Wind Tunnel Investigation of Typical Strategic Missile Configuration at High Angle of Attack

Abstract

The present wind tunnel investigation is a part of a project studying the effectiveness of flat fin control on short-range strategic missile at high angle of attack. As a part of this program, the longitudinal aerodynamic coefficients were computed analytically and were compared with estimates obtained through wind tunnel testing. Wind tunnel tests were conducted over a range of angle of attack from -15° to +45° at a free stream speed of 60m/s. Aerodynamic coefficients were generated for various missile configurations. These coefficients were then compared with the estimates obtained analytically. It was conjectured that, at high angle of attack, vortices shaded by the body interact with the local flow near the fins and drastically alters the stability characteristics of the missile. The subject missile has a small hemispherical nose as compared to most of the missiles having conical or ogival nose. For such a configuration sufficient theoretical/experimental data are not available. Thus, it was important to generate longitudinal aerodynamic data for the range of angle of attack upto which the theoretical model can be used to evaluate the aerodynamic stiffness of the missile. Such a model structure is required for postulating aerodynamic model in estimation algorithm, used for parameter estimation from flight data of the subject missile.