Theoretical Calculations of Supersonic Wave Drag at Zero Lift for a Particular Store Arrangement

An analysis, based on the linearized thin-airfoil theory for supersonic speeds, of the wave drag at zero lift has been carried out for a simple two-body arrangement consisting of two wedgelike surfaces, each with a rhombic lateral cross section and emanating from a common apex. Such an arrangement could be used as two stores, either embedded within or mounted below a wing, or as auxiliary bodies wherein the upper halves could be used as stores and the lower halves for bomb or missile purposes. The complete range of supersonic Mach numbers has been considered and it was found that by orienting the axes of the bodies relative to each other a given volume may be redistributed in a manner which enables the wave drag to be reduced within the lower supersonic speed range (where the leading edge is substantially subsonic). At the higher Mach numbers, the wave drag is always increased. If, in addition to a constant volume, a given maximum thickness-chord ratio is imposed, then canting the two surfaces results in higher wave drag at all Mach numbers. For purposes of comparison, analogous drag calculations for the case of two parallel winglike bodies with the same cross-sectional shapes as the canted configuration have been included. Consideration is also given to the favorable (dragwise) interference pressures acting on the blunt bases of both arrangements.