X-plane thread(United states next generation)

[ScienceRocks]

US military to test hypersonic vehicle over Pacific: X-51A to reach Mach 6
August 14, 2012

The US military plans to launch a hypersonic unmanned vehicle in a test flight Tuesday over the Pacific, with the X-51A due to reach mind-boggling speeds of Mach 6, a spokesman said. The US military plans to launch a hypersonic unmanned vehicle in a test flight Tuesday over the Pacific, with the X-51A due to reach mind-boggling speeds of Mach 6, a spokesman said.

The Waverider, which resembles a missile with a flat nose, will be dropped off the wing of a B-52 bomber off the California coast at an altitude of about 15,000 meters (50,000 feet), according to the US Air Force. The latest test of the experimental vehicle is tentatively scheduled for 10 am local time (1700 GMT) at Edwards Air Force Base in southern California, spokesman Kenji Thuloweit told AFP. A solid rocket booster will catapult the vehicle to a speed of about Mach 4.5 in 30 seconds before the X-51A's engine accelerates to Mach 6, six times the speed of sound or more than 7,300 kilometers (4,500 miles) per hour. After a scheduled flight of about five minutes -- in which it is expected to reach an altitude of 21,000 meters (70,000 feet) -- the Waverider will splash down in the Pacific, the Air Force said.

The X-51A WaveRider, an unmanned aircraft that could reach speeds up to 3,600 mph (5,793 kph), will be launched from the wing of a B-52 on a test flight over the Pacific Ocean on August 14. Powered by a Pratt Whitney Rocketdyne SJY61 scramjet engine, it is designed to ride on its own shockwavem and accelerate to about Mach 6.There are no plans to recover the test vehicle. The X-51, at eight meters (25 feet) long, reached Mach 5 during its first test in May 2010, but the flight -- which lasted a little over three minutes -- ended earlier than planned due to a technical problem. Hypersonic flight renders conventional turbine jet engines useless due to the extraordinary heat and pressure generated at such high speeds. But Pentagon strategists see hypersonic aircraft as a promising technology that could dramatically bolster America's air power, comparing it to radar-evading stealth warplanes that emerged in the 1970s. Hypersonic technology eventually could be employed for long-range bombing, reconnaissance or transporting troops, analysts say. The X-51 is one of several hypersonic projects currently under way. In November 2011, the Pentagon successfully tested an "advanced hypersonic weapon," a bomb. In August 2011, the Pentagon test flew a hypersonic glider dubbed HTV-2, which is capable of flying 27,000 kilometers (17,000 miles) per hour, but the test ended in failure.

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US military to test hypersonic vehicle over Pacific: X-51A to reach Mach 6

 

[ScienceRocks]

The last one!

Transformed X-48c flies successfully
August 7, 2012

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Credit: NASA/Sean Smith

(Phys.org) -- The remotely piloted X-48C aircraft successfully flew for the first time Tuesday at Edwards Air Force Base in California's Mojave Desert.

The aircraft, designed by The Boeing Co. and built by Cranfield Aerospace Limited of the United Kingdom, is flying again in partnership with NASA. The new X-48C model, which was formerly the X-48B Blended Wing Body aircraft, was modified to evaluate the low-speed stability and control of a low-noise version of a notional, future Hybrid Wing Body (HWB) aircraft design. The HWB design stems from concept studies being conducted by NASA's Environmentally Responsible Aviation project of future potential aircraft designs 20 years from now.

"We are thrilled to get back in the air to start collecting data in this low-noise configuration," said Heather Maliska, X-48C project manager at NASA's Dryden Flight Research Center. "Our dedicated team has worked hard to get the X-48C off the ground for its first flight and we are excited learning about the stability and control characteristics of this low-noise configuration of the blended wing body."

Primary changes to the C model from the B model, which flew 92 flights at Dryden between 2007 and 2010, were geared to transforming it to an airframe noise-shielding configuration. External modifications included relocating the wingtip winglets inboard next to the engines, effectively turning them into twin tails. The aft deck of the aircraft was extended about 2 feet to the rear. Finally, the project team replaced the X-48B's three 50-pound thrust jet engines with two 89-pound thrust engines.

Because handling qualities of the X-48C will be different from those of the X-48B, the project team developed flight control system software modifications, including flight control limiters to keep the airplane flying within a safe flight envelope. This will enable a stronger and safer prototype flight control system suitable for future full-scale commercial hybrid or blended wing aircraft.

