Bell has released a concept for a sea-based, high-speed uncrewed aircraft system (UAS) that can rearm and reload itself on floating rafts.

The concept was released as part of Bell’s confirmation on Nov. 27 of a contract award from DARPA for the Speed and Runway Independent Technologies (Sprint) X-plane program. Aviation Week reported on Nov. 7 that Bell was among four companies to receive Phase 1 awards to continue conceptual design work on aircraft with the ability to hover and reach speeds of more than 400 kt.

As part of the Sprint program, Bell is continuing development of a design concept known as Sea-based Logistics Unmanned Rearm/Refuel Platform (Slurrp). The concept shows the light version of a proposed family of aircraft that can use a nascent folding tiltrotor system to take off and land vertically, yet fly more than 33% faster than the top speed of a V-280 Valor or V-22 Osprey.

“The image shows a network of connected aircraft that are communicating locally with each other passing [command and control] or other data,” a Bell spokesperson told Aviation Week. “They are simultaneously launching from their autonomous refuel and rearm platforms where they sat dormant.”

The concept is part of a vision for conducting contested operations in the vast maritime domain of the Indo-Pacific region. On the assumption that most land-based options for landing to rearm and refuel will be denied by an enemy, the Slurrp concept would have the UAS perform those functions from prepositioned rafts, which would be loaded with fuel, munitions and automated loading systems.

Bell’s high-speed vertical takeoff and landing technology is based on a new approach to tiltrotor flight. After rotating from vertical to horizontal orientation after takeoff, the rotors would slow down until they stop as the aircraft accelerates. The rotors finally fold back along the nacelle to reduce drag, allowing the aircraft to achieve speeds typical of subsonic jets rather than aircraft optimized for taking off and landing vertically.

DARPA also selected Aurora Flight Sciences, Northrop Grumman and Piasecki Aircraft for Phase 1A contracts under the Sprint program. The agency plans to achieve first flight of an X-plane in fiscal 2027.