DaveS,

Concerning "FAA-driven kitefarm window (600M high x 1200M wide reference-unit)" we had some discussion with some discord not about theoretical possibilities but, for me, about efficiency on method involved. So the number you gave (a fraction of 60 MW, 20 MW (?) please correct me if it is not that) seems correct. The number I gave (1/520 of it ) was about what I saw on the method involved and by taking account (rightly or wrongly) of a schema of both not directional HAWT and WECS as looping-units, since I do not saw (rightly or wrongly) arch as (easily) directional.

So I propose to take again numbers, then refining them, then going to methods. For it take us for example Vestas V164 , swept area 21,124 square metres, diameter of rotor 164 metres , output 8 MW, wind speed 11 m/s , total height 220 metres.

Note for conventional wind turbines 11 m/s is often the value of reference. So the altitude of AWES being from 50 metres to 600 metres instead of from 56 metres to 220 metres, we can push to something like 13 m/s to make equal things. So the 8 MW/21,124 m² become 13 MW.  Swept area is a little reduced: 550 m x 1150 m = 632,500 m². Power in HAWT features raised in 13 m/s wind speed:  389 MW. An AWES being able to take 1/10 ( 39 MW) of it would be more than excellent.This value is not too far the value you provided, the difference here being wind speed reference. 

 

PierreB

 

"since I do not saw" corrected in "since I did not see"

 

PierreB

 

Circa 1990

Pierre: I try to discern what you mean when you write.  Don't worry if you don't get every nuance (french word?) of the English language correct.  Nobody expects you to have perfect English.  Your English is probably way better than anyone else's French.  By the way, I read last night that since the Norman invasion, 30% of English IS French.  Also: English has more words than any other language - I think the next down the list is German with less than half as many words.

"A marginal kite energy notice at present, but AWE will surely figure, and India will be a huge player:" ***Dave S. Lie-Watch: 1) "a kite energy notice": The notice is of a "planned launch" of a KITE MAGAZINE, coincidentally using the NAME "Kite Energy" (capitalized) - we have no indication at this time that it is a "kite energy" (uncapitalized) announcement, as pertains to the subject of this Yahoo list.  Instead it is announcement of a planned launch of a kite magazine, with no other information given.  Everything else, you JUST MADE UP out of THIN AIR. (Lies about the present)

2) Related "AWE will surely figure" ***IF AWE does NOT figure, then this phrase will turn out to be lie #2. (Lies about the future)

3) "India will be a huge player:" *** If India is NOT a huge player, then this will turn out to be lie #3. (more lies about the future)

What amazes me is, after being flagged as a consistent liar, your wanton disregard for the truth pushes you to stack up lies faster than you can stack up kites:  3 probable lies in ONE sentence.  And that is normal for your writing.

Just for the record, an honest sentence might read: "A planned kite magazine notice at present, but AWE may figure, and India could be a huge player:"

The problem with pathological liars is they are so far out on the lying curve they can't even see that they lie more naturally than they breathe.

A kite magazine about kites would de facto be serving AWE.

Baptiste:  I still have not seen anyone comprehending my explanation, which has to do with momentum versus kinetic energy.  Momentum is mv, whereas kinetic energy is 1/2mv^2, so as flow speed increases, kinetic energy increases faster than momentum. 

Since power to keep the kite aloft is kinetic energy per unit time, if you can reduce the kinetic energy in the downdraft that holds up the kite, you can reduce the kinetic energy per unit time, which is power. 

Mother nature dictates that the momentum of your downdraft holds up the kite, but you can CHOOSE to accomplish this momentum by using more air volume in your downdraft, at a lower speed.  The momentum is the same, the kinetic energy is lower. 

Assuming geometric similarity (no change in aspect ratio) for simplicity, if you double your kite area, you can push twice the volume of air down.  To get the same momentum exchange as the smaller kite, you can then halve the downward velocity.  When you halve the downward velocity, you impart 1/4 the kinetic energy, which, even when multiplied by the doubled volume still uses only HALF the total energy per unit time, (which is power) to lift the same weight (call it 1 kg). 

So, double your wing area, and, for the same weight, you use HALF the power.  This is an idealized case, of course.  A moment's reflection by anyone with even a child's level of aviation awareness bears this out:  It's well-known that a design using less wing loading requires less power to fly.

