Hoops to Ring-Wings //Re: [AWES] Re: Hard lessons from testing
- Detail Notes-Roddy can fill in the plywood hoop with light cloth to boost overall vertical lift and improve L/D with little added weight or complexity. The hoop will then develop self-lift, and even boost overall torque and RPM, rather than adding downforce, as is currently the case.Flying hoops (ring-wings) are roughly classifiable by how they are set (square, or tilted windward, or tilted leeward) and how they are shaped (ring-torus (round cross-section), or ring-disc or ring-tube (flat cross-sections). For square-set or backward-tilted hoops, a (short) tube ring-wing is best. For a forward-tilted hoop, a ring-disc is favored. The round cross-section is not really a wing, for lack of useful lift, but a general compromise for highest structural efficiency, with moderate drag.In Rod's concept a ring-disk is best, and the added fabric creates it. An apex hole (~1/5D) is a nice refinement, making it a proper ring-wing.A LTA ring-disk made of made of inflated tubes is an interesting kytoon variant.
Inflatable shaft has been a topic in this forum,the problem being drag,the tower leaning due to the force of the wind.
> Message du 04/09/13 17:44
> De : dougselsam@...
> A : AirborneWindEnergy@yahoogroups.com
> Copie à :
> Objet : [AWES] RE: Hard lessons from testing
> Nice image of the Makani patent to inflate the SuperTurbine(R) shaft.
> I am honored that Makani has a patent on an "improvement" to SuperTurbine(R).
> Of course their idea was already thought of years ago by me, among many many possibilities, and it has its downsides that have already been pointed out here.
> Anyway, if anyone is serious about wanting to get economic AWE systems up and running I am open to collaboration.
> Doug S,
> --- In firstname.lastname@example.org, wrote:
>One goal is to have enough fat shaft to make both higher swept area and better transmission.But lift from rotating kites is not enough (see here trials http://youtu.be/0GflQyDDQec for space maximization:the kite is held by one of the two lines:the kite turns on itself _ it is a little like Rotokite but with only one kite _ by going down slowly).Blades working both as like-autogyro and wind turbine should also not be enough (Dimitry Cherny works on a light like-autogyro for reel/out-in,the wind being at least 4.5 m/s instead far more higher value for usual like-autogyro) for reliable operation since rotors are superimposed (even with an angle) and can touch each other.With ropes flight is maybe impossible.So a light structure working by tension (ropes) but also by compression (?) is needed.A solution is making an inflatable (Tensairity [R]) fat shaft and maybe filling it with helium or hydrogen (joined schema;it looks like Leaning Tower of Pisa ).Now I return to my own schemes.PierreB