Messages in AirborneWindEnergy group.                           AWES8731to8780 Page 72 of 440.
Group: AirborneWindEnergy Message: 8731 From: dave santos Date: 3/1/2013
Subject: Re: Groundgen Assertion Correction   //Re: [AWES] Crosswind kite po

Group: AirborneWindEnergy Message: 8732 From: dave santos Date: 3/1/2013
Subject: Review: Loyd on AWES Megascale Dominance

Group: AirborneWindEnergy Message: 8733 From: Doug Date: 3/1/2013
Subject: Re: Mothra and Superturbine

Group: AirborneWindEnergy Message: 8734 From: Doug Date: 3/1/2013
Subject: Re: Crosswind kite power vs conventional wind turbine

Group: AirborneWindEnergy Message: 8735 From: Joe Faust Date: 3/1/2013
Subject: Re: Flap-Valve as Aero-Diode to Tap Vertical-Lapse of the ITCZ

Group: AirborneWindEnergy Message: 8736 From: Pierre BENHAIEM Date: 3/2/2013
Subject: Groundgen Assertion Mutual Corrections   //Re: [AWES] Crosswind kit

Group: AirborneWindEnergy Message: 8737 From: Pierre BENHAIEM Date: 3/2/2013
Subject: re: Groundgen Assertion Mutual Corrections   //Re: [AWES] Crosswind

Group: AirborneWindEnergy Message: 8738 From: Joe Faust Date: 3/2/2013
Subject: Surveillance

Group: AirborneWindEnergy Message: 8739 From: dave santos Date: 3/2/2013
Subject: Re: Groundgen Assertion Mutual Corrections   //Re: [AWES] Crosswind

Group: AirborneWindEnergy Message: 8740 From: Joe Faust Date: 3/2/2013
Subject: Groundgen Assertion Correction //Re: [AWES] Crosswind kite power v

Group: AirborneWindEnergy Message: 8741 From: Joe Faust Date: 3/2/2013
Subject: Groundgen Assertion Correction //Re: [AWES] Crosswind kite power v

Group: AirborneWindEnergy Message: 8742 From: Pierre Benhaiem Date: 3/4/2013
Subject: Crosswind kite power vs conventional wind turbine

Group: AirborneWindEnergy Message: 8743 From: dave santos Date: 3/4/2013
Subject: Re: Crosswind kite power vs conventional wind turbine

Group: AirborneWindEnergy Message: 8744 From: Pierre BENHAIEM Date: 3/4/2013
Subject: Re: Crosswind kite power vs conventional wind turbine

Group: AirborneWindEnergy Message: 8745 From: dave santos Date: 3/4/2013
Subject: MagaScale Soft Kite Power vs Everything Else

Group: AirborneWindEnergy Message: 8746 From: Pierre BENHAIEM Date: 3/4/2013
Subject: Re: MagaScale Soft Kite Power vs Everything Else

Group: AirborneWindEnergy Message: 8747 From: Doug Date: 3/5/2013
Subject: Re: Crosswind kite power vs conventional wind turbine

Group: AirborneWindEnergy Message: 8748 From: Joe Faust Date: 3/5/2013
Subject: Swept area versus swept area per time unit

Group: AirborneWindEnergy Message: 8749 From: roderickjosephread Date: 3/5/2013
Subject: Re: Swept area versus swept area per time unit

Group: AirborneWindEnergy Message: 8750 From: Joe Faust Date: 3/5/2013
Subject: Kinetic art and AWES?

Group: AirborneWindEnergy Message: 8751 From: Joe Faust Date: 3/5/2013
Subject: Discuss drawing?

Group: AirborneWindEnergy Message: 8752 From: harry valentine Date: 3/5/2013
Subject: Re: Discuss drawing?

Group: AirborneWindEnergy Message: 8753 From: dave santos Date: 3/5/2013
Subject: Why AWES cannot achieve the High "Betz Efficiency" of Conventional W

Group: AirborneWindEnergy Message: 8754 From: Joe Faust Date: 3/5/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention

Group: AirborneWindEnergy Message: 8755 From: Joe Faust Date: 3/5/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention

Group: AirborneWindEnergy Message: 8756 From: dave santos Date: 3/6/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention

Group: AirborneWindEnergy Message: 8757 From: Joe Faust Date: 3/6/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention

Group: AirborneWindEnergy Message: 8758 From: Joe Faust Date: 3/6/2013
Subject: TetheredWings and updated resume

Group: AirborneWindEnergy Message: 8759 From: Doug Date: 3/6/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention

Group: AirborneWindEnergy Message: 8760 From: Joe Faust Date: 3/6/2013
Subject: Makani Power news note: Quarterly is published.

Group: AirborneWindEnergy Message: 8761 From: Bob Stuart Date: 3/6/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention

Group: AirborneWindEnergy Message: 8762 From: dave santos Date: 3/6/2013
Subject: Why Makani must avoid the AWES Forum //Re: [AWES] Makani Power news

Group: AirborneWindEnergy Message: 8763 From: roderickjosephread Date: 3/7/2013
Subject: Why Makani must avoid the AWES Forum //Re: [AWES] Makani Power news

Group: AirborneWindEnergy Message: 8764 From: Doug Date: 3/7/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention

Group: AirborneWindEnergy Message: 8765 From: Doug Date: 3/7/2013
Subject: Why Makani must avoid the AWES Forum //Re: [AWES] Makani Power news

Group: AirborneWindEnergy Message: 8766 From: dave santos Date: 3/7/2013
Subject: USWindLabs, Makani Power, and the AWES Forum //Re: Why Makani must a

Group: AirborneWindEnergy Message: 8767 From: Joe Faust Date: 3/8/2013
Subject: Line handling

Group: AirborneWindEnergy Message: 8768 From: Doug Date: 3/8/2013
Subject: USWindLabs, Makani Power, and the AWES Forum //Re: Why Makani must a

Group: AirborneWindEnergy Message: 8769 From: Joe Faust Date: 3/8/2013
Subject: Release the energy bottled in mines left in soils

Group: AirborneWindEnergy Message: 8770 From: dave santos Date: 3/8/2013
Subject: Re: USWindLabs and the AWES Forum

