Torsional Impulse in Gun Launched Projectiles
Abstract
This report describes an investigation of torsional impulse in rocket-assisted projectiles due to 'free run.' A combined analytical and experimental program was carried out to quantify the phenomenon. The basic factor was the presence of 'free run' which is characterized by positive forward motion of a projectile before reaching the origin of gun-tube rifling. This factor permits the projectile to reach an appreciable forward velocity before the rotating band becomes effective and starts the rotational acceleration. Experiments were also conducted by Sandia Laboratories-Livermore with instrumentation installed in the rocket motor section. The results indicate that the amplitude of the angular acceleration pulse due to free run was greater in tubes with more wear. The acceleration pulse was higher at the nose than at the rear of the projectile and the magnitude of the acceleration pulse in worn tubes was as great as and in some cases (8 inch) greater than the predicted angular acceleration at peak pressure. Test results at ARRADCOM and Sandia were in qualitative agreement. The point where the angular acceleration pulse occurs seems to correlate with the position of travel where a sufficient amount of rotating band material has been formed (swaged) in the gun rifling.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1981
- Accession Number
- ADA096799
Entities
People
- Albertus E. Schmidlin
Organizations
- United States Army Armament Research, Development and Engineering Center