Optimal Projectile Shapes for Minimum Total Drag
Abstract
An analytical method for theoretically predicting the projectile shape which yields the minimum total drag for a fixed length, diameter, and supersonic Mach number (2< or = free stream mach no < or = 6) is derived. The pressure drag was estimated by modified Newtonian theory on the nose and Prandtl-Meyer expansion on the afterbody. The skin-friction drag was approximately by Van Driest method and the base drag by a semiempirical technique. The drag on the forebody is optimized using a new numerical technique and on the afterbody by using the method of steepest descent. The optimum body shape has a base diameter of about 70 percent of the maximum diameter and a forebody length varying between 60 and 80 percent percent of the total length depending on the Mach number and overall fineness ratio. The forebody ogive shape lies between the well-known hypersonic optimum 2/3- and 3/4-power law ogives and the afterbody is conical. Results further indicate that a change of 5 percent in nose length from the optimum results in only about a 1-percent drag penalty.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1977
- Accession Number
- ADA042180
Entities
People
- Frank G. Moore
- Fred R. Dejarnette
- William Ward Hager
Organizations
- Naval Surface Warfare Center Dahlgren Division