Aerotech News and Review, April 19, 2019

World’s largest airplane makes first flight
by Peter W. Merlin
special to Aerotech News
Stratolaunch, the world’s largest airplane, took to the air for the first time April 13, following more than eight years of development at Califor- nia’s Mojave Air and Space Port, 70 miles north of Los Angeles.
The massive jet is the centerpiece of Seattle- based Stratolaunch Systems Corporation, a space transportation venture established in 2011 by Mi- crosoft co-founder Paul G. Allen. It was designed to carry small rocket boosters to place satellites into low Earth orbit. Lofting small payloads into space from an airplane reduces launch costs and offers greater operational flexibility than fixed, ground-based launch pads.
“What a fantastic first flight,” said Jean Floyd, CEO of Stratolaunch. “Today’s flight furthers our mission to provide a flexible alternative to ground launched systems. We are incredibly proud of the Stratolaunch team, today’s flight crew, our part- ners at Northrup Grumman’s Scaled Composites and the Mojave Air and Space Port.”
Formally known as the Model 351 the airplane was built at Mojave by Northrop Grumman sub- sidiary Scaled Composites, which has produced numerous revolutionary aircraft and spacecraft designs. The Stratolaunch has a high-wing, twin-fuselage configuration with two separate tail booms. Although each nose section appears to have its own cockpit, the three-person crew only occupies the right one. The left-hand com- partment is reserved for electronics and instru- mentation. Each fuselage assembly is 238 feet long. The tip of each vertical tail fin towers 50 feet above the ground. Company engineers nick- named it the “Roc” after a giant mythological bird most widely known for its ability to snatch and carry an elephant with its talons.
At 385 feet, the Roc’s wingspan is the lon- gest of any airplane ever assembled, stretching more than the length of an American football field, including end zones. A reinforced center wing section provides space for pylons to carry a variety of launch vehicles, such as the Pegasus XL. With a mission radius of 1,000 nautical miles and a 550,000-pound payload capacity, Strato- launch could carry up to three Pegasus rockets on a single flight, or one larger launch vehicle.
For increased structural strength and overall weight reduction, the airframe was constructed mostly of carbon fiber composite materials in- stead of conventional aluminum alloys. The Mod- el 351 weighs more than 550,000 pounds and is designed to sustain a maximum gross operating weight of approximately 1.3 million pounds.
To save money and reduce risk, designers used as much off-the-shelf hardware as possible. The jet is powered by six Pratt & Whitney turbofan engines salvaged from two Boeing 747 airliners and also employs landing gear from the 747. To safely accommodate high operating weights there are 28 wheels in total, two each for the twin nose
See FLIGHT, Page 3
April 19, 2019• Volume 33, Issue 6
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Photograph by Peter W. Merlin
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