Group: AirborneWindEnergy Message: 8771 From: Pierre BENHAIEM Date: 3/8/2013
Subject: Superturbine (tm) light cage as shaft

Group: AirborneWindEnergy Message: 8772 From: Doug Date: 3/8/2013
Subject: Re: Superturbine (tm) light cage as shaft

Group: AirborneWindEnergy Message: 8773 From: Joe Faust Date: 3/8/2013
Subject: Re: Hot-Seated Single-Kite Altitude Record

Group: AirborneWindEnergy Message: 8774 From: Pierre Benhaiem Date: 3/9/2013
Subject: Re: Superturbine (tm) light cage as shaft

Group: AirborneWindEnergy Message: 8775 From: dave santos Date: 3/9/2013
Subject: Makani Flying Wing Crash Cover-Up

Group: AirborneWindEnergy Message: 8776 From: Pierre BENHAIEM Date: 3/9/2013
Subject: Re: Makani Flying Wing Crash Cover-Up

Group: AirborneWindEnergy Message: 8777 From: dave santos Date: 3/9/2013
Subject: "The good [AWES] scheme"

Group: AirborneWindEnergy Message: 8778 From: Doug Date: 3/10/2013
Subject: Re: Makani Flying Wing Crash Cover-Up

Group: AirborneWindEnergy Message: 8779 From: Bob Stuart Date: 3/10/2013
Subject: Re: Makani Flying Wing Crash Cover-Up

Group: AirborneWindEnergy Message: 8780 From: dave santos Date: 3/11/2013
Subject: Re: Makani Flying Wing Crash Cover-Up



Group: AirborneWindEnergy Message: 8731 From: dave santos Date: 3/1/2013
Subject: Re: Groundgen Assertion Correction   //Re: [AWES] Crosswind kite po
After the last few years of discussion, how strange that we still do not understand each other! Are you a sailor?

Its well known that a kite buggy can progress upwind, just like a sailboat. If the kite buggy were loaded with a small groundgen, it could still be made to progress to windward (at a reduced rate) while generating electricity. This would prove that a groundgen system is not inherently required to move downwind, but can even make progress to windward while generating.

Here is a simple AWES that meets Loyd's actual definition of Crosswind Power ("[kite motion] approximately transverse to the wind..."), even though he neglected to explicitly identify cross-wind load-velocity as such-

http://energykitesystems.net/KiteLab/awecs01.jpg
Group: AirborneWindEnergy Message: 8732 From: dave santos Date: 3/1/2013
Subject: Review: Loyd on AWES Megascale Dominance
Loyd writes about the same megascale AWES reality that Beaujean and KiteLab Group see, that the "potential advantages of kites over conventional turbines are thought to dominate in very-largescale [sic] power production."

Quoting more amply from Loyd's Conclusions section of "Crosswind Kite Power"-

"....a kite may produce twenty times the power output of 
a turbine (~200MW today)... For a given level of large-scale
power production, this offers a possibility of simpler
machinery because fewer units are involved. In addition, the
usual tower supporting the turbine and generating machinery
is not required. These potential advantages of kites over conventional 
turbines are thought to dominate in very-largescale power production.


There are several important questions that must be answered before 
the economics can be clearly understood. 

How large can kites be made? 

What ratios of strength to weight and
lift to drag can be achieved? 

How do the costs vary with such
factors? 

What are the relative site and land-use costs? 

Even with such far-ranging questions to be answered to establish an
economic advantage of such kites over other forms of wind
power conversion, the large single-unit output of kites and the
relatively well-understood technology make kites appear
attractive..." 
Group: AirborneWindEnergy Message: 8733 From: Doug Date: 3/1/2013
Subject: Re: Mothra and Superturbine
Well then, what the heck, why not try it?
Group: AirborneWindEnergy Message: 8734 From: Doug Date: 3/1/2013
Subject: Re: Crosswind kite power vs conventional wind turbine
Wind energy has been sorted into what works best (crosswind) and what doesn't work so well (non-crosswind) for 2000 years now and counting...
Group: AirborneWindEnergy Message: 8735 From: Joe Faust Date: 3/1/2013
Subject: Re: Flap-Valve as Aero-Diode to Tap Vertical-Lapse of the ITCZ
DaveS, this direction will prove to be a strong player!   The one-way flap valves in pumping systems are core players.    Some bird feathering actions come close to flap valve actions.  Blood circulation like the one-way dynamic.  I am pumping air into a landing cushion using one-way flap valves.   Fence coverings and advertising signs frequently have "relief" holes with the flaps still in place, but the holes give the relief of gusts and strong winds; such is a cousin to the relief you mention from the flap valve.  Membrane reverse osmosis may be a cousin to the diode means.  Some reversals in kite motions will be made easier for the having of flap valving.  Turnabout severe depowering of a kite's wing may come from one-way flap valving.  Free-flight kite hang gliding may benefit from some one-way flap-valve constructions by lowering the negative load from a downing burst, especially at the edge of thermals; such might mitigate the challenge of tumbling from the vertical shears.  

My youthful first "vertical flight" machine designing consisted of a huge array of tiny flap valves over a network of fine lines; push up fast (flaps open) and then pull down fast (flaps close); an array on feet and an array for arms; pump up vertically. Aircraft not made ...   Like climbing stairs. 
Group: AirborneWindEnergy Message: 8736 From: Pierre BENHAIEM Date: 3/2/2013
Subject: Groundgen Assertion Mutual Corrections   //Re: [AWES] Crosswind kit

DaveS,

 

After years it is sometimes not bad to question our old or new schemes.

 

In our discussion,we have two main different things:crosswind motion,and conversion system.[And also a third by adding motion producing lift and force from bottom up (perhaps the good way for Mothra) during conversion (and sitting down by trailing edge during retrieval for Mothra).]

 

http://energykitesystems.net/KiteLab/awecs01.jpg :this scheme with 2 spaced pulleys is a little like the lever system from Payne, experimented by Darin Selby (hello!):the kite tows both the two sides by going crosswind,so a big part of potential conversion is lost.The part of conversion which is kept corresponds to alternate downwind motion from a pulley,then from the other.

