Boeing offers new 155mm ramjet shell to US Army

20th October, 2021

- Advertising -

With the arrival of new ammunition, such as the American XM1113 or the Italian Volcano, the range of artillery shells has increased considerably in recent years. So, there or a M109A6 Paladin equipped with a 39-caliber L / 39 gun (either 39 times the diameter of the 155 mm shell, or 6,05 m) struggled to hit targets at 20 km with traditional shells, it can now hit targets 40 km away with the XM1113, moreover with greatly increased precision thanks to GPS, inertial or laser guidance. In addition to the arrival of these so-called “added propulsion” shells, that is to say benefiting from an additional thrust via a rocket motor on the ascending phase of the ballistic trajectory, the weapons engineers have also undertook to lengthen the tubes of the artillery guns. Thereby, the French CAESAR is equipped with a 52-caliber cannon, i.e. 8,06m, allowing it to reach targets at more than 30 km with conventional shells, and at 40 km with ERFB-type shells with optimized aerodynamics, and more of 60 km with shells with added propulsion like the Katana of Nexter.

Boeing engineers have, for their part, decided to replace the powder-added propulsion system of the extended-range shells, to replace it with a mini-ramjet, a nozzle in which atmospheric air is used as an oxidizer to ignite liquid fuel in order to provide a push. This solution, a French specialty initially, was used on several types of supersonic long-range missiles, such as the French ASMPA nuclear missile, or the European long-range Méteor air-to-air missile. Its integration into an artillery shell offers two major advantages. The first, perfectly obvious, is that the propulsion system does not need to transport its oxidant in addition to its fuel, which significantly lightens the device, or at least gives it an increased capacity to carry fuel to mass. and identical size.