نتایج جستجو برای: transition flight

تعداد نتایج: 306504  

Journal: :Physical review letters 2003
K Xu T Mukaiyama J R Abo-Shaeer J K Chin D E Miller W Ketterle

Ultracold sodium molecules were produced from an atomic Bose-Einstein condensate by ramping an applied magnetic field across a Feshbach resonance. More than 10(5) molecules were generated with a conversion efficiency of approximately 4%. Using laser light resonant with an atomic transition, the remaining atoms could be selectively removed, preventing fast collisional relaxation of the molecules...

2004
Scott A. Berry Robert J. Nowak Thomas J. Horvath

Active and passive methods for tripping hypersonic boundary layers have been examined in NASA Langley Research Center wind tunnels using a Hyper-X model. This investigation assessed several concepts for forcing transition, including passive discrete roughness elements and active mass addition (or blowing), in the 20-Inch Mach 6 Air and the 31-Inch Mach 10 Air Tunnels. Heat transfer distribution...

The feasibility of using a stand alone Fluidic Thrust-Vectoring (FTV) system for the purpose of longitudinal trim of an unmanned aerial vehicle is the focus of the research presented in this paper. Since the fluidic thrust vectoring requires high pressure secondary air to deflect the engine exhaust gases, this research also provides an analytical toolset for preliminary sizing of a suitable sec...

2016
Alexander J. Stimpson Jason C. Ryan Mary L. Cummings

The proposed transition to single-pilot operations (SPO) in commercial and military aircraft has motivated the development of advanced autonomy systems. However, a detailed analysis of the impact of advanced autonomy on pilot workload through various phases of flight and contingency scenarios has not been conducted. To this end, this paper presents the development of the Pilot-Autonomy Workload...

2005
Fen Wu Ashok Gopalarathnam Sungwan Kim

A multidisciplinary research effort that combines aerodynamic modeling and gain-scheduled control design for aircraft flight at post-stall conditions is described. The aerodynamic modeling uses a decambering approach for rapid prediction of post-stall aerodynamic characteristics of multiple-wing configurations using known section data. The approach is successful in bringing to light multiple so...

A. R. Toloei M. Pirzadeh,

In this research, Generalized Predictivecontrol (GPC) is proposed for the control of a stabilizing loop from a two axis gimbal seeker. In fact, there are some views about using GPC type controller which are two folds. First, it drives the stabilization loops that are made by a DC motor, Rate Gyro, inertia and cross coupling unit in between two channels using the predictive model type controller...

A near-optimal midcourse trajectory shaping guidance algorithm is proposed for both air and ballistic target engagement mission attributes for generic long range interceptor missile. This guidance methodology is based on the maximum final velocity as the objective function and maximum permissible flight altitude as the in-flight state constraint as well as the head-on orientation as the termina...

1998
Patricia May Ververs Christopher D. Wickens

An extensive investigation of the format for head-up display (HUD) instrumentation was conducted in a two-part experiment. First, a pilot’s information requirements for the tasks of approach, landing, and taxi were determined through a survey administered to professional commercial pilots via the world wide web. The results of the survey were applied in the development of two symbology sets, on...

2003
Jonathan Fleming

A valuable new resource being developed for today’s soldier are small ducted fan VTOL UAVs. Although beneficial in many ways, a major operational problem of ducted fan vehicles is precise control when flying in crosswinds and turbulent conditions in general. There are two significant, inherent issues associated with ducted fan control in crosswinds; 1) lateral momentum drag and 2) a duct stabil...

2005
Thomas Prevot Todd Callantine Paul Lee Joey Mercer Vernol Battiste Walter Johnson Everett Palmer Nancy Smith

Co-Operative Air Traffic Management (COATM) is a concept under exploration at NASA Ames Research Center for transformation of aircraft and air traffic management operations towards the Next Generation Air Transportation System (NGATS). A goal of the CO-ATM concept is to provide a scalable framework to significantly increase NAS capacity and efficiency while maintaining safety. A second goal of ...

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