Please login or register.

KRCM

Author Topic: Perlan 2 Stratospheric Glider - Upcoming Altitude Record Attempt  (Read 100 times)

0 Members and 1 Guest are viewing this topic.

Offline Deerslayer

  • Administrator
  • *****
  • Posts: 696
  • Fly hard, Learn stuff, Have fun!
    • View Profile
 I have been following this development for quite awhile.The Perlan project home is at http://www.perlanproject.org/

 Back in my soaring days, I longed to do wave soaring. Once, at Sugarbush VT, I was able to ride the wave, but not to a very high altitude. It was pretty exciting, nevertheless. The tow was quite demanding and violent, as we climbed through the rotor (that is where many aircraft have been taken down in mountainous regions when a wave is working and they encountered the rotor). I was a very inexperienced pilot, only a handful of flights past solo and it was a bit sweaty!

 Then, as we entered the wave, I released from the towplane and everything got quiet and smooth; he dove back down through the mess to pick up the next flight. No sensation of climbing, apart from the variometer showing about 2000 ft/min, as I flew pointed upwind. The winds aloft were in the 50 mph neighbourhood, so you could set up at that sort of airspeed and have 0 groundspeed. You just sit there and ride the wave, watching the vario and keeping track of where your landing area is.

  My flight was cut shot when cloud started to develop below me and I had to find a hole to let down through. Altogether, a flight that I remember in great detail some 45 years later. In those days, Paul Bickle held the world altitude record of 46,000 ft., in the mountain wave at Bishop CA. That record stood of decades.

 So much for all of that! Now, on to the real flying.

The following is an article from Aviation Week:


Airbus
The Perlan 2 stratospheric glider has arrived in Argentina as the Airbus Perlan Mission II team bids to set a new altitude record for sailplanes.
The pressurized Perlan 2 is designed to reach 90,000 ft., but chief pilot Jim Payne is hoping to reach 60,000-65,000 ft. this year, enough to beat the record of 50,727 ft. set by Perlan 1 in 2006.

Perlan 2 arrived by ship in Mendoza, Argentina, and on July 2 will begin the 2,600-km (1,600-mi.) road trip to El Calafate in Patagonia. From there the glider will be launched to ride standing mountain waves—air currents formed by the Andes—to successively higher altitudes.

The two-seat aircraft is designed to use mountain waves that reach into the stratosphere to achieve wing-supported flight at higher altitude than any previous aircraft, unpowered or powered. This becomes possible when mountain waves interact with the polar vortex.

Perlan 2 made its first flights from El Calafate in 2016, but was late arriving in Argentina and missed most of the winter season—one in which the polar night jet was weaker than usual. Since returning to the U.S., the aircraft has exceeded 30,000 ft. in flights from Minden, Nevada.

As the glider is expanding its flight envelope as it flies, altitude will be increased in increments of 5,000 ft. At each new altitude, a flutter test will be conducted using exciters built into the wing. If the results match the aeroelastic modeling, Perlan 2 can proceed to the next altitude.

Payne dose not expect to reach 90,000 ft. during this season. “The conditions are only right for a few days a year, and some years not at all,” he says. Ahead of this year’s flying campaign, wind speeds have been increasing in the stratosphere—a promising sign, he says.

Mountain waves would normally not extend above the tropopause, but in winter near the poles they can join with the polar night jet so that wind speeds keep increasing through the tropopause and into the stratosphere. As long as wind speed is increasing, Perlan 2 can keep climbing, Payne says.

Perlan 2 is similar in design to an Open Class competition sailplane, but with a larger wing area and an airfoil optimized for high altitude. It is unique in being pressurized. Perlan 1 was not, but it was hard for pilots to control the glider once their pressure suits had inflated and stiffened.

Pressurization required careful design to prevent leaks, but has been successful, Payne says. Nonetheless, a 115 ft³ scuba tank is carried to replace any air that does escape. Air and battery supplies are sized for an 8-hr. mission. The nominal mission is a 1-hr. tow to the waves, 3-hr. climb and 1-hr. descent.

Perlan 2 has been modified and upgraded since the 2016 flights from El Calafate. This includes adding heating for some systems because of the very low temperatures at altitude. Also the glider can now be flown unpressurized at lower altitudes to prevent the buildup of condensation early in the flight.

The glider is flown at its minimum sink-rate speed of 40 kt indicated airspeed (IAS) and climb/descent rates as high a 2,500 ft./min. have been seen in mountain waves. The allowable speed range at high altitude is 38-54 kt IAS—the latter equating to Mach 0.62 at 90,000 ft. because of the low air density.

In case the crew needs to descend rapidly in an emergency there is a drogue chute in the tail that will bring the glider down at 80 kt IAS. There is also a ballistic recovery parachute to bring the fuselage and crew down safely if the wings break off. This is safer that trying to bail out, Payne says.

Airbus is sponsoring the Perlan 2 mission and providing engineering expertise. One reason is the opportunity to explore the upper atmosphere. “With time, aircraft will have to fly higher” as air traffic grows, says Ken McKenzie, senior vice president of strategy and development of Airbus in the U.S.
My purpose in Life is to serve as a Warning to others

Offline Deerslayer

  • Administrator
  • *****
  • Posts: 696
  • Fly hard, Learn stuff, Have fun!
    • View Profile
Perlan 2 Stratospheric Glider - New Altitude Record
« Reply #1 on: September 07, 2017, 07:03:04 AM »

Airbus Group
El Calafate, Argentina--The Perlan 2 stratospheric glider flew to 52,172 feet over the Andes mountains on September 3, establishing a new world altitude record for sailplanes and marking a key step on the way towards an eventual target of 90,000 ft.

The 82-ft span pressurized aircraft was lifted to high altitude by stratospheric mountain waves which developed over South America in early September. The favorable weather pattern occurred just days before the Airbus Perlan Mission II project team was due to complete its 2017 southern winter test campaign and return to its base in Minden, Nevada.  It was the longest Perlan 2 flight at 6.6 hours and was piloted by chief pilot Jim Payne and co-pilot Morgan Sandercock.

The flight was an important step towards using the Andean waves to reach even higher altitudes where Airbus Perlan hopes to intersect with a seasonal polar Jetstream wind that circles the South Pole at speeds up to 260 kt.  Using this mechanism the team hope to achieve sustained flight at altitudes where the Perlan could support investigations into phenomenon ranging from climate change and radiation impacts on crew to control concepts for future exploration vehicles operating in low-density altitudes like that of Mars.


Airbus Group
The flight, which beat the previous 50,727-foot glider record set in the unpressurized Perlan 1 by Perlan Project founder Einar Enevoldson and lead project sponsor Steve Fossett in 2006, was a welcome change in fortune for the program which had been frustrated in its efforts to reach higher altitudes by several weeks of unfavorable conditions. The aircraft has been based at El Calafate, in southern Patagonia, since July waiting for suitable high-level mountain waves to form which propagate into the stratosphere.

The record mission also goes a good way towards achieving the target for this year’s campaign which was to expand the flight envelope towards an interim altitude target of 60,000-65,000 ft. 
My purpose in Life is to serve as a Warning to others