It is true, the exospheric helicopter has many of the same issues as the Aerovator, and is probably less rather than more viable, despite its smaller scale. Mostly, this is because the power requirement does not scale down much with size.

It is not true that subsonic lift is used by the Aerovator, lift is distributed over the entire structure at all speeds, mostly hypersonic. The propulsion is subsonic, though, via standard jet airplane engines. I have convinced myself, but not a lot of other people, that the Aerovator is actually more practical than the SE, due to a few key points: It is completely Earth based, is smaller, launches faster, has higher throughput, and can be made with near current materials (~6-10 GPa).

There once was a page on the Aerovator on Wikipedia. It was rightly removed because of the "no original research" policy. The Aerovator is now slowly fading from the Web, being replaced by a lawn care device of the same name. Here is what seems to be the last Wikipedia leech site that still has it online, unfortunately minus the pictures:

http://www.cassiopedia.org/wiki/index.php?title=Aerovator.

Get it while it lasts ... :-)

I have saved the source, perhaps one day I will upload onto a more suitable place.

Andreas

I got the lift concepts wrong for Aerovator. At any rate I agree that the Aerovator is more doable that a SE. Once a SE is in place it might be a better solution for GEO orbit where the Aerovator may be a better solution for other orbits.

I good place to put the Aerovator article is http://www.socialtext.net/wikinomics/index.cgi?elevator_to_space or at least a link to the  socialtext page

Bert

Another concept along the same lines, using the idea of a motor to drive the tether http://www.spaceelevator.com/docs/iac-2004/iac-04-iaa.3.8.2.10.mckenzie.pdf

Interesting. If I read it correctly, though, they attach the payload to a resting tether and then spin it up, let go, and then spin it down. This is a huge waste of time and energy, because the tethers are much more massive than the payload. For a sling to work efficiently, it must be kept rotating continuously, and the payload let slide from the hub. Once the sling is initially spun up, the motor is then needed exclusively to replenish energy that was given to the payload, no more. What's better, a payload can be launched every few minutes, provided the motor power allows for it.

The sling works best when attached to something large, like an asteroid or a moon. If it is free flying, its orbit will be changed with each payload, and either propulsion or some very sophisticated juggling of payloads are needed to keep it from drifting away. In addition, a free flying sling also needs to be backed by a second, counterrotating sling to give the motor something to work against. I guess that's where the rocket drive comes in, but I am not yet convinced that a rocket powered sling will actually require less fuel then just a rocket.

Andreas

That link is dead but this one still works.  For now at least.