The AEDC Aerodynamic and Propulsion Test Unit at Arnold Air Force Base supports recent testing for the Air Force Research Laboratory Medium Scale Critical Components Scramjet program. The Northrop Grumman-produced engine was successfully operated at conditions above Mach 4 and has set the record for highest thrust produced by an air-breathing hypersonic engine in Air Force history. (U.S. Air Force photo/Holly Jordan)
An Air Force Research Laboratory and Air Force Test Center ground test team set a record for the highest thrust produced by an air-breathing hypersonic engine in Air Force history.
"AFRL, in conjunction with Arnold Engineering Development Complex and Northrop Grumman, achieved over 13,000 pounds of thrust from a scramjet engine during testing at Arnold Air Force Base," said Todd Barhorst, AFRL aerospace engineer and lead for the Medium Scale Critical Components program.
The 18-foot-long Northrop Grumman engine endured a half hour of accumulated combustion time during the nine months of testing.
"The series of tests, ran in conjunction with AEDC and AFRL, on this fighter-engine sized scramjet was truly remarkable," said Pat Nolan, vice president, missile products, Northrop Grumman. "The scramjet successfully ran across a range of hypersonic Mach numbers for unprecedented run times, demonstrating that our technology is leading the way in delivering large scale hypersonic platforms to our warfighters."
"The plan for a larger and faster hypersonic air breathing engine was established 10 years ago during the X-51 test program, as the Air Force recognized the need to push the boundaries of hypersonic research," Barhorst said. "A new engine with 10-times the flow of the X-51 would allow for a new class of scramjet vehicles."
An evaluation of the nation's test facilities concluded that none could test an engine at this large of a scale in a thermally-relevant environment. To address the issue, AEDC's Aerodynamic and Propulsion Test Unit facility underwent a two-year upgrade to enable large-scale scramjet combustor tests over the required range of test conditions.
The AEDC team also successfully leveraged technology developed by CFD Research Corporation under the Small Business Innovative Research program. This technology proved crucial in achieving most of the required test conditions.
"Our collective team has worked hard over the past few years to get to where we are today," said Sean Smith, lead for the AEDC Hypersonic Systems Combined Test Force ground test team. "We've encountered numerous challenges along the way that we've been able to overcome thanks to the dedication and creativity of the team. We've learned quite a bit, and I'm proud of what we've accomplished. These groundbreaking tests will lead the way for future hypersonic vehicles for a range of missions."
"After years of hard work, performing analysis and getting hardware ready, it was a great sense of fulfillment completing the first successful test of the world's largest hydrocarbon fueled scramjet," added Barhorst.
Pentagon working on 9 separate hypersonic missile projects to take on Russia, China
Cadet 2nd Class Eric Hembling uses a Ludwieg Tube to measure the pressures, temperatures, and flow field of various basic geometric and hypersonic research vehicles at Mach 6 in The United States Air Force Academy's Department of Aeronautics, Thursday, Jan. 31, 2019
Earlier this year, the US Air Force announced that it was in a 'race' with Russia and China to develop new hypersonic missile systems, with the Pentagon saying it would use President Trump's new 'Space Force' to try to counter Russian and Chinese advances in this area. The US expects to test at least two hypersonic missiles by the end of 2019.
In addition to the seven Pentagon hypersonic missile-related projects which have already been publically acknowledged, the US is also working on 'at least two more' similar programmes, and they are shrouded in mystery, anonymous officials have told Aviation Week magazine.
The precise nature of the new weapons is unknown, although the outlet discovered that they are represented by the acronyms "HACM" and "HCCW." These clues were found on the LinkedIn profile of one Mr. Greg Sullivan, an engineer with knowledge of every one of the Defence Department's other publically revealed hypersonic programmes.
According to the magazine, the "HACM" and "HCCW" acronyms disappeared from Sullivan's LinkedIn page soon after it had contacted the Air Force for more information. The Air Force did not acknowledge the existence of any programme with those names.
Hypersonic weapons historian and former Air Force senior adviser Richard P. Hallion told Aviation Week that HACM could be almost any type of weapon, from a scramjet-powered cruise missile to an air-launched boost-glide system.
"Well, the H is obviously 'Hypersonic'. The rest suggests a mix of 'A' for Advanced' or 'Air-Breathing' or 'Air-Launched'. 'C' for 'Conventional' or 'Capability' or 'Concept', 'M' for 'Missile'," Dr. Hallion explained.
For his part, Justin Bronk, a research fellow at the Royal United Services Institute, a UK-based defence think tank, said HCCW could stand for "Hypersonic Counter-Cruise Weapon," which would support his theory about the US's gap in developing an intercept capability to counter Russian and Chinese hypersonic cruise capabilities.
Bronk's logic follows from the fact that the US's seven acknowledged programmes already include a variety of air, sea and ground-launched systems, among them two types of boost-glide systems and a scram-jet powered cruise missile. The programmes cover the gamut of strike options, from tactical and conventional to strategic.
Each of the projects features a lavish budget and is contracted out to major US aerospace companies, including Lockheed and Raytheon. The Pentagon is projected to spend over $10.5 billion on the research efforts between 2020 and 2024, with only $7.95 billion of that accounted for with the seven other projects.
Earlier this year, US Strategic Command Chief Gen. John Hyten told the Senate Armed Services Committee that his command would have problems containing state-of-the-art Russian hypersonic weaponry in the years to come. According to the general, this justifies efforts to extend the New Strategic Arms Reduction Treaty to cover such weaponry. That treaty is set to expire in 2021 unless Russian and US negotiators can agree on its extension.
Russia's hypersonic capabilities were first revealed by President Vladimir Putin in a speech last year, with the systems including air, sea and ground-launched missile systems designed to guarantee a Russian strategic response in the event of war, regardless of US anti-missile defence systems, and even in the event of a US first strike.
Putin previously warned Russia's partners that the US exit from the Anti-Ballistic Missile Treaty in 2002, and Washington's refusal to partner with Moscow on a common European-wide anti-missile shield in the early 2000s, would prompt Russia to build up its own capabilities in this area in order to guarantee global strategic stability.