These UAVs can travel at supersonic speeds

Unmanned vehicles (UAV’s) are used for a number of purposes including reconnaissance, carrying and deploying payloads both lethal and non lethal, providing attack capabilities and acting as a decoy.

Currently, when UAVs operate in a hostile environment, they are vulnerable because of their slow speeds.

The patented UAV can travel at supersonic speeds (in the range of Mach 1 to Mach 5). Some missiles can travel at supersonic speed, but their method of propulsion includes a rocket engine that relies on carrying and combining fuel and an oxidizer. This means they tend to operate for a period of time that are proportional to their size. Therefore, a missile engine is not suitable for use in a UAV, as the UAV is relatively small and therefor has limited space for carrying the fuel and oxidizer required to operate for longer periods of time.


The patent discloses innovative engine including a rocket and a ram jet engine formed from an intake and a combustion chamber. The rocket engine includes an oxidiser combustion chamber which exhausts through the combustion chamber. The engine also includes a nozzle. Both the intake and nozzle include rectilinear ducts, which are adjustable to adjust the airflow characteristics.

The core focus of the invention is to provide robust and affordable miniaturization of ramjet technology.

Making use of variable geometry supersonic air inlets and nozzles, it is capable of producing 500 pounds of thrust and delivering efficient flight up to Mach 3 over a large range of altitudes. The unit maintains effective combustion throughout its operational envelope by systems regulation performed by an electronic engine control system developed in-house. With a robust design, the regeneratively-cooled unit can reliably withstand sustained operation over a wide speed range.

An extensive aerial test program is currently underway to expand the operational flight envelope of the patented UAV, which is named Evader MLG-RAM Supersonic Aerial Target. In developing an airborne deployment capability from a fixed-wing carrier aircraft, Evader MLG-RAM will be able to accelerate through the subsonic flight regime and on to supersonic speed. This eliminates the need for a rocket booster to reach supersonic speed, an operational limitation associated with conventional ramjet propulsion systems.

The Evader MLG-RAM supersonic aerial target represents the high performance potential of the world’s fast evolving UAV industry.

Patent Information
Publication number: US 9,371,800
Patent Title: Engine for use in an aerial vehicle
Publication date: Jun 21, 2016
Filing date: Feb 29, 2012
Inventors: Mark Grollo;
Original Assignee: GROLLO AEROSPACE