Bell Boeing Quad TiltRotor
From Wikipedia, the free encyclopedia
| Quad TiltRotor | |
|---|---|
| Type | Cargo helicopter |
| Manufacturer | Bell / Boeing |
| Status | Study |
The Bell Boeing Quad TiltRotor (QTR) is a proposed four-rotor derivative of the V-22 Osprey tiltrotor being developed jointly by Bell Helicopter Textron and Boeing Integrated Defense Systems. The concept is a contender in the U.S. Army's Joint Heavy Lift program. It would have a cargo capacity roughly equivalent to the C-130 Hercules, cruise at 250 knots, and land at unimproved sites vertically like a helicopter.[1]
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[edit] Development
Bell and Boeing have received a cost-sharing contract worth US$3.45 million from the U.S. Army's Aviation Applied Technology Directorate for an 18-month conceptual design and analysis study lasting through March 2007, in conjunction with the Joint Heavy Lift program.[2][3] The contract was awarded to Bell Helicopter, which is teaming with Boeing's Phantom Works. The QTR study is one of five designs; another of the five is also a Boeing program, an advanced version of the CH-47 Chinook.[1]
During the initial baseline design study, Bell's engineers are designing the wing, engine and rotor, while the Boeing team is designing the fuselage and internal systems.[4]
A one-fifth-scale wind tunnel model has undergone testing in the Transonic Dynamics Tunnel (a unique transonic wind tunnel) at NASA's Langley Research Center during summer 2006. The "semi-span" model (representing the right half of the aircraft) measured 213 inches in length, and had powered 91-inch rotors, operational nacelles, "dynamically representative" wings.[5]
The primary test objective was to study the aeroelastic effects on the aft wing of the forward wing's rotors and establish a baseline aircraft configuration.[1] Alan Ewing, Bell's QTR program manager, reported that "Testing showed those loads from that vortex on the rear rotor [are the] same as the loads we see on the front [rotors]," and "Aeroelastic stability of the wing looks exactly the same as the conventional tiltrotor". These tests used a model with a three-bladed rotor, future tests will explore the effects of using a four-bladed system.[4]
Besides the research performed jointly under the contract, Bell has funded additional research and wind tunnel testing in cooperation with NASA and the Army.[6] After submission of initial concept study reports, testing of full-scale components and possibly a sub-scale vehicle test program was expected to begin.[1] Pending approval, first flight of a full-scale prototype aircraft was slated for 2012.[4]
The study was completed in May 2007,[7] with the Quad TiltRotor selected for further development. However, additional armor on Future Combat Systems (FCS) vehicles caused their weight to increase from 20 tons to 27 tons which requires a larger aircraft.[8]
[edit] Design
The conceptual design is for a large tandem wing aircraft with V-22 type engines and 50-foot rotors at each of the four wing tips. The C-130-size fuselage would have a 747-inch-long cargo bay with a rear loading ramp that could carry 110 paratroopers or 150 standard-seating passengers. In cargo configuration, it would accommodate eight 463L pallets.[4]
In addition to the baseline configuration, the Bell-Boeing team is including eight possible variants, or "excursion designs", including a sea-based variant. The design team is planning on payloads ranging from 16 to 26 tons and a range of 420 to 1000 nm. The baseline version includes a fully retractable refueling probe and an interconnecting drive system for power redundancy.[4]
One of the design excursions explored by the team, dubbed the "Big Boy", would have 55-foot rotors and an 815-inch-long cargo bay, making it able to carry one additional 463L pallet, and accommodate a Stryker armored combat vehicle.[4]
[edit] See also
Related development
Comparable aircraft
Related lists
[edit] References
- ^ a b c d "Diversity in Design: Boeing offers 2 of 5 development options in rotorcraft program", Boeing Frontiers magazine, January 2007.
- ^ "Boeing receives two study contracts from U.S. Army for Joint Heavy Lift", Boeing press release, 2005-09-23
- ^ Bell-Boeing's QTR selected for Heavy Lift study
- ^ a b c d e f Fein, Geoff , "Bell-Boeing Quadtiltrotor completes first wind tunnel testing", Defense Daily, 2006-10-13.
- ^ Wind Tunnel testing completed on Bell Boeing quad tiltrotor, Helis.com, September 13, 2006.
- ^ "Wind Tunnel testing completed on Bell Boeing quad tiltrotor", Rotorbreeze, p. 14, October 2006.
- ^ "Heavy duty: US Army backs tiltrotor as future battlefield airlifter", Flight International, 14 January 2008.
- ^ Osborn, Kris. "USAF, Army Merge Heavy-Lift Efforts", Defensenews.com, 14 April 2008.
[edit] External links
- V-44: Pentagon's Next Air Transport, Popular Mechanics, September 2000
- Quad Tiltrotor QTR page on GlobalSecurity.org
- Bell Tilt Rotors on VTOL.org
- "CH-53X HLR & JHL: Future Heli Programs on Collision Course?", Defense Industry Daily, 2005-09-27
- Bell and Boeing working on quad tilt-rotor design, Dallas Morning News, 2006-08-24
- "US Army looking at three configuration concepts for large cargo rotorcraft", Flight International, October 9, 2007
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