Transformed X-48c flies successfully

File:X-48B from above.jpg - Wikipedia, the free encyclopedia

 

[waltky]

X-51A Waverider hypersonic test fails...

Air Force's hypersonic test fails
August 15th, 2012 - A hypersonic aircraft launched by the Air Force Tuesday spiraled out of control and was destroyed before it could reach its goal of speeding to 4,600 mph, Pentagon officials said Wednesday.

The third test of the X-51A Waverider was launched Tuesday off the California coast from a B-52 modified bomber aircraft and was to fly for 300 seconds, reaching hypersonic speeds of Mach 6, but only flew for 16 seconds, according to the Air Force.

Officials said a problem with a tail fin caused the missile-like vehicle to fly out of control before the main engine could be ignited, leading researchers to destroy it early. "A fault was identified with one of the cruiser control fins. Once the X-51 separated from the rocket booster, approximately 15 seconds later, the cruiser was not able to maintain control due to the faulty control fin and was lost," said a statement issued by the Air Force. It's unclear what, if any, information was gleaned from the test. According to the statement, "Program officials will now begin the process of working through a rigorous evaluation to determine the exact cause of all factors at play."

The Air Force plans to go public with details of the failed test in a few weeks, after researchers are able to analyze the data from the flight. "It is unfortunate that a problem with this subsystem caused a termination before we could light the Scramjet engine," said Charlie Brink, X-51A Program Manager for Air Force Research Laboratory. "All our data showed we had created the right conditions for engine ignition and we were very hopeful to meet our test objectives." The Air Force had four X-51A Waveriders and has tested three. Officials said they do not yet know when or if the fourth Waverider will be tested.

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Will we be flying hypersonic jets one day?
August 15th, 2012 - Who needs business class when your overseas flight will last less than an hour? Some of the first tests of such a technology happened Tuesday off the California coast as the Air Force tested its hypersonic X-51A Waverider vehicle.

At just 25 feet long and only a few inches in diameter, the Waverider is a far cry from an aircraft that can carry people anywhere. But the technology one day could send people or troops across the world in just minutes. Hypersonic travel, meaning speeds of Mach 5 (3,800 miles per hour) and above, has been a focus of the military as it looks to perfect a technology that can become the new stealth. The Pentagon says that countries are becoming wiser to US stealth technology and it is increasingly becoming a less effective tool. Hypersonic flight does away with stealth because its speeds allow for greater flexibility and control for missions that are not possible with current jet technology. But in the commercial world, it can mean flights are so quick a flight attendant hardly would have time to serve drinks and a meal, and there would be no more groggy feeling after those transcontinental flights.

The technology is significant because a hypersonic aircraft breaths oxygen, like a regular jet engine, but reaches speeds five times that of commercial aircraft. To get similar results, the only other option is rocket power. "You would have to have bulky fuel tanks, nozzles and plumbing and that makes rocket power more heavy and more expensive," says Dora Musielak, an adjunct professor of physics at the University of Texas at Arlington. Musielak's research focuses on high-speed propulsion. "Hypersonic technology only requires the aircraft to stay in the atmosphere and is much lighter and efficient," she says. As it cuts through the atmosphere, the design of the craft captures the shock waves it creates as it goes beyond the speed of sound, adding lift to the airframe. "All of that adds to better engine performance and better aerodynamics, making it a more aerodynamically efficient aircraft," says Mark Lewis, the former chief scientist for the Air Force.

How far away are we to seeing this technology as a reality? It's hard to say, according to analysts. But the Air Force says that by 2016, it would like to have a working weapon flying with hypersonic technology. "The vehicles need to be predictable, more cost effective and there still is a need to design on-board flight control systems, so it is several years away," Lewis says. But while the military is in a rush to seize this technology, Musielak says commercial aviation should focus on mastering supersonic air transport first. "First we need to travel at supersonic speeds.I think we need to first develop the technology to go beyond the Concord, and we still need a step between what we have and hypersonics," Musielak says, referencing the only supersonic commercial aircraft that entered service.

That said, can humans even withstand hypersonic travel? With the break-neck speeds and airframe temperatures reaching highs in the thousands of degrees, are there limits? It turns out speed is a factor, but only when you are traveling at Mach 20, then it becomes a bit bumpy. "Staying at Mach 5 or 6, you can have an aircraft that would give passengers a smoother ride," according to Musielak. "But higher speeds would produce higher forces on the body and a more jittery ride like astronauts face while launching into space," she said.

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