 

Please make the following simple experience (I made it):two spaced pulleys worked by a tether being a triangle,exactly like on the photo you provide.You hold the free end of triangle tether with your fingers (being the kite) you tow while you move left,right,left,right:you can see the pulleys turn with some difficulties;but if you alternate slacking of one side while towind on the other side the pulley will turn with no difficulty.But in this case you must retrieval (a complex mecanism would be required) the slack part then the other...It is the same thing for  OrthoKiteBunch where a winch must retrieval the slack tether for each stroke,while downwind motion produces conversion on one side,then the other by alternating. 

However there is some exception concerning requirement of downwind motion to make conversion with generator at ground:rotating tower like Superturbine.But there are other problems.

 

PierreB

 




 
Group: AirborneWindEnergy Message: 8737 From: Pierre BENHAIEM Date: 3/2/2013
Subject: re: Groundgen Assertion Mutual Corrections   //Re: [AWES] Crosswind

DaveS,

 

A sail on mast can work on 270°.Indeed the derive or the wheels provide some resistance on the sides.A kite can work only on 180° (in fact far less),being the half of hemisphere in downwind place.For doing better,on water,the implementation of "chien de mer" (a sort of derive) by Didier Costes or Stéphane Rousson,is required,but why not... 

 

PierreB
Group: AirborneWindEnergy Message: 8738 From: Joe Faust Date: 3/2/2013
Subject: Surveillance
For thousands of years kite systems have been looked at by people and animals.  That is one branch of surveillance. Means of looking at the kite systems are of a wide variety.  Radar may look at kite systems. Cameras may look at kite systems.  Binoculars, telescopes, sound receptors, infrared sensors, effects readers, etc.  

Another branch of surveillance is the use of kite systems to look at scenes (scenes in the air or on the ground).  Kite systems may look at other kite systems or at themselves. 

The purposes for looking vary.   

Tech advancing the use of kite systems in the surveillance department is invited.  Identification of effective uses of kite systems for surveillance of scenes or for the watching of a kite systems or kite farms are subject for sharing. 

In part service toward these matters, a chapter "Surveillance " in our online book Airborne Wind Energy by Upper Windpower  is open for notes, papers, illustrations, plans, etc.   http://www.energykitesystems.net/Surveillance/index.html      The forum may be a peer-reviewing table for the tech shared. 

JoeF
Group: AirborneWindEnergy Message: 8739 From: dave santos Date: 3/2/2013
Subject: Re: Groundgen Assertion Mutual Corrections   //Re: [AWES] Crosswind
Pierre,

I am still misunderstanding you. There is no error in stating that a groundgen AWES need not move downwind. Loyd even mentions that groundgens are desirable for scaling-up, without ever suggesting they cannot do crosswind power (since they obviously can).

In the crosswind AWES drawing, the kite goes "approximately transverse to the wind", just as Loyd requires. It generates in both directions (a simple diode bridge is used to rectify the reversing electrical polarity). Even when it turns, it does need to go downwind but stays in-plane as it crosses Zenith.

A kite buggy or boat goes into the wind because its wheels or keel resist the sideforce of being pulled downwind. The only requirement is for the kite is to be pulling from Forward of Abeam (Pocock). The Kite Window is wide enough for that ( font-style:normal;">
 
Group: AirborneWindEnergy Message: 8740 From: Joe Faust Date: 3/2/2013
Subject: Groundgen Assertion Correction //Re: [AWES] Crosswind kite power v
Clarification on "crosswind"
Left to right to left, etc. is common, but up and down, and oblique at any angle besides zero 
involve crosswinding. 
Group: AirborneWindEnergy Message: 8741 From: Joe Faust Date: 3/2/2013
Subject: Groundgen Assertion Correction //Re: [AWES] Crosswind kite power v
Group: AirborneWindEnergy Message: 8742 From: Pierre Benhaiem Date: 3/4/2013
Subject: Crosswind kite power vs conventional wind turbine

I ask the question again,in another way.Can efficiency of (flygen or groundgen,rigid or soft,working in crosswind loop or figure-eight) kite reach the efficiency of conventional turbine,for a same swept area?

You take a 3-blades wind turbine diameter is 100 m.You keep only tip blades for 10 m.So swept area is 2826 m².Wind speed being 12 m/s,power is something like 1,5 MW.

Now you take three (groundgen or flygen) AWES making loops which vertical diameter is 100 m.The span of each wing is 10 m.So the swept area is the same.Global power: probably less than 0.15 MW.The simplified formula gives 10 m² x 2/27. x density 1.2 x 12 x 12 x12 x (L= 1/D= 0.125)² = about 100 kW;it is very well if the real power is 40 kW before conversion.So it is 10 times less or lesser.

What can be improved?

Design?L/D ratio?Tether drag?...

What cannot?

G on structure and loss of lift during turn requiring more power,above all if radius of loop is low?

Lift design (kite) vs torque design (rotor)?

A rotor can be quite crosswind,a kite cannot and produces variations and losses of power.

Tether drag?...

If crosswind kite working in loops or figure-eight has a too low efficiency regarding conventional wind turbine by unity of swept area,it cannot be economically viable.

PierreB

http://flygenkite.com

Group: AirborneWindEnergy Message: 8743 From: dave santos Date: 3/4/2013
Subject: Re: Crosswind kite power vs conventional wind turbine
Pierre,

The answer is "No", the conventional HAWT wins in "Betz Efficiency" by swept area, due to far higher L/D. But this obvious fact does not tell us much. With both the resource and methods so different, AWE and wind-tower comparisons are very misleading. 

AWE wins by higher altitude (if "aviation costs" can be kept low enough). Surface wind and upper wind are very different resources. Upper wind is not just far denser in power, its hundreds of times more abundant.

Soft kites win the lowest capital-cost parameter.  Felker showed us that we must invent a lower cost aviation (Mothra bulk-lift was the response).

AWE "Drag Force" (as Loyd formally defined it) has value, but is so misunderstood that it enrages some "wind experts". A mix of lift and drag forces seems the best AWE trade (for inherent flight stability at best ROI).

Site costs, as Loyd noted, are a key economic parameter. If AWE can operate over existing land-uses, it gains a huge economic advantage over towers, which are hard to site.

