AFRL Advances Hypersonic Research Through HIFiRE

  • Published
  • By Holly Jordan
  • Aerospace Systems
WRIGHT-PATTERSON AIR FORCE BASE, Ohio --  The Air Force Research Laboratory recently took another step toward a greater understanding of hypersonic flight with the successful launch of an experimental vehicle as part of the HIFiRE project.

HIFiRE, which stands for Hypersonic International Flight Research Experimentation, is an effort to develop a deeper understanding of the fundamentals of hypersonic flight (defined as flight over Mach 5, or five times the speed of sound) through the launch of up to ten experimental vehicles equipped with an array of sensors and specialized data-gathering equipment. This flight program represents an important opportunity, because wind tunnels cannot fully simulate hypersonic conditions.

The HIFiRE 2 vehicle, an experimental hydrocarbon-fueled scramjet, launched from the Pacific Missile Range Facility in Hawaii and climbed to an altitude of approximately 90,000 feet, accelerating from Mach 6 to Mach 8 and operating for approximately 12 seconds. Following deployment of the payload shroud at Mach 5.2, fuel flow was initiated and ignition of the supersonic combustor was achieved. As the vehicle accelerated from Mach 6 to 8, the combustor transitioned from dual-mode to scramjet-mode operation at a near-constant fuel-air ratio. The successful operation of the experiment itself represented a major achievement for hypersonic flight.

During the flight, more than 700 pressure and temperature sensors recorded and transmitted data to researchers on the ground. This data, coupled with measurements from a unique laser-based instrument developed to monitor the combustor exhaust, provides researchers with new information about hydrocarbon scramjet operation at high Mach numbers and the transition from subsonic to supersonic combustion. Researchers will use this data to further refine design, modeling, and simulation tools to help them design future hypersonic air-breathing engine concepts.

Over the coming months and years, researchers expect to gather even more data from the launch of future HIFiRE vehicles. The ultimate goal of HIFiRE is to give researchers the information and tools necessary to achieve practical and affordable hypersonic flight, an objective long sought for both military and private application. Theoretically, a hypersonic flight could leave New York City in the morning, landing in Tokyo in time for lunch the same day.