Posted on 04/20/2004 4:17:59 PM PDT by BenLurkin
FORT STOCKTON, Texas - NASA's Dryden Flight Research Center, the U.S. Air Force Flight Test Center and Blacksky Corp. joined forces on the prairie lands of West Texas to fly small aerospike rocket nozzles. The effort, called the Dryden Aerospike Rocket Test, provided the first known data from a solid-fueled aerospike rocket in flight.
Two 10-foot-long solid-fueled rockets with aerospike nozzles were flown successfully on two consecutive flights March 30 and 31. Under perfect skies and calm winds, the rockets ascended from the King Ranch launch site at the Pecos County Aerospace Development Corp. Flight Test Range in Fort Stockton, Texas.
"The success of the Dryden Aerospike Rocket Test project opens up a whole new way of obtaining flight research data for not only the aerospike nozzles but for other rocket technologies as well, such as dual-bell nozzles," said NASA Dryden's Trong Bui, the project's principal investigator. "This inexpensive, high-speed flight research platform allows us to take new ideas to flight quickly and, at the same time, increases the technology readiness level of new aerospace concepts."
Aerospike nozzles can be thought of as inside-out rocket nozzles. Rather than the rocket engine's exhaust plume exiting out the traditional bell-shaped nozzle, the plume travels externally. The main advantage of aerospike nozzles is that, as the rocket climbs, atmospheric and airstream pressure act on the plume to keep it at an optimum setting along the entire trajectory, allowing very efficient engine performance in flight. With traditional rocket engines, the bell nozzle is most efficient at only one point in the rocket's trajectory.
Although the advantages of the aerospike nozzles are well understood through analysis and ground test data, the lack of flight test data has precluded their use in current and next generation space launch vehicles. In addition, the configuration of an aerospike nozzle presents unique challenges to designers and fabricators.
The rockets reached supersonic speeds in excess of Mach 1.5 and peak altitudes of more than 26,000 feet. However, speed and altitude weren't the project's aim. The goals were to obtain aerospike rocket nozzle performance data in flight and to investigate the effects of transonic flow and transient rocket flight conditions on aerospike nozzle performance.
"The successful planning and integration of the Dryden Aerospike Rocket Test project clearly demonstrates the capability of the low-cost technology approach used," said Scott Bartel of Blacksky Corp., of Carlsbad, which built the rockets. "The flight operations support from the Tripoli Rocketry Association and Fort Stockton shows that enthusiasm for aerospace research is universal," Bartel said.
Blacksky Corp. coordinated development of the experimental aerospike nozzles and solid propellant motors used in the tests with Cesaroni Technology Inc. of Ontario, Canada. Cesaroni provided key support to the project with the rapid design and development of both aerospike nozzles, as well as the custom solid propellant rocket motors.
"For many years, NASA Dryden has built small radio-controlled and remotely piloted research models flown at subsonic speeds to explore new concepts such as lifting bodies, parafoil landing systems and the testing of hypersonic shapes for landing feasibility," said Chuck Rogers, AFFTC project investigator. "With the demonstration of this rocket flight test technique, these models can now be tested at transonic and supersonic flight conditions at very low cost."
"We are very excited to have been part of the Dryden Aerospike Rocket Test, and hope that the data collected during the flights at the Pecos County Aerospace Development Center will further the development of the aerospike rocket motor," said George Riggs, president of the Pecos County/West Texas Aerospace Development Corp. "Pecos County looks forward to continued relations with NASA Dryden, Blacksky Corp. and Cesaroni Technology Inc. as the aerospike project moves forward."
NASA Dryden funded the project and instrumented the rockets. Dryden and the Air Force Flight Test Center, developed the project's flight test concept, worked the conceptual design of the aerospikes and are analyzing the flight data.
NASA Dryden and the AFFTC are at Edwards Air Force Base.
They are also heavier than conventional nozzles.
They are more difficult to cool than conventional nozzles.
They perform worse than conventional nozzles in some flight regimes.
That's right. Worse. Aerospikes introduce a powerful turbulent shear layer between the free stream and the exhaust; these sheer forces are not accounted for in industry-standard performance estimates.
IMHO an extendible nozzle would offer all the benefits of the aerospike and few of the drawbacks.
--Boris
Interesting, thanks ! ...Aerospike nozzles can be thought of as inside-out rocket nozzles. Rather than the rocket engine's exhaust plume exiting out the traditional bell-shaped nozzle, the plume travels externally. The main advantage of aerospike nozzles is that, as the rocket climbs, atmospheric and airstream pressure act on the plume to keep it at an optimum setting along the entire trajectory, allowing very efficient engine performance in flight. With traditional rocket engines, the bell nozzle is most efficient at only one point in the rocket's trajectory.
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