Recently, Boeing and Norwegian defense company Nammo announced that they had successfully tested a new "suction" shell in the test conducted in Northern Europe. The two companies announced that this is the latest development in the U.S. Army's development of long-range artillery for future conflicts.
According to Boeing, the Ramjet 155 shell is fitted with a ramjet engine that increases the range of the U.S. Army's 155 mm gun from 40 km to 70 km. However, this figure was 100 kilometers two years ago!
Why did the Americans put ramjet engines on artillery shells? Shell head with air intakes? In the end, it is to increase the range. Traditionally, the most important way to increase the range of artillery is to increase the length of the gun barrel, the main American howitzer M-109 and M777 are 39 caliber barrels, which is very different from the 52 caliber barrel howitzers of China, Russia, Germany, France and Germany.
The U.S. Army is also trying to develop long-barreled howitzers, such as the latest test of the 58-caliber barrel "Army Long-range Artillery System", but the US military weapons development speed is slow, and a large amount of equipment requires a lot of money. In addition, the U.S. M777 ultralight howitzer needs to be hoisted by helicopter, and it is difficult to replace it with a longer body tube, so increasing the range can only open up another way.
In addition to increasing the length of the barrel, the development of new shells is also a method, such as bottom concave shells, bottom discharge shells, rocket range extenders, etc., but the potential of these shells has been almost tapped. For example, the US military's 155 mm "Excalibur" shell uses gliding wings and other technologies, and the range is only 47 kilometers, which is still far lower than the range of 155 mm extended range shells such as Germany and other countries of more than 70-80 kilometers.
Arguably, the installation of ramjet engines on artillery shells reflects that the Americans are trying to take shortcuts and avoid the hassle of purchasing a large number of new howitzers. However, the "ramjet" shell was not invented by the United States.
In 2004, The South African company Daniel launched a 155 mm ramjet rocket booster shell, which is said to have a range of 88 kilometers. In 2016, South Korea's Pengshan Company also demonstrated a ramjet rocket booster shell with a range of 80 kilometers. In 2018, the Norwegian company Nammo demonstrated the concept of a 155 mm "extreme gun", which also includes stamped jet propulsion artillery shell technology.
Ultimately, Boeing chose to partner with Nammo to jointly develop the Ramjet 155 ramjet shell as part of the U.S. Army's XM1155 program, signing a research and development contract with the U.S. Army in 2019. The main purpose of the XM1155 program was to explore advanced technologies to increase the range and power of artillery shells, and to develop artillery range extended ammunition kits. At the time, the expected range of the ram shell reached 100 kilometers.
However, in the latest tests in the United States and Norway, the Ramjet 155 ramjet shell did not verify "increased range". Still, Boeing claimed that tests proved "significant progress is being made." Dan Palmert, head of business development at boeing's Phantom factory, said range was the next step.
Palmert said the tests successfully verified that shells with ramjet engines can remain stable in flight, and the engines can successfully ignite and fully advance the warhead. Palmert et al. said the biggest challenge of the study was to ensure that "the shells flew steadily," and that the engine surviving the cannon firing was a victory in itself. "Once the propulsion and stability have been determined, the next step is range, guidance and the rest of the system," Palmit said.
According to Boeing, the test team has conducted 450 artillery tests and suggested that "stable flight" has always been a serious problem, and whether the engine can withstand the impact of artillery fire is a serious challenge. It wasn't until recent tests that stable flight was finally achieved. The next test, which will incorporate guided flights, is expected in 2023 and 2024.
According to a Boeing manual, the ramjet engine technology is designed to extend the range of the 155 mm howitzer from 40 kilometers to more than 70 kilometers. That is to say, this indicator barely matches The new German extended-range artillery shell, nor does it match Nammo's original design indicator.
Ramjet 155 range indicators are not high, the key reason is that the US howitzer still uses a 39x barrel (Nammo's original plan is to cooperate with a 52x barrel), even if the black technology that adds "ram engine" still cannot make up for these gaps. If other countries had also developed the stamping artillery technology, combined with the 52 caliber body tube, the range would have been stable and once again overwhelmed the American artillery. (Author: Tao Mujian)