A new ramjet test facility has opened in West Virginia which varies the airflow around the intake to simulate varying flight paths. Jonathan Newell reports.
Used widely in the defence industry as propulsion units for Unmanned Aerial Vehicles (UAV) or drones, air breathing solid fuel ramjets operate in a similar way to conventional ramjets but are simpler.
Unlike a solid fuel rocket, the fuel is inert and isn’t used as a propellant but is burnt as part of the combustion process in the same way as if it were a liquid fuel, thereby lending greater simplicity to the engine.
The testing process for such engines needs to replicate the high speeds and harsh environments that they’re exposed to during their service life.
Built primarily for the US defence industry, the Allegany Ballistics Laboratory (ABL)’s new Ramjet Test Facility in West Virginia is the first of its kind to offer new features which more accurately replicate the flight conditions of missiles and projectiles powered by air-breathing propulsion systems.
The test bed is the brainchild of aerospace propulsion experts at Orbital ATK, who has just finished its final validation and testing of the facility which is owned by the US Naval Sea Systems Command, the organisation which funded its setting up.
The purpose of the ramjet testing site is to provide real-world simulations of flights for tactical air-breathing solid propulsion systems, with the flow of air mass reaching speeds of up to Mach 4.5 and reaching temperatures of over 800C.
However, what makes this site different is the variable programmable air flow and the “clean air” environment that replicates flight conditions more accurately by venting combustion by-products from the chamber.
“In a nutshell, our new facility is for testing solid fuel ramjet engines and there are a couple of things that distinguish it from most of the others that are available,” said Orbital ATK’s Missile Products Divisional Vice President and General Manager, Pat Nolan. “To begin with, it is a “clean air” simulator which means we vent the by-products of the engine combustion, which wouldn’t be present in a real-world flight, from the simulator. The second distinguisher is that the air flow is programmable, so we can change the flow to match an actual flight path.”
Orbital ATK is a major supplier to both the space and defence industries and supplies a range of launch vehicles and propulsion systems. The creation of the new ramjet testing facility stems from the company’s experience in testing complex propulsion systems; these include its extensive facilities for testing “scramjets”, variants of the familiar ramjet propulsion system but where the combustion occurs within a supersonic airflow environment.
The company’s hypersonic system test, development and validation activities currently take place at the Aerothermal Research and Test Facility in Ronkonkoma in New York which is now complemented by the new test centre in West Virginia.
Commenting on the latest innovations for ensuring that real-world flight conditions are simulated at the test facility, Nolan said “This new facility provides us with the means to test the next generation of missile propulsion components by giving us the ability to fly an accurately simulated mission during the test and thus helping the end user to reduce the costs associated with conducting multiple point tests.”
Although the Allegany Ballistics Laboratory ramjet testing equipment will be used initially for testing applications in the defence industry, it is also planned to make it available for commercial use.