Innovative designs of mufflers for engines of small airplanes have been investigated in an effort to satisfy conflicting demands to maximize the reduction of exhaust noise while minimizing back pressure, size, and weight. Automotive-type muffler designs are not suitable for this purpose because they entail...

A computer program estimates great-circle-arc (GARC) flightpaths of multiple aircraft, given time-tagged point locations from radar sightings of the aircraft. The problem of generating such estimates is called a "clustering" problem, and is solved in this instance by use of a neural-network...

A report discusses a class of balloon-borne robotic instrumentation systems that have been proposed for use in exploring Venus, Jupiter, Saturn, Uranus, and Neptune. The balloons would be of the Montgolfier type; that is, buoyancy would be achieved through heating of atmospheric gases contained...

A low-density, creep-resistant ceramic composite material has been developed as a prototype of such materials for use at high temperatures in the next generation of aircraft engines. The material consists of Nextel (or equivalent) ceramic fibers in a matrix that is, itself, a composite of...

Advanced aerobots that would be powered by solar photovoltaic batteries and that would be capable of storing energy for occasional operation during short intervals at power levels far beyond those of the photovoltaic batteries have been proposed. Aerobots are robotic balloon-buoyed airborne...