[Avionics Today 08-23-2016] The Airbus Perlan II stratospheric glider is currently en route to Argentina for its mission, to set a new world gliding high-altitude record by soaring to 90,000 feet. Now, the team of engineers, pilots and researchers of the Airbus Perlan Mission II team are waiting on the right conditions to perform the flight. Avionics Magazine recently caught up with Jim Payne, chief pilot for the Airbus Perlan Mission II project, as he and the team prepare for the record-setting mission set for their engineless aircraft.
The Airbus Perlan II sailplane. Photo: Airbus Group.
Perlan II is the second generation glider of the Perlan Project, which was originally founded as an aviation record-setting research project by NASA Test Pilot Einar Enevoldson, meteorologist Elizabeth Austin and late businessman and aviator Steve Fossett in the late 1990s. In 2006, the Perlan I achieved its first flight to greater than 50,000 feet. Immediately following that flight the team envisioned a better, pressurized aircraft that could fly higher. But the next project would become stalled indefinitely in 2007 when Fossett died due to an unrelated flying accident. In 2014, Airbus Group became the Perlan Project’s primary sponsor, leading to the Perlan II’s first flight in 2015, and eventually a planned flight to 90,000 feet.
The Perlan II is also equipped with scientific instruments that will be used for climate, aerospace and stratospheric research that cannot be measured via other means. Among the research related goals are to measure the atmospheric concentration of aerosols and greenhouse gases, including ozone, methane and water vapor. Perlan II will also collect data on exchanges between gases and energy within the two lower layers of the Earth's atmosphere, the troposphere and stratosphere, according to the Perlan Project website.
Payne explained how the team will fly the manned glider.
“We aero tow [the Perlan II] the same as any other sailplane. For the 90,000-foot flights we will tow up to about 9,000 feet [Mean Sea Level] MSL. We will release from tow in the mountain wave lift. We will then maneuver as needed to stay in the zone of rising air. We’ll be towing from the airport at El Calafate, Argentina into the wind to about 9,000 feet, and that will put us in the looking zone for the mountain wave, release from tow there and join the mountain wave and climb,” said Payne.
Laviasa Aeroindustria, the Argentinian manufacturer of the Piper PA-25 Puelche, will provide the aero two for the Perlan II. According to Payne, the 1,100-pound, 84-foot wingspan glider’s attempt to reach 90,000 feet will ride layers of high-altitude winds that the Perlan team calls stratospheric mountain waves, as the waves are created by strong winds that blow over the tops of high altitude mountains and then are driven up towards space.
“The southern and northern regions of the world have a phenomenon called the polar vortex, and basically what that does is it causes strong winds at very high altitudes. In our case, the strong winds will be perpendicular to the Andes and as they come over the mountains, they cause a wave in the air that’s invisible unless there are clouds present. We fly in the area where the air is rising, and propagates all the way up to 90,000 feet, although meteorologists say it may go up to 130,000 feet,” said Payne.
Along with its pressurized cabin — which was not featured on Perlan I — and relatively low aspect ratio, a key feature for the success and validation of the Perlan II flight is its avionics, the LX-9000 integrated flight control computer. Payne refers to the Perlan II’s conventional mechanical flight control system as being “reversible” and notes that the moving map display function provided by the LX-9000 flight computer will aid the pilots in keeping the Perlan II within the lifting zones of the mountain waves.
LX-9000 is also key to proving that the Perlan II achieves the world record, as it is an International Gliding Commission (ICG)-approved, high-altitude flight recorder. When turned on, it records a plethora of data for every minute of the aircraft’s flight, including pressure altitude and GPS altitude. Once Perlan II completes the 90,000-foot flight, the Perlan Project team will download the recorded data from the aircraft and transfer it to ICG for validation, Payne said.
The pilot’s main source of “back up” power to the aircraft are iPads and a Garmin GDL 39 3D GPS receiver.
“As a back up to the [Attitude Heading and Reference System] AHRS in the LX-9000, we have a Garmin GDL-39 3D GPS receiver, which connects to an iPad. On the iPad we also have Garmin Pilot software. We have AHRS in the LX-9000 and we decided we wanted a backup. Garmin provided us with a GDL 39 3D, and Garmin Pilot Software; we do have an iPad we’ll be carrying in the Glider with the GDL 39 as a completely independent backup. The GDL 39 has a battery in it, and the iPad has a battery in it, so if you have a complete electrical failure in the Perlan II you still have AHRS attitude, and GPS so our location is known, and you can still glide back to the airport,” said Payne.
But now, the team must wait for the right climate conditions to arise in Argentina.
“It looks like now by the end of the month we’ll be in good shape to start making flights. Typically the polar vortex, which causes the high-altitude wave, is best in August and September. So far, August has been disappointing; we haven’t had the high-altitude winds. The one downside of this is that we’re totally at the mercy of the weather,” said Payne.