Hello Pierre:
I’m trying to figure out what the lift-to-drag ratio of a supporting kite has to do with the RPM of a turbine?
Also, the idea of enhancing the wind speed through a rotor by mounting it on the tip of a turbine blade “sounds like” a good idea, but the problem wight become keeping that generator cool. There are two ways high winds destroy turbines:
- high RPM and gusts rip the turbine apart;
- Sustained high output leads to generator heating until the windings burn up the insulation and/or sometimes melt.
All these “armchair engineer” ideas sound great as long as everything remains “on-paper”.
I’ve mentioned in the past, having a visitor - a girl with zero wind or engineering experience, who on the plane ride thought up the idea of putting small turbines on the tips of larger rotor blades. I had to tell her that it is an idea that gets mentioned every so often, and may work OK, but as far as I knew, nobody had ever tried it, and that was maybe 14 years ago?
One big question is: “Why hasn’t anyone tried turbine-reeling on the ground, or blade-tip turbines?” Should they? Are we missing out on the next “big breakthrough in wind energy”? Or is there a lesson to be learned here? If these ideas are absurd on a tower, is it possible they are absurd in the air too?
Anyway, just as it would be possible to do kite-reeling on the ground using an unloaded turbine on a tower on rails, pulling a cable as it rolls downwind, then being reeled back upwind, and seeing how much intermittent energy you could extract from the reel, minus the energy used to reel the turbine back in, GE or anyone else could build a tower-mounted turbine with turbines and generators on the blades.
So why hasn’t anyone done it?
Well, to start, you want the blade tips to be light weight. Adding turbines and generators at the tips would make that impossible.
I think examining whether any concept would seem “viable vs absurd” when applied to tower-mounted turbines can be instructive for AWE.