The 1998 version of the aeroprediction code (AP98)

Abstract

5.Dv,cpwo A%, -syAPI-08/03 ABSTRACT The AP05 code was evaluated when applied to configurations with boattails. Results of the evaluation indicated the AP05 predictions for normal force, center of pressure, pitch and roll damping moments needed improvement. As a result new and improved methods were developed and incorporated into the AP05 to be released as the AP09. Improvements include body alone lift characteristics for Mach numbers less than 2, low angle of attack improvements for roll and pitch damping for configurations with long boattails, incorporation of an improved boundary layer displacement model and refinement of several other existing methods. In addition, new methods were developed to predict nonlinear roll and pitch damping. Comparing the new and improved methods to existing experimental data indicated significant improvements in roll and pitch damping, normal force and center of pressure predictions compared to the AP05. However, validation of the AP09 code was not as complete as desired due to limited generic nonlinear roll and pitch damping data. Also, most of the available nonlinear dynamic derivative data has larger than desired accuracy boundaries due to model sting and wind tunnel wall interference issues. Weapons affected most by the new AP09 methodology are mortars, low drag bombs and projectiles in that order. However, the nonlinear dynamic derivative predictions affect all weapons. The AP09 is thus the most accurate and robust of the Aeroprediction Codes to date.

A design tool for missile system rocket motor scaling

“…This first version of the rocket motor scaling routines program is capable of basic rocket motor scaling and performance parameter prediction and estimation. By inputting specifications for an existing motor and specifying various 1 American Institute of Aeronautics and Astronautics desired motor parameters, the program will perform scaling calculations and output specifications for a new engine.…”

“…Upon establishing the structural configuration the aerodynamics are calculated. Typical computational tools used for this portion range from computational fluid dynamics (CFD) to quick aeroprediction codes such as AP98 1 and Missile Datcom 2 ' 3 . After utilizing these tools for the aerodynamic characteristics the next step is to fly the preliminary or modified design in a 3 degree-of-freedom or 6 degree-of-freedom analysis to ensure that the vehicle can perform the desired task.…”