The Extended Range Cannon Artillery (ERCA) weapon system has made headlines in recent years for its ability — as its name states, to fire at an extended range. Yet in early August the weapon system made history by firing at the highest velocity on record with this program at Yuma Proving Ground (YPG). While shooting far distances is desirable and part of the Army’s modernization strategy, firing at a high-velocity is also a vital element to eliminating threats through Multi Domain Transformation, in this case, increasing the range, speed, and convergence of cutting edge technologies. In general, artillery systems can be more cost efficient compared to using missiles and rockets. An artillery round can potentially complete the same mission at a fraction of the cost.
“We want to get this projectile in the air and to its target as fast as possible because the targets are getting faster. “We come up with different configurations of the propelling charge, and we fire it in the ballistic simulator and we study the video. We see the transport phenomenon, we get an idea of the temperature, speed of ignition, the turbulence and we conceptualize how we can control the burning. Our goal is to have uniform burning to minimize pressure waves which damage the gun and projectile.,” explains Paul Henderson, lead hypervelocity propulsion engineer with the Combat Capabilities Development Command-Armament Center (DEVCOM-AC).
The effort of designing and building the propelling charge for this high-velocity test. The YPG Ammunition Plant personnel constructed the propelling charge specific to this project based on historical data collected from the DEVCOM-AC team. The team determined that they needed to see what happens to the propellant in the gun during ignition. Since the charge is inside the gun chamber when fired and unable to be observed visually, the team developed a ballistic simulator (BSIM) to aid propulsion development and emplaced it at YPG. The BSIM tube is transparent and bursts at a low pressure, but the few milliseconds of video data before it bursts are critical to the design of the propelling charge.
All this work is for a propelling charge design with a predictable and optimized pressure profile to enhance the projectiles performance, a key factor to achieve this is a design that approaches uniform ignition. The ignitor, which is part of the ignition system, is behind the propelling charge, which sits behind the projectile. The force of the propellant gas on the projectile is what causes the round to shoot out of the cannon, when optimized breakthroughs in projectile velocity are achieved. During test fires, the YPG team collects data such as high-speed video, pressure, and muzzle velocity. The projectile team monitors the projectiles then compares the data collected at the test site against the data of the model.
