Brig. Gen. John Rafferty : Long Range Precision Fire New Attack Options
photo: Brig. Gen. John Rafferty
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Brig. Gen. John Rafferty, Director, Long Range Precision Fires Cross Functional Team, Army Futures Command
Warrior: How does the Army’s Long Range Precision Fires technology achieve precision, given that the weapon is much longer range than standard guided precision shells?
Rafferty: “With Long Range Precision Fires (LRFP), there is a challenge adapting a precision guidance kit that has a much more violent gun launch environment. We use more propellant to shoot farther. The muzzle velocity is much higher so the “g loading” is much more substantial. It requires modification to precision guidance kits. When your apex is much higher, you get into thinner air. There is less air for canards to work with to steer and turn.”
Warrior: We understand the Army is now using a newly configured “shaped trajectory” 155m Excalibur round able to change course in flight and hit otherwise unreachable targets -- such as enemy armored vehicles hidden under a bridge or on the other side of a mountain. What tactical advantages does this round bring to war?
Rafferty: “We do have some adversaries who use reverse slope protection that challenges normal artillery because the descending portion of the trajectory can be masked by that reverse slope. A shaped trajectory is a different projectile used in limited numbers. In rugged terrain it allows a modified trajectory that can enable new effects against targets. We are working with industry to see what is possible.”
Warrior: We understand that your units are working with the Army Research Laboratory to develop even more advanced artillery rounds. What are some of the areas of focus?
Rafferty: “We are working with our Army laboratories to provide changes to material. Primarily we are working on coordinate seeking, GPS, alternative sources of navigation and target seeking, and also working toward assurance from jamming.”
Warrior: We understand that the Army’s Extended Range Cannon Artillery weapon has successfully destroyed targets at more than 62km, roughly twice the range as existing artillery. How is this accomplished?
Rafferty: “ERCA fires a 58 Caliber, which is about 30-ft long. It has a bigger chamber which allows for a different propellant and different breech. Muzzle velocity is generated through the length of the tube.”
Warrior: What are some of the engineering techniques used to handle a larger explosion for a longer-range round?
Rafferty: “Behind the projectile is a super-charged propellant and a sliding block breech. A robust hunk of metal seals the back of the cannon. The explosive train is ignited electronically and the larger chamber coupled with the longer gun tube allows for much greater muzzle velocity as it exits the cannon. On ERCA we have a sliding block breech which is like a tank gun. It is a block of steel that slides up which seals the launch tubes and allows for the generation of the chamber pressure. Otherwise the round would come out the back because of the least resistance. The sliding block breech is more robust and can handle a greater explosion. The higher the chamber pressure, the bigger the explosions.”
Warrior: How is the longer cannon engineered to withstand these kinds of larger explosions?
Rafferty: “A muzzle brake at the end of the cannon helps with recoil by dispersing the fumes and blast. It helps direct the blast overpressure. The muzzle brake performs engineering functions. It helps with recoil, helps dispense the fumes and blast and it helps to direct the blast overpressure. When the round is locked in place, the breech rotates into a locked position, then the back end of the breech is sealed.”
Warrior: How does ERCA ensure a U.S. Army advantage over advanced adversaries?
Rafferty: “At the division level, ERCA addresses some of the challenges associated with multi-domain ops. Multi-domain is layered enemy standoff. ERCA can suppress and neutralize enemy integrated air defenses and enable combined arms maneuver. Combined Arms allows us to close with and destroy an enemy. It requires armor, infantry and combat aviation to work together in a synchronized fashion. If we lose this synchronization we are far less lethal. If an enemy has range, he can separate the combined arms team. Our adversaries have watched us and learned how we fight. They have invested in areas to offset our advantage.”
Warrior: How is LRPF being networked with ground combat vehicles, air assets for targeting or other key combat assets?
Rafferty: “All of this will be integrated on a tactical network that the network Cross Functional Team is working on. We will bring the combined arms effect of LRPF, FVL (new Army Future Vertical Lift helicopters) and NGCV ( Next Generation Combat Vehicle) networked together. Multi-domain tenets involve convergence.”