Boeing and defense company Nammo partnered with the U.S. Army to set a new range record with a ramjet 155mm round fired from the 58-caliber Extended Range Cannon (ERCA) in an indirect fire test of the ramjet-powered projectile. Modern artillery has made many advances, but when it comes to range, the artillery used by the Western powers has not improved much. This is regrettable because adversaries such as Russia rely heavily on artillery, especially rocket launchers, which have more than three times the range of cannons.
To overcome this problem, Boeing and Norway's Nammo have collaborated to develop a new ultra-long-range gun under the U.S. Army's XM1155 program that uses advanced ramjet technology but can be fired from a standard gun without modification.
The 155mm rounds used in recent record-setting tests at the Army's Yuma Proving Ground in Arizona and earlier tests with a 39-caliber towed gun at Andoa Test Center in Norway look very similar to conventional rounds, but that's just the surface.
Boeing/Nammo shells have an air inlet at the fuze of a conventional shell, from which an air spur protrudes. There is solid rocket fuel inside the projectile body, which does not contain oxidizer and therefore takes up very little space. After the projectile is fired, it will quickly accelerate to supersonic speeds, at which point the ramjet engine will start working. The air in front of the projectile is sucked in, compressed, mixed with fuel and burned to create thrust.
As a result, the range of the Ramjet 155mm round increased from approximately 14 miles (22 kilometers) to 93 miles (150 kilometers). The exact recorded distance of the "Yuma" trial has not yet been announced, but this gives an idea of what its goals were.
According to Boeing, the purpose of the test is to prove that the new ramjet can be safely fired from the ERCA gun and demonstrate its flight performance. The next goal will be to focus on improving the accuracy of the artillery shells.
Nammo CEO Morten Brandtzæg said: "The project now has a fully tested propulsion system that ensures a significant increase in the range of all guns. We believe that the main development obstacles have now been cleared and production is feasible in a relatively short period of time."
"Our successful testing demonstrates that ramjet projectiles - a true collaboration between Boeing and Nammo - have the range and accuracy the Army requires. Ramjet technology heralds a revolution in artillery that will significantly extend range and provide strategic advantages to our users."
The video below discusses the Ram Jet Cannon.