Hi Joe:
It is accurate that twisting tethers have been used in proposed AWE patents for decades, as a power transmission to a ground-based generator. You use the word "We" many times in your post. Not sure if it is the "Royal We" or what, but let's remember who on this list has been vehemently maintaining for 2 years that a rotating tether cannot possibly work for power transmission, calling it a "torque tube", in a quite derogatory way.

"We" on this list have suffered through some pretty detailed "analyses" of why a driveshaft into the sky can't possibly work, and why it is a completely useless concept. Perhaps "scolded" is the right word. We've been "scolded" that a spinning tether absolutely cannot work, in no uncertain terms.

Perhaps the scolder should have looked further into the existing literature.

So like I say, I'm not sure whom you are referring to when you say "We" in this case, but any serious player in this space does have at least the passing familiarity with the underlying patent backdrop, to which you refer. Public information, like telling someone they can turn right on red after a stop: Well-known and redundant to those who drive, useless info for those who don't.

Thanks for all you do!
:)
Doug S.

Wow the Magnus Effect.
One more concept already found lacking and ineffective for wind energy, suddenly taken into the sky, as though being skyborne can rescue what has already been found lacking on towers.
Someone should just construct a book of known losing concepts in wind energy, and then we can wait for companies to come in with press releases announcing their airborne version, and just paste it into the pre-existing slot we have already set up for them!
I also see no evidence of Magnus rotors in the video link offered.
Doug S.
P.S. By the way didn't Magnus wings also revolutionize aviation? They didn't? bbbbbut they had a press release and everything!

Maybe a clarification on Omnidea:       .... more in their view than the Magnus effect method ... :

http://energykitesystems.net/Omnidea/index.html

1. I do not have the facts of what was presented at conference yet, but apparently in this thread there is insufficient respect for what Omnidea might have in their focus. 

2. The Omnidea patent application faces planer airfoils for non-rotating lifting processes as well as facing an option of VAWT Magnus effect rotation; they seemed simply to cover the spectrum in their application, shown below:
Click at least one of the images to get the full patent application.     I have personally yet to study the claims in detail.

Hi Darin:
Thanks for your constructive comment.
I agree with your synopsis: I've envisioned carbon fiber whiskers as one possibility for "landing gear" for several years now. If it's gonna contact the ground, it needs a way to do so without damage, that is for sure!
As far as all the excitement that goes with this effort, hey anyone who places themselves in the spotlight must expect lots of detractive comments.
Ask any politician, actor, theoretician, author, entrepreneur, or anyone who purposely places their actions or ideas into the public spotlight, who must expect a mix of reactions, including strongly negative emotional reactions. These must be taken in stride without undue emphasis on this predictable percentage of negative comments.
Ever heard about actors that cannot even read their own reviews because any negative comments might cause an emotional collapse? Gotta stay positive no matter what and, without completely disregarding detractive observations that may express legitimate concerns, in general, let the negativity wash away like water off a duck!
:)
positive, positive, positive!
:)))
Doug Selsam

Bob,
 
Those islands are located close to Hydro Quebec' s James Bay hydroelectric installations .   .  .   .  . the biggest (of several) hydrodam is rated at over 10,000MW (the Robert Bourassa dam). The islands are the jurisdiction of Nunavut territories .  .  .  . option to connect power cables into either Ontario of Quebec, for resale into other markets.
 
 
Harry
 

---

To: AirborneWindEnergy@yahoogroups.com
From: bobstuart@sasktel.net
Date: Sun, 29 May 2011 20:13:53 -0600
Subject: Re: [AWECS] Meeting with Dave Santos in Sommariva Perno

 

The hydro power projects had no options for relocating elsewhere, and while their power lines may sometimes have excess capacity, the submarine cables from the islands would be very costly.  I just think that wind power can be gathered nearer to the markets, especially if a submarine cable is involved.  Have you heard of a  fabulous wind pattern there?  BTW, my bathwater eventually finds its way to Hudson's Bay.