Beware of drawing any definitive conclusion from just a few factors in any high-dimensional "constraint resolution" problem. In such cases, heuristics do better than incomplete math. Here is the heuristic summary-

Best ROI wins the economic race, regardless of particulars. There will be profitable niches for all categories of wind tower and AWES. Only AWE has the potential to fully power civilization, no matter how much better conventional wind's Betz efficiency continues to be,

 
daveS
Group: AirborneWindEnergy Message: 8744 From: Pierre BENHAIEM Date: 3/4/2013
Subject: Re: Crosswind kite power vs conventional wind turbine

DaveS,

 

"The answer is "No", the conventional HAWT wins in "Betz Efficiency" by swept area, due to far higher L/D [only?]. But this obvious fact does not tell us much. With both the resource and methods so different, AWE and wind-tower comparisons are very misleading [except if the difference is too high,at least for some places due to their cost]."

 

Your searches about high density,low cost,low L/D ratio has sense,and crosswind kite power (Loyd's sense)has some limits.But low L/D high density has also some limits (low efficiency,high maintenance, frequent replacements of blue tarp,but why not...).So it is also possible no AWE design wins.In conventional wind energy a single design won.Is it possible different AWE designs win,that according to the variability of the costs of chosen locations among other parameters?For the moment I do not see any AWE winner as utility-scale system.AWE is possible but a real jump (for example like J.Beaujean's design) in technology will be required. 

 

PierreB
Group: AirborneWindEnergy Message: 8745 From: dave santos Date: 3/4/2013
Subject: MagaScale Soft Kite Power vs Everything Else
Pierre,

You are exactly right, a "cloud-of-sail" as an AWES does require "sailors/pilots". Yes, this can be dismissed as a "labor disadvantage" (compared to a science-fiction robot), but MegaScale Soft Kite Power is also the finest sort of Royal Sport. I would pay to fly such an AWES, and to be paid to do so is a dream. 

The Blue Tarp lasts far longer than its payback, which is why its currently far better than carbon-fiber in the AWES race. Of course we plan to use performance-engineering materials for our "tarps" (real kite fabrics). Our ropes will upgrade to UHMWPE.

I feel very sad for those who wait for for a perfected high-complexity AWES, for as George Pocock so long ago asserted- "...those who travel by kite travel as Kings”.

daveS
 
Group: AirborneWindEnergy Message: 8746 From: Pierre BENHAIEM Date: 3/4/2013
Subject: Re: MagaScale Soft Kite Power vs Everything Else

DaveS,

 

So the next steps for Mothra are trials for conversion systems.When all sorts of AWES will be built,things will become clearer on the next AWE horizon.

 

PierreB
Group: AirborneWindEnergy Message: 8747 From: Doug Date: 3/5/2013
Subject: Re: Crosswind kite power vs conventional wind turbine
It seems that this is part of the extended effort to substitute endless talk for any progress whatsoever.
I wonder if the internet has in some ways become more of a distraction than a facilitator of progress. It goes back to an idea that talking about what you (think) you are going to do takes energy away from actually DOING it. Like Nike says "(shut up and) Just Do It!"
You first spell out the amount of wind energy in a given circle.
Then you ask if AWE can meet the same standard as regular wind turbines with regard to how close they can come to beating Betz?
Well, since AWE is still at the stage of a few experiments and no real useful product, I guess that does place AWE systems in a position where they also make poor use of swept area compared to systems that have evolved for 3000 years to use propellers.
But that doesn't mean AWE CAN'T meet that same performance standard with regard to swept area. It just means that, as part of AWE not really getting off the ground at all, OBVIOUSLY the performance is not up to snuff yet. That does not mean it CAN'T, just that it HASN'T YET. I'm not sure what you are even asking? Do you not know that AWE to date has not approached a reasonable fraction of Betz? Or are you asking if it ever can? What about the rotors of a SuperTurbine(R) Has anyone checked to see how close to Betz that could come?
Group: AirborneWindEnergy Message: 8748 From: Joe Faust Date: 3/5/2013
Subject: Swept area versus swept area per time unit
Not sure how some of the posts are treating "swept area,"
so I keep reminding myself: 
Swept area 
versus 
swept area per time unit
Group: AirborneWindEnergy Message: 8749 From: roderickjosephread Date: 3/5/2013
Subject: Re: Swept area versus swept area per time unit
A lot of my designs aim for
greatest percentage of streamtube energy extraction by
greater unit time surface area streamtube engagement.

Bet I can beat one of those whirly tripod monsters eventually.

the smoke trail wake patterns left in wind tunnels when testing conventional turbines are already densely packed...
but we can go way bigger and beat that.
Group: AirborneWindEnergy Message: 8750 From: Joe Faust Date: 3/5/2013
Subject: Kinetic art and AWES?
Kinetic art and AWES?

Start: 

Reuben Margolin: On Kinetic Art
Group: AirborneWindEnergy Message: 8751 From: Joe Faust Date: 3/5/2013
Subject: Discuss drawing?
http://assets.knowledge.allianz.com/img/alternative_energy_kite_wind_power_51375.jpg 
Open for discussion. 
Something special in the drawing caught my eye.
Group: AirborneWindEnergy Message: 8752 From: harry valentine Date: 3/5/2013
Subject: Re: Discuss drawing?
Hello Joe,


Excellent Graphics .  .  . . this is the ultimate development of the Kite-Gen carousel concept .  .  .  . the railcars would each have wheel driven electrical generators and transfer power via a 3rd rail technology .  .  . well-proven  technology here. 


Harry


To: AirborneWindEnergy@yahoogroups.com
From: joefaust333@gmail.com
Date: Tue, 5 Mar 2013 19:34:23 +0000
Subject: [AWES] Discuss drawing?

 
http://assets.knowledge.allianz.com/img/alternative_energy_kite_wind_power_51375.jpg 
Open for discussion. 
Something special in the drawing caught my eye.
Group: AirborneWindEnergy Message: 8753 From: dave santos Date: 3/5/2013
Subject: Why AWES cannot achieve the High "Betz Efficiency" of Conventional W
Reason 1- Lift force required to keep the AWES mass aloft robs power-extraction.

Reason 2- Tether-drag also robs available power.

