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Technology update
X-43 approaches first flight
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Hyper-X flight profile.
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While ground testing continues at NASA's Langley Research Center in Hampton, VA, the first of three experimental vehicles, designated X43A, has arrived at the NASA Dryden Flight Research Center in Edwards, CA, to prepare for its first flight, scheduled for May. The X-43A is being built as part of NASA's Hyper-X program to develop hypersonic technology for aircraft and reusable space launch vehicles that would weigh less and carry more payload than conventional rocket launch systems. NASA Langley manages the Hyper-X program, including on-site engine and aerodynamic ground testing in several wind tunnels that provide a close replication of the flight environment. Dryden manages the last phase of testing in which actual flight research takes place.
The 8-ft high-temperature wind tunnel at Langley is being used for X-43 engine and aerodynamic testing. The tunnel can accommodate testing at speeds up to Mach 7.
The X-43A, one of three vehicles in NASA's Hyper-X program, has been delivered to the Dryden Flight Research Center for its first flight test scheduled for May.
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The engine being tested in the Hyper-X program is a Mach 7 scramjet (supersonic combustion ramjet) design developed by Langley from more than 20 years of research. The scramjet engine has no moving parts and depends on the speed of the aircraft for its operation. Scramjet combustion takes place when compressed air traveling at hypersonic speed ignites the engine's hydrogen fuel. This reduces aircraft weight because it eliminates the need for onboard oxygen, which is found with conventional rocket systems. Engineers will use the body of the aircraft to form critical elements of the engine, with the forebody acting as the intake for the airflow and the aft section as the nozzle. According to Langley, its Hyper-X scramjet will mark the world's first hypersonic flight of an independent air-breathing scramjet aircraft.
Langley Research Center's 8-ft high-temperature wind tunnel
| Wind tunnel type: | aerothermodynamic
| Mach Numbers: | 4, 5, and 7
| Reynold's Number: | 0.3-5.09 (depending on the
Mach number)
| Test section dimensions: | 8-ft in diameter and 12-ft long
| Test medium: | products of combustion; oxygen-enriched products of combustion
| Model support types: | sting mount to model elevator; model support pedestal mounted on an external force measurement balance
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The aircraft itself was built by Micro Craft, Inc., in Tullahoma, TN. It is an unpiloted vehicle measuring 12-ft long. Three flights are planned for the aircraft - two at Mach 7 and one at Mach 10. These tests will be conducted within the Western Test Range off the coast of southern California.
Each Hyper-X vehicle will ride atop an Orbital Sciences Corp. booster rocket, which will be air-launched by Dryden's B-52 airplane. After launch, the X-43 will separate from the rocket at a predetermined altitude and velocity. It will then fly a pre-programmed trajectory, conducting aerodynamic and propulsion experiments before it impacts into the Pacific Ocean.
According to Langley, Hyper-X propulsion could be a high-speed, efficient means of moving aircraft through the lower atmosphere and other vehicles into space, but it has never been tested in an independent single-flight vehicle design. Hypersonic speed is reached when the velocity is above Mach 5 - equivalent to about 1 mi/s or 3600 mph at sea level. The highest speed reached by NASA's rocket-powered X-15 was Mach 6.7. Currently, NASA's SR-71 is the world's fastest air-breathing aircraft, soaring slightly above Mach 3.
Frank Bokulich
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