Conventional rockets are known to be fired by jet engines that use a fuel and an oxidizer. In turn, artillery shells are ejected from the gun barrel by the pressure of powder gases.
The Norwegian company Nammo proposes to increase the speed and range of missiles and howitzer artillery shells by installing ramjet engines on them. As reported by Air Force Technology, the company has completed the first phase of 150 tests of test ramjet engines. During the second stage, 155-mm shells with installed engines will be fired.
To understand what we are talking about, you need to remember that during a flight, a rocket or jet plane compresses the oncoming air in front of it. The ramjet, instead of overcoming the resulting air resistance, sucks it in, using the abundant amount of oxygen it contains as an oxidizing agent for its work. By mixing with fuel and burning the resulting mixture, thrust is created.
Thus, a ramjet rocket does not need an oxidizer tank, which makes it more compact, accommodates an additional payload, and significantly increases its flight range.
Nammo plans to upgrade the Sea Sparrow surface-to-air missile. The current version has a range of 50 km. With a ramjet engine, it will increase to 400 km. Likewise, an artillery shell with a ramjet engine will fly not only farther, but also faster. It is assumed that the 155-mm howitzer, equipped with ramjet projectiles, will be able to hit targets at a distance of 100 km, which is 4 times more than usual indicators.