Doug, I have designed a portable wind energy harvesting system which could be held aloft by a tensairity kite.   In my drawing, I show a 'kytoon'. 

Please share some feedback on this design drawing utilizing a flexible, Darrieus 'V-wing' blade. Four of them could lay flat in the roof rack on a cross-country electric vehicle. 

The generator doubles as a motor to spin the V-blades up to operating speed:  http://darinselby.1hwy.com/images/gorlovhdarrieuswingblades.jpg  Then, after discovering about Tensairity, which requires no lifting gas, I believe that it is a marked improvement over the kytoon.  

Perhaps this Tensairity elaboration isn't necessary at all, and a hexagonal Manlifter kite is simpler for a backyard enthusiast to construct? http://darinselby.1hwy.com/gophiakite.html

The aerodynamic, flexible 'V'-wing blade is my original design, and is a take-off of the Darrieus blade invention.

Pressurize air into a lightweight with a DIY mini-air tank to take along on the trip.  This inflates the tensairity kite when it's needed.
The entire system becomes very portable.  Only an enclosed roof rack container space is needed, on top of an electric vehicle, to bring this wind energy harvester along!

So, imagine the deflated, folded-up tensairity kite with four flexible "V"-shaped wingblades that can be quickly disassembled to lay flat.

Six  support rings, an electric generator, kite hand winch, & a conductive tether.

---

To: AirborneWindEnergy@yahoogroups.com
From: doug@selsam.com
Date: Tue, 31 May 2011 17:08:59 +0000
Subject: [AWECS] Re: New Flying Superturbine(R) Kite Tether Video

 

Since the generator in that video was not loaded, we still have not seen power transmission by torque in the tether, IHMO.  Is there an easy formula for predicting the minimum tension/torque ratio to prevent knotting in a rope?  A semi-rigid tube would do much better.

Link replacement for Darin's message.

http://darinselby.1hwy.com/cgi-bin/i/images/gorlovhdarrieuswingblades.jpg

Darin,

It appears that a fundamental challenge of aerostat or Tensairity supported structures is the thrust vector that resolves as downward force. Your lifter must support not just the weight of the blades, but also this downward force. A capture scheme that also generates lift seems almost a necessity unless the lifter is quite large. Is a Darrieus V-wing able to generate lift?

Your Tensairity would also have to be filled with helium or hydrogen since without the buoyant force it acts similarly to a leading edge inflatable airfoil.

Cheers,

DavidC

DavidC in another thread:
 "A capture scheme that also generates lift seems almost a necessity
unless the lifter is quite large. "

ROI in mind, and without having the numbers here, very frequently mind flashes invite me to aim to keep lifter function separted from rotation generation function.  Let lifting of system be specialized and let rotation-generation be specialized; separate the two.  Lift mass aloft with perfected low-cost solutions. Cause rotation for generation from perfected parts.      The tease for this comes from the tickle that combining the two functions may detract from ROI and detract from the best of lifing and the best of rotating. Further tease comes from a drive for simplicity for replacement-of-parts considerations.  And further tease comes to me from the consideration that a part that is rotating for purposes of generation is costing downwind drag no matter the orientation, and that drag component will pull tether down; such downs have to be lifter in one way or another, either in an integrated part that is with a vertical lifting component or separated into a separate vertically-lifting set of parts.    Dave Culp once quipped ...(paraphrased in memory here:) "Are we just going to lift up turbines?"   Airbine and others are aiming to lift up turbines with kytoons or lifting shaped LTA wings. Some of those in such direction offer up like Omnidea to escape bad weather by LTA racing systems above the weather with only tether in the tough weather.     Ultimately, AWECS will be facing the ROI as regards integrated lifter-turbines versus separated lifter from rotating turbine components.  It might be pretty to see a combine like SWP quad rotors that play an integrated oblique-to-wind stream lifting and rotating-generation, but would the same money spent for that integration be better spent in having severe specialized lifters coupled separatingly with full-on HAWT fully facing the stream?