Any idiot knows gliders have more wing per unit weight so they can remain aloft using less power.  Why does the Gossamer Albatross require so little power for its weight to remain aloft?  A large wing area compared to its weight, that's why, and it is not in question, but in fact a well-known rule-of-thumb in aviation.  Repeat: This is NOT MY OPINION, but instead, one of the most basic facts of aviation and airplane design.  More power requires less wing to stay aloft.  Less power requires more wing to stay aloft.  Period.  End-of-story.

Regarding your other point, it would be nice on this forum if anyone could actually reply to any simple point without trying to turn it into a lying word-game.  I don't enjoy it either.  It's interesting to step back and witness the lying desperation of someone who can't balance units across an equation suddenly declaring themselves "an engineer" in an attempt to try and seemingly win an argument.  The thing I'm still wondering is, why do they want to have an argument in the first place?

"A kite magazine about kites would de facto be serving AWE.~ JoeF"
*** It COULD not necessarily WOULD, since nobody knows if kites will even play a role, if and when a successful AWE may be developed.  All it takes to change a hopeful statement to an outright blatant lie is one letter.  Joe, I know it is not YOUR intent to lie, so I'd be careful which words you use.  If you make statements in the absolute, about topics that involve uncertainty, there's a high probability the "absolute" statement could turn out to be untrue.

JoeF,


Conventional wind towers have a standard as 3-bladed turbine. AWES should have a standard in a same way. By analysing parameters and making some trials such standard can be found. Actually in the world of universities and companies reel-in/out method works as temporary standard, being not marketed. In my opinion this method does not allow a maximization of space, but is still preferable in many other studied methods.

 

PierreB,

http://flygenkite.com

"and you stand corrected by a working engineer daveS" *** Your desperation to always "seem" to win every argument, no matter how many lies upon lies it may take, is really bad.  In this case you are STILL trying to rationalize NOT being able to come up with an engineer to refute my point (that has no refutation available), by maintaining your recent fiction that you are "an engineer". 

Have fun lying, and lying more, attempting to bolster your previous lies.  As Dave Lang et al have pointed out, the only reply to you involves going over remedial high-school material.  That is NOT indicative of "an engineer".  Not sure how long you want to go on with THIS lie - don't you have more new ones that are more important?

"reel-in/out method works as temporary standard, being not marketed"
*** Reeling is an artifact of mental laziness, not comprehending the real solutions.  People try it because it is easy to understand, and can be accomplished using a kite that can be purchased. 

Reeling is "being not marketed" like so many wind energy "inventions" that cost too much for the amount of energy they can provide, because it was a bad idea, and the results bear this out.  The idea is to provide wind energy at a lower cost per kWh, not a higher cost.  Many with a better understanding would not have wasted their time with reeling. 

Certainly by this point, one might expect to have heard some good results if reeling, per se, were really a good method.  To me, I don't think a cursory initial assessment would rationalize a reeling program.  Nonetheless, the first few people trying it could perhaps be forgiven, in the sense of "hey, ya never know..." but by now, it's approaching the level of a trip to Vegas as an investment: It might seem to work out for a moment or two, but at some point it will become obvious that it was a bad idea.

I'm looking for a clutch which engages based on axial tension...

e.g. when the input torque shaft tries to pull out of the clutch with enough force...

The output plate is engaged

Do you know of any clutch design which fits this criteria?

This would help with any spaced ladder transmission. where by you want a tight lift line before trying to transmit torque so that the ladder does not over twist.

Really struggling to find one off the shelf... Seems like a really easy thing to make
Surely somewhere..

"First you say Doug is "right" about a "parachute" model, but my search of old messages does not find any Doug "parachute"" *** I cited the fact that a larger parachute falls slower than a smaller parachute, for the same weight.  (Your search didn't work, and you've missed reading important points).

This was an attempt to explain what should be obvious, requiring no explanation:
A larger surface area allows a weight to be held aloft using less energy.  In the case of the parachute, the power is the potential energy of height being "used up" as the parachute falls. Or consider a fan blowing an updraft to keep the parachute in one place.

The general idea COULD BE described USING THE LANGUAGE OF MATH as commonly seen in the fields of SCIENCE AND ENGINEERING, that the power required to keep a given mass aloft APPROACHES zero as the area APPROACHES infinity.  This is shorthand language so the educated reader can imagine the shape of a graph of power/area.

Note: NOBODY using this terminology actually BELIEVES that the ZERO power, or the INFINITE area could actually be reached.  They can only be "approached", and are illustrative terms denoting asymptotic trends in a hypothetical graph of area versus power required.

Being unfamiliar with the shorthand mathematical language of science and engineering, one might mistakenly believe the engineers are really talking about an infinite area or a zero power situation, but that is an erroneous interpretation.