I'm Roddy, an engineer, teacher & househusband who loves the ecological ideal of kite power. The practice and development of kite power is harder, but doable. (Older Instructions)
I see massive benefits in using kite networks for Airborne Wind Energy Systems (AWES.) I design, test and openly publish details of my kite work. To read more on AWES I recommend Here and Here. I also recommend the new Springer AWES book (I'm Chapter 21) I started Windswept and Interesting Ltd to develop kite power. (Overview of W&I)
Network kites are very different to the other AWES schemes. Networking kites makes them stable flyers. Extra lines make networks fault tolerant and fail safe. Networks give you more kite per line drag.
This is a network kite turbine. I call them "Daisy". It works as a multi-stage, tilted, hollow axis, tensile auto-gyro kite turbine. (If you're keen, this work is in conjunction with Oliver Tulloch's PhD at University of Strathclyde.) It uses a central axis lift line to guide and limit the travel of the rotary blades.
A recent long exposure pic of my Daisy kite turbine flying at night. Flash exposed the lines and kites, a torch exposed the rotor motion of the middle ring of kites.
Idea and Challenge
I've been asked to make a kite turbine, for local scouts to take with them, to an International Scouting Jamboree in Austria this year. The scouts have an eco camping challenge.
So I need to make this light as possible and safe to transport. Compatible with an e-bike will be a real bonus because even kids can work that regen tech. I want it to be capable of powering the bike itself and some camping gadgets. (Heavy juice ones like an electric kettle as well as USB toys.) We should be able to do this, the kite turbines have been outputting ~300W/kg flying material max so far.
I want to dual purpose as many bike parts as I can without killing bike functionality.
Having said that, I'm going use a small geared hub motor and wheel to convert rotary power to electrical power. Using a small geared hub motor for regen may be controversial among cycle purists as there will now be a cogging resistance if you cycle without using the motor. (why would you? E-bikes are amazing fun with the motor on). As explained here you have to weld or otherwise lock the freewheeling planetary gear for regen to work.
A couple whacky but possible extensions might be possible for this project. 1 Use the kite powered up from below for turbo fan propulsion (sounds fun) 2 Host the kite turbine in a tensile aerial network
I'm lucky to have a family who let me be a househusband / mad scientist. I'm no positive on the domestic balance sheet so I keep the budget minimal. This allows the projects to be fully replicable. I do spend on the motor controller for this project. (VESC6 has a very good open source hardware history and cheap derivative alternatives are available) I also spend quite a bit on carbon tubes. Cheaper fibreglass rods have worked on designs I've shared before.
Oliver Tulloch and I have a small budget for parts from ETP Scotland.
Whilst helping Ollie with his PhD, it has become apparent that, Daisy can be an efficient and clean way to to source energy at scale. Our much larger prototype had 30kg CO2 emissions equivalent in production, the complete prototype has a predicted carbon cost of energy of only 17g CO2/kWh in year 1 (already better than solar over its lifespan) and only 1.7g CO2/kWh with consideration of replacement components thereafter.
So we have been having fun making and testing both physical and mathematical models.
As for sticking to a rigid plan... Maybe. Reminds me, We're going to test more rigid rotor wings soon too.