CERTAIN PORTIONS ARE ILLEGIBLE , IT IS BEING RELEASED IN THE INTEREST OF MAKING
A review of the factors affecting the helicopter market for the past, present, and future is presented. The trade-offs involving acquisition cost, mission reliability, and life-cycle cost are reviewed, including civil and military aspects. The potential for advanced vehicle configurations with substantial improvements in energy efficiency, operati.ig economics, and characteristics to satisfy the demands of the future market are identified. Advanced propulsion systems required .o support these vehicle configurations are, in turn, discussed, as well as the component technology for the engine systems. Considerations for selection of components in areas of economics and efficiency are presented.
Rotorcraft Researchers and Operators-Is There a Common Ground?
An investigation is conducted concerning the extent to which a program for rotorcraft research presented by NASA meets the user needs. Problems of civil operators are examined, taking into account powerplants, reliability and maintainability, environment, noise and vibration, and lack of space for passengers' baggage. A description of applicable technology is provided, giving attention to aerodynamics and structures, propulsion, power transfer methodology, flight control, avionic systems, human factors, and vehicle configurations. One of the most difficult challenges in trying to bring research to bear on operator problems is that in general researchers are working on long-term solutions while operators are seeking short-term answers. Attention is also given to potential technological bright spots, higher risk technologies, highest technological risks, and advanced vehicle configurations.
A new power measuring circuit using a bridge-connected magnetic circuit and another magnetic core
The authors describe the operating characteristics of an oscillating circuit using a bridge-connected magnetic circuit and another magnetic core. A square-shape output voltage is obtained in the oscillating circuit. The pulsewidth in positive and negative half cycles of output voltage changes with the current of the U-form core windings and with the signal voltage applied to the exciting windings. The mean value of the output voltage varies in proportion to the product of the current and the signal voltage. Utilizing this feature, an application of the oscillating circuit to a novel power measuring circuit of simple construction is presented. >