Concerns are being raised within industry about the new direction mandated by the Pentagon for the US Navy’s unmanned carrier-launched surveillance and strike (UCLASS) aircraft programme.
The reason for the concern is because the Pentagon’s Joint Requirements Oversight Council (JROC) has fundamentally altered the requirements for the UCLASS from a long-range penetrating strike platform to something akin to a modestly stealthy carrier-based Predator. “Where it leaves us is developing an alternative that meets the requirements that the navy has outlined,” says one industry source – which means spending even more company money after funding nearly three years of internal research and development designing an aircraft without any guidance from the service.
“This looks like a giant runaway for General Atomics and Predator, I would not be surprised if the other companies ‘no-bid’,” says Dan Goure, an analyst at the Lexington Institute. Companies such as Boeing, Lockheed Martin and Northrop Grumman have spent a large sum of their own money on UCLASS and may not want to dump even more into what amounts to a stacked deck, he says.
“It does damage to an industrial base that is already fragile,” Goure adds.
Congress is also concerned about the direction of the USN acquisition strategy, which has been described as “atypical”. In a letter to navy secretary Ray Mabus, congressmen Randy Forbes and Mike McIntyre – chairman and ranking member of the House Armed Services Committee’s sea power subcommittee respectively – question the service’s plan to field four carrier air wings worth of UCLASS aircraft before the completion of operational testing or even a formal “Milestone B” decision to enter engineering and manufacturing development.
This is a concern shared by some in industry. “I have had similar concerns regarding the navy trying to procure one to four carriers worth of UCLASS aircraft for early operational capability as part of a technology demonstration phase that is pre-Milestone B,” says another industry source. “The only type of technology development programme which results in ‘residual operational assets or capabilities’ used to be called a JCTD [Joint Capabilities Technology Demonstration] – which the UCLASS programme is not.”
However, more fundamentally for the industry, both sources concur that the USN has deviated significantly from the normal process for developing a new aircraft. Typically, industry would have been developing solutions over the past two years based on an initial set of navy-issued requirements. Those specifications would have been refined and updated as needed, based on various industry-informed trade studies, they say. That procedure would likely have yielded more relevant industry investment, more affordable requirements and a better overall competition.
The USN, however, did not issue any aircraft performance specifications or draft requirements until the spring of 2013. That means that for nearly three years, industry teams have been developing potential UCLASS candidates using their own money and based on their own assumptions about the navy’s requirements, both sources agree. That means each competitor is now trying to “force-fit” their aircraft into the UCLASS preliminary design review phase, which is now requiring even more investment, one industry source says.
The lack of industry feedback has had some unforeseen consequences. Superficially, the shift to an aircraft designed for long-duration orbits over permissive airspace would appear to favour General Atomics Aeronautical Systems, which builds the MQ-1 Predator and MQ-9 Reaper. However, the current requirements are not as simple as they look, says one industry source. “They want to span the deck-cycle, the means the endurance has to be greater than 12h,” he says. “From a carrier that’s pretty significant because you have limitations on wing-span just because of the carrier environment.”
Fundamentally from an engineering standpoint, to achieve better endurance, the aircraft must have a higher aspect ratio wing, which means a longer wingspan. However, on board a carrier, the wingspan is limited to about the same length as a Northrop X-47B unmanned combat air system demonstrator. The absolute maximum is probably 70ft (21m), which means, by necessity, weight reduction is the key to meeting the USN’s new requirements.
“If you were allowed to refuel in the air then you might actually have a much broader performance spectrum,” one source says. “With that gone, you’re into designing as light a weight structure as can survive the carrier environment and hold as much fuel as you can."
Although the navy says that the UCLASS is going to be designed to operate in “permissive and low-end contested environments”, one industry source says that the low-observable requirement was not completely removed. “I don’t think the survivability requirements are trivial,” he says. However, he concedes that “the overwhelming design driver now is endurance without refuelling”.
An aircraft carrier would be expected to deploy enough UCLASS aircraft to maintain two orbits about 600nm (1,110km) distance from the ship, or maintain a single orbit at a range of 1,200nm. If the UCLASS were called on to conduct a light strike mission, it could attack lightly defended targets at a distance of 2,000nm. As currently envisioned, the UCLASS will have a total payload of 1,360kg (3,000lb), of which only 454kg would consist of air-to-ground weapons.
Either a flying-wing or wing-body tail configuration could meet the requirements, an industry source says. However, the endurance requirement is strenuous enough that the source says that he is not sure that a turbofan engine is a “viable option”.
Boeing and General Atomics appear to have selected a wing-body tail design, while Lockheed Martin has disclosed its RQ-170-derived flying-wing concept. Presumably, the Northrop design will resemble its X-47B demonstrator.
Source: Flight International