Boeing X-48

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X-48
X-48B
Role Experimental unmanned aerial vehicle
Manufacturer Boeing
First flight July 20, 2007
Status In testing
Primary user NASA
Produced 2

The X-48 is an experimental unmanned aerial vehicle (UAV) for investigation into the characteristics of blended wing body (BWB) aircraft, a type of flying wing. It is currently under development by Boeing and NASA.

Contents

[edit] Design and development

[edit] Background

Boeing had studied a blended wing body design. It found that passengers did not like the theater-like configuration of the mock-up. The company dropped the design for passenger airliners, but reserved it for military aircraft such as tankers.[N 1]

McDonnell Douglas developed the X-48 concept in the late 1990s, and presented it during an annual Joint AIAA/ASME/SAE/ASEA Propulsion Conference in 2004.[2] The McDonnell Douglas engineers were confident that their design had all the advantages mentioned, but their concept, code named "Project Redwood" found little favor at Boeing after their merger.[3] The most difficult problem they solved was that of ensuring passengers a safe and fast escape in case of an accident, since emergency door locations were completely different from those in a conventional aircraft.[4]

The blended wing body (BWB) concept offers advantages in structural, aerodynamic and operating efficiencies over today's more conventional fuselage-and-wing designs. These features translate into greater range, fuel economy, reliability and life cycle savings, as well as lower manufacturing costs. They also allow for a wide variety of potential military and commercial applications.[5]

[edit] X-48

Boeing X-48B flight test vehicle on display at the 2006 Edwards Airshow

Boeing Phantom Works is developing the blended wing body aircraft concept in cooperation with the NASA Langley Research Center. In an initial effort to study the flight characteristics of the BWB design, a remote-controlled propeller-driven blended wing body model with a 17 ft (5.2 m) wingspan was successfully flown in 1997. The next step was to fly the 35 ft (10.7 m) wide X-48A in 2004, but that program was later canceled.[6]

Boeing Phantom Works is focusing current research on a pair of models, called the X-48B, which were built under contract by Cranfield Aerospace in the United Kingdom. Norman Princen, Boeing's chief engineer for the project, said, "Earlier wind-tunnel testing and the upcoming flight testing are focused on learning more about the BWB's low-speed flight-control characteristics, especially during takeoffs and landings. Knowing how accurately our models predict these characteristics is an important step in the further development of this concept."[7]

The X-48B has a 21-foot (6.4 m) wingspan, weighs 392-pound (178 kg), and is built from composite materials. It is powered by three small turbojet engines and is expected to fly at up to 120 kn (220 km/h) and reach an altitude of 10,000 feet (3,000 m).[7][8] The X-48B is a scaled down from a conceptual 240-foot wide design. Though passenger versions of the X-48B have been proposed, the design has a higher probability of first being used for a military transport.[9]

X-48B on its first flight

Wind tunnel testing on a 12 ft wide blended wing body model was completed in September 2005.[10][11] During April and May 2006, NASA performed wind tunnel tests on X-48B Ship 1, an 8.5% scale model, at a facility shared by Langley and Old Dominion University.[11][12] After the wind tunnel testing, the vehicle was shipped to NASA's Dryden Flight Research Center at Edwards Air Force Base to serve as a backup to X-48B Ship 2 for flight testing.[13] In November 2006, ground testing began at Dryden, to validate the aircraft's systems integrity, telemetry and communications links, flight-control software and taxi and takeoff characteristics.

X-48B at first flight, seen from below

The X-48B first flew on July 20, 2007, reaching an altitude of 7,500 ft (2,286 m); the flight lasting 31 minutes.[13][14][15] This began flight testing. The remotely-piloted aircraft was successfully stalled for the first time on September 4, 2008, with fixed leading edge slats, a forward center of gravity, and 23-degree angle of attack (2° beyond the maximum coefficient of lift). Stall testing was repeated on September 11 with a NASA pilot at the console.[16]

On March 19, 2010, NASA and Boeing successfully completed initial flight testing of the X-48B.[17] Fay Collier, manager of the ERA Project in NASA's Aeronautics Research Mission Directorate commented on the completion of the first phase of testing saying, "This project is a huge success. Bottom line: the team has proven the ability to fly tailless aircraft to the edge of the low-speed envelope safely."[18]

Following the installation of a new flight computer later this year, the Boeing X-48B will continue a new phase of flights tests that are to focus on additional parameter identification investigations. In addition, the team managing the project is also preparing a second hybrid wing body aircraft: the X-48C for future flight tests, which is intended to have a lower noise profile.[19]

[edit] X-48C

A second phase of flight tests with the X-48B was to begin in September 2010. Afterward, the second X-48B will be modified into the X-48C for flight tests in 2011. The X-48C will have its vertical stabilisers moved inboard on either side of the engines, and its fuselage extended aft, both in an attempt to reduce the aircraft's noise profile, and will be powered by two JetCat turbines, each producing 80 pounds-force (0.36 kN) of thrust.[20][21]

[edit] Variants

A three percent scale model of the X-48C being tested in NASA Langley's 12-Ft Low-Speed Tunnel.
X-48A
The initial planned 35 ft (10.7 m) wide version. It was canceled before manufacture.
X-48B
Two 8.5% scale aircraft that have been used for flight testing.
X-48C
A modified version of the X-48B.

