Europe, opening up new air travel routes to South America, Africa, and Asia. Foynes, Ireland and Botwood, Newfoundland and Labrador were the termini for many early transatlantic flights.In areas where there were no airfields for land-based aircraft, flying boats could stop at small island, river, lake or coastal stations to refuel and resupply. The Pan Am Boeing 314 "Clipper" planes brought exotic destinations like the Far East within reach of air travelers and came to represent the romance of flight.

In 1923, the first British commercial flying boat service was introduced with flights to and from the Channel Islands. The British aviation industry was experiencing rapid growth. The Government decided that nationalization was necessary and ordered five aviation companies to merge to form the state-owned Imperial Airways of London (IAL). IAL became the international flag-carrying British airline, providing flying boat passenger and mail transport links between Britain and South Africa using aircraft such as the Short S.8 Calcutta.

In 1928, four Supermarine Southampton flying boats of the RAF Far East flight arrived in Melbourne, Australia. The flight was considered proof that flying boats had evolved to become reliable means of long distance transport.

By 1931, mail from Australia reached Britain in just 16 days - less than half the time taken by sea. In that year, government tenders on both sides of the world invited applications to run new passenger and mail services between the ends of Empire, and Qantas and IAL were successful with a joint bid. A company under combined ownership was then formed, Qantas Empire Airways. The new ten day service between Rose Bay, New South Wales (near Sydney) and Southampton was such a success with letter-writers that before long the volume of mail was exceeding aircraft storage space.

A solution to the problem was found by the British government, who in 1933 had requested aviation manufacturer Short Brothers to design a big new long-range monoplane for use by IAL. Partner Qantas agreed to the initiative and undertook to purchase six of the new Short S23 'C' class or 'Empire' flying boats.

Delivering the mail as quickly as possible generated a lot of competition and some innovative solutions. One variant of the Short Empire flying boats was the strange-looking "Maia and Mercury'". It was a four-engined floatplane "Mercury" (the winged messenger) fixed on top of "Maia", a heavily modified Short Empire flying boat. The larger Maia took off, carrying the smaller Mercury loaded to a weight greater than it could take off with.

This allowed the Mercury to carry sufficient fuel for a direct trans-Atlantic flight with the mail. Unfortunately this was of limited usefulness, and the Mercury had to be returned from America by ship. The Mercury did set a number of distance records before in-flight refuelling was adopted.

Sir Alan Cobham devised a method of in-flight refuelling in the 1930s. In the air, the Short Empire could be loaded with more fuel than it could take off with. Short Empire flying boats serving the trans-Atlantic crossing were refueled over Foynes; with the extra fuel load, they could make a direct trans-Atlantic flight. A Handley Page H.P.54 Harrow was used as the fuel tanker.

The German Dornier Do-X flying boat was noticeably different from its UK and US-built counterparts. It had wing-like protrusions from the fuselage called sponsons, to stabilize on the water without the need for wing-mounted outboard floats.

This feature was pioneered by Claudius Dornier during World War I on his Dornier Rs. I giant flying boat, and perfected on the Dornier Wal in 1924. The enormous Do X was powered by 12 engines and carried 170 persons. It flew to America in 1929 crossing the Atlantic via an indirect route. It was the largest flying boat of its time but was severely underpowered and was limited by a very low operational ceiling.

Only three were built with a variety of different engines installed, in an attempt to overcome the lack of power. Two of these were sold to Italy.

The military value of flying boats was well-recognized, and every country bordering on water operated them in a military capacity at the outbreak of the war. They were utilized in various tasks from anti-submarine patrol to air-sea rescue and gunfire spotting for battleships. Aircraft such as the PBY Catalina, Short Sunderland, and Grumman Goose recovered downed airmen and operated as scout aircraft over the vast distances of the Pacific Theater and Atlantic. They also sank numerous submarines and found enemy ships. In May 1941 the German battleship Bismarck was discovered spotted by a PBY Catalina flying out of Castle Archdale Flying boat base, Lower Lough Erne, Northern Ireland.

The largest flying boat of the war was the Blohm & Voss BV 238, which was also the heaviest plane to fly during World War II and the largest aircraft built and flown by any of the Axis Powers.

In November 1939, IAL was restructured into three separate companies: British European Airways, British Overseas Airways Corporation (BOAC), and British South American Airways (which merged with BOAC in 1949), with the change being made official in 1 April 1940. BOAC continued to operate flying boat services from the (slightly) safer confines of Poole Harbour during wartime, returning to Southampton in 1947.