Case Discussion- SuperTurbine (R)

The rotors are angled diagonal into the wind, helping lift the AWES, but reducing extractable power. The thick drive shaft adds parasitic drag and down force. A lifting aerostat or kite adds more frontal area drag, without any direct power extraction. The resulting overall extraction efficiency of this AWES concept looks to be somewhere around 20%, in small versions, and progressively less with further scaling. 

Even so, a less efficient AWES in sufficiently superior Upper-Wind can beat a more efficient HAWTs in inferior Surface Wind. The real problem for the SuperTurbine is how to reach Upper Wind safely and economically.


 
Group: AirborneWindEnergy Message: 8754 From: Joe Faust Date: 3/5/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention
Towered tri-blade has the blades AND the tower disturbing the wind; looking only at the blades and forgetting the tower's contribution to slowing the wind seems like a neglecting of part of the equation.     

AWES has its tether; towered HAWT has its very fat tower (its tether analogue). 
Group: AirborneWindEnergy Message: 8755 From: Joe Faust Date: 3/5/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention
Also, the towered blades' tower "lifts" the HAWT and there is an induced cost for that lifting. 
A complete comparison between the towered blades and the tethered AWES "blades" would give 
full respect for the cost of the towered "lift" and towered "drag" costs of placing the tri-blades into the flow; and one would cost the slowing of the wind caused by the tower. 
Group: AirborneWindEnergy Message: 8756 From: dave santos Date: 3/6/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention
The modern HAWT puts the turbine rotor ahead of the tower, which minimizes interference and drag loss. So the efficiency penalty due to the tower is small (can be less than 2%, if memory serves). In a tethered AWES, tether drag can dominate performance, both in marginal low-wind conditions, when any loss is critical, and also in the quest for high-speed sweep, where tether-drag grows exponentially.

Once again, direct comparisons between wind-towers and -aircraft are tenuous, suggesting that AWE and SWE (surface wind energy) are quite different animals. Its like comparing a snake and a hawk; both eat rabbits, and are successful evolutionary solutions, but operate very differently.
 
Group: AirborneWindEnergy Message: 8757 From: Joe Faust Date: 3/6/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention
Note on the circular cross-section towers holding blades: 
  • Placing the tower projectively aft of blades does not prevent two things: 
    1. Frontal stagnation and the blunt redirection of the stream. Slope effect of tower body.  The tower's affect on blades passing by it is forms a scene that is very different from what the blades experience high where there is not the tower. 

    2. Non-streamline disturbance of the stream making aft turbines in the farm having to deal with the slowed wind from the leading towers; the slowed and disturbed wind of leading towers affect siting and effectiveness of downwind towered turbines, if any.   The drag of a circular cross-sectioned tower is many times more than if the the tower was cross-sectioned in wind-cocking teardrop streamlined shape.   "Tower shadow"
Note on cost of wakes of AWES versus ground-hugging towered turbines: 
     A wake from a ground-hugging towered turbine is formed by the tower and the turbine blades; the wake affects ground dwellers downwind; the downwind effects cost something.    
    The wakes from AWES smooth aloft with less cost on ground dwellers.  However, AWES aloft wakes will be noticed downwind by aircraft. 

JoeF
Group: AirborneWindEnergy Message: 8758 From: Joe Faust Date: 3/6/2013
Subject: TetheredWings and updated resume
Update for TetheredWings' and Soaren.com
(stealth mode, one will not see AWE content at that site)
owner's resume

Document title and linked document: 
Group: AirborneWindEnergy Message: 8759 From: Doug Date: 3/6/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention
There are lots of downwind machines in the mid-to-large small wind category, such as Skystream. There are a few somewhat (supposedly) reliable induction turbines from 20 kW - 100 kW that are downwind and use induction generators with gearboxes.
And my SuperTwins and both upwind AND downwind, using two rotors.
In my experience, the problem with tower wakes is not a loss of power (Never measured that but it seems logical) but that the tower shadow can just beat the living hell out of the blades and actually the whole turbine. Imagine water skiing in circles at 120 mph on glassy water except with every rotation you hit a big hole in the water a few feet deep. Boom! Ouch! That is why the Skystream has curved blades. We've found that you need to keep downwind blades WAY away from a fat tower, or your machine will get beaten to death.
Wind: invisible yet watch out or it will get you!
Wind: soft at low speeds, and like concrete at 200 mph!
Boom!
:)
Group: AirborneWindEnergy Message: 8760 From: Joe Faust Date: 3/6/2013
Subject: Makani Power news note: Quarterly is published.
It is yet unclear why MP does not post their note here. 
Their quarterly notes progress on an Integrated Ground Station (IGS). 
Group: AirborneWindEnergy Message: 8761 From: Bob Stuart Date: 3/6/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention
The lack of tower fairings, especially on downwind machines, has long puzzled me.  They may seem unimportant on an upwind machine, but they do add a bit to the overall drag, and, as Doug notes, upset the upstream airflow, adding cyclic stresses to the system.  Almost any kind of fairing would help, and even badly made prototypes would fail safely.  They would add nothing to the tracking force needed.  With whole companies specialized down to just tightening the bolts on these things, and fine-tuning the tracking devices you'd think somebody would make an aftermarket accessory fairing.

Another keen idea might be blade-tip pods that deploy a kite to help on low-wind days.  They might also be rigged as emergency brakes, if other systems fail.  

Bob Stuart

On 6-Mar-13, at 3:36 PM, Doug wrote:
Group: AirborneWindEnergy Message: 8762 From: dave santos Date: 3/6/2013
Subject: Why Makani must avoid the AWES Forum //Re: [AWES] Makani Power news
Joe wrote- "It is yet unclear why MP does not post their note here."

Answer- The AWES Forum is the one place where Makani's hype-driven ethos is relentlessly exposed. If they ever do engage expert critics in open debate, it will time-stamp "guilty-knowledge" on their part, increasing legal jeopardy from any eventual claims arising from investor losses.

Read the MP Quarterly Report closely for a belated print admission that they have yet to ever perform an end-to-end all-flight-modes AWES session, the sort of fact that appears here first (a year ago), clearly presented.