JoeF

JoeF:

The idea of separation of function is sound. My earlier point is that incorporating lift is a helpful property given how big a LTA structure must be. Tether mounted generator means can be examined and compared for lift vs. power output vs. weight. A Darrieus appears to be fairly heavy for its output, with no lift. A turbine set has lift prospects if the tether angle is correct (see Doug's videos). A parafoil has lift, but needs a torque coupling or on-board gen set.

In a design space where weight makes a tremendous difference, and the wind is fickle, there really seems to be only one choice. Of course, I hear that when you get above a couple of hundred feet, the wind speed is as reliable as taxes and my next in-laws visit.

DavidC

I may not have explained this "V" wing blade with its 'lift' qualities.  At a certain RPM these blades, due to their contour will start pulling themselves around, and will actually spin faster than the wind itself.  The tensairity kite also is designed with aerodynamic lift and has very good weight-lifting characteristics.

---

To: AirborneWindEnergy@yahoogroups.com
From: david@carmein.com
Date: Wed, 1 Jun 2011 14:59:00 +0000
Subject: [AWECS] Re: New Flying Superturbine(R) Kite Tether Video

 

Bob:
I agree it doesn't show or prove that much. It was a very toe-in-the-water weak demo, but it sure did work easy, and sure was easy to make!
Doug S.

Hi Dave S.:
Yes who WAS that masked man?
:)
I agree with your (latest) statement that a torque tube would be more appropriate means of transmitting rotation to the ground(?).
(Is this tantamount to a religious conversion?)
I normally use a more rigid tube for a driveshaft, just like Ford, GM, Toyota, and the rest. In fact my turbines often simply use (drumroll please) a driveshaft, as a driveshaft! Yes I just pick up the phone and order driveshaft grade steel tubing! For a driveshaft! Who knew!

But a rope was light and cheap. Have yet to see a car using a rope for a driveshaft but there's always a first time!
Doug S.

Is anyone besides me heading for Stevens Point, WI, on June 13th?

DavidC

In this thread there seems to be some forgetting of the groundgen methods that are not reel-in-out (with its retraction or cost phase). For instance, non-Yo-Yo groundgen AWECS methods:

• Railed traction method with generator shaft as axle perhaps of the railed car
• And there is the traction cable-way cart with generator on the wheels riding the cable.
• And there is the counter-weight boom method where the tether draws the boom left and right with one-way clutch where the turnaround moments are short while the tether length remains fix (can be varied to reach different strata when needed).
• And the several fan-belt loop methods driving groundgen from rotaries aloft (including, but not limited to the lifted laddermill of sort that is airfoil lifting upside of loop and airfoil negatively lifting downside of loop .... with loop driving one direction ground generator shaft)
• And the tracted barge set in water with the large water turbines generating
• And the upper working parts driving upper ambient air through hollow tether to drive ground generators or pumps (looping oil might be considered, but air is one-way and available from above deliverable below)
• OrthoKiteBunch beam oscillations
• Rocker-arm WPI method
• Arch kites with HAWT driving fanbelt
• Tri-tether of Santos  KiteLab
• ?  [this listing is not complete ...]

ROI will rule ...

JoeF

 

Grant, I appreciate your insights very much.  DaVinci had an interesting drawing for a helicopter. Add to this 'widened screw' a  tapering, spiraling, Bernoulli-contoured wing effect.  Two of them entwined onto a central axis.  This, there is still lift, yet the chopping helicopter sounds in high-winds could be lessened. 

With your understanding of the 'autorotation' and 'rope-spinning drag' I wonder if something such as this would not work better?  Yet use a tensairity kite to have the horizontal-spinning blade assembly. 

Imagine substituting the paddle wheel with the curved V wing blade design. Much quieter this way, for the blades get pulled around by the wind, at a certain rpm speed.  The on-board generator could work backwards as an electric motor as well, switching back-and-forth to keep the rpm's optimal. 

