Special Coverage


Magnetic Fluids Deliver Better Speaker Sound Quality

NASA’s liquid magnetization technology helps Sony increase sound amplitude while reducing distortion. In the early 1960s, NASA scientists were trying to move fuel into an engine without the benefit of gravity. A scientist at Lewis Research Center (now Glenn Research Center) came up with the idea to magnetize the liquid with extremely fine particles of iron oxide. That way, fuel could be drawn into the engine using magnetic force.

Posted in: Articles, Electronics, Joining & Assembly


An Operationally Based Vision Assessment Simulator for Domes

Applications include remote visualization, flight simulation, virtual environments, and planetariums. Ames Research Center, Moffett Field, California The work described here is part of the U.S. Air Force-sponsored Operational Based Vision Assessment (OBVA) program that has been tasked with developing a high-fidelity flight simulation laboratory to determine the relationship between human vision and performance in simulated operationally relevant tasks. The OBVA simulator was designed and built to provide the Air Force School of Aerospace Medicine (USAFSAM) with a scientific testing laboratory to study human vision and testing standards.

Posted in: Briefs, Computers, Simulation Software


Ad Hoc Adaptive Pitch Axis Pilot Model

Neil A. Armstrong Flight Research Center, Edwards, California Flight research has shown that adaptive flight control systems can be susceptible to adverse pilot-controller interactions, including pilot-in-the-loop oscillations (PIO). Conventional PIO analysis is performed using a static pilot model and a linear, time-invariant model of the aircraft and its control system. For aircraft with time-varying dynamics such as damage or failure, pilot technique may change rapidly to maintain control. An adaptive pilot model can be used to evaluate potential interactions between the pilot and an adaptive flight controller. An ad hoc algorithm was designed for the real-time adaptation of a pilot model describing a pitch angle gross acquisition task. The pilot model consists of an adaptive gain and a fixed time delay. The adaptive gain is adjusted based on the magnitude of the tracking error and the aggressiveness of the response. The algorithm was shown to match human pilot adaptation (simulation) to changes in dynamics including nominal, increased, and decreased loop gain; increased and decreased damping; and increased and decreased natural frequency. The algorithm also exhibits the classic pilot crossover theory response of –20dB/dec@0dB. Unique features of the pilot model are: Continuous adaptations in which gain adjustments are updated continuously and naturally converge to a solution when the aircraft dynamics are time-invariant. Bidirectional adaptation in which the pilot gain increases or decreases as required. Explicit modeling of the pilot’s ability to phase-correlate command/response. Adaptation is normalized to be proportional to the piloting task. This work was done by Curt Hanson of Armstrong Flight Research Center. For more information, contact the Armstrong Technology Transfer Office at 661-276-3967. DRC-012-007

Posted in: Briefs, Aviation


Development of a Turnkey Clear Air Turbulence Detection System

Turbulence is determined via three infrasonic microphones. Langley Research Center, Hampton, Virginia Currently, the only available means of reporting clear air turbulence (CAT) is the pilot report (PIREP), whereby a pilot experiencing turbulence reports their location and associated data. In this report, a system is proposed that would allow the detection of CAT through infrasonic emissions.

Posted in: Briefs, TSP, Aviation, Detectors


Editor’s Choice

For 20 years, I’ve been interacting with engineers in all different industries as the Editorial Director of NASA Tech Briefs. I’ve talked with our readers about their work and the products they use. Many of them are CAD users, and many of them are unhappy with some aspect of their CAD software.

Posted in: UpFront, Consumer Product Manufacturing, Computer-Aided Design (CAD)


Watching Alloys Change Could Lead to Better Metals

If you put a camera in the ice machine and watched water turn into ice, the process would look simple. But the mechanism behind liquids turning to solids is actually quite complex, and understanding it better could improve design and production of metals. A recent investigation aboard the International Space Station (ISS) involved experiments using transparent alloys to observe microstructures that form at the point the material solidifies.

Posted in: UpFront


3D Printed Jet Engine Debuts

Researchers at Monash University in Australia have produced a 3D printed jet engine. Professor Xinhua Wu, head of the Monash Centre for Additive Manufacturing (MCAM), is leading initiatives to develop 3D printing. The Centre is working to provide answers for manufacturers seeking new manufacturing processes that make components lighter and cheaper than traditional ones, but without any reduction in performance.

Posted in: UpFront, Aviation