The Makani Charade cannot continue indefinitely; sooner even the popular press must notice they are not on track to deliver a viable utility-scale AWES (by 2015, the latest slipped date), that their MTBCF will not soon approach pay-back, if ever.
Group: AirborneWindEnergy Message: 8763 From: roderickjosephread Date: 3/7/2013
Subject: Why Makani must avoid the AWES Forum //Re: [AWES] Makani Power news
A wild approach to open AWE promotion would be to expose closed practices to the press.
Or shame companies we have approached, who will not sponsor nor share research into AWE, despite following complementary, yet polluting technologies (e.g. rolls royce)

but i'm not that low
Group: AirborneWindEnergy Message: 8764 From: Doug Date: 3/7/2013
Subject: Re: Why AWES cannot achieve the High "Betz Efficiency" of Convention
They DO have blade tip emergency drag-based centrifugally-deployed brakes... That is the old way.
A company that iincludes friends of mine, promoting telescoping blade tips (not kites but the same idea of sweeping more area in low winds) has had little-to-no luck with them so far, despite quite an extended effort, including a special transmission (longer blades lower RPM and in light winds you need to RAISE RPM), and patent protection, over many years now and these are windfarm maintenance people who run and repair windfarms, not just idiots.
"Improved" wind turbines are everywhere. Take away the finger-quotes and the number of improved machines decreases dramatically.
:)
Group: AirborneWindEnergy Message: 8765 From: Doug Date: 3/7/2013
Subject: Why Makani must avoid the AWES Forum //Re: [AWES] Makani Power news
I agree that the reason they do not participate is likely the fact that you will attack them and rip them apart. Great, that saves me having to do it. Plus, what do they have to gain by being in this group? How does it help? It's mostly discussions about nothing - it purports to support AWE but what results support that notion? Still, you can probably start to see by now that all the empty talk means nothing anyway. Oh well I got sucked in.

Still, pointing out that one more AWE team is full of hot air is less than a lifetime achievement. It also really counts for next to nothing. There are always 1000 idiots promoting new "improved" wind turbines. They are almost always completely full-of-it.

I'd say there are few statements made by humans more suspect than the statement "We have developed a new type of wind turbine better than the old" Almost NEVER true. Wind energy is a magnet for crackpots and airborne wind energy is a neodymium super-magnet for extreme crackpots.
Even Profethor Crackpoth that thpray it insthead of thaying it! With real beards and glasses coated with imitation dandruff for that authentic look! How 'bout adding abowtie? With polka dots! OK fine, a propeller beanie if you insist, but now you're exaggerating...
Some of you know exactly what I mean! Break out the tinfoil hats! sheesh!
:O...................................................
Group: AirborneWindEnergy Message: 8766 From: dave santos Date: 3/7/2013
Subject: USWindLabs, Makani Power, and the AWES Forum //Re: Why Makani must a
Doug,

I think its Makani's NDAs and competitive business advantage that limit public interaction, not fear of being "ripped to shreds", which happens regardless.

Likely the most persistent exaggerated and dubious Forum claims about "fantasy turbines" concern utility-scale SuperTurbines (as based on a thousand-foot carbon fiber "rotating tower"); claims which may well even exceed the Makani offshore jumbo aerobatic E-VTOL AWT in impracticality. Your rambling bitter anti-intellectual "know-nothingism" is perhaps the worst thing about the AWES Forum, but still patiently tolerated, you must admit.

The redemptive value of the AWES Forum is its shared-knowledge content. Even you have added such value, you must concede. Its been quite exciting for many of us to learn so much so fast about AWE, even as you failed to keep up with the knowledge fire-hose, and only feel threatened and cheated by open-source thinking.

A consistent Forum theme is the need for open testing of even bad AWES ideas, to shut up pretenders. USWindLabs and Makani Power should focus on preparing their AWES architectures for that looming historical challenge, whether they studiously avoid the Forum, or endlessly whine about the Forum, on the Forum. Testing is the man thing now...

daveS
 




==========================
I am sorry for the Yahoo "CSNBC Jobs" Spam Virus 
that hijacked the Contact List for this mail account. 
Please accept this apology for any trouble caused.
Group: AirborneWindEnergy Message: 8767 From: Joe Faust Date: 3/8/2013
Subject: Line handling
Group: AirborneWindEnergy Message: 8768 From: Doug Date: 3/8/2013
Subject: USWindLabs, Makani Power, and the AWES Forum //Re: Why Makani must a
Ha ha ha Dave:
Nice try, but my "rambling bitter anti-intellectual "know-nothingism"" will never hold a candle to your "fight for ignorance".
At least I produce real working systems (which I should be doing now instead of THIS!).

Seriously though, I think the reason Makani is not on here is simply that there is no reason - nothing to be gained. They at least target their activities to things that help move them forward rather than dragging them down. Immersing oneself in ignorance is no way to advance. Talk is no substitute for work.

In my case, sorry but I don't remember receiving very much in the way of "shared knowledge content". The knowledge I have gained is the same as in regular wind energy - that most people who would purport to improve it are simply not sufficiently up-to-speed to make a difference, or to have any meaningful input. They think it's meaningful but without a background in actually producing power, they just don't know. They confuse the idea that an art might be advanced in some way, with the idea that nobody in the art has any idea what they are doing, and everything they have discovered can be ignored. You are a great example.

As far as YOUR "rambling bitter anti-intellectual know-nothingism", (nice description) such as your flapping whatevers and quantum whatever-it-was-that-made-no-sense-whatsoever, OMG I think you should take it over to a real wind energy group and get the spanking you deserve. Your brain is like a supercharged V-8 engine, connected to nothing, with the throttle stuck on full. Ahhhh! (stand clear!)

You rightly point out that some SuperTurbine(R) renderings show incomplete ideas that would need a few band-aids of their own to really work well. Some may even over-reach a bit. But your blanket condemnations of SuperTurbine(R) technology don't pass muster. A lot of it isn't worth taking the time to rebuke - after all, where does rebuking everything you say in detail get me? The next day you will bring up everything I rebuked as though it is all fresh and I had never taken the time to explain it to you in the first place. The battle is between the wind and the power grid, not you.

After all the tearing down of the SuperTurbine(R) idea, last I knew your blue tarp arch kite was still a solution in search of a problem, and I was hearing that it might find a good use supporting an array of SuperTurbines. One more stated project that will never happen? I guess they would use those pesky "torque tubes" that "can't work", right?

