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The problem of synthesizing a transport aircraft at the conceptual design level is considered. A direct sizing algorithm that does not require iteration is developed. Such direct synthesis methods can be used as important building blocks in an aircraft optimization process. New statistical equations based on current aircraft are derived for approximating the widths and lengths of the cabin and fuselage. A more accurate static thrust over gross weight, which is based on the equations of motion specified by the FAR part 25 climb requirements, is presented. A cruise at constant altitude with optional step-climb is taken into account. The operating empty weight is directly estimated using a statistical correlation for current twin turbofan transport aircraft. The analyses of the layout, performance, and weights are finally assembled in a direct sequential algorithm. This design method is tested on an existing transport aircraft and the results agreed well with the actual design.

This thesis documents the efforts of the writer and his colleagues over the past several years to improve the theoretical foundation of the arbitrary quadrilateral shear panel used in structural analysis codes to model aircraft structures. An equilibrium stress-based element with pure shear resultants on its sides was developed using the principle of complementary virtual work. The internal stress field was derived from a complete polynomial Airy stress function. The element was numerically tested as a pure stress element and a hybrid element to assess the deflection properties for highly distorted planar panels. Linear-stress and quadratic-displacement rods were used, as appropriate, to model the stiffeners required to surround the shear panels. Panel displacements were compared with other well-known shear panels as well as with a finite element model of the shear panel. The pure-stress element, based on a third degree stress polynomial, was finally chosen because it gave displacements in agreement with the other shear panels (but usually on the order of twice the magnitude of the displacement-based finite element model) and panel performance was essentially unchanged with choice of higher-order stress polynomials. Performance of the hybrid version of the panel was spurious and further study is required to understand its behavior.

After a five year study of General Aviation (GA) accidents, the National Transportation Safety Board (NTSB) has concluded that aircraft cabin environments place the occupant at high risk of suffering severe injuries in an emergency crash situation. Studies of Federal Aviation Administration (FAA) seat tests were used to form the basis of a computer analysis to address dynamic cabin environments. In this effort a simplified system of masses, springs, and dampers are used to simulate the more complex configuration of cabin structure, seat, pilot, and restraints on a personal computer. The primary objective of this study is to accurately simulate the motions observed in real life tests performed at the FAA Civil Aeromedical Institute (CAMI) with a commercially available dynamics software. Working Model® was chosen based on its performance, availability, and cost. Design students can use the simulation to evaluate cabin arrangements early in the design phase, making for a useful design tool.

"The photograph shows planes under construction at Bell Aircraft."

"The photograph shows planes under construction at Bell Aircraft."