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These are two articles that Dryden Flight Research Center wrote on their SR-71 research. Now that the SR-71 research program has been terminated, there will be no more news to report here. However, I do report the latest Blackbird moves and events at the SR-71 Online News page.

These articles are courtesy of Dryden Flight Research Center.

SR-71 wraps up flight research series

Leslie A. Williams
Public Affairs Specialist

"A 1999 four-flight research series for the SR-71 Blackbird, with a 41-foot-long test fixture mounted atop of the rear section of the aircraft, wrapped up Sept. 27 at Dryden.

The flights showed that the fixture barely impacted the SR-71's stability, handling and flying characteristics while soaring at Mach 3, or three times the speed of sound.

SR-71 Project Manager Steve Schmidt is pleased with the flight series.

'It went better than we predicted. Now we will wait for an opportunity, or a customer with a project. There are several in the wings,' he said.

'It flew like a scalded cat,' said the SR-71 flight test engineer Marta Bohn-Meyer. She said the plane was unbelievable in how it pushed to go faster.

The SR-71 stopped short of reaching one test point of going more than Mach 3 due to the failure of the liquid nitrogen system that was used to purge the test fixture. Without proper purge, there was a concern of overheating the fixture's internal systems. This purge system has proven very effective in past flights, said Tim Moes, Dryden's chief engineer for these research flights.

He added that the cause of the purge system failure is now well understood and procedures will be instituted to prevent this failure in the future. Although the two-hour flight did not reach Mach 3.2, the combined four-flight series proved that the SR-71 is a viable testbed for future technologies that need a high-speed, high-altitude flight environment.

Data obtained on the previous flight to Mach 3 can be confidently extrapolated to Mach 3.2, Moes said. Unlike wind tunnels that are constrained by its walls, the SR-71 airplane flies in actual atmospheric conditions, such as moisture and temperatures, at extreme altitudes and speeds making it an ideal testbed for supersonic flight.

NASA's Revolutionary Concepts (REVCON) project is one example of possible future use of the SR-71 as a testbed. The RevCon project encourages the development of ideas that could lead to revolutionary experimental planes.

The Pulse Detonation Engine (PDE), one of the first RevCon projects, is a revolutionary approach for future high-speed jet propulsion. The engine will have fewer parts, yet greater propulsion efficiency, resulting in lower maintenance and direct operating costs. A proposal to fly the PDE captive carry atop the rear section of Dryden's SR-71 Blackbird is being discussed."

NASA's SR-71 is back to work

Leslie Mathews
Public Affairs Specialist

"Dryden sent its fastest and highest-flying airplane, the SR-71A, into the air for further research flights to evaluate the its performance, handling and flying qualities with a test fixture mounted atop the aft section of the aircraft. This test fixture was originally used for the Linear Aerospike SR-71 Experiment (LASRE), supporting research for the X-33 program.

The flight of the SR-71 A model June 30 was the first flight of this aircraft since October 29, 1998. The aircraft reached a maximum speed of Mach 2.25, about 1,450 mph at 55,000 feet. Three more flights are scheduled between July and September.

"The long anticipated prospect of getting the SR-71 aircraft back in the air is exhilarating," said Steve Schmidt, Dryden's SR-71 project manager. "This phase of the flight research program has gotten off to a great start in that the aircraft and project team performed flawlessly, which is further testament of the cooperative teamwork that has been a sustaining hallmark of the SR-71 program."

NASA's B model is used for proficiency training for pilots and the flight test engineers. Recently the B model completed its planned 200-hour phase inspection and has been put into flyable storage. These two SR-71s have been on loan to NASA from the U.S. Air Force, which just transferred ownership to NASA.

In addition to those two SR-71s, the Air Force turned over possession of its other two other flyable SR-71s, which will complement the two NASA planes in future flight research programs, providing unsurpassed flexibility as well as additional capabilities to perform multiple high-speed research experiments.

The SR-71 can fly more than 2,200 miles per hour, more than Mach 3, or three times the speed of sound, and at altitudes of more than 85,000 feet. Data from the SR-71's high-speed research program will be used to aid designers of future supersonic and hypersonic aircraft and propulsion systems. SR-71 flights have also provided information on the presence of atmospheric particles at extremely high altitudes, where future hypersonic aircraft will be operating.

As research platforms, the SR-71s carry out research and experiments in a variety of areas: aerodynamics, propulsion, structures, thermal protection materials, high-speed and high temperature instrumentation, atmospheric studies and sonic boom characteristics.

The LASRE project was a small, half-span model of a lifting body positioned on the rear of the SR-71 aircraft, which operated like an "airborne wind tunnel." The SR-71 has also acted as a surrogate satellite for transmitters and receivers on the ground, assisting in the development of a commercial satellite-based, instant and wireless, personal-communications network, called IRIDIUM.

Another project with the SR-71 joined NASA and the University of California-Los Angeles (UCLA), investigating the use of charged chlorine atoms to protect and rebuild the ozone layer. Ongoing research in high-speed, high-altitude flight continues to gain interest among the scientific community, industry and other government agencies."