Oh I gotta stop - we have half a foot of fresh powder up in the mountains and I am sitting her at a computer arguing with Dave Santos Again? About absolutely nothing, to boot? OMG yes I remember why I quit this forum! I hope for your sake that out-of-control supercharged V-8 engine runs out of gas at some point so you can get a rest!

I finally noticed where you got that term "torque tube". It's a term from a method of controlling aircraft, instead of cables or push/pull rods. But these "torque tubes" don't rotate constantly at high speed. The more accurate term for a driveshaft would be "driveshaft".

But the real reasons I don't take the time to rebuke all your detractive statements about my designs, (and everyone else's) is that some of the answers are just giving away ideas and maybe I.P. ahead of the fact. I've actually learned after years as an inventor:
1) Most inventions don't really work very well at all;
2) Ones that DO work well seldom have the exact form as when they were first on paper - they usually need adjustment as you see what really happens after you start building and testing them;
3) Saying you will build something takes away the energy to actually build it.

Imagine makani or anyone else, planning on a solution to some aspect of their system. They have ideas and maybe they are testing them or maybe looking to file a patent. They probably are not sure what they will try to patent til they see what really works. Next they come on
this forum, you rip them apart, and they are tempted into disclosing all their proposed solutions ahead of the fact just to rebuke you. Result? You screwed them up - they lost out by being on the forum.
Get it? Nothing to gain and everything to lose.

So for me to sit here all day trying to endlessly explain away every ignorant thing you come up with, often but not always in trying to rip apart my designs, has no purpose for me. Headed for the mountains... Seeya!

:)
yer buddy
Doug S.


--- In AirborneWindEnergy@yahoogroups.com, dave santos <santos137@...
Group: AirborneWindEnergy Message: 8769 From: Joe Faust Date: 3/8/2013
Subject: Release the energy bottled in mines left in soils
Group: AirborneWindEnergy Message: 8770 From: dave santos Date: 3/8/2013
Subject: Re: USWindLabs and the AWES Forum
Doug,

What you might have learned form the AWES Forum, that conventional wind power forums do not cover, is the aviation aspects of AWE (flight safety in shared airspace). True, USWindLabs hardly seems poised to be a player in the NAS, so maybe you can skip those lessons. The rest of us must ace these aspects of true AWE, with or without trollish ridicule.

Note also that a "torque-tube" is in fact a "drive-shaft", in the form of a tube. Its use in aviation to drive control surfaces was motivated by the need to save weight (so you get to learn something more). Torque-tubes can be driven just as you propose, with no semantic contradiction. Of course, cable-driven aircraft controls proved far lighter and more robust, and thus supplanted tubes; which bodes poorly for thousand foot shafts. The longest torque tubes found in my "similarity-case" study were in massive dam-spillway actuators, of less than 200ft.

Its really a stretch to propose that my ongoing championing of academia's role (and knowledge generally) in AWE is anti-intellectual in the same way that your "Professor Crackpot" angst. We are on opposite poles of that issue. 

Testing superturbines under a Mothra makes sense, even if other WECS seem more promising. No specific endorsement is implied in the consistent KiteLab philosophy- "Test Everything" (including FlipWings),

daveS
 
Group: AirborneWindEnergy Message: 8771 From: Pierre BENHAIEM Date: 3/8/2013
Subject: Superturbine (tm) light cage as shaft
Attachments :

    There were some discussions about Serpentine (tm):there is a problem if the (thin) shaft is too long (bad transmission);problem if the inflatable shaft is too fat (air force on the structure);problem with Rod's configuration (not enough lift to hold the structure containing ropes).

     

    An helium balloon in the top,or sustaining with arch,look like the marriage of the carp and the rabbit.

     

    So the shaft should be fat to be long,but that without too much air force on the structure.A wire-mesh (or similar) "squirrel" cage as shaft (and also rotor of generator in the low part)?

     

    Other discussions on the forum and the lack of investors in AWE shows no plan of utility-scale AWES was yet found in a clear and obvious way.And regular wind turbines are not yet satisfactory (too much materials,winds at low altitude...) but work.So discussions stay open.

     

    PierreB

    		   @@attachment@@
    Group: AirborneWindEnergy Message: 8772 From: Doug Date: 3/8/2013
    Subject: Re: Superturbine (tm) light cage as shaft
    Thanks Pierre:
    Actually I have a patent on that too. It includes vertical axis machines made like that - they would not need a central axle or pole.
    And the mesh is comprised of Darrieus blades too, so the driveshaft itself contributes power.
    :)
    Doug S.
    PS I WISH this forum was helping to move things forward.
    Wouldn't we all like to sit in a chair and barely move and yet be effective. So tempting. Having an airborne wind energy forum online is beyond any fantasy I ever had, but now that we have it, it seems to take a lot of time and doesn't seem to get anyone anywhere. Well just a point to note I guess.
    Group: AirborneWindEnergy Message: 8773 From: Joe Faust Date: 3/8/2013
    Subject: Re: Hot-Seated Single-Kite Altitude Record
    Group: AirborneWindEnergy Message: 8774 From: Pierre Benhaiem Date: 3/9/2013
    Subject: Re: Superturbine (tm) light cage as shaft
    Doug,

    "...so the driveshaft itself contributes power." ,but also will tend to
    lie down.


    From your patent US2002192068,Fig.31 and 32 show "a latticework
    tower/shaft"which seems to have more potential:the best part of blades
    is preserved,blades provide both lift and power,so the tower perhaps can
    be straight (better than curved tower by the weight of rotors preventing
    the free rotation of the tower/shaft) and large enough,that (perhaps)
    without opposing too much to the strength of the wind.When there is no
    wind,the structure should be a little like an...arch.But when there is
    wind,lift from rotors should be enough to stretch out the structure.

    But is that really a good and/or possible solution?