---

To: AirborneWindEnergy@yahoogroups.com
From: grant@skymillenergy.com
Date: Thu, 2 Jun 2011 10:08:17 -0700
Subject: Re: [AWECS] Re: Separated functions: lifter from generation worker

 

To prior post by Darin in this thread:

http://darinselby.1hwy.com/cgi-bin/i/images/kitegenerator.jpg  

http://darinselby.1hwy.com/cgi-bin/i/images/gorlovhdarrieuswingblades.jpg 

This suggests that during calms, the only thing aloft could be a cubic meter of hydrogen in a kytoon, a hundred meters up, ready to initiate the launch sequence of an acre or more of kites.  Sounds good to me.

--- In AirborneWindEnergy@yahoogroups.com, Bob Stuart <bobstuart@...

Yes.
The potential of a small LTA kytoon for startig the launch of large--or even huge--kite arrays.  Think of the power of a small spark igniting a huge plains grass fire. Reverse domino cascade effect.  Launch-after-lull via tiny LTA kytoon.
JoeF

 

 

One could also put a light hoop structure around the tips. This would prevent damage but would not allow rotation until lifted.

DavidC

Added link to Aerial Products Corp., maker of Kingfisher line of aerostats.

http://www.aerialproducts.com

DavidC

Hi Dave Santos and group,
 
           No it was not I who put it forth to the group, but I was thinking along those line you've stated below after I heard about the landing. Was thinking of something simple lite weight, strait shaft for length of SpiralAirfoil two bearings, one in front and the other bearing in the back with trianglizations attached, possible pontoons on both ends and then pontoons on self launching kite, pontoons could be designed with lift in mind.
 
                                                                                                                                                                                                                            Dan'l

---

To: airbornewindenergy@yahoogroups.com
From: santos137@yahoo.com
Date: Fri, 3 Jun 2011 09:13:03 -0700
Subject: [AWECS] Landing Legs Idea

 

It was Darin: 
* Darin Selby  wrote:
 ..." I say this is an astounding invention that really only needs some
 lightweight "V"-shaped landing stands hanging down every so often to keep the
 ruler blades from ever hitting the ground. "

http://www.energykitesystems.net/CoopIP/Legs.html 

How do you stop your LTA device from blowing away in a storm like this
one
http://articles.janes.com/articles/Janes-Defence-Weekly-97/KUWAIT-LOSES-LASS-AEROSTAT-IN-STORM.html ?

Robert.

Grant,
It does appear that using torque alone to keep the generator at the
desired altitude will be difficult but in practice angle of attack will
also be used. In low winds the device will have to be nearly horizontal
just to stay aloft and very little power will be generated. In high
winds it can be nearly vertical so it will intercept more wind so much
more power could be generated.

When you first use the generator to take power out of rotor its speed
will not change much for a given torque. Increasing the torque will
yield diminishing returns until you reach a point where the rotor will
suddenly come to a halt.

These 2 considerations make it clear that any particular SWP type device
could only operate in a narrow range of wind speeds. It is one of the
reasons I proposed a hybrid device where the airborne rotors are only
just big enough to help control the wing. Most power will be generated
at the ground based winch.

Robert.

My guess: depower working turbines to reduce system drag;  such will give higher angle to the holding tether set; perhaps increase buoyancy of lifter LTA with onboard gas controls.  Get above weather; avoid fighting bad weather at ground (or bad guys in Desert Storm wars.)

To follow up my post after a moment's reflection. As the wind speed
rises beyond the speed that can get the device airborne it will be
tilted increasingly towards the vertical. When we reach the point where
the generators (and/or rotors) cannot handle any more power we would
tilt back towards the horizontal. That would increase the useful wind
speed range quite considerably. Controlling both angle of attack and
power will be a delicate balancing act - but possible using modern
computers. However, I still doubt it will be cost effective to put large
generators into the air.

Robert.

Joe,

To get above the weather requires crazy high altitudes. Tether mass and
drag then starts to become a major problem. Tether expense also goes
stratospheric because of the need for fancy materials. It makes more
sense to me to concentrate on technologies that can be operated at low
level. There is plenty of wind below 1000m for all our needs.

