NASA’s Gulfstream III fitted with the FlexSys-designed ACTE flaps (photo: NASA)
Thu 18 Dec 2014 — NASA is currently testing two inventive technologies that could potentially improve flight efficiency and reduce environmental impacts. The first involves computer software, called Airborne Spacing for Terminal Arrival Routes (ASTAR), that is designed to provide pilots with specific speed information and guidance so that planes can be more precisely spaced when approaching their destination airport, so minimising flight path deviations, allow more efficient use of existing airspace and possibly reducing noise over communities surrounding airports. The second is a wing surface made from advanced lightweight materials that can change shape in flight and could help airliners of the future become quieter and more fuel efficient. The Adaptive Compliant Trailing Edge (ACTE) project has recently included a successful flight test of a modified Gulfstream III at NASA’s Armstrong Flight Research Center in California.
The ASTAR software is being tested on a laptop in the rear of Boeing’s ecoDemonstrator 787 test airplane, which is currently trialling a range of technologies aimed at reducing the environmental impacts of aviation. As a second aircraft flies in front of the 787, ASTAR computes and displays the speed required to follow safely behind, which is then communicated to the pilots.
“NASA has tested ASTAR in laboratory simulations, but this flight test on board the ecoDemonstrator 787 gave us the chance to see how well it works in a real-life flight environment,” said Will Johnson, a project engineer at NASA’s Langley Research Center in Virginia.
The team will apply the lessons learned from the flight test programme to improve the software and then begin development of actual flight hardware for further testing and eventual certification for use. Air traffic management software tools such as ASTAR are developed under NASA’s Airspace Systems Program, which is part of the agency’s Aeronautics Research Mission Directorate.
ASTAR is the first of several NASA tests on board ecoDemonstrator test airplanes. During 2015, two experiments will take place on an ecoDemonstrator 757, the first using active flow control technologies on the aircraft’s tail to determine if future tail designs can be altered to reduce drag and the second will test the effectiveness of coatings applied to the leading edge of a wing section to reduce turbulence-inducing buildup of insect residue.
On the ACTE project, researchers this past summer have replaced a Gulfstream’s aluminium flaps with shape-changing assemblies that form seamless, bendable and twistable surfaces. The flight testing is expected to determine whether flexible trailing-edge wingflaps are a viable approach to improving aerodynamic efficiency and reducing noise generated during takeoffs and landings.
The project is a joint effort between NASA and the US Air Force Research Laboratory (AFRL), using flaps designed and built by FlexSys. With AFRL funding, FlexSys developed the variable geometry airfoil system, called FlexFoil, which can be retrofitted to existing airplane wings or integrated into new airframes. Its inventor, Sridhar Kota, is hopeful the testing of the modified Gulfstream will confirm the design’s flight worthiness and open doors to future applications and commercialisation.
“We have progressed from an innovative idea and matured the concept through multiple designs and wind tunnel tests, to a final demonstration that should prove to the aerospace industry that this technology is ready to dramatically improve aircraft efficiency,” said AFRL Program Manager Pete Flick.
Reported ACTE Project Manager, Thomas Rigney: “The first flight went as planned and we validated many key elements of the experimental trailing edges. We expect this technology to make future aircraft lighter, more efficient and quieter. It also has the potential to save hundreds of millions of dollars annually in fuel costs.”
A part of a futuristic hybrid wing body aircraft was last week delivered to the NASA Langley Research Center for stress testing. The revolutionary carbon-fibre architecture test article, representing a uniquely shaped fuselage cross-section, is made out of a low-weight, damage-tolerant, stitched composite structural concept called Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS). Langley’s Combined Loads Test System will subject it to conditions that simulate loads typically encountered in flight. It was built and assembled for NASA by Boeing Research & Technology in California, after NASA had worked with Boeing and AFRL to develop the concept.
Structural testing at Langley and the ACTE flight test are two of eight large-scale integrated technology demonstrations designed to further the goals of NASA’s Environmentally Responsible Aviation project to reduce aircraft fuel consumption, noise levels and emissions of future aircraft.
NASA Aeronautics Research
NASA ACTE Project
US Air Force Research Laboratory
Copyright © 2018 GreenAir Communications