The Martin Company produced the prototype XPB2M Mars based on their PBM Mariner patrol bomber, with flight tests between 1941 and 1943. The Mars was converted by the Navy into a transport aircraft designated the XPB2M-1R. Satisfied with the performance, 20 the modified JRM-1 Mars were ordered. The first, named Hawaii Mars, was delivered in June 1945, but the Navy scaled back their order at the end of World War II, buying only the five aircraft which were then on the production line. The 5 Mars were completed, and the last delivered in 1947.

The Hughes H-4 Hercules, in development in the U.S. during the war, was even larger than the Bv238 but it did not fly until 1947. The "Spruce Goose", as the H-4 was nicknamed, was the largest flying boat ever to fly. That short 1947 hop of the 'Flying Lumberyard' was to be its last, however; it became a victim of post-war cutbacks and the disappearance of its intended mission as a transatlantic transport.

During the Berlin Airlift (which lasted from June 1948 until August 1949) ten Sunderlands and two Hythes were used to transport goods from Finkenwerder on the Elbe near Hamburg to the isolated city, landing on Lake Havelsee beside RAF Gatow until it iced over. The Sunderlands were particularly used for transporting salt, as their airframes were already protected against corrosion from seawater. Transporting salt in standard aircraft risked rapid and severe structural corrosion in the event of a spillage. In addition, three Aquila flying boats were used during the airlift. This is the only known operational use of flying boats within central Europe.

After World War II the use of flying boats rapidly declined, though the US Navy continued to operate them (notably the Martin P5M Marlin) until the early 1970s. The Navy even attempted to build a jet-powered seaplane bomber, the Martin Seamaster. Several factors contributed to the decline. The ability to land on water became less of an advantage owing to the considerable increase in the number and length of land based runways during World War II. Further, as the speed and range of land-based aircraft increased, the commercial competitiveness of flying boats diminished; their design compromised aerodynamic efficiency and speed to accomplish the feat of waterborne takeoff and landing. Competing with new civilian jet aircraft like the de Havilland Comet and Boeing 707 proved impossible.

BOAC ceased flying boat services out of Southampton in November 1950.

Bucking the trend, in 1948 Aquila Airways was founded to serve destinations that were still inaccessible to land-based aircraft. This company operated Short S.25 and Short S.45 flying boats out of Southampton on routes to Madeira, Las Palmas, Lisbon, Jersey, Majorca, Marseilles, Capri, Genoa, Montreux and Santa Margherita. From 1950 to 1957, Aquila also operated a service from Southampton to Edinburgh and Glasgow. The flying boats of Aquila Airways were also chartered for one-off trips, usually to deploy troops where scheduled services did not exist or where there were political considerations. The longest charter, in 1952, was from Southampton to the Falkland Islands. In 1953 the flying boats were chartered for troop deployment trips to Freetown and Lagos and there was a special trip from Hull to Helsinki to relocate a ship's crew. The airline ceased operations on 30 September 1958.

The technically advanced Saunders-Roe Princess first flew in 1952 and later received a certificate of airworthiness. Despite being the pinnacle of flying boat development none were sold, though Aquila Airways reportedly attempted to buy them. Of the three Princesses that were built, two never flew, and all were scrapped in 1967. In the late 1940s Saunders-Roe also produced the jet-powered SR.A/1 flying boat fighter, which did not progress beyond flying prototypes.

Helicopters ultimately took over the air-sea rescue role.

The land-based P-3 Orion and carrier-based S-3 Viking became the US Navy's fixed-wing anti-submarine patrol aircraft.

Ansett Australia operated a flying boat service from Rose Bay to Lord Howe Island until 1974, using Short Sandringhams.

The shape of the Short Empire was a harbinger of the shape of later aircraft yet to come, and the type also contributed much to the designs of later ekranoplans. However, true flying boats have largely been replaced by seaplanes with floats and amphibian aircraft with wheels. The Beriev Be-200 twin-jet amphibious aircraft has been one of the closest 'living' descendants of the earlier flying boats, along with the larger amphibious planes used for fighting forest fires. There are also several experimental/kit amphibians such as the Volmer Sportsman, Quikkit Glass Goose, Airmax Sea Max, Aeroprakt A-24, and Seawind 300C.

The ShinMaywa US-2 (Japanese: US-2) is a large STOL amphibious aircraft designed for air-sea rescue work. The US-2 is operated by the Japan Maritime Self Defense Force.

The Canadair CL-215 and successor Bombardier 415 are examples of modern flying boats and are used for forest fire suppression.

Dornier announced plans in May 2010 to build CD2 SeaStar composite flying boats in Quebec, Canada.

The Iranian military unveiled a squadron of flying boats, named Bavar 2, equipped with machine guns in September 2010.

 

 

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Aversa, R., R.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2016i. Mitochondria are naturally micro robots-a review. Am. J. Eng. Applied Sci., 9: 991-1002.

Aversa, R., R.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2016j. We are addicted to vitamins C and E-A review. Am. J. Eng. Applied Sci., 9: 1003-1018.

