Flying wing

Flying wing : in aeronautics, call the plane that does not need a tail for stable flight, its design being an airplane that all its elements such as cockpit, weapons depots, fuel, among other things are housed in a wing proper. In some cases it totally lacks a differentiated fuselage. Despite its futuristic design, the concept of this aircraft began to arise in the 1920s and 1930s and it was not until 1944 when the first aircraft of these characteristics came to light.

Summary

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  • 1 History
    • 1 The Horten Brothers
    • 2 In the United States
  • 2 New concept
  • 3 Sources

History

The first studies of delta wings led aeronautical designers to think whether an entire aircraft could consist of only one wing, without basically any fuselage whatsoever. Such an all-wing aircraft would have excellent payload and range capabilities because they would produce less friction than a conventional aircraft. This was true because the tail and the fuselage normally cause a significant amount of friction. Remove the tail and the fuselage and you will have eliminated a lot of friction, enhanced performance, reduced the amount of fuel required, and improved airplane steering capabilities. These supposed designs of the wing of the flight were for a long time a dream of a many designers but they did not become practical until recently.

Hugo Junkers patented in 1910 an air transport design with only one wing. He saw in this the natural solution to the problem of constructing a large enough airline to carry a reasonable number of passengers and load the fuel that would allow him to cross the Atlantic .

In 1919 he began working on the design of his JG1, designed to seat passengers inside the thick wings, but two years later the Allied Commission for Aeronautical Control ordered that the incomplete JG1 be destroyed for exceeding the limits imposed on aviation German in the post-war.

Even so, Junkers devised futuristic flying wings, with capacity for up to a thousand passengers. The closest he got to making them a reality was in 1931 , with the Junkers G-38 , a line plane that had a large wide wing with room for fuel, engines and two passenger cabins. However, I still needed a small fuselage to house the crew and a part of the passage.

In the 1930s and 1940s, the wing configuration was extensively studied, notably by Jack Northrop and Cheston L. Eshelman in the United States and Alexander Lippisch with the Horten brothers in Germany . In the USSR , Soviet designers such as Boris Ivanovich Cheranovsky began their studies independently after 1920 .

Jack Northrop, innovative designer and aircraft builder decided to develop a flying wing. In the 40s, he began working on a closed number of flying wing designs. These included the Mx-334 “Rocket Wing,” the “Flying Ram” interceptor, the Xp-79b, the Mx-543 piloted glider and the Jb-1a flying pump. But his latest progress was the Xb-35 and the flying wings Yb-49, which were prototypes of strategic bombers. The Xb-35 were powered by four large piston engines with additional rockets mounted behind each engine. It had a range of more than 5,000 miles (8,047 kilometers) with a payload of 10,000 pounds (4,536-kilograms). Northrop received an initial contract for an Xb-35, approved in November 1941 and an order for an additional Xb-35 as a reservation in January 1942. But the design was too complex because of its power plant and lost strength against the Convair B-36 for the role of the next air force strategic bomber in the 40s, of the 15 B-35s built, only three flew. The Xb-35 served as a test bench for the Yb-49, which was “pushed” by eight turbojet engines. The Yb-49 had four relatively small vertical tailfins mounted at the rear of the wing, but it was a startling aircraft, it looked like a giant arrowhead. Although of radical design, the Yb-49 had numerous problems. The most significant was his lack of stability, which made it extremely difficult to fly. A fall in June 1948 in which five crew members died, including Captain Glen Edwards, (which gave name to the Edwards base) further damaged its commercial possibilities. The project was canceled in 1949 and Jack Northrop was practically banned from the bomber construction business, fell into depression and bitterness, feeling that the air force had treated his plane unfairly.

Northrop was not the only person interested in flying wings. Walter and Reimar Horten were two German brothers who were interested in delta wings in the 1930s. By the 1940s they proposed a tailless jet airplane that was a flying wing, the Ho IX or GOTHA 229. The Ho IX was a fighter that It would have had a top speed of 620 miles per hour (998 kilometers per hour), assuming it could be done to fly. But although the work was started in a prototype, the world war ended before it was finished. Many of those who built Ho IX doubted that he had always flown successfully on all types of missions.

