Author Topic: Would it make sense to have a base near each polar ice cap and swap between them  (Read 8040 times)

Offline colbourne

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The more I read on this thread the more I'm convinced that the whole idea is a total non-starter. Perhaps review it in a hundred years.
Ground effect only works on a very flat surface, hence it was designed for the ocean. There is nothing flat on Mars.

Pedantry: Ground effect works near the ground, hence the name. It even works on slopes. It's more effective the closer to the ground you get, which is why flat ground (ice/water/dedicated-tracks) is the only viable option for practical GE vehicles. However, in theory, if it works at all under Mars conditions, a well mapped and marked route should be possible.

There have been lots of ground effect craft anf they are normally able to clear quite large objects
Ground effect only works on a very flat surface, hence it was designed for the ocean. There is nothing flat on Mars.

Pedantry: Ground effect works near the ground, hence the name. It even works on slopes. It's more effective the closer to the ground you get, which is why flat ground (ice/water/dedicated-tracks) is the only viable option for practical GE vehicles. However, in theory, if it works at all under Mars conditions, a well mapped and marked route should be possible.


That is nonsense.
 It was called ground effect because it is on the ground. It still needs to be a smooth surface. Try it with a piece of paper on a table then put a 2mm high obstacle in the way, it will come to a sudden crashing halt. It didn't really work on the sea very well either (due to waves). Hence it never went into production and no one else has made one.
If you have a marked smooth route then that is called a road. Just use wheels.
That is nonsense.
 It was called ground effect because it is on the ground. It still needs to be a smooth surface. Try it with a piece of paper on a table then put a 2mm high obstacle in the way, it will come to a sudden crashing halt. It didn't really work on the sea very well either (due to waves). Hence it never went into production and no one else has made one.
If you have a marked smooth route then that is called a road. Just use wheels.
There have been many ground effect craft built and most can clear quite large objects (up to 2m) when necessary. One of my favorite is a ground effect  assisted hovercraft such as this





« Last Edit: 09/07/2021 04:18 am by colbourne »

Offline daedalus1

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None of those in the videos are ground effect machines clearing 'two metres'. The first video is clearly an aircraft with wings.
The poor video of one ground effect machine in the second video is clearly just skimming the water.

Offline hkultala

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But the issue is how do you fuel it? Jets have high Isp because they aren't carrying their oxidiser. No such free lunch on Mars.

Turbofans at subsonic speeds have high isp because they use much higher reaction mass.

Turbopump-powered rocketfan which carries it's oxygen would work on mars and could have much higher isp than rocket engine - but would not work well at supersonic speeds. And the atmosphere of Mars is so thin that the wings would have to be huge to stay on air at subsonic speeds.
« Last Edit: 09/07/2021 09:01 pm by hkultala »

Offline hkultala

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Ground effect only works on a very flat surface, hence it was designed for the ocean. There is nothing flat on Mars.

Pedantry: Ground effect works near the ground, hence the name. It even works on slopes. It's more effective the closer to the ground you get, which is why flat ground (ice/water/dedicated-tracks) is the only viable option for practical GE vehicles. However, in theory, if it works at all under Mars conditions, a well mapped and marked route should be possible.


That is nonsense.
 It was called ground effect because it is on the ground. It still needs to be a smooth surface. Try it with a piece of paper on a table then put a 2mm high obstacle in the way, it will come to a sudden crashing halt. It didn't really work on the sea very well either (due to waves). Hence it never went into production and no one else has made one.
If you have a marked smooth route then that is called a road. Just use wheels.

Many ground effect vehicles have been built, most in soviet union, but also some elsewhere.

Those did work, and those did work over ocean.

https://en.wikipedia.org/wiki/Caspian_Sea_Monster










And ground effect vehicles are not flying 2mm over the ground, they were typically flying something like 3-7 meters above the ground. When the craft is flying 3 meters above the ground, everything is ok as long as there is nothing over 3 meters high on the ground. Like trees or big stones that are over 3 meters high. And you can go higher than 3 meters, the ground effect just gets weaker the higher you are.

Typical altitude for the big caspian sea monster was about 20 feet, 6-7 meters. That's enough to go over 1-floor house.
« Last Edit: 09/07/2021 09:15 pm by hkultala »

Offline daedalus1

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I didn't say they were flying 2mm above ground, obviously that relates to the paper size example.
They were obviously so successful that they are in production now?

Offline colbourne

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I didn't say they were flying 2mm above ground, obviously that relates to the paper size example.
They were obviously so successful that they are in production now?
They are in production now

https://yle.fi/uutiset/osasto/news/winged_sea-skimming_gevs_planned_for_half-hour_helsinki-tallinn_trips/10652946

The advantage for Mars is that a ground effect vehicle is more efficient than a plane. On Earth the optimum height to fly is 5% of wing span. I dont know how this changes on Mars. A catapult could be used to get up to flying speed. Maybe using small rockets for landing, although if smooth the ice cap might make  a suitable runway.


I am looking forward to the first time a ground effect vehicle hits a tree on Mars :)

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