Aircraft

Solar aircraft designed to stay aloft for a year makes maiden flight

Solar aircraft designed to sta...
PHASA-35 flying in the predawn
PHASA-35 flying in the predawn
View 10 Images
PHASA-35 infographic
1/10
PHASA-35 infographic
The PHASA-35 making its first flight over the Woomera Test Range in Australia
2/10
The PHASA-35 making its first flight over the Woomera Test Range in Australia
PHASA-35 in flight
3/10
PHASA-35 in flight
PHASA-35 ready to take off
4/10
PHASA-35 ready to take off
Nose camera on the PHASA-35
5/10
Nose camera on the PHASA-35
PHASA-35 tail camera
6/10
PHASA-35 tail camera
PHASA-35 taking off
7/10
PHASA-35 taking off
PHASA-35 wing camera view
8/10
PHASA-35 wing camera view
PHASA-35 can stay aloft for a year
9/10
PHASA-35 can stay aloft for a year
PHASA-35 flying in the predawn
10/10
PHASA-35 flying in the predawn
View gallery - 10 images

A super-endurance unmanned solar-electric aircraft built for year-long flights has completed its maiden run. Built by BAE Systems subsidiary Prismatic, the Persistent High Altitude Solar Aircraft (PHASA-35) took to the air over the Royal Australian Air Force (RAAF) Woomera Test Range in South Australia for its first fully-integrated flight test.

Backed by Britain's Defence Science and Technology Laboratory (DSTL) and the Australian Defence Science and Technology Group (DSTG), the PHASA-35 is a High Altitude Long Endurance (HALE) vehicle designed to fill the gap between aircraft and satellites. According to BAE Systems, it went from design to first flight in 20 months with two full-size prototypes completed in 2019.

Cheaper than satellites to build and operate, the PHASA-35 is a persistent, stable aerial platform with military and civilian applications, including surveillance, communications, security, remote sensing, environmental science, forest fire detection, and maritime surveillance.

PHASA-35 infographic
PHASA-35 infographic

With a wingspan of 35 m (115 ft) and proprietary carbon-composite monocoque structure weighing 150 kg (331 lb), the PHASA-35 can spend up to a year in the air thanks to its gallium arsenide solar array and lithium-ion batteries running two brushless, direct-drive electric motors with bespoke high-altitude propellers. This allows it to run against prevailing winds as it operates at altitudes of up to 70,000 ft (21,000 m) and speeds of 50 to 78 knots (58 mph, 93 km/h to 90 mph, 145 km/h).

"This is an outstanding early result that demonstrates the pace that can be achieved when we bring the best of British capability together," says Ian Muldowney, Engineering Director at BAE Systems. "To go from design to flight in less than two years shows that we can rise to the challenge the UK Government has set industry to deliver a Future Combat Air System within the next decade."

More flight tests are slated for 2020, with initial operations to begin within 12 months.

Source: BAE Systems

View gallery - 10 images
1 comment
christopher
Dorks put the propellers on the wrong side, and made the underwing payload the wrong shape. Anything under-wing must not be curved, else it's sucking against the airfoils above and causing tons of unwanted wake turbulence. And you'd think they'd have at least an inkling of Bernoulli's theorem since they want to all that effort to make "bespoke high-altitude propellers". Hey - clueless engineers - what happen to the airflow after a propeller speeds it up? And what happens to it before it got the the propeller? Now look at your design - what have you got in-front and behind the propeller?, and what's that going to do to the airflow?. Yeah dummies - where it's low-pressure and "sucking in", there's nothing, and where it's high-pressure and "blowing out", you've got the motors and wing and other junk all in the way fighting against it. Put it on the other side (push instead of pull), and *both* those effects work *with* you, instead of against you. Sheesh.