Boeing 2707
| Boeing 2707 | |
|---|---|
 Draft of the B-2707-300 |
|
| Type: | Supersonic - airliner |
| Design country: | |
| Manufacturer: | |
| First flight: |
Never happened |
| Commissioning: |
Development canceled in 1971 |
| Production time: |
Was never produced |
| Number of pieces: |
0 |
The Boeing Model 2707 (until September 1966 Model 733 ), the project was a supersonic - commercial aircraft of the US manufacturer Boeing .
history
Boeing's research into civil supersonic flight began in 1952, but was discontinued after a short time when it became clear that the cost of designing and manufacturing a corresponding prototype would far exceed the capabilities of a single company. Only concept studies were carried out until 1958, only afterwards the project status was achieved and finally in 1966 the “supersonic transport division ” was founded at Boeing. NASA and other American aircraft manufacturers worked with Boeing to solve the problems in this area.
In 1963, the US government also recognized that the development costs for a supersonic airliner could not be raised by a single manufacturer, and therefore announced a design competition for an American SST ( Supersonic Transport ). Funding of one or more prototypes of the winning design should then largely come from government funds. Since no adequate engine was available for the SST, a jet engine in the 35,000 to 40,000 lb class (156 to 178 kN) was to be developed in a separate competition.
The development was funded by government grants from the SCAT project (Supersonic Commercial Air Transport), the later SST project, which advanced 75% of the development costs.
Competitive designs in the SCAT project were the Convair model 58-9 , Douglas 2229 , Lockheed L-2000 and the North American NAC-60 . The NAC-60 was eliminated prematurely because of its excessive air resistance. In addition to General Electric , Pratt & Whitney and Curtiss-Wright also applied for the engine contract. Curtiss-Wright was also eliminated.
Model 733
At the end of the first phase of the SST competition in January 1964, Boeing presented a design for 150 to 227 passengers, which was given the factory designation Model 733. The intended cruising speed was Mach 2.7 (about 2900 km / h). The expected heating of the airframe as a result of air friction forced the designers to use a titanium alloy for the structure instead of the aluminum alloy customary in aircraft construction. The Boeing 733 had a relatively conventional fuselage with a tail unit and four individual engines in nacelles. These had to be located under the non-pivoting wing extensions (similar to where the engine nacelles for two engines were attached later on the Rockwell B-1 or Tupolew Tu-160 ). The wings were pivotable between a sweep of 74 ° and 20 °. In the 20 ° position, the supersonic aircraft should be able to get along with the same runways as were required by the intercontinental aircraft of that time.
2707-100
Even before the end of the second phase of the SST competition in September 1966, Boeing reconsidered the expected economic viability of the previous concept and then presented a revised, enlarged design, which was now referred to as Model 2707 or B-2707. The old name Model 733 has been completely dropped. The swivel wing design was retained, but the passenger capacity was increased to over 300 passengers - other sources only give 241 - and the engines were relocated to the rear under the surfaces of the horizontal stabilizer. When fully swiveled back, the structure formed a delta wing . To improve slow flight characteristics, triple slit flaps and nose flaps were provided.
To improve visibility during take-off, landing and taxiing, a lowerable nose was introduced, as was also used on the Concorde . To ensure the necessary ground clearance, a second joint was provided further forward so that the radome can be pivoted upwards a little.
2707-200
On December 31, 1966, the Federal Aviation Agency announced Boeing as the winner of the SST competition and General Electric as the winner of the engine competition. On September 23, 1969, Richard Nixon approved the construction of two prototypes, the first flight for early 1973 and the start of production for 1973/74 were considered realistic. Approval should then take place in 1978. Since the 2707-100 had problems with stability in the wind tunnel, it was further developed into the Boeing 2707-200. This had a longer body and additional duck wings , which led to significant excess weight. The 2707-200 would have had 292 seats at 97 m length.
2707-300
In the meantime, Boeing had removed the use of a swivel wing from the concept and provided a fixed delta wing together with a conventional tail unit for the 2707-300. The wing structure should be converted from the original panel planking (machine planking) to a sandwich planking. The four engines were mounted in individual nacelles on the wing's trailing edge. The machine was shortened. The new version should only have 234 seats. Unlike the competition from Tupolew and Concorde , it should have a classic tail unit with elevators at the rear . The General Electric GE4 / J5P intended for the 2707-300 would have achieved a thrust of 290 kN with an afterburner and 222 kN without it. The consumption per engine would have been 35,000 l / h with or 14,200 l / h without an afterburner.
