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Transportation Space Build Technology

Perlan II Project Aims To Fly a Glider To the Edge of Space 44

Posted by Soulskill
from the bring-a-jacket,-it'll-be-chilly dept.
Zothecula writes: In an ambitious attempt to break every wing-borne sustained flight height record for a manned aircraft, the Perlan ll project intends to construct and fly a glider higher than any sailplane has gone before. Riding on the colossal stratospheric air waves generated over mountains, the team plans to fly their craft to more than 90,000 ft (27,000 m), which will shatter their own existing glider altitude record of 50,671 ft (15,400 m) set by Perlan l in 2008.
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Perlan II Project Aims To Fly a Glider To the Edge of Space

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  • 100km (Score:5, Insightful)

    by Anonymous Coward on Saturday August 02, 2014 @05:05PM (#47590395)

    At 27km up, you're closer to ground than to the edge of space. Stop sensationalizing.

    • Re:100km (Score:4, Insightful)

      by dreamchaser (49529) on Saturday August 02, 2014 @05:19PM (#47590453) Homepage Journal

      That was my first thought as well. Don't get me wrong, it will be an impressive feat, but it's nowhere near 'the edge of space'. I haven't done the math or looked it up but one would probably see the curvature of the Earth more noticeably than at sea level, but still, the title of this entry is complete sensationalism.

      • I'll give them this one, considering one of the purposes of this project is to prove the feasability of extraterrrestrial flight in atmospheres as thin as that of Mars.

      • If you do actually Google "where does space start" you'll get a popular definition of 100km, so yes, quite a bit short.

        I'm also not sure yet about the claim that they had the previous record. If you visit [] you'll see that in 2006 the late great Steve Fossett has a claim to a little higher than the Perlan claim. The Perlan claim doesn't even show up on the site.

    • I agree.
      These are exercises in Semantics and Sophistry rather than Spaceflight or Physis.

      Lunatics --I choose that word with purpose-- without any sense of proportion have taken over 'Space'.
      They prob. even think the moon is one small glide further out.

    • by Anonymous Coward

      Isn't something like 90+% of the atmosphere below you at that altitude? Only 10% more to go to reach vacuum. That seems to be the edge.

      • Re: 100km (Score:5, Informative)

        by calidoscope (312571) on Saturday August 02, 2014 @08:43PM (#47591221)

        Something on the order of 97% of the atmosphere's mass is below 90,000'. 100km is an arbitrary value for the start of space, as the air at 100km is too thick to orbit and too thin to fly in (except dynamic soaring?). In imperial units, 100,000' seems to be the upper limit for flying and 100 miles is about the lower limit for orbiting.

        The Perlan II sounds like it will handle like an unpowered U2 - where the planes ceiling will be defined by the "coffin corner" were the low speed stall (classic stall) approaches the high speed stall (Mach tuck from transonic airflow). Perhaps they will be using a more refined airfoil than the U2 to increase the Mach number for high speed stall.

        IIRC, the pre-Perlan I sailplane altitude record of approx 47,000 feet was set sometime in the 1960's, surprising it took that long for someone to break that.

        • by iggymanz (596061)

          The "lower limit" is lower than that, the Zenit sattelites had a perigree of 135km, or 84 miles.

      • Re: (Score:1, Interesting)

        by Anonymous Coward

        Isn't something like 90+% of the atmosphere below you at that altitude? Only 10% more to go to reach vacuum. That seems to be the edge.

        When you stand at sea level, 99.99999% of the earth's mass is below you. So we are all at the edge of space.

    • by w0mprat (1317953)

      At 27km up, you're closer to ground than to the edge of space. Stop sensationalizing.

      At 27km up your above 98% of the atmosphere if you go by density. It's not sensationalizing at all.

      • Re:100km (Score:4, Informative)

        by jklovanc (1603149) on Sunday August 03, 2014 @01:38AM (#47592103)

        The Kármán line [], or Karman line, lies at an altitude of 100 kilometres (62 mi) above the Earth's sea level, and commonly represents the boundary between the Earth's atmosphere and outer space. This definition is accepted by the Fédération Aéronautique Internationale (FAI), which is an international standard setting and record-keeping body for aeronautics and astronautics. By saing "edge of space" and then "90,000ft" (27.4km) they are making a mockery of the "Edge of space". When has 27.4% towards a goal ever been "close" to a goal? They further exagerate using this [] artist's rendering. The curvature of the earth would be much less. Here is an actual photo taken at 90,000ft.

        In the end 27.4kM is not close to 100km and therefore not close to the edge of space. Sorry but you can't re-define something that has been internationally agreed upon to make your aircraft look better.

  • Err , how exactly do they plan on getting to those speeds? Sure , you could get to those speeds in a dive but to do a dive you've got to get up that high in the first place which requires already going at those speeds. Catch 22. And the air currents sure as hell won't be strong enough to do it so unless they plan on having an SR-71 tow them up there I don't see this happening.

    • by drerwk (695572)
      The lift produced by a wing is partly a function of the rate of air mass that passes over the wing. Keeping density constant an increase in velocity will increase lift. If the density of the air decreases, as it does with altitude, then one must increase velocity to get the same air mass to pass over the wing and generate the same lift. At the altitude they will be flying, they may well have to fly near the speed of sound to get enough air over the wing to provide sufficient lift. The higher they go, the hi

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