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The most recent designs in commercial airplanes have necessitated a change in the nature of airplane safety assessment. It used to be sufficient to examine each separate system to determine the safety of the airplane as a whole. This is no longer the case. Commercial airplanes have become highly integrated machines. New methods and tools must be employed to ensure the safety of new airplane designs. The companies responsible for the design of new airplanes have independently developed methods and tools to accomplish this. New standards have been written which bring these tools together and present them in a logical and usable form.

Leading edge roughness is known to influence the aerodynamic performance of wings and airfoil sections. Aerodynamic tests show that these effects vary with the type and texture of the applied roughness. The quantification of the relationship between different types of roughness is not very clear. This makes the comparison of results from different tests difficult. An attempt has been made to find a relationship between randomly distributed roughness using cylinders of different heights and densities, roughness using ballotini, and equivalent sand grain roughness. A CFD method based on the Cebeci-Chang roughness model was used to generate correlations with experimental data. It is found that the variation of the size and density of individual roughness elements can be represented using one roughness parameter, Rp, which is equivalent to the sand grain roughness parameter used in the Cebeci-Chang model.

A part-task instrument flight simulation study, conducted at the University of Illinois, compared certified flight instructors' traffic avoidance performance using coplanar (2D) and perspective (3D) cockpit displays of traffic information (CDTI). Traffic avoidance was generally better when using the coplanar display format, although display type was also found to interact with the approach geometry of the traffic to influence performance. Observed performance differences are discussed in terms of the maneuvering strategies adopted by the pilots in the context of how traffic information was conveyed by the coplanar and perspective displays.

This paper examines two general considerations for designers of CDTI: the information required for intended applications, and the mechanisms capable for providing the pilot with that information. Methods for defining information requirements are summarized, and a case study using control theory analysis is given. The information available from procedures and from CDTI are compared. Finally, suggestions are given for the design of CDTI and air traffic procedures.

The effects of an electronic moving map and a HUD on ground taxi performance in reduced visibility were examined in a high-fidelity simulation. Sixteen commercial flight crews completed 21 trials, each consisting of an autoland arrival to Chicago O'Hare and taxi to an apron area. Relative to a baseline (paper-chart only) condition, the EMM/HUD combination increased forward speed by 21%, and reduced navigation errors by nearly 100%. These results, together with workload ratings, situation awareness ratings, analyses of crew interactions, and pilot feedback, provide strong evidence that the combination of head-up symbology and an EMM can substantially improve both the efficiency and the safety of ground operations.

The High-Speed Research Program Technology Tracking and Assessment Process is the process by which NASA and its industry partners measures the technical progress of the program's technology development efforts. Metrics are established for each technology area and tracked against end-of-program projections. The process is probabilistic in nature and consists of two phases. The technology audit phase is where the data is gathered and compared to previous assessments. The metrics integration phase is where uncertainties in system-level figures of merit are quantified by using a Monte-Carlo approach to propagate uncertainties at the technology level.

This paper outlines a comprehensive, structured, and robust methodology for decision making in the early phases ofaircraft design. The proposed approach is referred to as the Technology Identification, Evaluation, and Selection (TIES) method. The seven-step process provides the decision maker/designer with an ability to easily assess and trade-off the impact of various technologies in the absence of sophisticated, time-consuming mathematical formulations. The method also provides a framework where technically feasible alternatives can be identified with accuracy and speed. This goal is achieved through the use of various probabilistic methods, such as Response Surface Methodology and Monte Carlo Simulations. Furthermore, structured and systematic techniques are utilized to identify possible concepts and evaluation criteria by which comparisons could be made.

The impact of inlet unstart phenomena on supersonic transport (SST) was investigated by wind tunnel testing. Inlet unstart condition was simulated by controlling the captured mass flow by the inlet. Unsteady pressures on the lower surface of wing and unsteady forces of the wind tunnel model were measured. Unsteady pressure measurement was carried out to detect shock wave motion. Unsteady force measurement by using both internal balance and accelerometers was to estimate axial/angular acceleration of airframe when inlet unstart was occurred. The pressure measurement data revealed that shock location fluctuated with dominant frequency although the controlled mass flow was steady. And it was analytically shown that the dominant frequency is corresponding to the first order frequency of organ pipe resonance.

A study has been conducted into the employment of ailerons as a brake augmentation device capable of minimising landing distance whilst maintaining the aircraft on the runway centre line. The idea is to use ailerons to increase the normal force on the undercarriage, which has the effect of increasing the available friction force in favour of the gear that is most likely to skid. The paper evaluates, the aerodynamic forces and moments produced by ailerons, the achievable increase/decrease in the applied normal undercarriage loading, the aircraft roll rates, dynamic lags due to fully deflecting the ailerons, and the responsiveness of the anti skid system. This paper shows that the ailerons have the aerodynamic effectiveness to enhance differential braking and describes the concept for shortening landing distances. The paper introduces the methodology to achieve this proposed effect.

In this paper, the problem of estimation and prediction of the projectile trajectory, MET data, and the impact point is formulated within the extended Kalman filtering framework. Factorized implementations of extended Kalman filtering, smoothing, and prediction algorithms are presented. Different wind models are discussed. The algorithms are demonstrated through simulation.