End of program
In 1970, 26 airlines had already placed orders for a total of 122 aircraft. However, before construction of the two prototypes could actually begin, the US Congress suspended the project on March 24, 1971. These decisions were confirmed by the 1973 oil crisis , as it made passenger traffic with supersonic aircraft unprofitable. The elaborately manufactured dummy of the 2707-200 was sold and was supposed to be exhibited in an amusement park in Florida. After the front part of the mock-up was exhibited in the Hiller Aviation Museum for a few years , it was acquired by the Museum of Flight in 2013 and is currently in its restoration department.
The Smithsonian has still a General Electric GE 4 - Turbojet -Triebwerk.
construction
At the planned cruising speed of approx. Mach 2.7, the hull heats up to over 200 ° C due to air friction, so that aluminum can no longer be used as a structural material. The machine was therefore to be made of a titanium alloy and also had a double fuselage shell to reduce the risk of decompression at altitudes of up to 21,000 meters.
Orders
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Technical specifications
| Data | 2707-100 | 2707-200 | 2707-300 |
|---|---|---|---|
| Passengers | 292-350 | 292 | 200-300 |
| length | 96.93 m | 85.34 m | |
| span | 43.18 m | ||
| height | 15.24 m | ||
| payload | 22,185 kg | ||
| Max. Takeoff mass | 306,200 kg | ||
| Cruising speed | Mach 2.7 | ||
| Cruising altitude | 18,300-21,340 m | ||
| Climb performance | 1100 m / min | ||
| Range with 234 passengers | 5900 km | ||
| Fuel consumption while cruising | 56,000 l / h | ||
literature
- Bernhard Aib: The shrunken sky. In: Flug Revue November 1966, p. 14ff.
- Peter M. Bowers : Boeing Aircraft since 1916. 2nd edition, Putnam Aeronautical Books, 1989, ISBN 0-85177-804-6
- Helmut Kreuzer: Supersonic airliners. The history of supersonic aviation . From vision to reality. 1st edition. Air Gallery Ed., Erding 2003, ISBN 3-9805934-4-4 .
- Norman Lynn: The long road of the American SST. In: Flug Revue February 1969, pp. 24–28.
- Norman Lynn: SST object of dispute. In: Flug Revue March 1971, p. 16ff.
- Günther Molter: The American SST. In: Flug Revue February 1967, pp. 9-16.
Web links
- Hiller Aviation Museum (English)
- The Boeing 2707 at globalsecurity.org (English)
- Section through a GE4 engine
Individual evidence
- ↑ Cruiser: Supersonic airliners. The history of supersonic aviation. 2003, p. 31.
- ↑ a b c d Patrick Hoveler: The US supersonic airliner projects. Defeat against Europe. In: Flug Revue March 2011.
- ↑ Chambers, Joseph R .: Innovation in Flight. Research of the NASA Langley Research Center on Revolutionary Advanced Concepts for Aeronautics. NASA Langley Research Center, 2005, NASA SP-2005-4539, on NASA Technical Report Server (PDF; 8.3 MB) p. 28.
- ↑ see pictures at GlobalSecurity.org
- ↑ In FLUG REVUE August 1966, p. 60, the name Boeing 733 is still used.
- ^ Bowers, p. 558.
- ↑ a b Flying from the propeller to the jet propulsion. Commercial Aircraft - Developments and Limits. Authorized edition for Kaiser Verlag, Klagenfurt, ISBN 3-7043-6030-9 , p. 167.
- ↑ a b cruiser: supersonic airliners. The history of supersonic aviation. 2003, p. 40.
- ↑ Norbert Norton: Flying in the future. Adventure aviation. Engelbert-Verlag, Balve 1972, ISBN 3-536-00956-5 , p. 72.
- ↑ Lynn: The long way of the American SST. 1969, p. 28.
- ↑ a b c d e cruiser: supersonic airliners. The history of supersonic aviation. 2003, p. 45