Sean Wakayama

Subsonic wing planform design using multidisciplinary optimization

This article presents basic results from wing planform optimization for minimum drag with constraints on structural weight and maximum lift. Analyses in each of these disciplines are developed and integrated to yield successful optimization of wing planform shape. Results demonstrate the importance of weight constraints, compressibility drag, maximum lift, and static aeroelasticity on wing shape, and the necessity of modeling these effects to achieve realistic optimized planforms.

Simultaneous Optimization of a Multiple-Aircraft Family

Multidisciplinary design optimization is considered in the context of designing a family of aircraft. Aframework is developed in which multiple aircraft, each with different missions but sharing common parts, can be optimized simultaneously.Thenewframeworkisusedtogaininsighttotheeffectofdesignvariablescalingontheoptimization algorithm. Results are presented for a two-member family whose individual missions differ signie cantly. Both missions can be satise ed with common designs. Moreover, optimizing both airplanes simultaneously rather than following the traditional baseline plus derivative approach vastly improves the common solution. A cost modeling framework is outlined that allows the value of commonality to be quantie ed for design and manufacturing costs. A notional example is presented to show the cost benee t that may be achieved by designing a common family of aircraft.

AERODYNAMICS OF HIGH-SUBSONIC BLENDED-WING-BODY CONFIGURATIONS

A Mach 0.93 Blended-Wing-Body (BWB) configuration was developed using CFL3DV6, a Navier-Stokes computational fluid dynamics (CFD) code, in conjunction with the Wing Multidisciplinary Optimization Design (WingMOD) code, to determine the feasibility of BWB aircraft at high subsonic speeds. Excluding an assessment of propulsion airframe interference, the results show that a Mach 0.93 BWB is feasible, although it pays a performance penalty relative to Mach 0.85 designs. A Mach 0.90 BWB may be the best solution in terms of offering improved speed with minimal performance penalty.

Subsonic wing design using multidisciplinary optimization

I 111s paper pl escnt s baslc iesults fi om wmg planfornl opt~mrmtion for rninimum drag with constraints on structr~ral welght and maxlinuin 11ft Analyses In each o f thrse dlsciplmes are drvelopcd and mtegrated to weld successful optiin~zat~on of wing planform shape l~esults demonstrate the ~mportance of weight constrarr~ts, compressibility drag, rnaxlmum hft, and static aero~ldstlclty on wmg shape, and the necessity of modclmg these effects to achieve realistic optimizrd planform5

DESIGN TRADES FOR A LARGE BLENDED-WING-BODY FREIGHTER

An advanced design study examined the capabilities of a large Blended-Wing-Body (BWB) freighter. Reductions in the cost of transporting freight were sought from cutting the time to transfer between air and ground transport modes through use of intermodal containers, capturing efficiencies of scale by configuring an aircraft to carry a maximum number of containers, and capitalizing on natural efficiencies of BWB configurations. The large size of intermodal containers, set by efficiency considerations for the truck transport mode, presented some challenges in determining the most efficient way to carry large numbers of containers in the BWB. Several BWB freighter configurations with different arrangements for carrying containers were analyzed and optimized with the Wing Multidisciplinary Optimization Design (WingMOD) code. Airport pavement loading and 80- meter box constraints ultimately limited the size of the BWB freighter. Measuring efficiency as the weight of freight carried divided by aircraft takeoff weight, a large, dedicated BWB freighter was shown to offer significant improvements in efficiency that could be used to develop new opportunities for the air cargo business.