In retrospect, it should come as no surprise that this story did not immediately appear on our radar: Last week, Aviation Week reported that the classified RQ-180 stealth drone has begun test flights at Area 51.

The unmanned airplane, built by Northrup Grumman, is meant to replace the piloted SR-71 Blackbird, a superfast Cold War spy plane that was retired in 1998.

Aviation Week cited unnamed "defense and intelligence officials":

"Neither the Air Force nor Northrop Grumman would speak about the classified airplane. When queried about the project, Air Force spokeswoman Jennifer Cassidy said, 'The Air Force does not discuss this program.'

"The RQ-180 carries radio-frequency sensors such as active, electronically scanned array (AESA) radar and passive electronic surveillance measures, according to one defense official. It could also be capable of electronic attack missions.

"This aircraft's design is key for the shift of Air Force ISR assets away from 'permissive' environments—such as Iraq and Afghanistan, where Northrop Grumman's non-stealthy Global Hawk and General Atomics' Reaper operate—and toward operations in 'contested' or 'denied' airspace. The new UAS underpins the Air Force's determination to retire a version of the RQ-4B Global Hawk after 2014, despite congressional resistance. The RQ-180 eclipses the smaller, less stealthy and shorter-range RQ-170 Sentinel.

"If the previous patterns for secret ISR aircraft operations are followed, the new UAV will be jointly controlled by the Air Force and the CIA, with the program managed by the Air Force's Rapid Capabilities Office and flight operations sustained by the Air Force. This arrangement has been used for the RQ-170, which is operated by the Air Force's 30th Reconnaissance Sqdn., according to a fact sheet the Air Force released after one of the aircraft turned up in Iran."

Defensetech, quoting an unnamed news report, says: "Northrop recently disclosed that an unnamed aircraft program entered early production — several years after reporting a $2 billion backlog increase in the unit that develops cutting-edge weapons programs."

U.S. Naval Institute News notes that while there's no confirmation, "there have been rumblings that some sort of stealthy new ISR aircraft had been in development at Air Force's classified flight test facility at Groom Lake, Nevada, since at least 2010. But the details of exactly what the program entails has always been murky—save for the fact that it had been described by some as a 'stealthy Global Hawk' equivalent."

USIN says that the RQ-180 is being described as about the size of the Global Hawk "but with long spindly wings designed for extreme efficiency at high altitudes. It was also known that the aircraft was designed to have 'wide-band' stealth that could operate against high and low frequency radars."

UAS Vision, which describes itself as "a global forum for the unmanned aircraft systems community," speculates that, "The RQ-180 could use a medium-­bypass-ratio engine [that] probably has more power than the Global Hawk's 7,600-lb.-thrust Rolls-Royce AE3007H, to provide better altitude performance and electrical power for payload growth.

"Operationally, the RQ-180's range could be extended by inflight refueling, though it is unclear whether the UAS takes advantage of this technology."

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