World's largest all composite aircraft makes its first flight

Materials World magazine
28 May 2019

The world’s largest all-composite aircraft with the longest wingspan has completed its first flight. Idha Valeur reports

An all-composite aeroplane with the world’s largest wingspan, measuring 117.3m, completed its maiden flight on 13 April, which lasted two and a half hours.

Named Stratolaunch, the aircraft is designed to launch rockets into space. It departed from the Mojave Air and Spaceport, USA, at 6:58AM Pacific Time for its test flight over the Mojave Desert.

Stratolaunch Founder, Paul Allen, described his aim of producing an aircraft that would function as a mobile launch platform, making entry to space easier and more affordable to support routine journeys.

To build the aircraft, Stratolaunch collaborated with Scaled Composites to design, build and test the composite aircraft.

The 72.5m-long Stratolaunch is a twin-fuselage platform, with the fuselages located 28.9m apart, purposely built to launch several payloads to multiple destinations during the same mission. The large wingspan has a reinforced middle wing that can bolster several launch vehicles with a total weight of 226,796.185kg. The craft also features six Pratt & Whitney 4056 engines and can accommodate a crew of two pilots and one flight engineer.

Stratolaunch CEO Jean Floyd said in a debrief that the plane reached altitudes of up to 4.57km and a top speed of approximately 304.1km/h. ‘The landing at Mojave Air and Spaceport was spectacular and was probably the most important part of today’s test, smooth and on the mark,’ he said.

While in the air, the team conducted several standard exercises to test the aircraft’s performance. These tests included several flight control manoeuvres to calibrate speed, as well as testing flight control systems including roll doublets, yawing manoeuvres, pushovers and roll-ups, and steady heading side slips, according to Stratolaunch.

‘For the first part of the flight, we checked out the handling qualities of the aircraft, which again, it flew very much like we had simulated and predicted which is exactly what we want,’ Scaled Composites Test Pilot, Evan Thomas, said. ‘We saw a few little things that were off nominal [...] Our air data system was really close and that was very nice.

‘We brought down the flaps and then we repeated our handling qualities, taking a look at what it was going to be like to land, checking the pitch response of the airplane, and then practicing some rolls and yaws to make sure we’d be able to line up with the runway like we wanted to,’ he added.

‘The systems on the airplane ran like a watch. It is a very complex airplane – the propulsion, the pneumatic system, the hydraulics – they all ran perfectly.’