The only successful flying wing was the Northrop-Grumman B-2 Stealth bomber. Northrop Corporation began in the late 1970s (the contract was granted in 1981 ; its first flight was in 1989) but did not become fully operational until a decade and a half later due to its complexity and numerous initial problems. The B-2 is an example of modern technology that relaunched an earlier idea. By the 1970s, aeronautical designers developed airplanes such as the F-16s that were unstable and therefore very maneuverable, controlling them in flight by sophisticated computerized control systems. The digital control systems also allowed to control the unstable design of the flying wing. The excellent advantages of efficiency in the operation and fuel of the Flying Wing were not only maintained but improved. But Northrop designers also chose a Flying Wing configuration because it offered stealth advantages; a vertical tail as in a conventional airplane produces reflexes that can be detected by a radar. Its elimination increased the stealthiness of the plane, particularly on the side. Only 21 of these aircraft are in service, they played an important role in the 1999 bombing of Yugoslavia, which had a sophisticated air defense system, and is generally seen as an amazing, but very expensive technological achievement.

The Horten Brothers

Walter Horten ( November 13, 1913 – December 9, 1998 in Baden-Baden) and Reimar Horten ( March 12 , 1915 to March 14 , 1994 in Villa General Belgrano, Argentina ). Known as the Horten Brothers , they were 2 young pilots and engineers members of the Hitler Youth and the Nazi Party .

Photograph of the Horten brothers during World War II

The Horten brothers had been interested in designing a flying wing as a method to improve glider performance. At that time, the German government was financing glider clubs because the production of motorized military aircraft was prohibited by the Treaty of Versailles after the First World War .

The Horten argued that the design of the flying wing eliminated any unnecessary surface, and at least in theory, led to the least possible resistance. This configuration consisted of two relatively shorter wings, without the resistance generated by the fuselage. The result was the Horten H-IV.

Although he had little, or no formal training in aeronautics or related areas, the Hortens designed some of the most advanced aircraft of the 1940s , including the first jet power jet, the Horten Ho 229 .

In the U.S

The aeronautical magazines of the thirties, with extensive reports on the work of the Horten, drew attention in North America to John Knudsen “Jack” Northrop, aeronautical engineer, who after occupying positions in the Douglas and Lockheed companies, began to develop aircraft completely of alar structure, in its own company, the Northrop Corporation. He became obsessed with flying wings, he considered that these were the next step in the aviation industry and the future of aviation.

Nothrop N-1M flying wing built in 1929

He made interesting projects like the Northrop N-1M , the N9-M , the YB-35 (the first flying wing bomber in history) and the YB-49 (jet bomber) although he could never get a plane in the form of a flying wing That will fly with full guarantees. His designs and tests were plagued with technical problems and accidents so his projects were gradually canceled.

Shortly before his death in 1981, “Jack” Northrop could see his dream come true in the B-2 Spirit that would finally adapt the design of a flying wing as a powerful bomber. As anecdotal data it should be noted that the B-2 Spirit (projected during the eighties) cost about 23 billion US dollars and about 13,000 people participated in its design and production. With this one can get the idea of ​​how extremely difficult it was to get a flying wing of optimal performance although the appearance of this aircraft is simply spectacular.

New concept

The pressure for the increase of the costs and for the search of a reduction of emissions, are causing that all the aeronautical industry investigates to obtain efficiency. Among them, NASA is conducting research on track to a new platform that could be available by 2020 .

The concept is not new, it comes from prototypes that were devised in the 1940s, but neither the technology of the time nor the economy allowed its development. It is the concept of “Flying Wing”. The advance in composite materials and the “fly by wire” concept can allow the flying wing format to develop. Among the benefits of this structure are the following:

  • Unlike tube-shaped fuselages, wing-shaped fuselages contribute to lift, reducing the power required for takeoff.
  • A global aerodynamic surface (general wing shape and without tail instep) will provide a substantial reduction in the resistance generated by said aircraft.
  • You can increase the number of passengers transported up to 1000 without increasing the physical space that the aircraft would need at an airport (compared to the A380).

However, these ideas are so easy to apply. A wing-shaped development implies difficulty in making the structure and surface of said aircraft. One of the advantages we currently have is the technological development achieved in the composting of composite materials, although a fuselage of composite material never ceases to be free of possible failures due to delamination of the material due in large part to the compression-decompression cycles .

Another essential element for the success of this project is the control of the aircraft. An aircraft without tail gear at low speeds is difficult to control. This necessitates the control of said aircraft and of the control surfaces in a “computational” way, that is to say by means of “fly by wire”. At present, 95% of the new developments that are carried out incorporate the “fly by wire” technology, but this does not imply that it has a sufficiently high level of reliability to be incorporated into the flying wing.

Therefore, it is optimistic to think about a complete and operational development of a flying wing by 2020 (as NASA expects), but without a doubt what is an achievable milestone is that before that date we will see the first prototypes flying.

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