This paper summarizes a body of research being conducted in the Cockpit Display Research Group at NASA Ames Research Center to support the development of a Cockpit Situation Display (CSD) for en route free flight and terminal area operations. The paper first presents an airline and FAA perspective on en route free flight operations. This discussion is followed by perspectives of free flight based on interactions with controllers from an Air Route Traffic Control Center. Next we discuss a concept of strategic en route separation and its benefits for both the airlines and ATC. We follow this with a brief summary of work in progress in the laboratory in support of the CSD design. Finally we conclude the paper by summarizing a completed CVSRF B-747 full mission simulation, where crews utilized an initial CSD designed to support en route free flight.

Mixed compression inlets of the type used for supersonic air breathing engines, such as for the SR-71 and the supersonic transport aircraft, perform efficiently at speeds of around Mach 2.0 to 2.5. These inlets are highly susceptible to unstart when operating in a fuel efficient configuration. An unstart margin allows perturbations in mass flow and incoming flow incidence angle, which result from combinations of many contributors, which may include: gust, engine misalignment, control system tolerance, sidewash and upwash due to maneuver, and structural flexibility effects. This paper develops a methodology by which the last two effects may be analyzed to determine their contribution to changes in incoming flow incidence angle.

An experimental wind tunnel investigation and computational performance evaluation was conducted which focused on reducing the incremental drag resulting from external modifications to the fuselage of the AC- 130U Gunship. The objective of this effort was to establish a solid foundation via experimental and computational ground efforts to support flight test of drag reduction modifications to an aircraft. Currently, additive drag resulting from AC- 13 0U modifications decreases the range of the aircraft, increases the infrared heat signature of the engine exhaust due to the need for higher power settings, and has an adverse impact on takeoff and engine out performance. Specifically, the program consisted of six major thrusts: 1. Wind tunnel testing of a 1/48 scale model of the AC-130U fuselage to determine the drag on eight specific protuberances. 2. Design and testing of fairing modifications in 1/48 scale on three of the high drag protuberances. 3.

The aircraft design curriculum at the United States Air Force Academy presents conceptual design in terms of nine fundamental technologies or activities, namely customer focus, design synthesis, engineering drawing and geometry modeling, aerodynamic analysis, constraint analysis, mission analysis, sizing, optimization, and performance and cost reporting. This paper describes these nine activities, explains how they fit together in the conceptual design process, and shows how they are taught and learned at USAFA. Examples of student work show the effectiveness of this approach. This paper also provides an overview of the aircraft design course to our own students.

HELIos is a single seat, three wheel, vertical take-off and landing (VTOL) flying car concept. It uses duct enclosed counter-rotating propellers. This technology eliminates the need for a tail rotor and makes the vehicle more compact. It needs no modification to switch between drive mode and flight mode. It uses a modified motorcycle or snowmobile engine for road travel and a two-stroke, aircraft, diesel engine for air propulsion. It is flown by wire for directional control, and a helicopter pitch control is used for vertical motion. HELIos is equipped with a guidance control system for safe and precise flying. In emergency cases, the driver/pilot can employ a ballistic parachute, which allows the vehicle to float safely down to earth. It will be street legal under the rules of the Department of Transportation (DOT); its three-wheel design categorizes it in the motorcycle and scooter category.

This paper describes those elements of a personalized airborne transportation system that are necessary and sufficient to make it usable in the future by a significant portion of the world's population. This system, which includes “powered lift aircraft” called volantors1 and the infrastructure in which they operate, must meet the user's personal needs while concurrently meeting societal needs as well.

This paper presents an advanced single stage-to-orbit (SSTO) design concept based on our understanding of Russian AJAX technologies. The concept brings together a unique set of subsystem components to enhance the performance of an advanced combined cycle engine powered SSTO design concept. A magnetohydrodynamic (MHD) generator-accelerator energy bypass system is used to maintain subsonic flow in the engine combustion chamber. And, an electromagnetic drag reduction system is used to reduce wave and base drag during ascent and reentry. The performance of the advanced highly reusable SSTO is compared to a reference advanced air-breathing rocket-based combined cycle ejector ram-scramjet powered SSTO design concept. The results indicate an approximate 15% performance increase compared to the reference design.

The Vectoria aircraft was designed last year by staff members and students from Linköping University in Sweden and is a fighter that is designed to play a role similar to the Saab JAS 39 Gripen. The design incorporates many new ideas in aircraft design including stealth and two-dimensional thrust vectoring capabilities. One of the aircraft's prime requirements was to utilise STOL whilst also maintaining a low radar signature and obtaining fighter performance. This in itself is no easy feat as to date no western aircraft has successfully combined these requirements, although these factors are being included in the different American JSF projects. The Vectoria was originally designed as a part of a structures project in which all the various components had to be fitted. It was decided that the aircraft should have two dimensional thrust vectoring in the form of a simple flap was the cheapest and most light form of achieving STOL performance and improved manoeuvre properties.

This paper describes some ways in which PC-based flight simulation can be used to teach aircraft flight performance and flight testing to aeronautical engineering students. Two PC-based flight simulation programs are used here for this purpose: the Jeppesen FS200 PCATD and Microsoft Flight Simulator 98. Examples of student flight test assignments using these programs are given for cruise (straight and level, unaccelerated) flight, climbs, descents (power off glide), and for (level) maneuvering flight. Simulation flight test data from these assignments are presented and compared to theory. It is concluded that PC-based flight simulation can be a valuable tool for illustrating flight performance and flight testing to aeronautical engineering students and can be challenging, interesting and fun for students.