Famous X-51 Waverider Hypersonic Scramjet Inspired Modern Weapons

By Kris Osborn, Warrior

As hypersonic weapons continue to breakthrough to new levels of operational capability, many are likely to recall the defining accomplishments of the X-51 Waverider, a scramjet powered hypersonic vehicle which launched from a B-52 to achieve speeds of Mach 5 before falling into the ocean.

The X-51 Waverider in 2013 flew above the Pacific Ocean at hypersonic speeds, a development which the passage of time now reveals as a defining moment in the development of US hypersonics. The X-51 waverider air vehicle used a scramjet engine to propel from a U.S. Air Force B-52, and after several failed previous experiments, the scramjet was able to achieve speeds of Mach 5.

X-51 Breakthrough

At that speed, about 3,400 miles per hour, a missile could travel from Washington, D.C., to Atlanta in several minutes—making it a potentially powerful weapon against enemy air defenses.

Achieving hypersonic flight for any period of time, particularly in 2013, can be regarded as a significant breakthrough, and it continues to inform current challenges associated with “sustaining” hypersonic flight.  Much progress has been made in this regard, and it can be directly tied to the pioneering success of the X-51 Waverider. At this time in  2013, the X-51A flight proved to be the longest air-breathing hypersonic flight ever. The specifics of this breakthrough flight are quite significant, as the X-51 flew on the wing of a B-52H before being released at 50,000 feet. Amazingly, the aircraft was able to accelerate to speeds of Mach 4.8 in 26 seconds, before ultimately reaching Mach 5.1.  Although the X-51 crashed into the ocean, the platform sent back crucial data that proved critical to the scientific advancement of hypersonic flight.

Hypersonic Attack Cruise Missile

Current progress on scramjet, air breathing hypersonic weapons can be clearly traced to the X-51A Waverider, as new scramjet propelled weapons have built upon the technology. The now in development Hypersonic Attack Cruise Missile, for example, will build upon successful tests of its precursor, called the Hypersonic Air Breathing Weapon Concept (HAWC). Built by Raytheon with a Northrop Grumman scramjet, the HAWC was successfully tested in 2022.  Once operational, the HACM will be able to travel 300 nautical miles at speeds over Mach 5. 

The complexity of hypersonic flight is well known to Pentagon weapons developers. One factor is temperature: Hypersonic projectiles or platforms need to be constructed with composite materials capable of operating at the extreme temperatures generated by traveling at hypersonic speed. Thermal management becomes critical to maintaining flight stability, which is one reason developers continue to experiment with various combinations of materials. For several years now scientists at the Army Research Laboratory have been intensely researching combinations of various different composites in anticipation of finding new breakthroughs in heat resistant materials

Heat management of a hypersonic vehicle is also quite relevant to the question of  aerodynamic variables such as “air-boundary layer” flow surrounding hypersonic projectiles. Weapons developers hope to engineer a projectile able to generate smooth or “laminar” air boundary, because a turbulent air flow, scientists explain, can move particles at high temperatures in the air surrounding the weapon and “derail” its flight trajectory or throw it off course.  

Kris Osborn is the President of Warrior Maven – Center for Military Modernization. Osborn previously served at the Pentagon as a highly qualified expert in the Office of the Assistant Secretary of the Army—Acquisition, Logistics & Technology. Osborn has also worked as an anchor and on-air military specialist at national TV networks. He has appeared as a guest military expert on Fox News, MSNBC, The Military Channel, and The History Channel. He also has a Masters Degree in Comparative Literature from Columbia University.