The 2002 Version of the Aeroprediction Code


Book Description

A new version of the aeroprediction code (APC), the AP02, has been developed to address the requirements arising from advanced weapon concepts. The AP02 was formed by adding significant new technology and several productivity improvements to the previous version of the APC, the AP98. New technology added included 6 and 8 fin aerodynamics, improved nonlinear aerodynamics, improved pitch damping predictions, improved power-on base drag estimates, base-bleed effect on base drag estimation, improved axial force of nonaxisymmetric bodies and trailing-edge flap capability. Other improvements and productivity enhancements include an aerodynamic smoother, ballistic and three degree-of-freedom simulation modules as well as refinements for the pre- and post-processor for inputs and outputs of the AP02. Comparison of the predicted aerodynamics of the AP02 to AP98 and experimental data showed the AP02 to be slightly better than the AP98 in most cases that both codes would handle. However, due to the additional new technology incorporated into the AP02, many new options are available in the AP02 that are not available in the AP98. Therefore, the AP02 is more robust and, on average, is slightly more accurate than the AP98 in predicting aerodynamics of weapons.




Parametric Fin-body and Fin-plate Database for a Series of 12 Missile Fins


Book Description

A cooperative experimental investigation has been performed to obtain a systematic fin-body and fin-plate database for series of 12 missile fins. These data are intended to complement and extend the information contained in the Triservice missile project and to provide a systematic set of experimental data from which fin-body interference factors can be derived. Data were obtained with the fins mounted on both an axisymmetric body and on a flat plate that was used to simulate fin-alone measurements. The experiments were conducted at Mach numbers from 0.60 to 3.95; fin deflection angles of 0°, 10° , and -10° ; and angles of attack up to 30° on the body and up to 95° on the flat plate. The data were obtained from three-component balances attached to the fins and a six-component balance located in the axisymmetric body. The data obtained in this project are documented in tabular form in this report. In addition, selected data are presented in graphical form to illustrate the effects of the test variables.










Stability and Control of Conventional and Unconventional Aerospace Vehicle Configurations


Book Description

This book introduces a stability and control methodology named AeroMech, capable of sizing the primary control effectors of fixed wing subsonic to hypersonic designs of conventional and unconventional configuration layout. Control power demands are harmonized with static-, dynamic-, and maneuver stability requirements, while taking the six-degree-of-freedom trim state into account. The stability and control analysis solves the static- and dynamic equations of motion combined with non-linear vortex lattice aerodynamics for analysis. The true complexity of addressing subsonic to hypersonic vehicle stability and control during the conceptual design phase is hidden in the objective to develop a generic (vehicle configuration independent) methodology concept. The inclusion of geometrically asymmetric aircraft layouts, in addition to the reasonably well-known symmetric aircraft types, contributes significantly to the overall technical complexity and level of abstraction. The first three chapters describe the preparatory work invested along with the research strategy devised, thereby placing strong emphasis on systematic and thorough knowledge utilization. The engineering-scientific method itself is derived throughout the second half of the book. This book offers a unique aerospace vehicle configuration independent (generic) methodology and mathematical algorithm. The approach satisfies the initial technical quest: How to develop a ‘configuration stability & control’ methodology module for an advanced multi-disciplinary aerospace vehicle design synthesis environment that permits consistent aerospace vehicle design evaluations?




Missile Aerodynamics


Book Description

The similarities between the airplane and the missile extend beyond their flying capabilities, and at higher operational speeds, the configuration distinctions become even less apparent. " Missile Aerodynamics," a classic now available from AIAA and Nielsen Engineering and Research, Inc., combines the best of missile and airplane aerodynamics, drawing extensively from numerous technical papers to present a rational and unified account of the principles behind missile projection. Evaluate the missile versus the airplane in a multitude of areas, from longitudinal acceleration, wing loading, roll and dynamic stability, guidance and navigation, and more. J.N. Nielsen covers every aspect of missile aerodynamics, from the classification of missiles and basic formulas to innovative aerodynamic controls. In one reliable reference, readers will find hundreds of schematics, equations, and tables with practical applications in missile design and engineering. Originally published by Nielsen Engineering and Research, Inc.










Modern Exterior Ballistics


Book Description

Modern Exterior Ballistics is a comprehensive text covering the basic free flight dynamics of symmetric projectiles. The book provides a historical perspective of early developments in the 19th century, the technology leading to World War I and that through World War II into the modern post-war era. Historical topics include the first ballistic firing tables, early wind tunnel experiments, the development of free flight spark ranges and the first supercomputer, ENIAC, which was designed to compute artillery trajectories for the U.S. Army Ballistic Research Laboratory. The level of the text requires an undergraduate education in mathematics, physics, and mechanical or aerospace engineering. The basic principles of ballistic science are developed from a comprehensive definition of the aerodynamic forces that control the flight dynamics of symmetric projectiles. The author carefully starts with the basic vacuum point mass trajectory, adds the effects of drag, discusses the action of winds, simple flat fire approximations, Coriolis effects and concludes with the classic modified point mass trajectories. Included in the discussion are analytical methods, change of variables from time to distance, numerical solutions and a chapter on the Siacci Method. The Siacci Method provides a historical perspective for computing flat fire trajectories by simple quadrature and is used in the sporting arms industy. The final six chapters of the book present an extensive physical and mathematical analysis of the motion of symmetric projectiles. The linearized equations of angular and swerving motion are derived in detail. The effects of mass asymmetry, in-bore yaw, cross wind and launch in a slipstream are discussed. Special consideration is given to the derivation and explanation of aerodynamic jump. These subjects are then expanded to include a complete chapter on nonlinear aerodynamic forces and moments. The final chapter in the book presents an overview of experimental methods for measuring the flight dynamics of projectiles. The great forte of Modern Exterior Ballistics is the author's effort to provide many fine specific examples of projectile motion illustrating key flight behaviors. The extensive collection of data on projectiles from small arms to artillery used to substantiate calculations and examples is alone a valuable reference. The ultimate joy of the book is the incomparable comprehensive set of flow field shadow graphs illustrating the entire spectrum of projectile flight from subsonic, through transonic and supersonic. The volume is a necessary addition to any undergraduate or graduate course in flight dynamics.