Robert.

Omnidea did not mention free-flight dual kite-group  where LTA wing group may be place in say the upper LTA wing set where the tether to the second coupled wing set could be at controlled lengths, even shortened during escape to upper strata, even while generating energy for operations and perhaps feed by powerbeam to other aircraft.      And open is the whole realm of saving jet fuel  by using free-flight dual-wing-set kite systems for travel without fuel; the flights would be directed to be out of bad weather....to the side or above or lag behind.

 

 

SkyWalker here is it's cousin,  http://www.youtube.com/watch?v=HoCAxS4vqwQ&feature=watch_response 
 

---

From: spiralairfoil@hotmail.com
To: notes@energykitesystems.net
Subject:
Date: Sat, 4 Jun 2011 15:59:50 -0400

Hey Joseph,
 
                You've prolly heard of something  called aerogel, http://www.youtube.com/watch?v=kHnen2nSmDY What can be done with this material. Seems like a thang.
 
                                                                                                                                                                                                    Dan'l

Joe,
 
             I saw this show on bird beaks, specifically bird bird beaks, incredible strong, yet very lite weight, that said would graphine and aerogel compliment one another?
 
                                                                                                                                                                                                             Dan'l
 
I am sure that I am way behind the curve on the one, but still dream on.
 
Thanks Joe!
 
                                                                                                                                                         
 

---

To: AirborneWindEnergy@yahoogroups.com
From: joefaust333@gmail.com
Date: Sat, 4 Jun 2011 13:33:22 -0700
Subject: Re: [AWECS] FW:

 

Daniel,

        Graphene and graphane for AWE is in futurescope.   So, far, in this group:

2714	Re: [AWECS] NASA involving in AWECS ...on-time & well-qualified to study issues like airspace-integration, & carbon nano-tubes as the ultimate tether material, & graphene as the ultimate membrane. Best of luck to Mark Moore in his study, daveS From: Bob Stuart To: AirborneWindEnergy@ Cc: Sent...	dave santos santos137@yahoo.com santos137	Dec 14, 2010 9:41 am
2494	Re: [AWECS] Lta windpower ...keeping be solved toward ever-up kytoon lifters of turbines or devices for fan-belt mechanical transmission? Will graphane or graphene stop hydrogen leaks ? Keep in mind toyAWECS, sportAWECS, and residentialAWECS besides utilityAWECS in this LTA sector; what...	Joe Faust joefaust333@gmail.com joe_f_90032	Nov 10, 2010 10:19 am
1000	Re: [AWECS] Stratospheric Return-Flow Resource ...membrane-based stratospheric ballooning inform that a suitably designed soft kite will work above the tropopause. Emergent graphene-based materials greatly enhance potential. The stratospheric upper-flow kite can be opposed by a much hotter smaller sweeping...	Dave Culp dave@kiteship.com dave_culp	Jan 25, 2010 7:56 pm
998	Re: [AWECS] Stratospheric Return-Flow Resource ...membrane-based stratospheric ballooning inform that a suitably designed soft kite will work above the tropopause. Emergent graphene-based materials greatly enhance potential. The stratospheric upper-flow kite can be opposed by a much hotter smaller sweeping...	dave santos santos137@yahoo.com santos137	Jan 25, 2010 3:21 pm
993	Re: [AWECS] Stratospheric Return-Flow Resource ...membrane-based stratospheric ballooning inform that a suitably designed soft kite will work above the tropopause. Emergent graphene-based materials greatly enhance potential. The stratospheric upper-flow kite can be opposed by a much hotter smaller sweeping...	Dave Culp daveculp@gmail.com	Jan 24, 2010 4:53 pm
992	Stratospheric Return-Flow Resource ...membrane-based stratospheric ballooning inform that a suitably designed soft kite will work above the tropopause. Emergent graphene-based materials greatly enhance potential. The stratospheric upper-flow kite can be opposed by a much hotter smaller sweeping...	dave santos santos137@yahoo.com santos137	Jan 24, 2010 3:04 pm
175	Re: [AirborneWindEnergy] Re: Tripod Tether COTS AWE Demo ...preferred load path fiber across ripstop polyester or nonprepreg carbon ribbon sandwiched in a polyester membrane is also good. Graphene (bucky tubes) is in the pipeline & will give another order of magnitude to play with. Wingloading by unit area remains constant... ===== ====================== Re: [AirborneWindEnergy] Re: Tripod Tether COTS AWE Demo ...preferred load path fiber across ripstop polyester or nonprepreg carbon ribbon sandwiched in a polyester membrane is also good. Graphene (bucky tubes) is in the pipeline & will give another order of magnitude to play with. Wingloading by unit area remains constant... dave santos santos137@yahoo.com santos137 Jul 7, 2009 =================================================== Then in EnergyKiteSystem.net   we have a collection file: http://www.energykitesystems.net/graphene/index.html   http://www.energykitesystems.net/graphene/articles.html And all are invited to place links and files in AWE Files section and Links section on new materials that may play in AWECS.

