Hypervelocity Projectiles (HPV)
Among projects in the works for the US Navy is the development of new gun rounds, including the possibility of a smaller version of the electromagnetic projectile launching technology used by the rail gun weapon now in development. The rail gun, which can hurl a projectile at well over 5,000 miles per hour, is being evaluated for possible mounting on a Zumwalt-class destroyer by the mid-2020s.
"When we take that projectile with the rail gun, why not make it small enough to put in a five-inch round ... with a couple of hundred five-inch rounds that now can shoot something as far, almost as accurately as a rail gun?" Rear Admiral Peter Fanta suggested.
As the Navy was developing EMRG (electromagnetic railgun), it realized that the guided projectile being developed for EMRG could also be fired from 5-inch and 155mm powder guns. Navy cruisers each have two 5-inch guns, and most Navy destroyers each have one 5-inch gun. The Navy’s three new Zumwalt class (DDG-1000) destroyers, which are under construction, each have two 155mm guns.
BAE Systems states that HVP is 24 inches long and weighs 28 pounds, including a 15-pound payload. The total length and weight of an HVP launch package, BAE Systems states, is 26 inches and 40 pounds. BAE states that the maximum rate of fire for HVP is 20 rounds per minute from a Mk 45 5-inch gun, 10 rounds per minute from the 155mm gun on DDG-1000 class destroyers (called the Advanced Gun System, or AGS), and 6 rounds per minute from EMRG. HVP’s firing range, BAE Systems states, is more than 40 nautical miles (when fired from a Mk 45 Mod 2 5-inch gun), more than 50 nautical miles (Mk 45 Mod 4 5-inch gun), more than 70 nautical miles (155mm gun on DDG-1000 class destroyers), and more than 100 nautical miles (EMRG).
The Navy describes the HVP as “a next generation, common, low drag, guided projectile capable of completing multiple missions for gun systems such as the Navy 5-Inch, 155-mm, and future railguns.... HVP’s low drag aerodynamic design enables high velocity, maneuverability, and decreased time-to-target. These attributes coupled with accurate guidance electronics provide low cost mission effectiveness against current threats and the ability to adapt to air and surface threats of the future.
Railgun tests and engineering to get to operational railgun by 2021
If the Navy does take the railgun out to sea on a fast transport, it will be in 2017 at the earliest. In lieu of testing the prototype rail gun in an at-sea environment, the Navy might instead proceed directly to developing an operational weapon system.
General Atomics Electromagnetic Systems (GA-EMS) railgun projectiles were fired from the company’s Blizter prototype railgun weapon during recent tests at the U.S. Army’s Dugway Proving Ground
Technologies unlocked for railguns and combat lasers and what remains is engineering
Fanta said that he believes that an operational railgun is feasible within the next five years. Indeed, the Navy hopes to replace one of the 155mm gun turrets onboard the third and final Zumwalt-class destroyer Lyndon B. Johnson (DDG 1002) with a rail gun. “I don’t know if I can get there from the engineering status yet. But that’s what we continue to look at,” Fanta told Defense.
According to Fanta, most of the key technologies behind railguns—which have until now mostly been in the realm of science fiction—have been unlocked. “It’s engineering at this point, it’s no longer science,” Fanta told Defense News. “It’s no longer the deep dark secrets of what can I do with this sort of energy. It’s engineering and how much power density can I get, how much beam quality can I get, what sort of metallurgy do I need to sustain multiple shots over multiple periods of time. The rail gun as well as the laser.”
SOURCES - Defense News, Aviation Week, FAS, General Atomics