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A description is given of the outboard horizontal stabilizer (OHS) system in which the horizontal tail surfaces are mounted outboard of the mainplane tips, in the wing upwash, at the extremities of booms projecting downwind from the mainplane tips. The theory of operation of the OHS concept is reviewed together with the current development status. Configurational geometries of OHS and comparable conventional aircraft are defined and first order, comparative, performance analyses are presented for cruise, take-off and landing modes of operation. It is shown that the pitch-mode control of OHS aircraft does not present any problems relative to the control, in pitch, of comparable conventional aircraft. It was also shown that the OHS concept makes possible a reduction of the drag of the wing and tail surfaces of about 20% together with a reduction in planform area of, typically, 13%.

To optimize the hydraulic system design and evaluate the system performance at the airplane level, a complete dynamic integrated hydraulic model is needed. This paper describes the development and usage of a dynamic model for the Boeing 777 hydraulic system. This model dynamically simulates the hydraulic power available as a function of the airplane events. This not only allows the designers to test their design prior to building the hardware but it also serves as a tool to evaluate the hydraulic system performance at the airplane level.

“Operation Heli-STAR” (Helicopter Short-haul Transportation and Aviation Research) “An Olympic Moment” The microcosm of activity surrounding the 1996 Olympic Games provided researchers an opportunity for demonstrating state-of-the art technology in the first large-scale deployment of a prototype digital communication/ navigation/ surveillance system in a confined environment. At the same time it provided an ideal opportunity for transportation officials to showcase the merits of an integrated transportation system in meeting the operational needs to transport time sensitive goods and provide public safety services under a real-world conditions. Five aeronautical CNS functions using a digital datalink system were chosen for operational flight testing onboard 91 aircraft, most of them helicopters, participating in the Atlanta Short-Haul Transportation System.

As aero engines mature the operator, the repair base, and the manufacturer look for controlled means of extending operational life, as a means of controlling maintenance costs. The approach must focus on component integrity and performance to ensure a cost effective release life can be achieved. The program must be dynamic if it is to address the needs of today's sophisticated gas turbine.

The aim of the project described in this paper is to control the behavior and trajectory of a vehicle when different parameters - such as the lift and/or the aerodynamic parameters - change, i.e., increase or decrease. The problem is tackled, whatever the mode of propulsion of the vehicle ( combustion engine or electric motor and wheel transmission - or reactor ). This paper describes one way of developing the architecture of such a system for the control of the functions of route guidance, of the changes in attitude which lead to a modification of the aerodynamic forces according to the speed variations and more generally the vehicle's dynamics. An active system based on torque and slip controls of each wheel allows the control of rolling. The wheel propulsion mode and freewheel mode are considered in a similar way. The function of attitude correction uses an active system controlling a hydraulic jack mounted in the suspension.

A review is made of a number of flying automobiles that have been built and flown including two that were granted Approved Type Certificates by the CAA (now FAA). Also reviewed are conceptual or visionary designs by a number of innovators. The author, although critical of certain designs, encourages creativity and continued exploration of new flying automobile concepts. It is possible that high technology advances may lead to a flying automobile that will satisfactorily combine the comfort and convenience of the automobile with the high cruise speed and efficiency of the airplane. Dreamers are urged to dream on, and on, into the 21st Century.

The Focke-Wulf Fw 190 was one of the truly outstanding fighter aircraft of the Second World War. It distinguished itself over all fronts on which the Luftwaffe fought in conditions ranging from arctic wastes to the deserts of North Africa. The Fw 190 represented the epitome of conventional piston-engine fighter design on the threshold of the jet age. Conceived nearly sixty years ago, flying for the first time on the eve of the war in 1939 and acknowledged as “the best all-around fighter in the world” in the mid-war years, derivatives of the Fw 190 were still pushing the ultimate capability boundary for this class of aircraft at war's end in 1945 (reaching maximum level true airspeeds of 470 mph [about Mach 0.7] at altitudes of well over 40,000 feet). This paper assesses the design attributes and technology approaches, including innovative use of advanced electrical systems, that were used to make the Fw 190 one of the great all-around fighters in aviation history.

The intent of a balanced engine design process is to satisfy all systems requirements including operability, performance and durability. Due to the complexity of the trade-off process of the various metrics it is possible that system improvements may be required after a turbofan engine enters production. Also, in the case of derivative engines, configured for increased performance, the flowpath aerodynamics may be challenged and may have to be examined to ensure there is no flow field anomaly. By incorporating special diagnostic aero instrumentation at the earliest opportunity any required operability improvement can be identified and corrective action taken. The paper first delineates the component matching challenges of twin spool mixed flow turbofan engines. Then it discusses investigation of various potential destabilizing influences.

A series of aerodynamically driven model mounts for dynamic wind tunnel testing were designed, built and evaluated at Wichita State University. The mount proved to be very responsive, stable and capable of generating a wide variety of pitching motions. However, the response of an early variant of this mechanism displayed “stair-step” like behavior during slow pitching motions and damped oscillations at the end of rapid pitching motions. Numerical and experimental evaluations demonstrated that these undesired characteristics are minimized when the size of the control surface is increased and the inertia of the apparatus is reduced. In addition, this novel mechanism was utilized to demonstrate the type of valuable data that can be obtained. Force data for an oscillating NACA 0012 wing section is provided.

The process of entrance of a pair of laminar rectilinear vortices into an atmospheric layer with stable stratification is modeled by solving numerically the two-dimensional time-dependent Navier-Stokes equations in Boussinesq's approximation. The solution is obtained on an 200x200 uniform grid using an explicit finite-difference scheme at a flow Reynolds number of Re=106 and a temperature anomaly gradient of 2K per 100m height increment. The computations have shown that at the initial phase of the immersion of the vortex pair into the stratified layer, a retardation of their descent is observed, then vortices bring together and the rate of their descent become higher.

