Direct-Connect Altitude Testing of Small, Low-Cost, Afterburning Gas Turbine for use in Future Increment CCA and/or Supersonic Munitions

The USAF needs more numerous and expendable air vehicles for anticipated conflicts. Whether drones or munitions, these vehicles need to be affordable, attritable, and numerous to face threats to exquisite platforms. The drones are usually called Collaborative Combat Aircraft (CCAs) or Autonomous Collaborative Platforms (ACPs) and are expected to augment existing manned platforms or fight in their place, often with novel tactics and strategies. The munitions are envisioned as more advanced versions of current ordnance such as cruise missiles, offering longer range and thus a safer launch point. In either case, many new small air vehicles are desired to enter USAF inventory in the next few years. One notable limitation of any small air vehicle the USAF could field today is that it would be limited to existing small jet engine options, all of which are subsonic. Supersonic (air-breathing) propulsion systems are enabled by something called an afterburner. An afterburner functions by creating additional thrust via combusting the remaining air from the turbine. The afterburner is an on-demand thrust device that increases a vehicles’ thrust by up to 2x. This allows a vehicle to attain momentary increases in thrust without having to carry a much larger base engine, which would increase vehicle weight and cause prohibitive increases in aircraft drag. The increased thrust from a much smaller centerline engine is what allows an aircraft to attain supersonic operation in flight. Additionally, due to the merits of the afterburner included in a supersonic propulsion system, a vehicle with supersonic propulsion is also a vehicle that can accompany a larger take-off weight, take-off from a shorter runway, and quickly increase its energy, which improves maneuverability.  Propulsion development has traditionally taken much time and money and is recognized as a high risk to any program that needs a new engine. Consequently, near-term vehicle concepts (and the requirements that drive them) limit themselves to the nation’s existing engine offerings, and planners assume that this is all they have to work with. The advantages of supersonic propulsion described above, including lower enemy response time, or engaging closer to enemy space, are neither thought of nor asked for in designing or requisitioning CCAs or air-breathing munitions.  Velontra aims to mature a supersonic jet engine from Technology Readiness Level (TRL)-5 to TRL-6. This engine will be based on a commercial-off-the-shelf (COTS) engine which Velontra has already demonstrated at TRL-5 outside the scope of this STTR. The improvement to TRL-6 entails more flight-like subsystems and static fire testing at simulated altitude conditions. Velontra has  demonstrated the transformation of a COTS engine to a TRL-5 supersonic engine with the PBS TJ150, calling the new supersonic engine Bronco Mk 1. Velontra’s small supersonic engines will allow the  Air Force to have parity or superiority over poten. adversaries.