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作者： Estock, Jamie L. McCormack, Robert Bennett, Winston Patrey, James Aptima Inc. Woburn MA 01801 United States Air Force Research Laboratory Mesa AZ 85212 United States NAVAIR/PMA205 Patuxent River MD 20670 United States 1726 M Street N.W. Washington DC 20036 United States 12 Gill Street Woburn MA 01801 United States 6030 South Kent Street Mesa AZ 85212-6061 United States Aviation Warfare Training Development 47123 Buse Rd. Patuxtent River MD 20670-1547 United States

ISBN: (纸本)9781563479458

Employing the proper level of simulator fidelity ensures better training results and reduces cost by eliminating investments in unnecessary training and technology. However, there is little guidance concerning how to build or acquire training simulators with the appropriate fidelity to achieve specified training objectives, fit within budgetary constraints, and maintain trainee acceptance. While the past few decades of theory and research can provide some guidance on the level of fidelity required for effective training, the existing literature is fragmented and difficult to use constructively for determining how best to design or purchase training simulators. Given this lack of cohesion, training designers and acquisition professionals often turn to end-users to provide fidelity requirements for training simulators. Fidelity requirements defined by end-users provide useful insight into the level of fidelity necessary to ensure that trainees 'buy-in' to the simulator but they do not necessarily help with determining how much and what kind of fidelity is important. There is also no guarantee that perceived effectiveness translates into actual effectiveness. Preliminary findings from our research on flight simulator fidelity revealed a discrepancy between trainees' subjective assessment of the effectiveness of simulators at different levels of fidelity, and objective measures of in-simulator performance and training effectiveness. Our findings underscore the need for data from multiple sources to provide the most accurate picture of the level of fidelity required for effective training. However, the simple compilation of information into a static reference tool or theoretical framework does not adequately represent the complex interactive relationships between fidelity and training effectiveness. A computational model-based tool is required to adequately represent and examine these complex relationships. This paper discusses our work to develop a computational modelba

关键词： Flight simulators

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A very simple and effective method for off-design simulation of modern aircraft piston engines

A very simple and effective method for off-design simulation...

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作者： Francia, D. Piancastelli, L. Renzi, C. DIEM Aerospace Div. University of Bologna Forlì 47100 Italy DIEM Aerospace Div. University of Bologna via Fontanelle 40 Forlì Italy

ISBN: (纸本)9781563479458

A new generation of aircraft piston engines is currently being introduced on the market. These new engines come directly from the huge experience achieved in the motorcycle and automotive racing and production. However direct use of automotive power unit is not advisable, since car engines work mainly in the first quarter of the power output, while sport motorcycles are used in a very "light" way, with the engines that span several times through the entire range of power outputs and rpm. The other problem is fuel. Aircraft spark ignition engine for ultralight and light aircrafts may continue to use automotive gasoline, while diesel engines for light up to cargo aircraft should use jet(A1) and jp4. However, the large experience obtained from racing/high-performance motorcycles, racing/high-performance cars and common rail engines cannot be ignored. Thousand of hours and billion of Euros have been spent for this development and the results are interesting. This paper tries to calculate the future aircraft engine performance from the many experimental data already available on a certain type of combustion chamber or better from a well defined and experimented cylinder unit. On the other side the "lean-thinking" approach to aircraft engine design may be not applicable. The lean thinking approach tends to prefer the time-to-market to the optimization of the engine unit. With engines that will probably stay on the market for 30 years this approach is not convenient. An important optimization during the design phase is possible with modern CAD tools. Mass and cost reduction may easily reach the 30%. On the other side the "brain storming approach" is not applicable to the heavily-constrained aircraft-engine design, where it is common that inapplicable solutions and ideas seem to be the best during the initial phase even to experts. Our research team developed three different families of engines: the first family uses the cylinder unit of a well proven motorcycle engine, whi

关键词： Cost reduction

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Dynamic coupling of the KC-135 tanker and boom for modeling and simulation

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JOURNAL OF AIRCRAFT 2007年第3期44卷 1034-1039页

作者： Smith, Austin L. Kunz, Donald L. USAF Res Lab Air Vehicles Directorate Wright Patterson AFB OH 45433 USA USAF Inst Technol Dept Aeronaut & Astronaut Wright Patterson AFB OH 45433 USA

One can see from the preceding analysis that no response is identical for anyof the boom models, but they all exhibit the same trends. Differences exist between responsedamping and frequency and the resultant steady-state equilibrium angles because of the differentapproaches used to model the dynamics. The analytical model developed in this Note offers dynamiccoupling and compatibility with an existing KC-135 tanker model that will improve aerial refuelingmodeling and simulation. Moreover, it exhibits sufficiently similar responses to the establishedBOPTT boom model. The coupled model, based on first principles rather than empirical aerodynamics orenigmatic experimental data, can be improved upon by eliminating current assumptions with moredetailed information about the boom, such as its exact mass distribution and cross-sectionalprofile.

