[Rick Masters]

To soar a glider to 90,000 feet without an engine – not possible! Yes, it is possible. Steve Fossett and Einar Enevoldson soared the Perlan 1 glider to 50,722 feet on August 30, 2006 using “stratospheric mountain waves.” Mountain waves form when winds of at least 15 knots cross over a mountain range perpendicularly and the atmosphere is “stable” waves will form on the lee side of the mountains. A glider uses the upward moving part of this wave system to climb.

Glider backers report successful test in quest for stratosphere
http://www.reuters.com/article/2015/09/24/usa-space-glider-idUSL1N11U39N20150924

Perlan Project Home
http://www.perlanproject.org/

What sets the Perlan Mission apart from just gliding on mountain waves is that we require one critical additional element to enable us to soar into the stratosphere: The Polar Vortex. The maximum altitude of mountain is usually at the boundary between the troposphere and the stratosphere. This is because the cold air of the mountain wave encounters warmer air at the boundary and cannot rise further. Winds in the Polar Vortex can reach speeds of 260+ knots allowing the mountain waves to propagate upwards into the stratosphere. These are called “stratospheric mountain waves.” The Perlan 2 will use these waves to soar to the edge of space.

[Frank Colver]

In the hills behind Laguna Beach CA we have, over many years, soared R/C gliders in waves on the lee side of hills that are only a couple of hundred feet high. The waves form in the late afternoon when the stable marine air has moved inland on a strong sea breeze. The wave is entered by ridge soaring a hill facing the wind flowing over the ridge in front. Once sufficient altitude has been reached by ridge lift then we fly straight out to pick up the wave behind the front ridge. One time I flew straight back from the front wave and the glider charted three distinct waves until I needed to return because it was getting too far downwind. I'm sure the waves continued for a distance beyond where I turned around. I could see by my glider's peak altitude that each successive wave was lower amplitude than the one before.

Generally we only soared the first wave (upwind of our ridge soaring hill).

This has demonstrated many times that waves can form from small rises in terrain under the right conditions. I'm sure a hang glider could have sustained in the waves our R/C gliders were soaring on.

Frank

[Rick Masters]

In the fall of 1979, I launched, very dangerously, flying a single surface hang glider, a Spectra Zodiac designed by Carlos Miralles, off the White Mountains into a substantial Sierra wave set up over Owens Valley. I could not come down and it was very cold up there. I did endless spiral sideslips past sunset to stay alive, struggling to stay below 12,000 feet in the powerful lift. Then, finally, I landed in the dark, under the stars, at Don Partridge's ranch near Chalfant, saved from flying into the ground only when my driver, Tim, flicked on the headlights of my old International Scout.