Launching soft kites

The discussion in here

brought me to a thought about launching soft kites.

You could use an unfolding/folding techniques like Kitesails does. In strong winds you could launch similar to kitesurfers orthogonal to the wind. For light winds you could go launch downwind parallel to the wind. And for even lighter wind you could additionally reel-in.

J

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to automate this you could fix the position of the winch and put folder/unfolder system on a rail with circular path to be able to adjust the angle.

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A rail sounds like quite a bit of infrastructure, which could also take up land from other uses… A portable launching crane may work instead at your launch site… Assuming you have a real need for your launch and ground site to be separate.

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Might be possible, but is even more compicated than skysails’ (I assume you meant them) system, which might have had some issues. (We don’t know for sure, but the original company did go under)
The kite was docked using a separate line just to get the valve in the right position, I think.
Maybe this would be the case here, too. The valve is at the back and there’s always a line going from there to the docking station.
If one has the packing station at a large enough distance I don’t think it’s neccessary to adjust the angle to the wind exactly. The winch can pull the kite up. Landing will probably be much more difficult.

The future is said to be rigid. Would make automation much easier. Just do it like zipline and let the kite hang there (or lower it into a container). To launch just tighten the winch line and release the hook. (The hook would have to be designed to allow for only two degrees of freedom, so that the plite doesn’t launch into the ground) Might even be possible for unpowered drones.

With a winch and some means to brake the kite on overpower I would think you should be able to launch in many windspeeds directly downwind. I think it would not be often you have to launch in really high winds, and very often you launch in the lowest flyable wind. You could perhaps get away with not being able to launch in the higher windspeeds altogether

For me the «dealbreaker» is most probably the amount of line that must be reeled out before launch. For the kite to be ensured into clean wind, the tether must have the altitude length plus whatever you reel in in the launching process.

The good thing is if you dont find said clean wind, you can just reel the kite safely back to the winch.

Assuming the propsed system with the winch and kite station separate, that’s impossible.

Yes and no. Though you would need a means to transport the kite back after an emergency landing, you might still save the equipment, so this might be an ok design choice.

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Rough Ilustrations


Landing

Capture

Landed

By having a distance (larger that pictured) between winch and drone capture point one can do a glider winch launch. No propulsion system on the kite neccessary at all.

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I was reminded of Drone assisted launching of a Lift Kite by an article on drone checklist planning.
In this case the drones are pulling lines to assist in cable pulling.

One of the largest U.S. electric and gas utilities recognizes cost and time savings to be just a few of the key benefits of using drones for tasks such as power line repair following severe wind events. During post-Hurricane Maria restoration work, Southern Company pulled 72,000 ft of rope for conductor wire using drones — a project that previously would have taken six to eight months was completed in just eight weeks.

A few years back I did some very cheap experiments with deploying a lift kite from a lifted bag.
A pre lifted kite in a bag can help to launch above calm ground air.
The idea was
Simulating having a drone lift a lightweight kite up to altitude in a sock. When the drone is high enough (and downwind) the kite tether tension is used to pull the bridles and kite out of the sock… This is akin to a fairly standard throw deployment for a ram air or single skin kite or parachute.


The obvious issue with this scheme is that the kite and drone separate so maybe you need a recovery drone manoeuvre, you also need to repack the kite to a launch sock on the ground to restart.

@floba Florian from KiteKraft had a scheme proposed at AWEC2017 (I think it was ; maybe it was 2015)
whereby the drone lifting device would be affixed to the tether near the bridle point. The lfit kite would be inverted fro the lift up to higher air. The advantage of the scheme was that the kite and drone stayed together and didn’t need reconnection (Sorry Florian I never really took to that idea. To me, the launch dynamic looked awkward)

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There’s a drone lifting experiments page here…

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After you have developed the mechanism to launch and recover your kite …
You need to be sure it works.
And your launcher / recovery system may well have 3x 9’s reliability of it’s own accord. But can you trust it?
Reliability of systems can always be improved with an extra layer of checking, - your control pod sensors are doing what they say they are.

An add on Kite flight visual recognition system doesn’t need to be complex or hard to implement.
Here’s a ready made, cheap to install version exploiting prior machine learning using TensorFlow.js and NodeRed

It may not be the fastest way to work and it relies on web connection…
But Look it’s found 3 x kites in the sky
Time to send the double happy kite flying signal to our controller

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Check out yolov5. You get to find a kite out of the box. Kites, rigid wings and «birds»…