Plane & Pilot
Tuesday, February 25, 2014

The Perlan Project


A former test pilot and a group of engineers are hoping to take a pressurized glider to FL900


With no form of motive power on the nose or wings, you might expect gliders to have limited altitude capability, but I quickly learned that's not the case. Finding a good thermal can be a problem, and staying in it presents an additional challenge, but on rare occasions, you can sometimes spiral up to 10,000 feet or more.

Some people dream of even higher altitudes without an engine, piston, jet, rocket or rubber band. Einar Enevoldson, an experienced USAF test pilot with time in practically everything up thru the SR-71 Blackbird, launched the Perlan Project in the early 2000s. He joined forces with meteorologist Dr. Elizabeth Austin in analyzing the possibility of flying a mountain wave to 90,000 feet, then enlisted support from publishing magnate Steve Fossett, who agreed to fund the project.

After several years of trying, the two explorers took a tow to 10,000 feet above the Patagonian Desert of Southern Argentina, cut loose and ascended toward the high sky. Fossett and Enevoldson finally set the ultimate glider altitude record of 50,671 feet in 2006 above the Andes Mountains, eclipsing the old record of 49,007 feet set over Mt. Whitney, Calif., in 1986.

Fossett and Enevoldson were wearing full pressure suits loaned to them by NASA, and the suits protected them from the low atmospheric pressure and the -80 degree F cold. The only reason they aborted their flight was that the suits had expanded so dramatically in the thin air 10 miles above sea level, the two pilots could barely reach the controls.

Now, Enevoldson hopes to continue the quest for extreme altitude with an all-new glider, the Perlan Project II, a 1,700-pound aircraft with an 84-foot-span wing. The Perlan I sailplane was a modified, DG505M, European glider, but problems with the first flight proved the team needed a fully pressurized, purpose-built aircraft designed specifically for high-altitude flight.

Accordingly, the new glider will offer a carbon-fiber cabin inflated to 8.5 psi. There's essentially no atmosphere at 90,000 feet, so an 8.5 psi pressure system will provide an Earth cabin altitude of about 14,000 feet MSL, easily survivable without supplemental O2. Perhaps more than coincidentally, a 90,000-foot altitude above Earth is roughly the equivalent of Mars atmosphere at average ground level. (There's no sea level on Mars.)

Enevoldson believes flight in the high stratosphere is possible, though that view isn't shared by everyone. In fact, some meteorologists refer to that high region irreverently as the "ignorosphere," because it has been mostly ignored by researchers. No current airplane can sustain flight at this altitude, because the air is too thin to support anything more than short duration pop-up flights by research aircraft.



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