Propulsion

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

Fundamental concepts of vectored propulsion

Abstract: Future fighter aircraft may maneuver, especially in the post-stall (PS) domain, by simultaneousl y directing their jets in the yaw, pitch, and roll coordinates. Consequently, thrust vectoring (TV) may gradually become a key element in helping fighters to survive and win in the close-combat arena. It also provides fighter aircraft with short-takeoff-and-landing (STOL) capabilities. This paper first defines the fundamental concepts associated with pure, or with partial TV powerplants. It then demonstrates that propulsion engineering should be expanded to include such unorthodox engine-design criteria as those of TV maneuverability and controllability. Second, the fundamental concepts of pure vectored propulsion are employed to design, construct, and laboratory test a new type of simultaneous roll-yaw-pitch TV system. Vectored remotely piloted vehicles (RPVs) were then constructed "around" these new propulsion systems. Flight tests of these RPVs since May 1987 have verified the STOL capability and enhanced maneuverability and controllability designable into vectored propulsion systems. They also became the first flight tests of pure vectored propulsion systems. The integrated methodology of laboratory/vectored-RPV-flight tests, as developed for this investigation, has been verified as cost effective and timesaving. Using this methodology a follow-up program was recently launched to help upgrade existing fighter aircraft, such as the F-15, F-16, and F-18, to become partially vectored PS aircraft. Finally, the basic conceptual changes associated with the very introduction of TV engines are summed up in terms of greater emphasis on highly integrated engine/flight-control testing methodologies and on reassessment of conventional concepts.

System and method for optimizing a path for a marine vessel through a waterway

Abstract: A system is provided for optimizing a path for a marine vessel through a waterway from an initial location to a final location. The system includes a propulsion system and a directional system on the marine vessel, which impart a selective propulsion force on the marine vessel at a selective direction based on a received propulsion command and direction command from a processor. The processor determines an optimal path for the marine vessel, an optimal propulsion command and optimal directional command at a respective incremental location along the optimal path, so to optimize a performance characteristic of the marine vessel. The determination of the optimal path, the optimal propulsion command and the optimal directional command is based on the initial location, the final location, at least one operating parameter, the performance characteristic, and navigational data of the waterway.

A Naval Integrated Power System with a Battery Energy Storage System: Fuel efficiency, reliability, and quality of power.

Abstract: Mechanical machinery has dominated the field of ship propulsion systems in the last century. Since fuel accounts for a large portion of the ship life-cycle cost, the current trend of moving toward fuel economy and environmental regulations in marine engineering has led to the efficient use of onboard energy. Incorporating power electronics into ship propulsion systems has been a very common method of improving fuel efficiency since approximately 1980. One high-profile example is the 1968-built Queen Elizabeth 2, whose steam turbines were replaced with a diesel-electric propulsion plant in 1986. Some commercial ships are now being built with electric drives, such as passenger ships, car ferries, shuttle tankers, cable-laying ships, icebreakers, and floating offshore platforms. Navies around the world have been actively exploring integrated power systems (IPSs) for use on future surface combatant ships since the late 20th ?century. Although the ship IPS has many distinct advantages, such as increased survivability and maneuverability, reliability inhibits further fuel economy improvement. The onboard battery energy storage system (BESS) was recently suggested to increase fuel economy and ensure reliability at the same time. Furthermore, an active front-end (AFE) converter can provide improved grid quality at transient states such as fault and future mission load in addition to steady state as with normal sea sailing.

Analysis of turbofan propulsion system weight and dimensions

Abstract: Weight and dimensional relationships that are used in aircraft preliminary design studies are analyzed. These relationships are relatively simple to prove useful to the preliminary designer, but they are sufficiently detailed to provide meaningful design tradeoffs. All weight and dimensional relationships are developed from data bases of existing and conceptual turbofan engines. The total propulsion system is considered including both engine and nacelle, and all estimating relations stem from physical principles, not statistical correlations.