Giant Stratolaunch Begins Engine Tests

Development continues for big low earth orbit transport aircraft.

Stratolaunch successfully started each of the massive aircraft’s six Pratt & Whitney turbofan engines for the first time.Dylan Schwartz/Stratolaunch

Paul Allen's enormous aircraft project has taken a big step toward success. With six Pratt & Whitney engines of the same kind used on a Boeing 747 strapped to its massive fuselage, the engine tests for Vulcan Aerospace's Stratolaunch is a critical step in the development process. This week, the engines were run for the first time at the company's development facility in Mojave, California.

A three-step process was used to give the Stratolaunch engines a successful beginning. First, the team used an auxiliary power unit to charge the dry engines. Then, fuel was introduced. Finally, each engine was started individually and allowed to idle. All six engines operated as expected.

One of the largest airplanes ever built, Stratolaunch first emerged from its giant hangar at the Mojave air And Space Port in May. Since then, the team has successfully tested the flight controls, fuel, electrical, pneumatic and fire detection systems.

All six of the Stratolaunch's engines operated as expected, completing the first phase of engine testing.Dylan Schwartz/Stratolaunch

The next step in the development program is testing higher power levels and varying configurations of the engines. Taxi tests will follow and the team hopes to take the Stratolaunch on its first flight in 2019.

Stratolaunch was conceived as a low earth orbit transport aircraft for a variety of missions. It is the largest composite airplane ever built and is expected to have a max takeoff weight of 1,300,000 pounds, a payload of 550,000 pounds, and a range of about 2,000 nm. Sitting on 28 wheels, it is 238 feet long, 50 feet high and has a wingspan of 385 feet. Unlike most aircraft capable of space flight, Stratolaunch will take off and land from a runway rather than a rocket launch platform.