Tech Briefs

Insulating Materials and Precursor Formulations, and Method of Forming

Methods were developed for forming an insulating material that combines a polysilazane, a cross-linking compound, and a gas-generating compound to form a reaction mixture, and curing the reaction mixture to form a modified polysilazane. The gas-generating compound may be water, an alcohol, an amine, or a matrix comprising one of a reaction product of a polysilazane and an isocyanate, and a reaction product of a polysilazane and an epoxy resin. The matrix also comprises a plurality of interconnected pores produced from a reaction of the polysilazane and the epoxy resin.

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Selective Clay Placement Within a Silicate Clay-Epoxy-Blend Nanocomposite

The resulting toughened epoxies and composites are used for commercial and military aircraft, and marine applications. John H. Glenn Research Center, Cleveland, Ohio The dispersion of a layered silicate into an epoxy matrix often increases the material strength and stiffness, but reduces resin toughness. This innovation is a method to selectively place organically modified clay within specific regions of an epoxy blend, where the clay provides maximum benefit to the material performance. By this process, the material yield stress was observed to increase by 40 to 100%, depending on the blend composition. The toughness of the material, as defined by the area under the stress-strain curve, was observed to increase or remain unchanged.

Posted in: Briefs, Composites

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Evaluation of Rail Gun Technology for Launch Assist of Air-Breathing Rockets

John F. Kennedy Space Center, Florida A prototype horizontal electromagnetic rail launcher has been demonstrated along with a corresponding theory. This system builds out of published work in augmented rail guns, but modifies this technology so that the motor can operate for seconds rather than milliseconds, and provide low acceleration (such as might be needed to launch an aircraft) rather than the extreme accelerations seen in the guns. The final system operates off of relatively low voltages (tens of volts), but with substantial currents. A lab bench prototype has been constructed and operated, demonstrating 13 Gs acceleration of a small 230-gram sled.

Posted in: Briefs, Motors & Drives

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Using Harmonics to Control Flutter in Wings with Electrical Motors

This control system concept applies principles of forced aeroelasticity to distributed electric propulsion systems. Armstrong Flight Research Center, Edwards, California As aeronautics engineers develop innovative distributed electric propulsion systems, they face new challenges in ensuring that these innovative aircraft are safe as well as fuel efficient. In particular, these systems involve a large number of electrically driven fan motors mounted across a wing that induce vibrations that negatively affect the aircraft’s stability. These vibrations cause problems regardless of whether the motors are bottom-mounted, top-mounted, or wing-embedded.

Posted in: Briefs, Motors & Drives

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Micropulse Detonation Rocket Engine for Nano-Satellite Propulsion

Goddard Space Flight Center, Greenbelt, Maryland An efficient propulsion system would use a micropulse detonation rocket engine (–PDRE) for nano-satellite maneuverability in space. Technical objectives are to design, build, and conduct a small detonation tube experiment in order to explore the feasibility of using –PDRE for propelling a nano-satellite. The plan is to study the requirement and predict the performance of –PDRE using various candidate propellants, as well as to conduct ground experiments, demonstrate useful thrust, and measure the specific impulse in a two-year time frame, so that a follow-on project can be proposed in a future NRI Center Innovation Fund.

Posted in: Briefs, TSP

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Experimental Testbed for 1-MW Turboelectric Distributed Propulsion Aircraft

A low-cost glider design mitigates risk in conducting experiments for cutting-edge “green” aircraft concepts. Armstrong Flight Research Center, Edwards, California Researchers at NASA’s Armstrong Flight Research Center are developing a concept aircraft for testing turbo-electric distributed propulsion (TeDP) experiments. TeDP generally involves providing thrust to an aircraft via wing-mounted ducted electric fans, which consist of an electric motor, a fan, stators, and other components surrounded by cylindrical ducting within a fan case. The fan motors are powered by a combined battery and turboelectric generator system. To sufficiently power an aircraft approximately 50 ft (≈15 m) in length and with a gross weight of 25,000 lb (≈11,340 kg), this system must be capable of generating 1 MW of power.

Posted in: Briefs, Aviation, Motors & Drives

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Propellant Loading Visualization Software

Monitoring of complex propulsion pressure systems has been simplified with colors. Goddard Space Flight Center, Greenbelt, Maryland Complex pressure systems are utilized during testing in the propulsion branch as well as during the propellant loading stage of a mission. Keeping track of the state of such a system becomes more difficult as the complexity of such a system increases, and when extensive procedures are being followed. A book-keeping system is needed for visualizing these complex systems.

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