New artillery round uses ramjet for extra range
Raytheon Missiles & Defense is developing a ramjet-propelled shell that will double the range of US military artillery to over 100 km (62 mi). Working under a US$7.9 million US Army contract, the tactical 155mm XM1155 Extended-Range Artillery Projectile is designed to combine increased range with precision targeting technology.
An artillery piece is about as simple a device as it's possible to imagine. Basically, it's a tube sealed at one end containing a propellant sitting behind a projectile. When the propellant is ignited, it produces hot gases that blow the projectile out of the tube to land a long distance away.
However, though this technology has been around for over 500 years, artillery is still a major component of the world's armies and navies, and there is still a lot of room for improvement to make such weapons more accurate and with a longer effective reach.
One example of this is the XM1155 project, which aims at creating an artillery round that doesn't just fly ballistically but incorporates a ramjet to propel it and extend its range. Though the details of how the new round will work have yet to be divulged, the principle of the ramjet means that the gun would fire the round, accelerating it to a fast enough speed to compress the incoming air inside the ramjet's combustion chamber to allow it to ignite and run.
The XM1155 is being developed by Raytheon in partnership with the Netherlands-based Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (TNO). Under the contract, TNO will build the ramjet while Raytheon will provide and integrate the airframe, seeker, warhead, and other components.
According to Raytheon, the XM1155 works in all terrain and weather conditions, is suited for both land and sea-based systems, and is compatible with all existing and expected NATO-standard 155mm artillery. In addition, the new round is based on Raytheon's Excalibur munition, which uses GPS and laser guidance to home in on its target to hit or damage it at ranges of over 50 km (31 mi).