Three major players remain in the now-revised United States Navy's (USN) unmanned aerial tanker program - Boeing, Lockheed Martin, and General Atomics (with Boeing as a notable backer). Northrop Grumman abandoned the program when the Navy switched directions from the original Unmanned Carrier-Launched Airborne Surveillance and Strike (UCLASS) approach to the tanker / reconnaissance-minded MQ-25 "Stingray" design. General Atomics Aeronautical Systems, Incorporated (GA-ASI), a proven player in the UAV market and makers of the famous "Predator" product line, has its sights on the same prize as the noted industry heavyweights Boeing and Lockheed - the prize potentially worth billions in procurement as well as the expected year-over-year support commitment.
The USN is the largest sea-going fighting force anywhere in the world, second to none, and fields the globe's largest collection of aircraft carriers.
General Atomics' still-in-development "Avenger" Unmanned Combat Air Vehicle (UCAV) is set to form the basis of its Stingray proposal. As such the design shares many external similarities to the aircraft including the dorsal-mounted intake aspirating the single engine installation, outward-cranked "V-style" tailplane arrangement, and retractable tricycle undercarriage. The fuselage is well-contoured and houses pertinent support equipment such as avionics and fuel. The engine is set in the rear of the design as is the case with many other medium-to-large-sized military drone aircraft. Unlike the Avenger's pseudo blended wing-body approach, the Stingray proposal's wing mainplanes are mounted high along the fuselage sides and each unit is capped by a winglet for added stability and fuel efficiency. The fuselage has a sensor blister at the "chin" position which allows the platform to undertake basic Intelligence-Surveillance-Reconnaissance (ISR) sorties (now part of the USN requirements). Under each wing mainplane will be fitted a fuel tank to satisfy the major fuel-delivery component of the USN requirement. Beyond this, the aircraft will sport some given stealth features, feature an arrestor hook for carrier-based landings, and sport folding wings for carrier storage. This on top of the usual requisites of navy aircraft such as protection from corrosive salt spray and a reinforced undercarriage for the rigors of carrier operations.
Internally, the MQ-25A offering from General Atomics is set to be wholly autonomous in which the system will actively read directions/commands from an on-deck flight director's wand actions.
General Atomics is currently (2018) ground-testing the Pratt & Whitney Canada PW815 turbofan for its Stingray, set to output in the neighborhood of 16,000lb of thrust, which is a departure from the Avenger's relatively weaker PWC PW545B turbofan fit. The company expects to meet and / or exceed all performance figures required by the Navy - including the all-important operational range capability which requires an aircraft operating relative far from its carrier "mothership" and over large swathes of unforgiving and volatile ocean. Of note is that the PW815 is not a military-certified powerplant which may work against the GA-ASI proposal.
The Stingray series is expected to be regularly operated from the Nimitz- and Ford-class of supercarriers currently in the USN fleet. Each design is required to deliver around 14,000lb of fuel to manned combat aircraft via a standard drogue refueling pod with a ground-based operator still part of the refueling equation (via real-time video and communications link). The Navy hopes to free its active fleet of F/A-18 Super Hornets currently modified for the "buddy tanking" role so these platforms can be returned back to their combat-capable forms. Of course the MQ-25 will also be a prime supplier of fuel to the new Lockheed F-35 Lightning II VTOL aircraft adopted by the USN as well.
The early stages of the Stingray program will see formal selection of a design in August of 2018 and, following this, the service will receive a modest fleet of drones for active evaluations. Should the project produce the expected fruit, the USN will move to procure as many as seventy-two unmanned MQ-25A models for operations from carrier decks all over the world.
Interestingly, Boeing has thrown its weight behind the General Atomics initiative as well as funding / promoting its own unique design (detailed elsewhere on this site) - showing just how important the program is becoming for the company.
Since this project remains in-development at the time of publication, this article will be updated as new information allows. Performance and structural specifications presented on this page are estimates on the part of the author and will be similarly updated as new information allows.