Showing posts with label aircrafts. Show all posts
Showing posts with label aircrafts. Show all posts

22 Oct 2011

‘Son of Osprey’ to Replace All Army Copters

The V-22 Osprey tiltrotor flown by the Marines and Air Force crashes or burns much more often than the military cares to admit. But that hasn’t stopped Osprey-maker Boeing from pitching a new tiltrotor for an ambitious Army program aimed at replacing almost everything the ground combat branch flies … with a single aircraft design.
That’s potentially thousands of new tiltrotors, which take off vertically like helicopters but fly fast like airplanes, thanks to their rotating engine nacelles — but which are also vulnerable to dangerous aerodynamic phenomena and, in the V-22’s case, have been plagued by engine problems.
By continuing to invest in the V-22, the Pentagon is doubling down on a risky bet. If Boeing’s “son of Osprey” gets the greenlight for the comprehensive Joint Multi-Role program, the military will be going all in. But a lot could change between now and 2025, when the first of the new rotorcraft is (loosely) scheduled to enter service. And there’s reason to believe a new tiltrotor could avoid the pitfalls of the Osprey’s design.
Boeing showed off some preliminary artwork of their Joint Multi-Role tiltrotor at an Army confab in Washington, D.C., last week. The art shows a small, sleek scout version and a larger cargo model. “Those images are nothing more than artist concepts and not necessarily associated with a specific design philosophy,” Boeing spokesman Chris Haddox told Danger Room. “The work is just getting underway.”
All the same, the Boeing concept shows apparent improvements over the V-22. Specifically, simpler wings and better rotors.
To fit aboard the Navy assault ships that carry Marines into battle, the V-22 had to have a wing that could fold back along the fuselage — at the cost of extra weight and complexity. The Osprey’s rotors also had to be smaller than ideal for a 25-ton aircraft, forcing the engines to work harder and run hotter.
Over the years, engineers have proposed solutions to this problem. Farhan Gandhi, an engineer at Penn State University, proposed a telescoping rotor blade that would automatically increase in length during a tiltrotor’s helicopter mode, increasing its lifting ability. One retired V-22 engineer told analyst Lee Gaillard that replacing the V-22’s three-blade rotor with a new, five-blade model (.pdf) would boost performance. In the end, Boeing opted for tweaks to the V-22’s software to squeeze every last bit of performance out of the existing design.
Boeing’s conceptual future tiltrotor seems to avoid these half-measures by incorporating bigger rotors from the outset on the scout model, and twin rotors — that is, two sets of blades on each nacelle — for the cargo version. An Army tiltrotor could probably also skip the folding wing mechanism, as seems to be the case in the artist’s renderings. The result could be a safer, better-performing tiltrotor than the troubled V-22.
Photo credit: US Air Force
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17 Oct 2011

First flight of X-47B unmanned aircraft demonstrator in cruise mode

The X-47B Unmanned Combat Air System flying with its landing gear up during a test flight at Edwards AFB, Calif.
Having completed its first flight earlier this year, the Northrop Grumman-built U.S. Navy X-47B Unmanned Combat Air System Demonstration (UCAS-D) aircraft achieved another milestone on September 30 with its first flight in cruise mode. Part of the on-going "envelope expansion" program to demonstrate the aircraft's performance under a variety of altitude, speed and fuel load conditions, the flight took place at Edwards Air Force Base and saw the aircraft retracting its landing gear and flying in cruise configuration for the first time.

The X-47B is being developed as a carrier-based unmanned aircraft offering a maximum refueled range of over 2,000 miles (3,219 km) and an endurance of more than six hours. The demonstrator carries no weapons, but has a full-sized weapons bay and is the same size and weight as the projected operational aircraft in order to provide realistic testing. The latest flight also tested precision navigation hardware and software that will allow the aircraft to land with precision on the moving deck of an aircraft carrier.

"Last week's flight gave us our first clean look at the aerodynamic cruise performance of the X-47B air system...and it is proving out all of our predictions," said Janis Pamiljans, vice president and Navy UCAS program manager for Northrop Grumman's Aerospace Systems sector. "Reaching this critical test point demonstrates the growing maturity of the air system, and its readiness to move to the next phase of flight testing."
Shore-based carrier suitability testing is due to begin in 2012, after the UCAS-D program begins transitioning aircraft to Naval Air Station, Patuxent River, Maryland, later this year. The three-year test program is set to culminate in sea trials in 2013.
(Gizmag)
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