Half a croissant, on a plate, with a sign in front of it saying '50c'
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Inter-city gliders

Improved method of public transport
  (+13, -1)(+13, -1)
(+13, -1)
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Each city should have a glider launching station at about 40,000 ft up, supported by tethered balloons. Gliders are hauled up to the launching station by electric winches, and passengers go up to the station either already inside the gliders, or in special lifts – also raised by electric winches. The gliders are launched by catapult, and then glide down to a landing strip at the foot of the tethers for the launching station at the next city.

A well-designed glider could easily fly 320 miles (very likely a lot further) from that initial 8 mile high launching station, with an average speed of around 80 mph. If the cities are too far apart, then you need an intermediate station. To cross the Atlantic, you need floating islands (tethered to the sea bed) at intervals all the way across.

The huge advantage over conventional planes is fuel saving. This system really would use much less fuel, for several reasons: (1) It flies slower. (2) It doesn't have to carry its fuel. (3) Jets (and for that matter propellers) are inherently inefficient, because they're always pushing against something that "gives" rather a lot (as compared with rails or roads, that scarcely move backwards at all when you push against them). (4) The aerodynamic lines of a glider can be much cleaner than an aeroplane.

There's even a couple of advantages over rail: (1) No need for tracks all the way from A to B. (2) Energy losses to air resistance are less, because a large part of the time you're flying through much thinner air. Speeds are similar to rail.

Small places couldn't have big enough launch stations to be able to lauch with catapults. They could launch gliders from small launch stations simply by lowering the nose of the glider and dropping it into a nose dive. Once the speed is high enough, the pilot pulls out of the dive and proceeds. The early stages of such a flight might be rather vomit inducing. A bit like some of the wilder roller coaster rides!

(The launch stations would make superb communications platforms – with enough of them, comms satellites would be pretty much obsolete.)

Cosh i Pi, Apr 13 2007

Glider transport system Glider_20transport_20system
[xaviergisz, Apr 13 2007]


       Indeed. I'm not proposing a tower - just some tethered balloons.   

       You can't actually hang a cable 40,000 ft - it'd snap under its own weight (so much for space elevator cables at 22,000 miles long) - but you could support the cables with intermediate balloons. Balloons at 40,000 ft up are horribly big if they've got much weight to support, but hey, this is the half-bakery.   

       Actually slightly under 25 times, incidentally... 8~)
Cosh i Pi, Apr 13 2007

       I like it. May I suggest?: Use the hoists to do a vertical launch of the gliders--that gives a bit more height, speed, and a reason to make the hoisting as quick as possible.   

       Oh, and a belated welcome to you, [CiPi].
baconbrain, Apr 13 2007

       I second that. Welcome [Cosh]. Please inform me when tickets become available.
wagster, Apr 13 2007

       Either you mean jetstream winds or your balloons are in the wrong place. And wet.
wagster, Apr 14 2007

       He's also got an interesting confusion about the direction of rotation of the Earth. If you were actually waiting for the Earth to rotate under you, you'd be travelling West, not East. But not to worry, it doesn't affect the point of the post.
Cosh i Pi, Apr 14 2007

       [Lt. Frank] 8~) If it was a matter of waiting for the Earth to rotate under you, you would indeed only be able to travel West. However, in most places on Earth, you'd actually travel East, because that's the way the winds blow (more often than not). This is due to convection in the atmosphere, coupled with the fact that the equator moves eastwards faster than the rest of the world because it's at a greater distance from the axis (there are other more precise ways of describing the situation, but they all boil down to the same thing).
Cosh i Pi, Apr 15 2007

       [humanzee] I like that idea - not one I'd thought of. I was thinking of a shortish runway with an electric winch, probably a pair of them pointing in opposite directions so you can always launch two gliders at once to avoid unbalanced forces on what needs to be the lightest possible airport ever.   

       You could have a matched pair of your tugs, too.
Cosh i Pi, Apr 15 2007

       I think it may be a candidate for the dreaded [marked-for-deletion] (redundant) - see xaviergisz's earlier notion ( sorry [Cosh i Pi] )
xenzag, Apr 15 2007

       I don't think that's fair. Granted [xaviergisz] had half the idea already, but unless we're going to add the tethered balloon gliderport idea to his thread, we'd be losing half this one if it gets deleted.   

       Perhaps I should rename it "Tethered Balloon Gliderport" and mention the link to [xaviergisz]'s idea in the description?
Cosh i Pi, Apr 15 2007

       // I think it may be a candidate for the dreaded [marked-for-deletion] (redundant) - see xaviergisz's earlier notion ( sorry [Cosh i Pi] ) //   

       I think the two ideas are about as similar as "bicycle glass broom" is to "Huge rolling wheel". By that standard, any category should only contain one idea. Or else, mark it baked, with the one-tier link in the Air-launched SSTs idea. Ayayay.
TheLightsAreOnBut, Apr 17 2007

       [admin: Fair enough. Let's keep it around for now.]
jutta, Jun 09 2007

       I like it! The perfect half-baked idea. If I was a billionaire I would fund this idea, and there would be champagne and gliders for all. Unfortunately, I'm only a thousandaire which is not enough.. Anyway have a bun..
DrWotsit, Jun 09 2007


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