Boeing and Nammo have jointly tested a ramjet-powered artillery projectile developed on behalf of the US Army with a long-range test place which took place at the Andøya Test Centre in Norway. According to Nammo, the test was successful, and consisted of firing a Boeing RAMJET 155 projectile from a 155 mm gun, followed by successful ignition of its ramjet engine. Nammo stated that in flight, the projectile demonstrated stability in flight and a well-controlled engine combustion process. The company added that further tests and demonstrations are planned in the coming months.
In operation, the projectile is fired out of a typical 155 mm gun and the ramjet is ignited shortly after it leaves the barrel, further accelerating the projectile and resulting in a range increase compared to conventional rounds. According to Nammo, the air drawn into the ramjet for combustion is compressed solely by the forward motion of the projectile at supersonic speeds.
The US Army’s “Long-Range Precision Fires” (LPRF) programme is examining ways to support combat troops with long-range precision fires. One solution is artillery shells that are further accelerated by rocket propulsion after firing. Under the US Army’s XM1155 Extended-Range Artillery Projectile (ERAP) programme, Boeing’s Phantom Works division and Nammo were awarded a contract to further develop the RAMJET 155 projectile in July 2019.
The LPRF programme aims to develop a common projectile design for use in 155 mm L39 and L58 guns, according to Nammo. The company has previously unveiled a ramjet-powered missile with a range of 400 km at the DSEI 2019 exhibition.