关键词： Aerodynamic Characteristics Automated Aerial Refueling Control Surfaces Angle of Attack Air Force Research Laboratory UAV Air Education and Training Command Lagrange Multipliers Telescopes Fuselages

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Circularly-towed lumped mass cable model validation from experimental data

Circularly-towed lumped mass cable model validation from exp...

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aiaa modeling and simulation technologies conference, 2006

作者： Williams, Paul Lapthorne, Peter Trivailo, Pavel RMIT University Melbourne Vic. 3083 Australia School of Aerospace Mechanical and Manufacturing Engineering PO Box 71 Australia AIAA United States

ISBN: (纸本)1563478218

When a long cable is towed in a circular flight-path, the system can exhibit quasi-stationary solutions for which the cable tip appears to remain stationary relative to the orbiting aircraft. For applications involving pickup and delivery of payloads, tighter turns at high speeds lead to nearly stationary motion of the cable tip in an inertial frame. Computer simulations of towed cable systems have been developed over the years for a range of applications, including underwater systems, aircraft towed systems, and tethered satellite systems. A popular modeling approach treats the cable as a series of lumped masses connected via viscoelastic springs. This paper seeks to compare results of a lumped mass model for a circularly-towed cable system with experimental data. A parameter optimization technique is used to determine some of the uncertain system properties.

关键词： Tetherlines

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modeling spray impingement using linear stability theories for droplet shattering

Modeling spray impingement using linear stability theories f...

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41st aiaa/ASME/SAE/ASEE Joint Propulsion conference and exhibit

作者： Yoon, Sam S. Desjardin, Paul E. Fire Science and Technologies Sandia National Lab P.O. Box 5800 Albuquerque NM 87185-1135 United States Mechanical and Aerospace Engineering University at Buffalo New York NY 14260 United States

This paper compares several linear-theory-based models for droplet shattering employed for simulations of spray impingement on flat wall surface or a circular cylinder. Numerical simulations are conducted using a stochastic separated flow (SSF) technique that includes sub-models for droplet dynamics and impact. Results for spray impingement over a flat wall indicate that the linear theory applicable for a single droplet impact over-predicts the number of satellite (or secondary) droplets upon shattering when compared to experimental data. The causes for the observed discrepancies are discussed. Numerical simulation results for spray impingement over for a circular cylinder in cross flow are obtained and discussed. © 2005 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

关键词： Circular cylinders

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Roughness-induced transient growth

Roughness-induced transient growth

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35th aiaa Fluid Dynamics conference and exhibit

作者： Choudhari, Meelan Fischer, Paul Computational Modeling and Simulation Branch NASA Langley Research Center M.S. 128 Hampton VA 23681 United States Argonne National Laboratory Mathematics and Computer Science Division 9700 S. Cass Avenue Argonne IL 60439 United States

ISBN: (纸本)9781624100598

Numerical simulations are used to model the boundary layer disturbance field due to a spanwise periodic array of circular disks at the surface. Our earlier computations (Fischer and Choudhari 2004) reproduced some of the major trends associated with roughness induced transient growth as measured by White and Ergin (2003), confirming the accuracy of their data reduction technique. The present paper explores the effects of roughness height, shape, and size on the transient growth along the wake of the roughness array. Results indicate the range of roughness heights over which the energy levels of the dominant stationary disturbance are consistent with the empirically determined Rek2 scaling of White and Ergin. Computations further reveal the intricate effects of disturbance nonlinearity on transient growth characteristics. At sufficiently large roughness heights, simulations indicate spontaneous vortex shedding behind the roughness array, which has been identified in previous experiments as a precursor to premature transition (i.e., tripping) of the laminar boundary layer. The effect of stationary, suboptimal transient growth disturbances on the amplification of Tollmien-Schlichting instability waves in the boundary layer is also assessed in the light of the recent findings concerning the stabilizing influence of optimal growth streaks (Cossu and Brandt 2002).

关键词： Laminar boundary layer

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New generation aerodynamic and multidisciplinary design methods for falcon business jets. Application to the F7X

New generation aerodynamic and multidisciplinary design meth...

