Structural Design for a Hypersonic Research Airplane

Abstract

A research airplane was studied which has potential for large-scale demonstration of advanced propulsive, structural, and aerodynamic technologies for hypersonic application. Versatility is achieved through the selection of a configuration that provides for scramjet engine integration by the extensive performance envelope and by large removable sections of the airplane. After a screening of alternative structural concepts, design criteria were applied to an effective heat-sink structure of Lockalloy (Be-38 AI), wherein thermal stress alleviation is a prime consideration in the design. Structural analyses were performed with the SPAR computer program. Results indicate that no critical problems exist, and the resulting weight is within the initial estimate. NomenclatureC p = specific heat E = Young's modulus of elasticity e = strain g = acceleration due to gravity k = thermal conductivity L = length M = Mach number N = load factor AP = pressure difference q = dynamic pressure AT = temperature difference p = density <j ty = tensile yield strength a ult = ultimate load stress a all = allowable stress cr lim = limit load stress Subscripts x = axial direction y = lateral direction z = vertical direction