DARPA/US Air Force hypersonic air-breathing weapon ready for free flight
Two variants of the Hypersonic Air-breathing Weapon Concept (HAWC) being developed for DARPA and the US Air Force have completed their final captive carry flight tests and are now cleared for their first free-flight tests within the next year.
In a scramble not seen in the military aerospace field since the sound barrier was broken in 1947, the race to develop hypersonic weapons by the major powers has the potential to revolutionize warfare in the 21st century. Being able to fly at over five times the speed of sound, hypersonic missiles and aircraft would literally be able to outrun conventional weapons. They would also allow only a very small window of time for targeting systems to lock onto them and would have so much momentum that some wouldn't even need explosives to destroy their targets.
However, to achieve this and make hypersonic weapons practical, a number of technologies need to be brought to maturity. Specifically, such missiles need next-generation flight controls and avionics, cooling systems to battle the high temperatures that hypersonic flight generates, and propulsions systems that can operate at hypersonic speeds.
The lattermost is particularly important because most hypersonic vehicles being tested today are boost-glide weapons, which are dropped from an aircraft, boosted to hypersonic speed at a high altitude by a rocket, then glide down to their target. This means that the missile has to be launched at a very long distance and requires the target to be in a more or less predictable place when the missile arrives.
The HAWC project's goal is to essentially build a hypersonic cruise missile that breathes air to feed its engine. This would allow the weapon to be launched at a low altitude and closer to the target, and would produce a more maneuverable missile that would be harder to detect.
To achieve this, contractors Lockheed Martin and Raytheon Technologies are each working on advanced air vehicle configurations that will have a hydrocarbon scramjet-powered propulsion and thermal management system for sustained hypersonic flight during the first free-flight tests.
"Completing the captive carry series of tests demonstrates both HAWC designs are ready for free flight," says Andrew “Tippy” Knoedler, HAWC program manager in DARPA’s Tactical Technology Office. "These tests provide us a large measure of confidence – already well-informed by years of simulation and wind tunnel work – that gives us faith the unique design path we embarked on will provide unmatched capability to US forces."