[edit] Specifications (X-48B)

Data from [22][23]

General characteristics

  • Crew: None
  • Wingspan: 20 ft 5 in (6.22 m)
  • Wing area: 100.5 sq ft (9.34 m2)
  • Aspect ratio: 4.1
  • Gross weight: 500 lb (227 kg)
  • Powerplant: 3 × JetCat P200 turbojet, 52 lbf (0.23 kN) thrust each

Performance

  • Maximum speed: 136 mph; 219 km/h (118 kn)
  • Endurance: 40 minutes
  • Service ceiling: 10,000 ft (3,048 m)

[edit] See also

Related lists

[edit] References

Notes
  1. ^ Quote: Boeing once toyed with a blended wing-body, a sort of flying wing, to produce dramatically better aerodynamics and fuel efficiency. Passengers would have sat in a wide cabin, rather like a small amphitheater. But tests with a mock-up produced such a negative reaction that the company dropped the technology, except for military refueling aircraft.[1]
Citations
  1. ^ "Aircraft emissions" (fee required). The Economist, June 8, 2006. Retrieved: April 11, 2007.
  2. ^ Liebeck 2004, p. 10.
  3. ^ Norris and Wagner 2009, p. 18.
  4. ^ Liebeck 2004, p. 24.
  5. ^ [www.boeing.com/companyoffices/financial/.../Boeing_06AR_10.pdf "Technology Development."] Boeing. Retrieved: June 26, 2011.
  6. ^ Parsch, Andreas. "Boeing X-48." designation-systems.net, November 24, 2009.
  7. ^ a b Koehler, Tom. "Boeing to Begin Ground Testing of X-48B Blended Wing Body Concept." Boeing, October 27, 2006. Retrieved: October 24, 2010.
  8. ^ Warwick, Graham. "British blend: UAV X-planes help Boeing with blended wing concept." Flight International, May 30, 2006.
  9. ^ Jacobs, Karrie. "Thinking Outside the Tube." Wired, February 2007. Retrieved: April 11, 2007.
  10. ^ Coppinger, Rob. "X-48B scale model to fly next year." Flight International, November 22, 2005. Retrieved: April 11, 2007.
  11. ^ a b Morris, Jefferson. "Blended Wing Body Prototype Wrapping Up Wind Tunnel Tests." AviationWeek.com, May 8, 2006.
  12. ^ Barnstorff, Kathy. "The X-48B Blended Wing Body." NASA Langley Research Center, May 4, 2006. Retrieved: April 11, 2007.
  13. ^ a b Koehler, Tom and Daryl Stephenson. "Boeing Flies Blended Wind Body Research Aircraft." Boeing, July 26, 2007.
  14. ^ Creech, Gray. "X-48B Blended Wing Body Research Aircraft Takes First Flight." NASA Press Release, July 26, 2007. Retrieved: July 26, 2007.
  15. ^ Creech, Gray. "Skyray 48 Takes Flight." NASA, September 11, 2007. Retrieved: July 25, 2011.
  16. ^ "Stall Success". Aviation Week & Space Technology, Vol. 169, No. 10, September 15, 2008, p. 20.
  17. ^ Paur, Jason. "NASA's Mini X-Plane Completes Initial Flight Testing." Autopia, Wired.com, April 6, 2010.
  18. ^ Creech, Gray. "X-48B BWB Team Completes Phase 1 Test Flights." NASA, April 6, 2010.
  19. ^ Cohen, Aubrey. "NASA-Boeing team done first flight phase of blended wing body plane." seattlepi.com, April 6, 2010.
  20. ^ "NASA Demonstrates Controllability of X-48B". Aviation Week & Space Technology, Vol. 172, No. 14, April 12, 2010, p. 19.
  21. ^ Mecham, Michael. "New Tests Pending For X-48 Flying Wing." Aviation Week & Space Technology, September 10, 2010.
  22. ^ Parsch, Andreas. "Boeing X-48." Designation-Systems.net, June 2009. Retrieved: April 7, 2010.
  23. ^ "X-48B Blended Wing Body." NASA, February 11, 2010. Retrieved: April 7, 2010.
Bibliography

[edit] External links

USAF/Joint Service experimental aircraft (X-plane) designations since 1941
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See also
1 Unused, to avoid confusion with the B-52.
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