Re: Trains and stacks of narrow-spread tether set
- OK on the array front...
Today my mission is a new kinda sketch... I think
A kite array with piezoelectric multilayer bending actuators. The array is going to be 3d.
Each kite will have one or more piezoelectric multilayer bending actuators.
The top layer of the array will be set out and addressed as per VGA (yes video) standards. e.g. a printed cut set of micro kite ribbons glued side by side with...
Below each node will hang a reciprocally vibrating fish tail ribbon(as per Dave S design) At the bottom of each tail will be Piezoelectric energy harvesting circuits.
below that will be a kite layer
below that will be a generator layer
I am concerned that "Particular attention must always be paid to ensuring that the mechanical strain arising during deformation of the piezoceramic shows the same orientation overall" http://www.piezoproducts.com/index.php?id=144&L=0
In a stable array like this though... Up is the average tension vector.
I'm pretty sure this can be done.
Phew back to electronics at last my home turf....
probably where I'll go furthest wrong
A tall wide shallow (shallow downwind single kite even) array is probably better than say a 640 (wide) x 480 (deep downwind) vga x tall standard.
Makes more sense ... downwind kites would all suffer wind shaddow ... but would add to structural redundancy and stability of mesh...
Single front array of kites with tails downwind can be print cut easily though.
And it will make for easy back attachment of generator wings using a reel to scroll the kite print sheet ... alligning the gen strings between the kite cuts at the back... yep that's it
ok off to draw
- Sketch should now be in the photos section ...
if not it's on my site.
Anyone know a good large scale rolling, cutting, seeming process facilities engineer?
Have been asking piezo folks about in-line stringing. awaiting response.
- Kite design is one of the most weight-sensitive jobs in engineering,
so I would like to recommend the works of J.E. Gordon as being by far
the easiest way to get a sense for what approaches tend to work, and
why. Rather than start right off with definitions and math, he tells
the story of the first students of science to come to an
understanding of what was going on all around them. In particular,
"Structures" has a chapter on designing for minimum weight that
explains why faster airplanes always have fewer wires and struts
exposed. Large, lightly loaded artifacts can only be made
efficiently if based on tension structures for a few inescapable
mathematical reasons, and he explains them in excellent, entertaining
english. Did you know that the "bicycle" wheel was actually invented
for an attempt at an airplane around 1850? The actual math is very
simple, but he keeps it to just a few handy formulas in the appendix
for those who want to start serious calculations. With a good
understanding of the forces at work, a few operations on a basic
calculator can tell you how light you can go on any particular
member, closer than the usual range for selection.
Forum members are invited to add links to the folder:
and add sub-folders that fit your focus, if needed.
- Rod,A Forum conclusion from years back is that conventional piezo is not a practical basis for AWE. The main reason is inefficiency in driving an inherently high-frequency (~10000hz) technology like thin-film piezo at far lower kite motion frequencies (~1hz). An exception is to somehow create the high frequency mechanical resonance to tap. Bulk piezo character of a megascale AWE latticework is of course based on different principles, where the frequency match is natural.Other objections to thin piezo relate to availability, capital cost, complex interconnects, durability, etc.. Far better to just use rag and conventional generators, for now,daveS
- A bicycle wheel is a wonderfully efficient design for its purpose, and can benefit from Kevlar spokes. If you have a bike wheel and want to cobble together a small generator, it can save time. However, as a turbine design, it leaves much to be desired. The spokes encourage a high-solidity disk, which is mostly superfluous. The rim, like other ducts, is material that would do more good adding to the swept area. A few designs take advantage of the high rim speed to improve transmission efficiency, but this comes at the cost of bearing complexity and friction.Bob StuartOn 27-Sep-11, at 1:55 PM, Muzhichkov wrote: