Re: Anchors and Archesï¿½Notes
- I agree, if work is to be extracted form an arch by means of foot pumping...
The arch foot and pumping energy conversion system should be sited directly above a fixed anchor point.
It'll be more efficient and robust.
Remember, our anchors, (even if they grow massive,) are not very damaging to their environment. And they're cheap. Can I have 20 please?
They are resisting an upward sideways force. A sunken filled mesh tonne bag (like a quarry bag) does the job perfectly...
To establish a ground anchor 1: remove topsoil, 2:dig hole, 3: line hole with water porous bag, 4:fill bag with excavated material, 5:replace topsoil
Probably best to bring the bag handles together at ground level and re-lay topsoil around the handle join.
An offshore vertical anchoring vector might be matched by lifting non porous seawater bags above surface level.
Horizontal anchor vectoring may even be run to the shore.
The reason to have a taught rope rail loop between anchors at arch foot level is foot transit safety. Always being able to hold onto anchoring is a must.
It's probably best if this ground loop component is largely "over engineered."
A foot belay system complements this idea. And can run in parallel (metaphorically and physically) with a rope rail loop.
Kit like this robot capstan would make the job a breeze.
The more anchor sites there are / the more finely set to wind a pumping arch will be / also the easier it will be to move an arch around, because the foot will lift less between anchor sites.
It may be that foot controls give a foot enough upwind lift and/or downwind drag to drive past the rise in a rope ring between two anchors.
Imagine what's needed for an arch foot to go downwind. It wants little vertical lift and more drag low down. e.g. feed out to raise the back catenary (for less overall lift), rotate the back catenary winching point inward (toward the circle centre) with respect to the trolley it is mounted on. (drags back at that foot)
To drive a foot forward tighten up the rear catenary for overall lift, sheet in (toward the centre) at the foot on the side to go upwind, release the sheet (outward) on the stationary side. The arch should deform to lift the foot upwind.
If you have reached the anchor site, fix the trolley position there. otherwise, re-cleat onto the line to stay in place.
However, when an arch hosts other non foot pumping AWE architectures. If we can steer around a ground loop by the foot steering methods described above.
Weather cocking the generator surfaces to optimal crosswind alignment could be easily automated, fast and elegant.
Anchoring, follows the same fractal relationship rule that governs kixel tether size is slimmer than, patch mesh tethering, is slimmer than catenary line mesh.
A tree is thickest at the trunk.
CC BY NC SA
- Are we trying to re-invent everything here? Let's look at how guy wires are anchored for radio towers, and then use enough for the range of vectors we want. I think you'll find giant screws to be the most economical method in many kinds of soil. Moorings are another well-developed technology, with proven solutions for every type of ground. I'm surprised that they are not used with guy wires to augment the foundations of conventional turbines offshore.Bob StuartOn 25-Feb-13, at 5:54 AM, roderickjosephread wrote:
- For Met tower guy wires
auger a 9 inch hole 5 feet deep
mix 1 bag of concrete and pour in hole
drop in 5-foot long galvanized agricultural auger-tip anchor used for tensioning wire in grape vineyards
fill hole with dirt and water packing the soil tight as you go up
Wait a few days before using
my information is these never pull out
they are used on 50 meter towers with 6 levels of guy wires
It would have to lift a huge cone of soil to come out
the pull is partly sideways
--- In AirborneWindEnergy@yahoogroups.com, Bob Stuart <bobstuart@...> wrote:
> Are we trying to re-invent everything here? Let's look at how guy
> wires are anchored for radio towers, and then use enough for the
> range of vectors we want. I think you'll find giant screws to be the
> most economical method in many kinds of soil. Moorings are another
> well-developed technology, with proven solutions for every type of
> ground. I'm surprised that they are not used with guy wires to
> augment the foundations of conventional turbines offshore.
> Bob Stuart
> On 25-Feb-13, at 5:54 AM, roderickjosephread wrote:
> > To establish a ground anchor 1: remove topsoil, 2:dig hole, 3: line
> > hole with water porous bag, 4:fill bag with excavated material,
> > 5:replace topsoil
> > Probably best to bring the bag handles together at ground level and
> > re-lay topsoil around the handle join.
- While a kite arch could lift a side-by-side array of SuperTurbines(R), this discussion indicates that such an arch, if it has two greatly-separated anchor points, would introduce aiming challenges that would not exist using a more conventional lifter kite.
Aim in real time is (usually) a major requirement in wind energy. Automatic aim is good (normal). Passive automatic aim is even better.
To go from passive automatic aim, to no aim at all, would reduce the available sites to unidirectional wind resources during optimal conditions. Even then, using this location as an example, our wind resource is predominantly unidirectional, but today the wind is coming from the "wrong direction" and that is not unusual.
The other thing that is not unusual is for the wind to change direction, pretty quickly sometimes. And if a dust-devil comes through, I can look out and see two turbines a couple hundred feet apart, spinning fast, both pointed in opposite directions!
My latest suite of hard-won and carefully thought-through patents covers arrays that do not aim (stationary arrays), among other things, but a ground-supported non-aiming system can survive having the wind quickly change direction, or come from the "wrong" direction, or from multiple directions.
To have an airborne wind energy system that cannot aim in real time (pretty quickly) might mean the apparatus would be subjected to surprise crash landings. Some of these non-aiming airborne ideas seem to require "optimal conditions" at all times. A problem with some of these ideas would emerge when conditions are less than optimal, which is most of the time in many cases!
If substituting "component B" for a "component A" in an airborne wind energy system adds new difficulties that require still further added components, just to get back to the original, simple functionality of using "component A", perhaps the substitution is the beginning of going down an inadvisable path.
--- In AirborneWindEnergy@yahoogroups.com, "roderickjosephread" <rod.read@...> wrote: [[SEE PRIOR POSTS ON THIS TOPIC]]
- Doug,The working ideas to rotate an array of Superturbines are-1- a row of generators on the ground that can wheel around like an irrigation circle, or2- a central turret with outriggers to create the suitable geometry.3- an intermediate cableway to carry forces to the side(s).Let the all the ideas be tested, including tacking wings >300m long, and we will see if tacking is really dead as a workable wind power principle,daveS
- Well then, what the heck, why not try it?
--- In AirborneWindEnergy@yahoogroups.com, dave santos <santos137@...> wrote:
> The working ideas to rotate an array of Superturbines are-
> 1- a row of generators on the ground that can wheel around like an irrigation circle, or
> 2- a central turret with outriggers to create the suitable geometry.
> 3- an intermediate cableway to carry forces to the side(s).
> Let the all the ideas be tested, including tacking wings >300m long, and we will see if tacking is really dead as a workable wind power principle,