Although there are many commonalties between fixed-wing and rotary-wing aircraft, both in terms of their performance and the missions they fly, their extensive differences demand that we recognize the training requirements that are unique to rotary-wing vehicles. In addition, the rotary-wing industry is made up of many widely distributed small operators whose training needs and logistics vary widely from those of the well-ordered, capital intensive, air carriers. The relative absence of large operators in the rotary-wing industry is a source of challenge to training-equipment manufactures and to the federal agencies responsible for supporting and regulating the development of aviation. In anticipation of growth in the rotary-wing industry, the Federal Aviation Administration (FAA) has proposed new rules, Part 142 Title 14 CFR, which will authorize and regulate certified training centers.

The work deals with the problem on aircraft vortex wake behavior in steady-flow formulation. Further approximations of slender-body theory are constructed with the aid of asymptotic methods. The mathematical approach proposed performs to calculate the aircraft wake up to breakdown. The nontrivial analytic solutions for the problem of motion of one and two vortex filaments with circular cross-section are obtained.

The possibility of visualization of an aircraft jet-and-vortex wake above a landing strip is investigated. The processes of water vapor heterogeneous condensation and droplets coalescence due to turbulent pulsation are taken into account. Numerical examples for the case of B-747-type flyer take-off are presented.

To help reduce operating costs of a High Speed Civil Transport aircraft, our External Vision System Technology Development Team at Honeywell, along with teams at NASA, Boeing and McDonnell Douglas, is investigating the feasibility of replacing forward windows with a synthetic version. The synthetic window will capture the greatest part of information normally visible to pilots. Ideally, it would capture the “look, feel, and functionality” of traditional windows. This paper discusses optical characteristics of certified windows. Measurements were taken from commercial aircraft windows at various stages of service up to and beyond 20,000 hours. Fundamental system attributes, relating to visual performance, were measured and evaluated. Measurement techniques are described. The resultant data provide the synthetic window systems designers a foundation on which to base their work and design goals.

Boeing is participating in a research program to study the feasibility of building a High Speed Civil Transport (HSCT). A program assumption is that the aircraft will not have a droop nose capability, requiring that the forward facing windows be replaced by large format displays showing the outside scene. We refer to this display as the External Vision System (XVS). The issues being addressed in this paper involve the integration of primary flight symbology into the XVS display. We point out how this integrated display is unique, falling someplace between a standard head-down primary flight display and a head-up display. We describe potential advantages of an integrated display as well as point out a number of possible problem areas. High level goals driving the display design are presented. We finish by describing a number of research and development issues, that if resolved, would contribute to the design effort.

An integrated cockpit display suite, the T-NASA (Taxiway Navigation and Situation Awareness) system, is under development for NASA's Terminal Area Productivity (TAP) Low-Visibility Landing and Surface Operations (LVLASO) program. This system has three integrated components: Moving Map -- track-up airport surface display with ownship, traffic and graphical route guidance; Scene-Linked Symbology -- route/taxi information virtually projected via a Head-up Display (HUD) onto the forward scene; and, 3-D Audio Ground Collision Avoidance Warning (GCAW) system -- spatially-localized auditory traffic alerts. In this paper, surface operations in low-visibility conditions, the design philosophy of the T-NASA system, and the T-NASA system display components are described.

Increased demand for machining with higher material removal rates necessitates the use of higher rotational speeds and higher side loads during the cutting process. These new machining parameters manifest themselves as chronic degenerative problems with spindles and tool holder taper interfaces. Regenerative vibrations serve to complicate this condition and greatly contribute to the severity of this degenerative process. This paper describes solutions for these recent machining process problems to manufacturing engineers and machine tool builders. An overview of the complicated processes that cause vibration induced damage to machine tools is presented in simple terms. The objective is to give the reader a basic understanding of vibration induced machine damage, and several ways to combat this problem.

We report the results of a part-task simulation evaluating the separate and combined effects of an electronic moving map display and newly developed HUD symbology on ground taxi performance, under moderate- and low-visibility conditions. Twenty-four commercial airline pilots carried out a series of 28 gate-to-runway taxi trials at Chicago O'Hare. Half of the trials were conducted under moderate visibility (RVR 1400 ft), and half under low visibility (RVR 700 ft). In the baseline condition, where navigation support was limited to surface features and a Jeppesen paper map, navigation errors were committed on almost half of the trials. These errors were virtually abolished when the electronic moving map or the HUD symbology was available; in addition, compared to the baseline condition, both forms of navigation aid yielded an increase in forward taxi speed.

This purpose of this research is to identify the information requirements and interaction issues associated with pilot use of an autoflight system for the high-speed civil transport (HSCT). The approach taken was to survey and evaluate existing research tools and methods for representing and understanding human interaction with complex engineering systems, to model a current-generation autoflight system representative of the capability required in the HSCT using the techniques found to be most appropriate, and then to use this model and other proposed HSCT guidance and control concepts to identify the necessary information requirements and interaction issues. The modeling representation chosen was the Operator Function Model (OFM).

During the commercial aircraft assembly process, many interrelated installations require alignment to a common reference centerline or location to a common reference plane. A rotational laser can be used to establish a vertical, horizontal, or other desired plane orientation to serve as a common installation reference for multiple assemblies. The cargo floor installation in the lower lobe of the 777 forward section requires that three physically separate cargo floor sections be aligned to a common centerline and lie in the same horizontal plane. Two rotational lasers are used in conjunction with laser positioning equipment, digital laser targets, and conventional tooling hardware to meet the installation criteria and provide a reliable, repeatable process.