The Sears–Haack body is a theoretical aerodynamic shape that produces the minimum wave drag for a slender body of revolution with a given length and volume in supersonic flow. It is named after engineers William R. Sears and Derek H. A. L. Haack, who independently developed the concept in the 1940s. The shape is derived from the area rule in supersonic aerodynamics and is characterized by a smooth, pointed profile that tapers symmetrically from the midpoint toward both ends.
The cross-sectional area distribution of a Sears–Haack body follows a specific mathematical function that minimizes wave drag under linearized supersonic flow assumptions. This theory assumes small disturbances and applies to bodies moving at supersonic speeds (Mach numbers greater than 1). The resulting shape is often used as a benchmark in aerospace engineering for evaluating the efficiency of fuselage or missile designs.
The Sears–Haack body is distinct from other low-drag profiles such as the von Kármán ogive, which applies to different flow regimes or constraints. While the theoretical shape provides optimal drag reduction under idealized conditions, practical applications may deviate due to structural, volumetric, or operational requirements.
Accurate information is not confirmed regarding the direct use of Sears–Haack bodies in specific aircraft or missile models, though the principles inform modern aerodynamic design. The derivation of the shape relies on the Prandtl–Glauert transformation for compressible flow and the theory of characteristics for supersonic aerodynamics.