Q: You say that the kite is pulled out when the wind pulls hard, and pulled back in when it pulls not so hard. What about when the wind blows consistently?
A: Consistent wind is actually the ideal. The variation in pulling force is effected by a combination of how the kite is steered and powered with multiple lines.
Q: What happens when there is no wind?
A: Kitebot won't be usable. Until I prove the viability of the system under manual operation, we'll deliberately ignore questions of automation. With mechanical decoupling of steering and drive/recoil, launching and landing the kite can be done with relative ease compared to fixed line-length scenarios.
Q: In my experience flying a kite, there's a somewhat delicate tugging and releasing interaction with the kite line(s) to get the kite to stay aloft, particularly in light winds. How would this be done with KiteBot?
A: A partial application of the brake attached to the planet ring in the planetary gear-set in the Drive/Recoil subsystem should allow for this sort of "tugging-and-releasing". In stronger winds, we would also want to adjust the length of the rear, braking lines to partially de-power the kite the same way a kiteboarder does. The partial de-powering may end up being the primary mechanism for creating the force differential allowing the wind to do a net positive amount of work on the system.
Q: What stage is the project at?
A: As of Feb, 2021 I've built a Drive/Recoil system that works reasonably well (see demo video). It's crude enough that it will be kinda dangerous to be near when attached to a large kite. Also, the amount of stored energy that's required to recoil line with any significant resistance is higher that I had hoped, suggesting that internal losses are high in my prototype.
I'm now brainstorming and soliciting ideas for steering systems that might accommodate both the low levels of efficiency and safety.
Q: Has Kitebot been patented?
A: Nope. There are dozens of patents covering varying aspects of and approaches to using kites to harness wind energy. These date from the 1970s to present, and surely there's many more on the way. Of ones I've seen, none seem to make claim to anything novel within my approach.
Q: Have you heard of Makani?
A: Yup. They had an interesting run, documented beautifully here. Early on, they decided to go for full automation, seeking viability in commercial energy production. This makes perfect sense for a large scale, highly funded venture. At the same time, it seems like trying to invent heavier-than-air flight starting with a 727, rather than a Wright glider. Sure, the technology for full automation probably exists, but producing a purely mechanical initial version might be the only realistic way to get there.