Dryden Flight Research Center
P.O. Box 273
Edwards, California 93523
Beth Hagenauer / Jonas Dino
NASA Dryden Flight Research Center / NASA Ames Research Center, Moffett Field, Calif.
Phone: 661/276-7960 / 650/604-5612
Thirteen aerospace engineering students from California Polytechnic State University at San Luis Obispo spent a recent Saturday on a lake - not sailing but helping NASA study aircraft takeoff and landing noise. Trading the classroom for on-site research on Rogers Dry Lake in California's Mojave Desert, each student was armed with a laptop computer and other equipment to participate in the C-17 Noise Mitigation Flight Test.
NASA, the United States Air Force and Northrop Grumman Corp. partnered for the test flights. NASA researchers from Ames Research Center, Moffett Field, Calif., and Dryden Flight Research Center, Edwards, Calif., led the collaborative effort. The C-17 flight experiment was sponsored by the NASA Aeronautics Research Mission Directorate's Vehicle Systems Program (VSP).
Seventeen microphones, covering approximately 15 square miles, were positioned on the dry lakebed to record the noise footprint of the Air Force Flight Test Center's C-17 Globemaster III as it attempted various landing approaches. In addition to conventional straight-in landing profiles, a new type of simultaneous and non-interfering (SNI) landing profile was flown. This new approach is similar to a descending spiral over the landing site.
Research participants, using laptops connected to GPS receivers and equipped with third-generation sound cards, collected data from the flights to validate a modeling tool for predicting SNI approach noise footprints. The flights also tested the hypothesis that employing this landing approach could help keep aircraft noise within the airport land use zone.
VSP has identified Extreme Short Takeoff and Landing (ESTOL) capabilities as an important area of research. Its goal is to enable development of an airliner capable of landing on a runway as short as 2,000 feet and with low-speed maneuverability that will contain the noise footprint within the airport area. Other requirements include a capability of carrying up to 100 passengers, a cruising speed of Mach 0.8, a range of up to 2,000 nautical miles, and operation in low-visibility conditions. Many current aircraft have most of these capabilities, but none can execute extremely short takeoff and landings. The other capabilities have been individually demonstrated but not functionally integrated into one aircraft.
"An aircraft that could use the shorter runways of smaller regional and community airports could bring commercial air travel to approximately 97 percent of the U.S. population because most Americans live within a half-hour of an airport," said John Zuk, NASA ESTOL Vehicle Section manager at Ames.
"Preliminary results indicate that the SNI approaches will concentrate the noise footprint into a narrow area and that the flight can be conducted safely, with commercial aircraft ride quality," said Zuk.
NASA research pilot Frank Batteas said the landing approaches were simple and safe.
"They were flown using the aircraft autopilot and navigation displays. With some software changes, the aircraft flight director could provide total flight guidance for these approaches including the SNI," he remarked.
Dennis Eckenrod, an American Airlines MD-80 captain, was onboard the C-17 during the test mission. He evaluated the rate of descent from a pilot's perspective and from the acceptability level of an airline passenger.
"The application of this research and the ESTOL program could open a portion of the approximately 8,000 airports around the country not currently used for commercial air travel," said Eckenrod. "These airports were built to accommodate propeller-driven aircraft rather than today's commercial jet-engine aircraft that require longer runways."
Student lead Erika Berg said involvement in this NASA research project has taken the students' classroom curriculum and given it a hands-on application. The students were even tasked with designing and building portable workstations to protect the computer equipment while being used on the lakebed. They created an inexpensive and lightweight workstation from PVC pipe and heavy fabric.
NASA Dryden has an agreement with the C-17 Systems Group at Wright-Patterson Air Force Base, Dayton, Ohio, and Edwards' 418th Flight Test Squadron's C-17 Follow-on Flight Test program to allow NASA to conduct aeronautical research using the Air Force's C-17 flight test aircraft with NASA instruments on board. NASA prepares for this research by using a Dryden C-17 simulator.
PHOTO EDITORS: Publication-quality photos to support this release are available for downloading from the Internet at: http://www.dfrc.nasa.gov/Gallery/Photo/C-17/index.html
TELEVISION EDITORS: Interview segments and B-roll footage to support this release will be aired during the Video File feeds on NASA TV beginning on Sept. 22. NASA Television is carried on an MPEG-2 digital signal accessed via satellite AMC-6, at 72 degrees west longitude, transponder 17C, 4040 MHz, vertical polarization. For those in Alaska or Hawaii, NASA Television is seen on AMC-7, at 137 degrees west longitude, transponder 18C, at 4060 MHz, horizontal polarization. In both instances, a Digital Video Broadcast (DVB)-compliant Integrated Receiver Decoder (IRD) is needed for reception. The NASA Television schedule is available on the NASA Television Web site, at http://www.nasa.gov/ntv
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