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This is an awesome idea. I remember reading about kite-based propulsion systems for large ships a few years ago, do you see any overlap with that area? How do

by J-dawg 10y ago

This is an awesome idea. I remember reading about kite-based propulsion systems for large ships a few years ago, do you see any overlap with that area? How do you deal with the possibility of the kite breaking free of the tether, or breaking up in the air? I guess it could be quite dangerous if there's a populated area downwind.

Grustaf 10y ago
There is definitely some overlap with SkySails (as that project was called), particularly in the control software part. But as far as kite power goes the principles are quite different. They use the pull (or "lift") of the kite to directly help propel the ship, while we have generators installed on the kite and harvest energy that way. This is called "drag mode" kite energy, vs "lift mode" where you let the kite pull on the tether and let it reel out and thereby generate power (or pull a ship). We haven't looked into it but I have a feeling it would be more efficient to use drag mode even on a ship and generate electricity that would be fed into a hybrid engine system. The scenario you mention is not really a major concern, for several reasons: First of all the tether is of course designed to withstand all reasonable situations, with a wide margin of safety. Secondly, the way the kite normally lands and launches itself as the wind drops and returns is by flying as a drone using the rotors-generators (see the website), so as long as the kite isn't completely broken it would just return to earth in a controlled manner. Furthermore, in a worst case scenario, an untethered kite is actually much _less_ dangerous as it can't travel faster than the wind, whereas while tethered it can go 10 times faster or more. (As a kite surfer the first thing you learn is that if something goes wrong you should release the kite.) While in use the kite will be some 200 m up, but several kilometres from land, so it will not be able to get very far in the time it takes to fall to earth.

by J-dawg 10y ago

Grustaf 10y ago

There is definitely some overlap with SkySails (as that project was called), particularly in the control software part. But as far as kite power goes the principles are quite different. They use the pull (or "lift") of the kite to directly help propel the ship, while we have generators installed on the kite and harvest energy that way. This is called "drag mode" kite energy, vs "lift mode" where you let the kite pull on the tether and let it reel out and thereby generate power (or pull a ship). We haven't looked into it but I have a feeling it would be more efficient to use drag mode even on a ship and generate electricity that would be fed into a hybrid engine system. The scenario you mention is not really a major concern, for several reasons: First of all the tether is of course designed to withstand all reasonable situations, with a wide margin of safety. Secondly, the way the kite normally lands and launches itself as the wind drops and returns is by flying as a drone using the rotors-generators (see the website), so as long as the kite isn't completely broken it would just return to earth in a controlled manner. Furthermore, in a worst case scenario, an untethered kite is actually much _less_ dangerous as it can't travel faster than the wind, whereas while tethered it can go 10 times faster or more. (As a kite surfer the first thing you learn is that if something goes wrong you should release the kite.) While in use the kite will be some 200 m up, but several kilometres from land, so it will not be able to get very far in the time it takes to fall to earth.