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

Ongoing student of graphene and graphane at layman's level,

JoeF

I'm finding there's sometimes little point in telegraphing my ideas ahead of the fact. I can only fit so much detail into my already-too-long posts, and by necessity must leave out most details, including the myriad of features already included in my existing patents, and most future improvements on the drawing board.

So then it seems that all I accomplish is for other people to start arguing about who invented my ideas. What's the point of advertising until you have a product for sale? This is why most of the bigger "players" in this "industry", or those with patents, funding, and working prototypes, do not post anything to this group. Or any other group. Yes, flying things can often benefit from landing gear. One more revelation.

So the topic of this thread is who first thought of landing gear for my flying wind turbines? Guess who? ME. About 25 or 30 years ago, long before I told any of you about flying wind turbines in the first place, and before some of you were born.

Yes the free glowing pull-string flying saucer toy given away at the AWEA Windpower 2011 show has a plastic propeller with a ring around it. Yes we noticed that the ring could potentially prevent blade tip damage if applied to a flying Superturbine(R), since we flew it the same day we flew the demo that, as predicted, broke it's under-a-dollar disposable blade tips upon landing. That's why we didn't fly it until we had film rolling. We knew it would break. We knew landing gear could cure that. We knew there are already off-the-shelf turbines in production with a ring around the blades. With or without a heavy, non-power-producing ring, any of our wide selection of off-the-shelf plastic blades would have survived the ground contact with little or no damage, just a lot of dust.

:) Doug S.

sounds logical

When time to reel in, less energy would be required if a radio-control signal slowly deflates the tensairity kite platform.

---

To: AirborneWindEnergy@yahoogroups.com
From: doug@selsam.com
Date: Sun, 5 Jun 2011 18:41:24 +0000
Subject: Re: [AWECS] High Altitude Operation Notes

 

http://darinselby.1hwy.com/contrawindspinnr.html

---

From: darin_selby@hotmail.com
To: airbornewindenergy@yahoogroups.com
Subject: RE: [AWECS] Re: Landing Legs Idea
Date: Mon, 6 Jun 2011 02:59:20 +0000

An arrangement of a graphite "^" landing stand, one for each propeller, is important to do.  You mention using rings for landing on?  How exactly would that work? 

Spinning the long rope as a sort of 'flexible drive shaft' has more friction involved than just spinning the generator that's directly coupled between two 'contra'-spinning blades.  This would double the rpm and cancel the torque on the conductive tether to the ground.

In this next drawing, eliminate the pole stand with the fin.  This is all what I learned by Doug's designs.  So now it is two sets of contra-spinning generators that are connected together by a graphite pole. 

Then, add a graphite "^" landing stand at each end.  That's one unit.  These units could be added like a train to each other, and the entire assembly held aloft by a radio-deflation control Tensairity kite.

