Always a bit doubtful that I’ve got anything useful to contribute…and no doubt I’m barking up the wrong tether here (or someone else has already been down this route and dismissed it) - but just in case the situation is otherwise…I wonder if anyone has investigated tensairity in regard to AWE. It seems of some relevance to the current situation (esp. re the Makani experience): personally I’ve always felt a bit nervous about having a lot of rigid material whirling about overhead. This is partly from the safety standpoint, but even if the contraptions were well out to sea or over tundra, the issue of catastrophic failure (and therefore the need for constant monitoring) seems a pretty serious one. It seems to me that this applies to virtually any AWES design. Of course one then runs up against the relative aerodynamic inefficiency of soft aerofoils. Tensairity would seem to offer a way of minimising the amount of rigid material in a wing/blade - and hence the potential for buckling failure, but the versions as advertised still have a rigid compressive spar running the length of the blade. I wonder whether this spar could be replaced by a semi-rigid one - either a high-pressure inflatable tube or rigid segments, say not more than 10% of the overall length with joints between them which would remain pretty rigid under normal conditions but which would flex under higher bending stresses. (This would also be the arrangement in the trailing edge which is difficult to taper in a pure inflatable.) Of course introducing this level of complexity into the blade/wing architecture only makes sense for blades over a certain size - ie. larger than what most people seem to be working on, but not necessarily as large as existing HAWT blades. If this were feasible, the advantages both in terms of deployment (which would be essentially by inflation) and survivability (by deforming into a relatively less efficient, lower velocity configuration) would seem to be worth investigating.