Projectile

About: Projectile is a research topic. Over the lifetime, 13047 publications have been published within this topic receiving 115563 citations.

Spinning shot gun projectile

Abstract: A spinning shot gun projectile comprises a cylindrical body having radially projecting vanes arranged with respect to the longitudinal axis of the body at an angle predetermined for air impingement during the flight of the projectile, thereby imparting a spinning motion to the same and insuring an accurate trajectory. The rearward portion of the projectile body has an axial bore dimensioned to receive in bearing engagement the ram portion of wad means located forwardly of the powder. The thrust of the explosion thus is transmitted to the projectile centrally and forwardly of the same by the action of the ram, thereby further insuring true flight of the projectile.

Influence of bore and rail geometry on an electromagnetic naval railgun system

Abstract: A large-scale railgun is being considered by the U.S. navy as a future long range (>200 nm) naval weapon system. The notional concept includes a 15 kg projectile with a 2.5 km/sec muzzle velocity. The choice of bore and rail geometry for such a weapon can influence key aspects of the total system design. This study explored a range of bore and rail geometries and looked at their effects on key railgun system parameters such as parasitic mass, inductance gradient, linear current density, required pulse forming network (PFN) size, and barrel mass. Preliminary solid modeling and structural analysis of the integrated launch package was performed in order to quantify parasitic mass. Inductance gradient calculations were based on a current density distribution analysis. A PFN/Launcher numerical simulation model was then used to determine linear current density and PFN size. Finally, barrel mass was estimated by structural analysis based on calculated rail repulsive forces. Trends and sensitivities of the different parameters to changes in the bore and rail geometries are presented and conclusions are given.

Passive electro-optical tracker

Abstract: A passive electro-optical tracker uses a two-band IR intensity ratio to discriminate high-speed projectiles and obtain a speed estimate from their temperature, as well as determining the trajectory back to the source of fire. In an omnidirectional system a hemispheric imager with an MWIR spectrum splitter forms two CCD images of the environment. Three methods are given to determine the azimuth and range of a projectile, one for clear atmospheric conditions and two for nonhomogeneous atmospheric conditions. The first approach uses the relative intensity of the image of the projectile on the pixels of a CCD camera to determine the azimuthal angle of trajectory with respect to the ground, and its range. The second calculates this angle using a different algorithm. The third uses a least squares optimization over multiple frames based on a triangle representation of the smeared image to yield a real-time trajectory estimate.

Onset of cavity deformation upon subsonic motion of a projectile in a fluid complex plasma

Abstract: We study the deformation of a cavity around a large projectile moving with subsonic velocity in the cloud of small dust particles. To solve this problem, we employ the Navier-Stokes equation for a compressible fluid with due regard for friction between dust particles and atoms of neutral gas. The solution shows that due to friction, the pressure of a dust cloud at the surface of a cavity around the projectile can become negative, which entails the emergence of a considerable asymmetry of the cavity, i.e., the cavity deformation. Corresponding threshold velocity is calculated, which is found to decrease with increasing cavity size. Measurement of such velocity makes it possible to estimate the static pressure inside the dust cloud.