    PierreB

    @yahoogroups.com, "Doug" <dougselsam@... machines made like that - they would not need a central axle or pole.
    itself contributes power.
    effective. So tempting. Having an airborne wind energy forum online is
    beyond any fantasy I ever had, but now that we have it, it seems to take
    a lot of time and doesn't seem to get anyone anywhere. Well just a point
    to note I guess.
    pierre.benhaiem@ wrote:
    if the (thin) shaft is too long (bad transmission);problem if the
    inflatable shaft is too fat (air force on the structure);problem with
    Rod's configuration (not enough lift to hold the structure containing
    ropes). An helium balloon in the top,or sustaining with arch,look like
    the marriage of the carp and the rabbit. So the shaft should be fat to
    be long,but that without too much air force on the structure.A wire-mesh
    (or similar) "squirrel" cage as shaft (and also rotor of generator in
    the low part)? Other discussions on the forum and the lack of investors
    in AWE shows no plan of utility-scale AWES was yet found in a clear and
    obvious way.And regular wind turbines are not yet satisfactory (too much
    materials,winds at low altitude...) but work.So discussions stay open.
    PierreB
    Group: AirborneWindEnergy Message: 8775 From: dave santos Date: 3/9/2013
    Subject: Makani Flying Wing Crash Cover-Up

    Makani Power's Composite AWES Flying-Wing architecture down-select was first announced to the Forum in 2009. Prototypes were confidently predicted doomed-to-crash, on the basis of well-known flying-wing flight dynamics & history, general UAV unreliability, and specific low-altitude autonomous-aerobatics challenges. The NASA Helios crash (and admirable mishap study) was used as a partial similarity model.

    Several Makani flying-wings were seen in PR in bench-test modes. A bare clue to a flight-test crash emerged in an former engineer's resume (of platform technology tested-to-the-limit). A brief glimpse of a wing in flight occurs in a new company video. A confidential leak now confirms there was a major crash of such a wing. Of course the "stealth company" never reported this dramatic event to the public, and has maybe even withheld crash information from the FAA and major investors (like ARPA-E). The crash sets a company MTBCF baseline.

    Joby Energy, with similar AWES architecture, was also plagued by crashes, but the company could not cover them up, insofar as they occurred in the presence of journalists.

    A long-standing protest from KiteLab Group (via my CTO role) is in effect against any AWES R&D effort that covers-up safety and reliability problems. Open safety knowledge is perhaps the most sacred obligation of Aviation Safety Culture. Stealth VCs seeking unfair commercial advantage by willful violation of this principle are unfit to earn airworthiness certifications.
    Group: AirborneWindEnergy Message: 8776 From: Pierre BENHAIEM Date: 3/9/2013
    Subject: Re: Makani Flying Wing Crash Cover-Up

    "general UAV unreliability" of both flygen and groundgen using M.Loyd's crosswind kite power (CKP),I presume?

     

    So,after a first good opinion about UAV-CKP (little material,high swept area),a second analysis shows some limits (irregularity of power,low efficiency,drag of moving tether,high space/land use,expected low reliability).

     

    The idea of harnessing HAWE is,so the AWES should be.But the good scheme is not yet found,or it is under our nose but we do not yet see it.

     

    PierreB
    Group: AirborneWindEnergy Message: 8777 From: dave santos Date: 3/9/2013
    Subject: "The good [AWES] scheme"

     Pierre, you wrote- "The idea of harnessing HAWE is, so the AWES should be. But the good scheme is not yet found, or it is under our nose but we do not yet see it."

    KiteLab Predictions- There have long been AWES developers who "see the good scheme", and are daily making good progress. What only a few see now, the final judgement of history will allow everyone to see.

    The good AWES scheme will prove to be mastery of kite and aviation knowledge and skills, high AWES domain experience, obedience to KIS, and relentless testing. There is no real mystery, just avoidable ignorance (behind our nose). Someday High Complexity AWES will make sense. These wonderful schemes just require more time than VC start-ups get.

    =======================

    Crashworthiness Note- Classic kites have an amazing robustness far beyond conventional modern UAS methods. In my extended experience, having seen hundreds of minor kite mishaps, the only critical failures (that could not be simply repaired in minutes) are line-break runaway of single-line kites, leading to a missing kite (twice). I have yet to see any modern kite actually wear-out, even as false experts lament the "short life" of fabric. Basic care and maintenance is all that is needed for "rag" to survive well beyond economic pay-back.
    Group: AirborneWindEnergy Message: 8778 From: Doug Date: 3/10/2013
    Subject: Re: Makani Flying Wing Crash Cover-Up
    I would expect hundreds of crashes as a matter of course in such experimentation. Not sure what is so remarkable about that. And Dave, S. yes they should be running all this stuff by you. What are they thinking? Do I publicize every failure? Nope, busy fixing whatever want wrong. A few years of that and after a while nothing goes wrong. Not as easy as one would imagine but persistence pays off eventually.
    Still wondering what exactly happened to Corwin, if anyone knows by now, and why, if they are in business, have they not answered their phone for 5 months now.
    Group: AirborneWindEnergy Message: 8779 From: Bob Stuart Date: 3/10/2013
    Subject: Re: Makani Flying Wing Crash Cover-Up
    This is just speculation, of course, but the mystery of the non-answered telephone may involve caller ID.  Telephony seems to be evolving into a network that only reliably accepts approved numbers.  

    Bob Stuart

    On 10-Mar-13, at 9:37 AM, Doug wrote:
    Group: AirborneWindEnergy Message: 8780 From: dave santos Date: 3/11/2013
    Subject: Re: Makani Flying Wing Crash Cover-Up
    Doug,

    A serious aircraft developer cannot afford "hundreds of crashes as a matter or course". There simply is to much time and money tied up in every major prototype, and real aerospace engineers are not so incompetent. Its even rather common to develop major new aircraft without a single crash, although Makani's premature choice of a risky architecture is an unusual worst-case situation (of a very inexperienced management team allowed to overreach).

    Ordinary corporate secrecy is in direct conflict with the moral and legal need in aviation to share all safety information. We understand the pressure to cover-up venture weakness, but must never condone withholding safety lessons. In fact, many an aviation developer that operates transparently in this regard can be admired as "the right stuff". A key fact to learn from the AWES Forum is that this is not the backyard-turbine world...

    Corwin's death still seems a mystery, but the coroner may just be reluctant to make a conclusive determination of of the most probable cause- Karoshi; death by by overwork. Anyone who knew how hard poor Corwin was working on Makani's "mission impossible" engineering goal need not be too puzzled. No clear-headed observer easily imagines foul-play occurred, for lack of evidence and a sensible motive,

    daveS