---

To: AirborneWindEnergy@yahoogroups.com
From: doug@selsam.com
Date: Sun, 5 Jun 2011 18:38:45 +0000
Subject: [AWECS] Re: Landing Legs Idea

 

An arrangement of a graphite "^" landing stand, one for each propeller, is important to do.  You mention using rings for landing on?  How exactly would that work? 

Spinning the long rope as a sort of 'flexible drive shaft' has more friction involved than just spinning the generator that's directly coupled between two 'contra'-spinning blades.  This would double the rpm and cancel the torque on the conductive tether to the ground.

In this next drawing, eliminate the pole stand with the fin.  This is all what I learned by Doug's designs.  So now it is two sets of contra-spinning generators that are connected together by a graphite pole. 

Then, add a graphite "^" landing stand at each end.  That's one unit.  These units could be added like a train to each other, and the entire assembly held aloft by a radio-deflation control Tensairity kite.

---

To: AirborneWindEnergy@yahoogroups.com
From: doug@selsam.com
Date: Sun, 5 Jun 2011 18:38:45 +0000
Subject: [AWECS] Re: Landing Legs Idea

 

When we were flying 71 meter aerostats for TCOM we could fly at 10,000
feet up through at least 45 knots but when the 40,000 foot squall
lines came across the desert we'd fire up the diesel and pull it down.

If you're going to go high enough to avoid most of the serious
thunderheads you need to go to 40,000 feet or better.

Helium expands by about 40% between sea level and 10,000 feet so we
could only fill 70% of the envelope with helium with the rest taken up
by an air ballonet.
As you climb to 10,000 feet the ballonet collapses allowing the
helium to expand.

When the ballonet is fully collapsed you are said to be at "pressure altitude".
Any further increase in height will allow the helium to expand further.
At some point you will have to vent off helium to avoid
overpressurizing the envelope.

If you wanted to go to 40,000 feet you'd only be able to fill 20% of
the envelope at sea level so you'd have to increase the envelope
volume by 350% to have the same amount of lifting gas.
This doesn't account for the possible increase in weight with a
larger envelope or the definite increase in the amount of tether you
need to lift.

In short you can lift a large weight to a small altitude or a small
weight to a large altitude.

For a real world example consider the Zepplin "height climbers" from
the war to end all wars.
They had the duraluminum structure lightened enough to allow them to
get to 20,000 feet but they would break in half if you put the wheel
hard over in the denser air of sea level.

Unlike an airline (or a dirigible) a tethered aerostat has limited
options for maneuvering around bad weather.
Sometimes you could rise above a small storm or local turbulence but
when the really bad weather comes you want to be moored.

If nothing else it makes it easier to find the pieces afterwards.

Andrew King
King Technical Services
Ann Arbor MI 408-1286
Consulting on technical challenges
Translating ideas into reality

Roger, The only sure way to weather a storm with an aerostat is to shelter in a hangar. The beauty of a small service aerostat is that the shelter is affordable. Also, an aerostat need not loiter aloft in calm, it can always climb up only as needed. An exciting trick is to raise loads against the drag of a kytoon, wing, or drogue being pulled down hard from a high starting point (coolIP), DaveS

As Doug has pointed out, using a ring to protect a propeller is not a new idea. But it was worth mentioning because it is simple and easily implemented.

A ring does two things. One, it prevents the blade from being sheared off when it hits the ground. Two, it significantly stiffens the blade, enabling thinner blades. DownsideS: 1. Does not permit free spinning when "landed," 2. Adds to parts count, 3. Adds to weight, unless offset elsewhere.

DavidC

In the brining-down an inflated part, consider:

1. The increasing atmospheric pressure on inflated parts; this will have
an effect on the part.

2. Keeping form, but changing angle of attack may win over deflation for
reduction of effort to bring down; too much loss of form might tend to
lose the opportunity to control the wing or part, and that might lead to
more drag.

JoeF


--- In AirborneWindEnergy@yahoogroups.com, Darin Selby <darin_selby@... wrote:
signal slowly deflates the tensairity kite platform.