9
$\begingroup$

My questions are related to a scenario discussed on Earth Science: A huge (heavier-than-air) kite sailing in and out of the jet streams.

The kite:

Kite Image

The scenario:

Cross section of atmosphere showing cells and jet streams

Illustration of kite in jet stream pulling an object trailing below

enter image description here https://earth.nullschool.net/#current/wind/isobaric/500hPa/orthographic=-49.74,279.00,346/loc=-56.357,-47.418

You can track the Jet stream for this purpose with a satellite link.

The assumptions:

  • Such an airship exists and there is a person aboard, with an oxygen mask.
  • The person is thermally insulated to keep the heat inside.
  • The jet streams are at an altitude around 9–12 km (30,000–39,000 ft) .

The Questions:

  • Can a kite like the one in the picture be built to hold a person? https://aviation.stackexchange.com/a/24426/20435
  • Does the human body require pressurization as well as oxygen and insulation? https://biology.stackexchange.com/a/42441/20863
  • Is it possible using the jet stream systems to go around the world?
  • Can the kite fly at speeds around 80-150 km/h related to the ground?
  • Can it sustain a free fall from its cruising altitude around 9–12 km so that the pilot can land maybe using a parachute?

Possible Solutions:

Launch Considering the altitude is up around 9–12 km then air would be thinner the size of it will have to be much larger to compensate. Use a cable and boat to lift the UltraKite into the Jet Stream. At preferred altitude cable then can be mechanically released from connected drag section of the kite. A drone or balloons could replace boat and then dropped. Maybe the person could ride in the drag section.

Long Term Altitude with Ultralights Gliders on Record.

The current 15460-meter glider height record was made with pressurized suits. But it is only 500 meters higher than Harris' previous record from 1986, which was done with just an oxygen mask. – Martin Argerami in a comment in Turbulent Jet Streams on Ultralights

As commented by @Jan Hudec: This is supposed to be a kite, but instead of being fixed to the ground as normal kite, it would have just a cabin with a braking parachute flying below the jet stream and the kite flying in the jet stream, so the whole thing would move at some speed between the slow speed of the wind at low altitude and the high speed of the jet stream.

Layers of the atmosphere with object in stratosphere

$\endgroup$
  • 3
    $\begingroup$ I'm confused. An airship is a lighter than air craft, so it could theoretically stay aloft indefinitely. en.wikipedia.org/wiki/Airship I don't see the difference between an airship and a blimp. In answer to your question, I think a huge issue is the time it would take and the level of human endurance. The round the world balloon flight lasted a few hours under 20 days en.wikipedia.org/wiki/Breitling_Orbiter The capsule was comfortable, but they had to consume a special diet to avoid needing the bathroom too much. $\endgroup$ – Level River St Jan 18 '16 at 10:37
  • 2
    $\begingroup$ @steveverrill, no, this is supposed to be a kite, but instead of being fixed to the ground as normal kite, it would have just a cabin with a braking parachute flying below the jet stream and the kite flying in the jet stream, so the whole thing would move at some speed between the slow speed of the wind at low altitude and the high speed of the jet stream. $\endgroup$ – Jan Hudec Jan 18 '16 at 15:03
  • 2
    $\begingroup$ @JanHudec I see. So you have opposing drag from your upper kite and lower parachute. The lower parachute will have to generate some (if not most of the) lift in order to prevent the line from sagging to vertical. I think you need more of a lower kite and upper parachute, actually, with the load suspended below and between them. In any case, I would avoid the word airship as in British English at least, it most definitely implies a lighter-than-air craft. $\endgroup$ – Level River St Jan 18 '16 at 15:39
  • 1
    $\begingroup$ @steveverrill, I agree that calling it airship is wrong. Otherwise the description was correct though. The upper part must generate lift (= kite), otherwise it wouldn't remain upper and the drag (it is a braking parachute, it produces horizontal force) produced by the lower part is enough to keep the line diagonal. $\endgroup$ – Jan Hudec Jan 18 '16 at 16:07
  • 1
    $\begingroup$ American or European football field? $\endgroup$ – SMS von der Tann Feb 22 '16 at 21:06
4
$\begingroup$

It's certainly possible to build a kite that could lift a person. Unless the person trails well below the kite, they will need some protection from the environment. Air gets colder at high altitudes, and the lower air pressure makes it harder for the body to get enough oxygen. Some type of suit or cabin could provide basic protection, and there would need to be some way to provide some combination of pressurization and supplemental oxygen. Higher pressure like that on airliners would require a heavier capsule, but occupants would not need to wear an oxygen mask as they would with lower pressures. As Andrius noted, at higher altitudes, even pure oxygen would not be enough and some pressurization is required.

While it's possible to ride the jet stream around the world, it would take some luck. The jet stream changes location over time and is not always continuous. The speed is also variable and may not always be more than 150 km/h. The kite will fly at some speed slower than the jet stream in order to continue providing lift.

For returning to earth, there are multiple options. A parachute system could be fairly light and compact, but would not allow as much control over the landing location. However, some type of gliding may also be an option. The kite will need some way to be steered in the air, and towing a glider would allow control, efficient lift, and protection for the occupants.

$\endgroup$
  • 1
    $\begingroup$ A Google executive made a parachute jump from 135,000 feet in a pressurized suit. Just for reference that would be FL1350! I guess he just couldn't let Felix Baumgartner have all the fun from a measly 128,100 feet. $\endgroup$ – TomMcW Jan 18 '16 at 19:25
  • 2
    $\begingroup$ "Use a cable and boat to lift the UltraKite into the Jet Stream": I think the weight of the cable would be huge, in the range of a ton maybe, a large area would be in the wind. The boat would need to be a large and fast one. $\endgroup$ – mins Jan 21 '16 at 7:00
  • $\begingroup$ Five people long enough to fly around the World? That means pressurized capsule, IMHO. A capsule might also be able to use dynamic soaring to do the trip without relying on the fast speeds of jet streams. $\endgroup$ – Ville Niemi Jul 6 '16 at 8:07
2
+100
$\begingroup$

If you asking about oxygen? Pressure of the oxygen has to be not below certain value even if you breath 100% mixture. After training it's possible to breath pressurized oxygen at high altitudes, bet at very high altitudes pressure suit is required anyways.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy