Page 4 - Aerotech News and Review, Feb 1, 2019 - Mission Update Edition

NASA Armstrong advanced science in 2018
by Peter W. Merlin
special to Aerotech News
In its seventh decade of operation, NASA’s Armstrong Flight Research Center at Edwards Air Force Base, Calif., continued to advance the agen- cy’s overall missions of aeronautics research, Earth and space science.
The center has also been working to integrate NASA technology into the commercial airspace sector, sup- porting development of aerospace technology, and sharing results with industry, academia, and the public. Researchers at Armstrong are dedi- cated to facilitating an understanding of aeronautics concepts and demon- strating the role that flight will play in the nation’s future.
Aeronautics X-56A MUTT
In 2018, NASA researchers contin- ued to explore the benefits of long, thin, high-aspect-ratio wings for use on future long-range aircraft includ- ing fuel-efficient airliners and cargo transports. Unlike shorter, stiffer wings found on most aircraft today, slender, flexible airfoils are suscep- tible to flutter and may be stressed by bending forces from wind gusts and atmospheric turbulence. To address this problem, NASA is using the X- 56A Multi-Utility Technology Test- bed (MUTT), a small, remotely pi- loted experimental aircraft developed by Lockheed Martin Skunk Works for the Air Force Research Labora- tory (AFRL), to investigate technolo- gies for active flutter suppression and gust-load alleviation. Hopefully, this will lead to improved ride quality, efficiency, safety, and improve the long-term health of flexible aircraft structures.
Lockheed Martin and AFRL per- formed initial testing of the X-56A in late 2013 and early 2014 to collect
Photograph by Peter Merlin
The ER-2 high-altitude research aircraft was used to collect burn scar images following a series of devastating California wildfires.
by Lockheed Martin to complete a preliminary design for a Quiet Supersonic Technology (QueSST) demonstrator, which was eventually designated X-59.
In advance of QueSST flights, re- searchers from NASA’s Armstrong and Langley Research Centers de- ployed to Houston and Galveston, Texas, for the Quiet Supersonic Flights 2018, or QSF18, test series. For this effort, a NASA pilot per- formed a unique diving maneuver over the Gulf of Mexico in a su- personic F/A-18 fighter plane. This technique transformed the usually sharp sonic boom into a quiet thump. Researchers used acoustic measuring equipment and collected public com- ments in order to better understand how to engage and obtain data from a community unaccustomed to phe- nomena associated with supersonic flight.
Another series of flights, using a modified subsonic Gulfstream III business jet, demonstrated technolo- gies to significantly reduce aerody- namic noise generated by aircraft during takeoff and landing. The Acoustic Research Measurement (ARM) flights tested technology to address airframe noise, that which is produced by non-propulsive parts of the aircraft. Several experimental concepts were applied to various air- frame components including landing gear fairings and wheel well cavity treatments, as well as the Adaptive Compliant Trailing Edge (ACTE) wing flap previously flight-tested to study aerodynamic efficiency. Research crews flew the aircraft at
an altitude of 350 feet over a sensor microphone array on the Rogers Dry Lake at Edwards Air Force Base. Re- sults showed a 70 percent noise re- duction, a crucial milestone that may lead to quieter aircraft, which will benefit communities near airports and foster expanded airport operations.
UAS Integration into the National Airspace System
Over the past several years, NASA has worked with the Federal Aviation Administration and industry partners to develop technologies that support safe integration of unmanned aircraft systems into the National Airspace System. Previous tests successfully demonstrated two detect-and-avoid algorithms developed by NASA, General Atomics Aeronautical Sys- tems Inc., and Honeywell that gen- erated precise alerts necessary for a pilot controlling a UAS from the ground to remain well clear of other aircraft.
Armstrong continued this effort in 2018, achieving a major milestone when NASA’s remotely piloted Ikha- na aircraft flew into the NAS without the need for a chase plane or visual observers while operating in various classes of airspace. Ikhana is the first UAS for which the FAA has granted a No Chase Certificate of Waiver Au- thorization.
Prandtl-D
This past summer, researchers at Armstrong continued working on an increasingly complex remotely
See NASA, Page 5
flight data on highly flexible struc- tures and flutter suppression control techniques. The MUTT was eventu- ally transferred to NASA Armstrong for research into lightweight struc- tures and advanced control technolo- gies for future efficient, environmen- tally friendly transport aircraft.
The subscale demonstrator is a hy- brid wing-body configuration span- ning 28-feet wingspan and weighing about 480 pounds, powered by two 90-pound thrust turbojet engines. Lockheed Martin built two center bodies and several sets of stiff and flexible wings to be used in various phases of testing. In November 2015, one of the two vehicles crashed dur- ing the first flexible-wing checkout flight, sustaining irreparable damage. The second vehicle has been used to validate improved flight control systems for flutter suppression. Test flights in 2018 focused on building good aerodynamic models to predict
the speed at which flutter will occur and then demonstrating flutter sup- pression with a modern flight control algorithm.
Aircraft Noise Reduction
NASA scientists are also exploring methods for reducing aircraft noise as well as controlling and lessening the effects of supersonic shock waves, in the hope that federal regulators may one day allow commercial and civil supersonic flight over land in the United States. Such flying is cur- rently restricted to military training operations within tightly controlled supersonic corridors in the National Airspace.
In February 2016, NASA awarded a contract for the preliminary design of a “low boom” flight demonstra- tion aircraft as part of the agency’s New Aviation Horizons initiative introduced in the Fiscal Y ear 2017 budget. NASA selected a team led
The remotely piloted X-56A on final approach to landing at Edwards.
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NASA photograph by Carla Thomas
A NASA F/A-18 demonstrates the quiet supersonic dive maneuver, creating a dull thump instead of a loud sonic boom.
NASA photograph by Lauren Hughes