Showing papers on "Trajectory of a projectile published in 1985"

Base pressure of a projectile within the transonic flight regime

Abstract: An equivalent body concept is developed to examine the base pressure problem of a transonic flow past a blunt-based projectile. The inviscid flow is established by finite difference computations of the axisymmetric potential equation. All viscous flow processes are treated through integral formulations. The strong viscidinviscid interaction is clearly illustrated from the method of approach to the problem. A definition of the base pressure that is compatible with that for the supersonic flow regime has been developed for the transonic flow regime. An analysis of the asymptotic far-wake condition relates a needed parameter to the total drag experienced by the projectile. Results are obtained for transonic (both subsonic and supersonic) approaching flow conditions and are also compared with the available experimental data. Extension to cases with small angles of incidence is also discussed.

Arrangement to determine the impact point, the velocity and the angle of incidence of a projectile hitting a target at supersonic velocity

Abstract: To determine the impact point and/or velocity and/or angle of incidence of projectiles hitting a target at supersonic speed, independently of the angle between the projectile trajectory and the perpendicular to the impact image plane, there are frames which are arranged in two planes parallel to one another and to the target surface and to the sides of which are attached acoustic sensors surrounding the expected flight trajectories of the projectiles. The impact point, projectile velocity and angle of incidence can be calculated from the sequence and difference in transit time of the electrical signals triggered in the sensors by the bow wave of the projectile.

Determination of atmospheric density using a space-launched projectile

Abstract: A method is proposed that provides advance information about unpredictable atmospheric density dispersions that must be accommodated during random operations of aeroassisted-orbital-transfer vehicles (AOTVs). The principal feature is that a test or 'scout' projectile precedes the AOTV through the same region of the atmosphere as that of the predicted transatmospheric flight trajectory. The atmospheric density structure is determined from the vehicle's aerodynamic deceleration characteristics by on-board or ground-based tracking equipment. The time lag between passage of the projectile and the AOTV can be adjusted to only that time necessary to implement required guidance, navigation, and control (GN&C) corrections. The various strategies available to control the projectile's flight characteristics are analyzed in detail. The results are correlated with aerothermodynamic heating and materials requirements to ensure the survival of the projectile and, consequently, the capability of the AOTV to navigate a variable upper atmosphere within specified limits.

Ideal ballistic trajectories revisited

Abstract: The various relations that can be derived to describe ideal ballistic trajectories are summarized when (i) the inclined plane is of negative, zero, or positive slope; (ii) the launch and target sites differ in elevation; and (iii) the launch site is obscured from the target site. It is shown that a new simple intuitive physical argument can be used to determine the launch angle θm which yields maximum range for (i) and (ii). This approach enables students without a knowledge of calculus to analyze these ballistic trajectory problems. Comments are made on the communality of analysis involved in these related kinematic problems.

Gasdynamic Quantities About Ramjet Projectile While in Transitional Ballistics Region.

Abstract: : A study was performed to determine whether the fins of a ramjet projectile are deployed in the reverse flow of the gun blast with adverse consequences. Two muzzle blast simulation schemes were utilized to compute the flow quantities about the rear of the projectile. An estimate of the pressures internal to the projectile was also made because the deployment process for the fins depends upon the relative pressures internal and external to the projectile pusher plate. The calculations show that the deployment process starts before the base of the projectile leaves the jet plume or reverse flow region. Nevertheless the impulse given the pusher plate, which deploys the fins, is so small that the fins do not move back far enough for the reverse flow to harm them. Originator-supplied keywords: Intermediate Ballistics, Computational fluid dynamics, Jet plume flow.

Device and method for impact point determination

Abstract: of EP01448901. A method for evaluating the impact point of a simulated projectile trajectory or of a simulated laser beam, respectively, on a simulated target movable within a simulated terrain, whereat the terrain, the target, a sight and a tracer trajectory of the projectile or the trajectory of the laser beam, respectively, are digitally stored image point-by-image point, and a composed image is generated on a TV-monitor in the field of view of the optics of a person to be trained and whereat at conformity of the simulated projectile trajectory or laser beam, respectively, with image points of the target a hit or a laser echo, respectively, is indicated, characterized in that a hit with a target is only indicated in the event where at range conformity between the projectile and the target the image points of the tracer trajectory coincide with image points of the visible target silhouette or a laser echo is only indicated where the image points correlated to the simulated laser beam coincide with the image points of the visible target, respectively.