Aversa, R., R.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2016k. Physiologic human fluids and swelling behavior of hydrophilic biocompatible hybrid ceramo-polymeric materials. Am. J. Eng. Applied Sci., 9: 962-972.

Aversa, R., R.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2016l. One can slow down the aging through antioxidants. Am. J. Eng. Applied Sci., 9: 1112-1126.

Aversa, R., R.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2016m. About homeopathy or jSimilia similibus curenturk. Am. J. Eng. Applied Sci., 9: 1164-1172.

Aversa, R., R.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2016n. The basic elements of life's. Am. J. Eng. Applied Sci., 9: 1189-1197.

Aversa, R., F.I.T. Petrescu, R.V. Petrescu and A. Apicella, 2016o. Flexible stem trabecular prostheses. Am. J. Eng. Applied Sci., 9: 1213-1221.

Mirsayar, M.M., V.A. Joneidi, R.V.V. Petrescu,    F.I.T. Petrescu and F. Berto, 2017 Extended MTSN criterion for fracture analysis of soda lime glass. Eng. Fracture Mechanics 178: 50-59.     DOI: 10.1016/j.engfracmech.2017.04.018

Petrescu, R.V. and F.I. Petrescu, 2013a. Lockheed Martin. 1st Edn., CreateSpace, pp: 114.

Petrescu, R.V. and F.I. Petrescu, 2013b. Northrop. 1st Edn., CreateSpace, pp: 96.

Petrescu, R.V. and F.I. Petrescu, 2013c. The Aviation History or New Aircraft I Color. 1st Edn., CreateSpace, pp: 292.

Petrescu, F.I. and R.V. Petrescu, 2012. New Aircraft II. 1st Edn., Books On Demand, pp: 138.

Petrescu, F.I. and R.V. Petrescu, 2011. Memories About Flight. 1st Edn., CreateSpace, pp: 652.

Petrescu, F.I.T., 2009. New aircraft. Proceedings of the 3rd International Conference on Computational Mechanics, Oct. 29-30, Brasov, Romania.

Petrescu, F.I., Petrescu, R.V., 2016a Otto Motor Dynamics, GEINTEC-GESTAO INOVACAO E TECNOLOGIAS, 6(3):3392-3406.

Petrescu, F.I., Petrescu, R.V., 2016b Dynamic Cinematic to a Structure 2R, GEINTEC-GESTAO INOVACAO E TECNOLOGIAS, 6(2):3143-3154.

Petrescu, F.I., Petrescu, R.V., 2014a Cam Gears Dynamics in the Classic Distribution, Independent Journal of Management & Production, 5(1):166-185.

Petrescu, F.I., Petrescu, R.V., 2014b High Efficiency Gears Synthesis by Avoid the Interferences, Independent Journal of Management & Production, 5(2):275-298.

Petrescu, F.I., Petrescu R.V., 2014c Gear Design, ENGEVISTA, 16(4):313-328.

Petrescu, F.I., Petrescu, R.V., 2014d Balancing Otto Engines, International Review of Mechanical Engineering 8(3):473-480.

Petrescu, F.I., Petrescu, R.V., 2014e Machine Equations to the Classical Distribution, International Review of Mechanical Engineering 8(2):309-316.

Petrescu, F.I., Petrescu, R.V., 2014f Forces of Internal Combustion Heat Engines, International Review on Modelling and Simulations 7(1):206-212.

Petrescu, F.I., Petrescu, R.V., 2014g Determination of the Yield of Internal Combustion Thermal Engines, International Review of Mechanical Engineering 8(1):62-67.

Petrescu, F.I., Petrescu, R.V., 2014h Cam Dynamic Synthesis, Al-Khwarizmi Engineering Journal, 10(1):1-23.

Petrescu, F.I., Petrescu R.V., 2013a Dynamic Synthesis of the Rotary Cam and Translated Tappet with Roll, ENGEVISTA  15(3):325-332.

Petrescu, F.I., Petrescu, R.V., 2013b Cams with High Efficiency, International Review of Mechanical Engineering 7(4):599-606.

Petrescu, F.I., Petrescu, R.V., 2013c An Algorithm for Setting the Dynamic Parameters of the Classic Distribution Mechanism, International Review on Modelling and Simulations 6(5B):1637-1641.

Petrescu, F.I., Petrescu, R.V., 2013d Dynamic Synthesis of the Rotary Cam and Translated Tappet with Roll, International Review on Modelling and Simulations 6(2B):600-607.

Petrescu, F.I., Petrescu, R.V., 2013e Forces and Efficiency of Cams, International Review of Mechanical Engineering 7(3):507-511.