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23rd aiaa Applied Aerodynamics conference

作者： Rostand, Philippe Dassault Aviation Saint Cloud France Dassault Aviation DGT 78 Quai Marcel Dassault 92214 Saint Cloud France AIAA United States

New generation methods are continuously introduced for the design of high performance business jets, incorporating state of the art technologies in terms of flow simulation and optimization algorithms. Actual aircraft designs are consequently modified, and the resulting performance improvements are the motivation of the effort required for the development and validation of new methodologies. Innovations have been introduced recently regarding: Flow solvers (CFD) Aerodynamic design and optimisation methods Multidisciplinary analysis and design A brand new high tech aerodynamic design has been derived between mid 2000 and mid 2002 for the FALCON F7X, which will make its maiden flight early in 2005. With previous generation methods, design solutions for a similar requirement would have been different;most notable difference is the use of high loading / high aspect ratio / low thickness wings which would have been impossible without high fidelity modeling of the buffeting, maximum lift and drag of a very flexible wing. Further R&D efforts are underway to develop and validate technology for future FALCONs;guidelines come from an analysis of future requirements in which very high expectations in terms of environment-friendliness are a large part.

关键词： Aerodynamics

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Turnaround bump reduction in a linear hydraulic actuator by mechanical means

Turnaround bump reduction in a linear hydraulic actuator by ...

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Collection of Technical Papers - aiaa modeling and simulation technologies conference

作者： Beard, Steven D. NASA Ames Research Center Moffett Field CA 94035-1000 United States Aerospace Simulation Operations Branch NASA Ames Research Center MS 243-5 Moffett Field CA 94035-1000 United States

ISBN: (纸本)1563476746

The Vertical Motion Simulator at NASA Ames Research Center utilizes custom non-hydrostatic hydraulic actuators to drive its roll, pitch, yaw and longitudinal axis. These actuators have operated flawlessly with one exception;they exhibit a phenomenon that is detrimental to the motion fidelity called "Turnaround Bump" (TAB). TAB occurs in all hydraulic actuators with seals at the onset of motion (extending or retracting) when the friction on the seals changes from the higher static (no motion) to the lower dynamic (motion) friction. The sudden change in the friction force causes an acceleration spike that can be felt by the pilot thus giving a false motion cue. In order to reduce TAB without going to costly hydrostatic actuators, a cost effective mechanism was designed that constantly rotates the piston rod end of the actuator so that the piston rod never stops moving relative to the seals even when the actuator stops moving in the linear direction.

关键词： Actuators

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In-flight simulation in support of an aircraft certification process

In-flight simulation in support of an aircraft certification...

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aiaa modeling and simulation technologies conference and exhibit 2003

作者： Leissling, D. Gestwa, M. Bauschat, J.-M. Institute of Flight Systems Lilienthalplatz 7 D-38108 Braunschweig Germany

ISBN: (纸本)9781624100918

More than other techniques, in-flight simulation is able to strengthen the pilots' confidence into predicted flying qualities and system capabilities of a new aircraft. Furthermore, the simulation of potential system failures and malfunctions makes a valuable contribution with regard to the entire certification process. In 2002 the flying test-bed ATTAS (Advanced technologies Testing Aircraft System) of the German Aerospace Center (DLR) was successfully used as an in-flight simulator for a new short- and intermediate-range commercial aircraft. This paper presents a survey upon the used facilities and applied methods concerning the in-flight simulation technique in the course of the flight test campaign. The sophisticated architecture of the experimental software system with its modular and flexible character is described. Selected flight test results which reveal the high in-flight simulation fidelity are presented and briefly discussed. © 2003 by the DLR Institute of Flight Systems.

关键词： Flight simulators

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simulation - to - flight correlation

Simulation - to - flight correlation

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aiaa modeling and simulation technologies conference and exhibit 2003

作者： Lee, B.P. Rodchenko, V.V. Zaichik, L.E. Yashin, Y.P. Boeing Seattle WA United States TsAGI Zhukovsky Russia Zhukovsky Russia

ISBN: (纸本)9781624100918

Presented is a theoretical approach to evaluate the effects of specific forces, angular accelerations and hazard factor on pilot ratings generalized for various aircraft and different control axes. Analysed are the peculiarities of specific forces, angular accelerations and hazard factor effects on lateral and longitudinal handling qualities for various piloting tasks. © 2003 by The Boeing Company.

关键词： Hazards

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