World’s Widest Airplane Completes Successful Second Test Flight

Stratolaunch’s “Roc” aircraft has two fuselages and a wingspan of 385 feet

The 385-foot-wide Roc aircraft flies in a clear blue sky above the desert with mountains on the horizon
Stratolaunch's large aircraft, nicknamed 'Roc,' flew for three hours and 14 minutes and reached a maximum altitude of 14,000 feet. Courtesy of Stratolaunch via Twitter

On Thursday, an aircraft with two fuselages, six engines and a wingspan of 385 feet spent three hours and 14 minutes cruising above the Mojave Desert in California, Joey Roulette reports for the Verge.

It was the second successful test flight of a behemoth aircraft designed by Stratolaunch and nicknamed "Roc" after the mythological bird said to carry off elephants as prey. The flight provided an opportunity to test how the plane would handle cabin pressurization and test new hardware upgrades and safety features that were added since the first test flight in April 2019.

“Today’s flight, at first review, has appeared extremely successful,” said Zachary Krevor, Stratolaunch’s chief operating officer, during a call with reporters, per the Verge. “We accomplished all test points as desired, we have not seen anything anomalous, and we are very pleased with the condition of the aircraft upon landing.”

When the plane touched down at the end of its flight, the wheels of one fuselage hit the ground while the other side of the aircraft remained in the air. While it appeared shaky to onlookers, Krevor says the lopsided maneuver is the proper procedure for landing the large plane in a crosswind, Alan Boyle reports for Geekwire. The test flight crew—pilot Evan Thomas, pilot Mark Giddings and flight engineer Jake Riley—worked in the right fuselage’s cockpit, while the left side held instrumentation.

Roc was originally designed to help launch satellites by ferrying rockets and their payloads to the upper atmosphere, removing the need for a first stage booster, Mike Wall writes for But when Paul Allen, co-founder of Microsoft and founder of Stratolaunch, died in 2018, the company was sold to new owners and its mission re-focused. Now, Stratolaunch is framing Roc as a testbed for hypersonic vehicles and intends to partner with the Department of Defense.

Hypersonic vehicles, or hypersonics, fly at beyond five times the speed of sound. Because they are both superfast and maneuverable, which makes them difficult to intercept, hypersonics are posed to be the next generation of missiles—although not everyone believes the hype. Stratolaunch is developing Roc to carry their hypersonic test vehicle, called Talon-A, high into the atmosphere and deploy it. That strategy avoids the effort required to launch it from ground level and get it up to speed from zero.

In the Thursday test flight, Roc reached 14,000 feet.

“Over the next year, the airplane will go higher, it will go faster, until we are in the envelope that’s required to drop our Talon testbed so it can achieve hypersonic flight,” said Stratolaunch’s chief technical officer Daniel Millman during the call, Jeff Foust reports for Space News.

Krevor adds that the next year of tests will include a “range of flights” of growing complexity, and that “the exact number of flights will be dependent on how we are able to complete the test objectives of each flight,” per Space News.

When Stratolaunch first took flight two years ago, it surpassed the H-4 Hercules, also known as the Spruce Goose, as the widest aircraft. The Spruce Goose first flew in 1947 and had a wingspan of 320 feet.

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