Petrescu, F.I., Petrescu, R.V., 2012a Echilibrarea motoarelor termice, Create Space publisher, USA, November 2012, ISBN 978-1-4811-2948-0, 40 pages, Romanian edition.

Petrescu, F.I., Petrescu, R.V., 2012b Camshaft Precision, Create Space publisher, USA, November 2012, ISBN 978-1-4810-8316-4, 88 pages, English edition.

Petrescu, F.I., Petrescu, R.V., 2012c Motoare termice, Create Space publisher, USA, October 2012, ISBN 978-1-4802-0488-1, 164 pages, Romanian edition.

Petrescu, F.I., Petrescu, R.V., 2011a Dinamica mecanismelor de distributie, Create Space publisher, USA, December 2011, ISBN 978-1-4680-5265-7, 188 pages, Romanian version.

Petrescu, F.I., Petrescu, R.V., 2011b Trenuri planetare, Create Space publisher, USA, December 2011, ISBN 978-1-4680-3041-9, 204 pages, Romanian version.

Petrescu, F.I., Petrescu, R.V., 2011c Gear Solutions, Create Space publisher, USA, November 2011, ISBN 978-1-4679-8764-6, 72 pages, English version.

Petrescu, F.I. and R.V. Petrescu, 2005. Contributions at the dynamics of cams. Proceedings of the 9th IFToMM International Symposium on Theory of Machines and Mechanisms, (TMM’ 05), Bucharest, Romania, pp: 123-128.

Petrescu, F. and R. Petrescu, 1995. Contributii la sinteza mecanismelor de distributie ale motoarelor cu ardere internã. Proceedings of the ESFA Conferinta, (ESFA’ 95), Bucuresti, pp: 257-264.

Petrescu, FIT., 2015a Geometrical Synthesis of the Distribution Mechanisms, American Journal of Engineering and Applied Sciences, 8(1):63-81. DOI: 10.3844/ajeassp.2015.63.81

Petrescu, FIT., 2015b Machine Motion Equations at the Internal Combustion Heat Engines, American Journal of Engineering and Applied Sciences, 8(1):127-137. DOI: 10.3844/ajeassp.2015.127.137

Petrescu, F.I., 2012b Teoria mecanismelor – Curs si aplicatii (editia a doua), Create Space publisher, USA, September 2012, ISBN 978-1-4792-9362-9, 284 pages, Romanian version, DOI: 10.13140/RG.2.1.2917.1926

Petrescu, F.I., 2008. Theoretical and applied contributions about the dynamic of planar mechanisms with superior joints. PhD Thesis, Bucharest Polytechnic University.

Petrescu, FIT.; Calautit, JK.; Mirsayar, M.; Marinkovic, D.; 2015 Structural Dynamics of the Distribution Mechanism with Rocking Tappet with Roll, American Journal of Engineering and Applied Sciences, 8(4):589-601. DOI: 10.3844/ajeassp.2015.589.601

Petrescu, FIT.; Calautit, JK.; 2016 About Nano Fusion and Dynamic Fusion, American Journal of Applied Sciences, 13(3):261-266.

Petrescu, R.V.V., R. Aversa, A. Apicella, F. Berto and S. Li et al., 2016a. Ecosphere protection through green energy. Am. J. Applied Sci., 13: 1027-1032. DOI: 10.3844/ajassp.2016.1027.1032

Petrescu, F.I.T., A. Apicella, R.V.V. Petrescu, S.P. Kozaitis and R.B. Bucinell et al., 2016b. Environmental protection through nuclear energy. Am. J. Applied Sci., 13: 941-946.

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Bucinell, Ronald; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017a Modern Propulsions for Aerospace-A Review, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Bucinell, Ronald; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017b Modern Propulsions for Aerospace-Part II, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Bucinell, Ronald; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017c History of Aviation-A Short Review, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Bucinell, Ronald; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017d Lockheed Martin-A Short Review, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017e Our Universe, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017f What is a UFO?, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, RV., Aversa, R., Akash, B., Corchado, J., Berto, F., Mirsayar, MM., Apicella, A., Petrescu, FIT., 2017 About Bell Helicopter FCX-001 Concept Aircraft-A Short Review, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, RV., Aversa, R., Akash, B., Corchado, J., Berto, F., Mirsayar, MM., Apicella, A., Petrescu, FIT., 2017 Home at Airbus, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, RV., Aversa, R., Akash, B., Corchado, J., Berto, F., Mirsayar, MM., Kozaitis, S., Abu-Lebdeh, T., Apicella, A., Petrescu, FIT., 2017 Airlander, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, RV., Aversa, R., Akash, B., Corchado, J., Berto, F., Apicella, A., Petrescu, FIT., 2017 When Boeing is Dreaming – a Review, Journal of Aircraft and Spacecraft Technology, 1(1).