Aircraft integrated design and analysis: A classroom experience

AAE 451 is the capstone course required of all senior undergraduates in the School of Aeronautics and Astronautics at Purdue University. During the past year the first steps of a long evolutionary process were taken to change the content and expectations of this course. These changes are the result of the availability of advanced computational capabilities and sophisticated electronic media availability at Purdue. This presentation will describe both the long range objectives and this year's experience using the High Speed Commercial Transport design, the AIAA Long Duration Aircraft design and RPV design proposal as project objectives. The central goal of these efforts is to provide a user-friendly, computer-software-based environment to supplement traditional design course methodology. The Purdue University Computer Center (PUCC), the Engineering Computer Network (ECN) and stand-alone PC's are being used for this development. This year's accomplishments center primarily on aerodynamics software obtained from NASA/Langley and its integration into the classroom. Word processor capability for oral and written work and computer graphics were also blended into the course. A total of ten HSCT designs were generated, ranging from twin-fuselage aircraft, forward swept wing aircraft to the more traditional delta and double-delta wing aircraft. Four Long Duration Aircraft designs were submitted, together with one RPV design tailored for photographic surveillance

An investigation of aeroelastic phenomena associated with an oblique winged aircraft

Oblique wing aeroelasticity studies are reviewed. The static aeroelastic stability characteristics of oblique wing aircraft, lateral trim requirements for 1-g flight, and the dynamic aeroelastic stability behavior of oblique winged aircraft, primarily flutter, are among the topics studied. The similarities and differences between oblique winged aircraft and conventional, bilaterally symmetric, swept wing aircraft are emphasized

Aeroservoelastic tailoring for lateral control enhancement

The need for effective aileron power for aircraft lateral control and turning maneuvers dates back to the Wright Brothers and their wing warping concept for active stabilization of their aircraft. Early researchers in Great Britain, Japan, Germany and the United States explored ways to increase the effectiveness of control aileron to generate a roll moment. The basic problem of aileron effectiveness and the interrelationship between structural distortion and the loads applied by the control surface is illustrated. A rigid wing/aileron surface will develop the capability to generate increased roll rates as airspeed increases. A flexible surface will become less effective as airspeed increases because of the twisting distortion created by the aft-mounted control surface. This tendency is further worsened by bending distortion of an aft swept wing. This study focuses its attention on the ability of a combined effort between structural redesign of a wing and sizing and placement of a control surface to create specified roll performance with a minimum hinge moment. This design optimization problem indicates the advantages of simultaneous consideration of structural design and control design

Interactive aircraft flight control and aeroelastic stabilization

Several examples are presented in which flutter involving interaction between flight mechanics modes and elastic wind bending occurs for a forward swept wing flight vehicle. These results show the basic mechanism by which the instability occurs and form the basis for attempts to actively control such a vehicle

Dynamics and control of forward swept wing aircraft

Aspects of non-zero differential game theory with application to multivariable control synthesis and optimal linear control law design using optimum parameter sensitivity analysis are discussed

Fostering growth in CEE countries: a country-tailored approach to growth policy

This paper analyses the long term growth experiences of the eastern European accession countries and the effect of various tailored growth policies. We find that there are two overarching growth-enhancing policies that can substantially increase long-term growth: competition and the quality of education. We find empirical evidence that if accession countries from the transition region want to achieve – and sustain – higher growth rates they will need to ensure competition by continuing to remove entry and trade barriers and by strengthening competition agencies. We also find evidence on the positive long-run impact of quality of education on growth, and hence the high return on public investment in education, particularly at the primary and secondary level. The private sector’s role in overcoming skill mismatches will benefit from deepening financial intermediation and reducing constraints in access to finance.

The design of a long range megatransport aircraft

During the period from August 1991 - June 1992 two design classes at Purdue University participated in the design of a long range, high capacity transport aircraft, dubbed the megatransport. Thirteen Purdue design teams generated RFP's that defined passenger capability and range, based upon team perception of market needs and infrastructure constraints. Turbofan engines were designed by each group to power these aircraft. The design problem and the variety of solutions developed are described in an attached paper

Flutter of asymmetrically swept wings

Two formulations of the oblique wing flutter problem are presented; one formulation allows only simple wing bending deformations and rigid body roll as degrees of freedom, while the second formulation includes a more complex bending-torsional deformation together with the roll freedom. Flutter is found to occur in two basic modes. The first mode is associated with wing bending-aircraft roll coupling and occurs at low values of reduced frequency. The second instability mode closely resembles a classical bending-torsion wing flutter event. This latter mode occurs at much higher reduced frequencies than the first. The occurrence of the bending-roll coupling mode is shown to lead to lower flutter speeds while the bending-torsion mode is associated with higher flutter speeds. The ratio of the wing mass moment of inertia in roll to the fuselage roll moment of inertia is found to be a major factor in the determination of which of the two instabilities is critical

The Long-Term Effects of the Chernobyl Catastrophe on Subjective Well-Being and Mental Health

This paper assesses the long-term subjective well-being and mental health toll of the Chernobyl disaster of 1986 in the general Ukrainian population and estimates the monetary differential necessary to compensate victims of the catastrophe. The analysis is based on two nationally representative Ukrainian data sets and reveals that even 20 years after the accident subjective well-being is negatively associated with self-reported assessments of having been affected by the catastrophe. The causal long-term effect of the disaster on life satisfaction is established by exploiting variation in official radiation data which are linked to survey respondents through information on their place of living in 1986. We find higher depression and trauma rates as well as poorer subjective life expectancy among those stronger affected by Chernobyl. Expressed in monetary terms, the estimated amount of income required to compensate for the experienced utility loss amounts to an annual cost of seven percent of Ukraine's GDP.Chernobyl catastrophe, subjective well-being, mental health, instrumental variable