World’s Largest Airplane Preps for Flight with Crucial New Test Equipment

The one-of-a-kind aircraft powered by six Pratt & Whitney PW4056 engines, and with wings measuring longer than an NFL football field was spotted Thursday performing low-speed taxi tests. But unlike previous excursions, this was the first time Roc was seen with an attached pylon, which is designed to carry and launch hypersonic Talon-A testbeds. 

The testbeds, which are being developed by Stratolaunch, are uncrewed, autonomous, rocket-powered aircraft, designed to blast across the sky at speeds of Mach 5 or faster after being released from the pylon in flight. The pylon is crucial. Without a fully tested and functional pylon, Roc won’t be able to perform its primary mission as a carrier aircraft for inflight aircraft launches.

“We’ve designed this pylon to hook up to four attach points that are easily accessible to the aircraft,” said Stratolaunch CTO Dr. Daniel Millman after Roc’s previous flight last February. “It’s less than a day’s effort to get the pylon on to the aircraft. Even better is how we will attach the adaptor that goes from the Talon to the pylon. We’ve got a very innovative design to make that go very quickly as well.”

The pylon hangs underneath Roc’s 95-foot long center wing, which is rated to support payloads weighing more than half a million pounds. Gathering data on how the pylon affects Roc’s flight dynamics will be part of the airplane’s fifth test flight, which is expected in the coming days.

Unlike Roc’s carbon composite twin-fuselages, the pylon is constructed of stainless steel with a unique releasing mechanism that will allow Roc’s pilots to create tailored trajectories for the Talons per the requirements of Stratolaunch’s customers—such as the Pentagon’s Missile Defense Agency. MDA has contracted with Stratolaunch to provide “threat replication” data to help scientists understand how to engage and intercept hypersonic weapons.

Roc’s next several flights will allow pilots the opportunity to explore the jet’s entire performance envelope, “to give customers the flexibility they need to execute their mission requirements.” said Stratolaunch president and COO Dr. Zachary Krevor last February.

During test flight four, back in February, Roc’s pilots pushed the massive airplane to speeds around 180 kias and a maximum altitude of FL150 (15,000 feet) during its 103 minutes in the air. The crew’s primary mission, to fully retract and extend in flight all eight landing gear and 28 wheels for the first time, was declared a success.

If Talon development and Roc’s test flights remain on track, the company has said it expects to conduct Talon’s first hypersonic test flight by the end of this year, with operational capability anticipated in mid- to late 2023.