Propulsion

About: Propulsion is a research topic. Over the lifetime, 24977 publications have been published within this topic receiving 200311 citations.

Review of Propulsion Technologies for N+3 Subsonic Vehicle Concepts

Abstract: NASA has set aggressive fuel burn, noise, and emission reduction goals for a new generation (N+3) of aircraft targeting concepts that could be viable in the 2035 timeframe. Several N+3 concepts have been formulated, where the term "N+3" indicate aircraft three generations later than current state-of-the-art aircraft, "N". Dramatic improvements need to be made in the airframe, propulsion systems, mission design, and the air transportation system in order to meet these N+3 goals. The propulsion system is a key element to achieving these goals due to its major role with reducing emissions, fuel burn, and noise. This report provides an in-depth description and assessment of propulsion systems and technologies considered in the N+3 subsonic vehicle concepts. Recommendations for technologies that merit further research and development are presented based upon their impact on the N+3 goals and likelihood of being operational by 2035.

Overview of United States Rocket Propulsion Technology and Associated Space Transportation Systems

Abstract: U.S. share of the world launch market fell to 20% by 2002. During that period, only two new booster engines have been developed and flight certified in this country. Only limited progress has been made in reducing engine costs or increasing performance although these factors are not necessarily directly related. Upper-stage and in-space propulsion in the United States have not fared much better in the world market. On the other hand, space-faring nations in Europe, the Middle East, Asia, and the former Soviet Union are believed to have developed 40–50 new, high-performance engines over the same period. This trend will have to be reversed to enable future exploration missions. The intent of this paper is to summarize past propulsion-system development, assess the current status of U.S. space propulsion, survey future options, evaluate potential impact of ultra low-cost, small launch-vehicle programs, and discuss some future propulsion needs for space exploration.

Rotary-wing drone with gearless-drive and fast-mounting propellers

Abstract: Each propulsion unit of the drone comprises a propeller ( 20 ) and a rotary-cage synchronous electric motor whose stator is connected to the drone body. The propulsion unit in of the gearless type, the rotor of the motor being rotationally integral with the propeller hub ( 24 ). The rotor is integral with an upper flange ( 56 ) extending in a radial plane with respect to the axis of rotation. Reversible means are provided for the fast coupling of the propeller to the rotor, implementing studs ( 62 ) with an enlarged head ( 66 ) formed on the flange, which cooperate with homologous curvilinear buttonholes ( 32 ) formed on the hub. The switching from the decoupled position to the locked position is operated by relative rotation of the propeller hub with respect to the flange by a fraction of a turn, in an opposite direction with respect to the direction of rotation of the motor.

Self-propelled harvesting machine

Abstract: A self-propelled harvesting machine having an internal combustion engine, a propulsion system that can be operated to cause the harvesting machine to move across a field with a propulsion speed, a crop material pick-up device for picking up the crop material from a field, a crop material processing device for processing the crop material that has been picked up, a control unit for specifying the speed of the internal combustion engine, and a through-put measurement device for determining the through-put of the harvesting machine. The control unit can be operated to vary the speed of the internal combustion engine depending on the signal from the through-put measurement device. In this manner the RPM of the internal combustion engine that is most favorable in terms of fuel consumption and that corresponds to the power to be applied at a given through-put can be specified.