U.S. Army engineers extend artillery's range and power using electrically responsive methods
NewsNovember 23, 2015
PICATINNY ARSENAL, N.J. By using an electrically responsive methodology to control energetics materials, Picatinny Arsenal engineers are extending the range and power of artillery. A team at the Armament Research, Development and Engineering Center, or ARDEC, at Picatinny Arsenal – part of the U.S. Army Research, Development and Engineering Command at Aberdeen Proving Ground, Maryland – strive to provide the warfighter with more control over the rocket propellant, which could ultimately increase the range, burn rate, power, and speed.
The team of engineers consists of David Thompson, Kimberly Chung, Eugene Rozumov, David Thompson, Dana Kaminsky, George Fischer, and Kelley Caflin. Their research is an Army Science and Technology-funded project.
"If you can control the burn rate and energy output of a propellant with electric voltage, this opens a whole new capability," says David Thompson, a chemical engineer and member of the research team. "Right now, we're considering it [electrically-responsive energetics] for rocket propellants found in extended range artillery rounds."
ARDEC personnel saw a presentation by Digital Solid State Propulsion, Inc. (DSSP), who demonstrated that energetics could be controlled with electricity by using a compound known as hydroxylammonium nitrate (HAN), an inorganic salt. DSSP's HAN-based formulation is a plastisol, a material that flows like a liquid but can be converted into a solid when heated.
After the presentation, ARDEC turned to Picatinny engineers to determine if similar material could be integrated into a weapon system and the project began in 2009. The focus of the project now yields to rocket motors, concentrating on two different types of motors the army uses for their extended range propellants
"One is called the base bleed motor, which gets some extended range over a normal round and burns right out of gun," Thompson says. "The other is a rocket assist motor, which doesn't burn until it gets the top of its flight, before it boosts and increases the velocity of the projectile.
"With electric voltage, you could use one motor that does both," Thompson said. "You could create a low-voltage, right out of the gun, and get that base-bleed effect, and then hit it with a high voltage and get the rocket-assist effect, ultimately increasing the range over that which either motor can provide on its own."
The XM1128 and the XM113 – a base-bleed motor and a rocket assist motor respectively – using the electric energetics would potentially travel farther, officials say. The Project Manager Combat Ammunition Systems (PM-CAS) manages them both, which is part of the Program Executive Office for Ammunition at Picatinny.
"When you fire a gun propellant at some tank, the performance differs in different temperatures," Thompson said. "For example, the round's velocity is different when it's fired in a hot temperature than in a colder temperature.
"So, the troops have their manual that basically says 'If you put your gun at this angle, and fire this charge, it will get this much velocity and you'll hit the target.' But, because the propellant's effectiveness can change in different environments, they have to compensate for temperature. Our idea was to use an electrical igniter with a propellant that we can control, allowing us to burn the propellant at different speeds and rates," Thompson continues. "We want to use the igniter to improve the round's performance in the cold, and maintain its performance in the heat, but also ensure that the performance is identical throughout. This way, the troops can fire the same thing and get a consistent result no matter what."
A main issue with the project is that many rocket artillery rounds don't have an embedded electrical source meaning that the team will need to find a power source to ignite their energetics, Chung says. Another concern is how much of the material’s burn rate they are controlling. However, the team is continuing on with their research, testing, and evalution.
"Usually, you make a propellant formulation and mix them. When you mix them, they're soft and fluid, like play dough, and you can pour it into a mold. Then, you put it in an oven and cure it and it gets hard," says Thompson. "Right now, the mixture seems to work a lot better uncured, which probably won't work in a projectile because the material is too soft - it probably won't survive gun launch."
"With rocket propellants, it [electrically-responsive energetics] would not cost any more than the propellants that we have fielded now," Thompson said. "You're adding that extra capability of turning it on or off and controlling its burn rate in flight, which now you can't do at all."
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