The United States Navy (USN) originally sought an attack-minded Unmanned Combat Aerial Vehicle (UCAV) drone vehicle and developed the "Unmanned Carrier-Launched Airborne Surveillance and Strike" (UCLASS) program around this requirement. The venture was based around the thinking of a long-ranged stealth-minded airspace penetrator that could also double as an armed reconnaissance platform when needed, all the while operating from the USN's Nimitz- and Ford-class "supercarriers". There were the usual defense industry takers involved: Boeing, General Atomics, Lockheed Martin, and Northrop Grumman. However, the USN eventually revised their requirement to become an unmanned aerial tanker which left Northrop to bail on the initiative to better serve company interests elsewhere (quite unfortunate because the company made good early progress in the field with active testing of their X-47B UAV aboard USN carrier decks). This has left just Boeing, General Atomics, and Lockheed in the running with Boeing interestingly also being a notable backer of the General Atomics venture (this based on the Sea Avenger UAV detailed elsewhere on this site).
The Lockheed MQ-25 "Stingray" proposal, revealed through artist renderings released from 2017 (note this was prior to the USN program requirements revision, moving away from UCLASS, later that year), makes use of a true triangle shaping which blends wing-and-body into a sleek "flying wing" aircraft. A single engine is installed in the aft-section of the fuselage and aspirated through a dorsal intake over (and aft) of the nose with exhaust through a ring at the rear. An external fuel tank is pictured fitting ventrally along the aircraft's belly. The Lockheed Stingray sits on a retractable, wheeled tricycle undercarriage which should be reinforced for the rigors of carrier-based operations. A retractable arrestor hook (mounted under the extreme aft-end of the fuselage) facilitates carrier deck landings and support for catapult launches. Folding wings will make for a smaller footprint for the Stingray aboard space-strapped carrier hangar decks - the wings folding at about their midway point over the wingroot.
An off-the-shelf single engine fit figures into the design mix as this approach lessens complication of logistics and maintenance while utilizing a proven power source. The MQ-25 will be a subsonic performer based on supplied details and some additional influence for the growing project is naturally being garnered from previous Lockheed stealth programs such as the soon-to-be F-35 "Lightning II" - of which the MQ-25 Stingray is said to borrow its tricycle undercarriage from.
The flying wing shape, as far as combat aircraft go, has (to some) offered the best prospects for the needed long-range, long-endurance air vehicle for it promotes inherently strong aerodynamic principles, including natural lifting properties, while also providing greater, continuous internal volume than a traditionally-arranged aircraft with a defined fuselage, mainplanes, and tail unit. Lockheed's original design direction for UCLASS was the "bat wing" shaped stealthy "Sea Ghost" so MQ-25 is somewhat a departure from this initiative.
It is expected that this vehicle, as it is currently rendered, will influence the upcoming Lockheed MQ-25 Stingray proposal - which is competing squarely with Boeing's MQ-25 offering detailed elsewhere on this site and unveiled through press release pictures. General Atomics is also in the running and is slowly shaping their own Stingray submission.
The USN plans to field an entire fleet of some seventy-two UAVs in the aerial tanker role aboard its supercarrier fleet - the most powerful warships in the world. These will be used to succeed the in-service, now-converted fleet of F/A-18 "Super Hornets" currently equipped for the aerial tanker role (as "Buddy Tankers"), freeing these airframes to continue their service lives in their original roles as strike fighters. Additionally, unmanned air systems do no risk pilots in wartime and can sometimes be a fiscally better procurement venture than manned aircraft which require additional avionics and life support systems.
The MQ-25 is being designed to carry upwards of 14,000lb of aviation fuel and to be able to operate with existing refueling technology found in current-generation strike fighters like the Super Hornet line (namely its extendable fuel probe). Range is expected to reach around 500 nautical miles from the carrier source to allow for return trips of the UAV system. An operator, with a real-time camera feed installed in the Stingray, will be part of the refueling action leading to the belief that completely autonomous in-flight refueling of combat aircraft is still some years (perhaps decades) away. The buddy refueling pod will be of an existing USN design which the MQ-25 will carry under a starboard underside hardpoint. The portside hardpoint will be reserved for special mission pods or ordnance. Also along port will be a retractable sensor-equipped traversing ball unit.
The MQ-25 from Lockheed will not be wholly autonomous as the General Atomics model plans to be. Instead, a pilot will be part of the operational flow, particularly during the deck movement phase. The human pilot will operate the aircraft through wide-angle real-time camera feeds featuring zoom capability to better coordinate with deck crew.