The Windward Performance Perlan 2 (English: Pearl) is an American mid-wing, two-seats-in-tandem, pressurized, experimental research glider that was designed by Greg Cole and built by Windward Performance for the Perlan Project.
The Perlan 2 is a follow-up design to the successful Perlan 1 and has as its design goal a flight exceeding 90,000 ft (27 km) in altitude. The aircraft will be used to study the northern polar vortex and its influence on global weather patterns. The program also hoped to beat the 85,069 ft altitude record set in 1975 by a SR-71.
The original funding for the Perlan Project was provided by Steve Fossett and he flew the Perlan 1, along with test pilot Einar Enevoldson to a glider altitude record of 50,761 ft (15 km) in the mountain waves of El Calafate, Argentina on 30 August 2006. Fossett was killed in a light aircraft crash a year later and the project floundered without funding. Since then, more than US$2.8M has been raised to build the Perlan 2, including a donation from Dennis Tito. In November 2013, a crowd-funding effort was undertaken. In August 2014 Airbus became a partner and major funder in the project.
The aircraft is made from composites. Its 83.83 ft (25.55 m) span wing has a high aspect ratio of 27:1 and is equipped with airbrakes. The pressurization system produces an 8.5 psi differential, and the two-person crew will not wear pressure suits. The landing gear is a non-retractable monowheel gear. Because the aircraft will operate at extreme altitudes, in only 3% of sea level atmospheric pressure, it will also be flying at true airspeeds in excess of 0.5 Mach. The aircraft was designed to minimize flutter and manage shock wave formation.
Perlan 2, benefitting from the lessons learned on Perlan 1’s ascent, incorporates a pressurized cabin to allow its pilots to enjoy unencumbered flight, with full control over stick and rudder, and many small switches. The cabin pressure of 8.5 pounds per square inch (psi) gives a cabin atmosphere equal to flight at about 14,000 feet. With an empty weight of 1,500 pounds, and a wing area of 262 square feet, the 84-foot span machine is amazingly light for the structural strength required for stratospheric flight.
With more wing area than a conventional sailplane, it would stay aloft, but never compete with such craft at lower altitudes. But in the thin air at 90,000 feet, with 98 percent of the earth’s atmosphere beneath it, it will be unrivalled. Because it carries two into a very hazardous realm, it is equipped with specialized equipment, including dual-redundant oxygen rebreathers, a drogue parachute to allow rapid descent in the unlikely emergency, and a ballistic chute for a lower-altitude emergency descent.
The aircraft first flew on 23 September 2015 at Redmond Municipal Airport, Oregon and started with flights in the U.S. Sierra Nevada mountain wave.
The record setting and research flights started in southern Argentina in 2016, by Einar Envoldson or Perrenod using rebreather oxygen systems. The aircraft was displayed at AirVenture in July 2015.
The first version of the Perlan reached 50,727 feet in 2006 with The Perlan Project’s founder Einar Enevoldson and lead project sponsor Steve Fossett at the controls setting a record.
The Airbus Perlan 2 reached new heights, flown by Jim Payne and Morgan Sandercock, breaking the world record for a glider flight as it soared to 52,172 feet on September 3 2017. An Aero Boero AB-180 tow plane pulled chief pilot Jim Payne and co-pilot Morgan Sandercock off the ground at Comandante Armando Tola International Airport, which sits at an elevation of 669 feet in El Calafate, Argentina.
The area around El Calafate is one of only a few places on Earth where mountain waves combine with a high altitude polar vortex; conditions critical to providing enough lift to bring a glider into the stratosphere.
Analyses by ground crews, which use data from weather balloons and meteorologists, did not indicate favorable conditions for a record flight. However, the pilots felt otherwise. They were right.
The glider was released at 10,500 feet and mountain waves carried the Perlan 2 to approximately 40,000 feet. There is generally a segment of altitude between the lifting layers where the glider can’t continue to gain altitude. An overlap is critical for bringing the glider into the stratosphere. And while the polar vortex did not quite overlap with the mountain waves, the glider was close enough that the pilots could redirect it to an area where they could continue to gain altitude.
The pilots said the climb rate was about 300 feet on average and the record flight lasted about 6.6 hours.
On 2 September 2018, Jim Payne and Tim Gardner reached an altitude of 76,124 ft (23,203 m), surpassing the 73,737 ft (22,475 m) attained by Jerry Hoyt on April 17, 1989 in a Lockheed U-2: the highest subsonic flight.
Perlan II
Wingspan: 83.83 ft (25.55 m)
Wing area: 263 sq ft (24.4 m2)
Aspect ratio: 27:1
Length: 33.33 ft (10.16 m)
Height: 7.25 ft (2.21 m)
Gross weight: 1,800 lb (816 kg)
Never exceed speed: 377 kn (434 mph, 698 km/h) true airspeed, 56kts indicated
Service ceiling: 90,000 ft (27,000 m)
g limits: +6/-4
Crew: two
All Aero 