What is possible with Payne's patent US3987987 figure 5?

In my opinion it would work back and forth like a linear track (NTS video below), or rather two linear tracks side by side with a kite for each, but being cheaper, and not requiring a moving generator as one pulley would rotate the generator, as for a ski lift which comprises a motor instead of a generator. The kite tether attach moves perpendicular to the wind on the pulley-rope-drive, as for the wagon on a linear track. The kite force transfer would be correct (unlike figure 5 for what I think) what I verified manually.

A carousel with a rope driving pulleys (or a cableway-like) would be perhaps also possible and has be evoked by Dave Santos in the old forum if I remember correctly.
Carousel with a circular rope driving pulleys

Yes that is the kind of configuration I’m referring to. One long horizontal loop, pull it back and forth across the wind with a crosswind kite to get crosswind kite power, if crosswind kite power is what you want to pursue.

Pierre: I believe a more carefully-constructed demo would need to be built to show potential. No substitute parts, such as a skateboard, but a real model of the actual configuration under consideration. I’d suggest a fixed position for the generator (like the drawings) that could be driven by the rope-drive concept we’ve read about so much for the past 12 years of internet-typing and flying kites for fun. Instrumentation could be applied to measure output if any version looks like it is working well enough to bother measuring.

Maybe these guys could help:


Check the video starting at around 10:00
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At 11:00 precisely. This system describes a conversion from a rotational motion towards a linear motion via connecting rods. It is the reverse of the conversion of a steam locomotive.

If we add a second pulley and a rope drive between the two pulleys, then the kite tether driving the rope drive, we obtain something like the rope drive sketched by @Windy_Skies, excepted that the pistons and the connecting rods are replaced with a generator driven by the first pulley.

In any case, the rope drive on the ground seems much closer to the NTS linear track than of US 3987987 figure 5, especially with regard to the transfer of kite force to a single mobile point (here the kite tether on the rope-drive).

Thanks, I hadn’t heard of NTS before. Looking at that it occurs to me you could perhaps make it so that the tether(s) don’t actually have to go around the pulleys. You could also make the pulley without the generator attached to it mobile, to be able to better orient the system to the wind.

As a sidenote, if I understand things right, one problem with that setup is that every pulley is less than a 100 percent efficient. Assuming a pulley is 97 % efficient you’d get at least an 1-0.97 ^{10} \approx 26 \% efficiency loss from using 10 pulleys.

Doug, let us credit Dave for doing the first test of US3987987 figure 5 AWES. All the elements, and in particular the two pulleys framing the skateboard via the tether triangular network, are present. You have to watch the video carefully and make stops to see it all.

I think the rope-drive system is very different as the kite force transfer is made on a single mobile point, as for the NTS linear track. As a result I think the force transfer can be better than that of US 3987987 figure 5 where the kite force acts on the two pulleys simultaneously and within the tether network, leading to a loss of useful transfer as I explained on several previous messages.

I compared the NTS linear track with the rope-drive you sketched (the carousel I sketched being another thing) for two reasons: kite force transfer on a single mobile point, and forth and back motion.

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image

I made a rough miniature of this as advised by @Windy_Skies. Here is a picture below:

Then I experimented it (video below) by pulling on the two ends of the lever (as for the initial figure 1b) then on one end (as for OrthoKiteBunch).

The figure 5 is significantly different because there is a linear move of the (power) segment between the two pulleys where the power is taken.
image

Below is also a miniature of the figure 5 device alone then with steelyards.


Distance between the two pulleys: 0.45 m.
Distance between the vertex (where the kite is, or here the orange steelyard) of the triangle and the point 0 in the middle of the two pulleys on the power segment: 0.45 cm when said vertex faces said point 0.
When the vertex of the triangle covers 0.45 m, the power segment moves linearly by about 0.2 m.

Concerning the measured traction, the orange steelyard located on the vertex indicated a value roughly 2 times the value indicated by the black steelyard located on the power segment. The photo shows where both steelyards are located.

These rough measures could be calculated and refined by using a simulation integrating kinematics then the resulting forces.

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That did help Pierre. I sometimes just use a loop of string and some extra fingers and tubes. Or maybe a board with some nails sticking out of them.

I misinterpreted this image before. I have now quickly read the patent. Payne knew his stuff to be able to write this in 1975 I think.

Here’s what the patent says about figure 1b:

FIG. 1b shows a first alternative preferred embodiment of the tethering structure shown in FIG. 1a. In this embodiment, the kite 10 is again tethered on cable 20 such that it tacks back and forth across the wind shown by arrow 18. However, rather than employing a succession of pulleys, the single tethering line is coupled to ends of a link member 40 at points 42 and 44. The link member 40 is pivoted about pin 46 such that it tends to oscillate back and forth in a motion directly corresponding to that of the kite. By the use of well-known transfer mechanisms the oscillatory motion of link 40 about pin 46 can be converted into electrical energy or dedicated to other purposes.

I don’t know what I’m talking about, but anyway…

I don’t see the point of this idea, other than for pumping, if I understand it. The kite can move hundreds of meters and here it is just used to wiggle a see-saw a bit? But let’s use it as a starting point. I don’t understand the reason for the see-saw, so let’s delete point 42 and the upper part of link member 40 so that we are left with a single tether that is connected to point 44. Now the tether can rotate link member 40 around 46. Let the boom rotate horizontally instead of vertically, maybe make the boom a bit longer now you can support the end connected with the tether with wheels, add more spokes maybe, maybe make a giant wheel out of it, and you end up with something like that Italian team was doing years ago? That’s no good, too complex and too much material. But it is better than the original idea in that your boom is longer and you can rotate the boom further so your working cycle duration increases and you can do more work. Let’s instead stand the wheel upright again, make it smaller, wider, and put grooves into the rim if tether wear is an issue, so it turns into an oversized drum for your tether to pull on. Now if you can wrap your tether around your 2 meter diameter drum 50 times, you have over 300 meters to work with, instead of maybe 4 meters with the original see-saw idea.

Figure 4 looks like it kind of describes a yoyo system.

Another preferred embodiment for utilizing the motion of a kite that more than supplies its own losses is shown in FIG. 4. The operation of the kite 90 is generally described in American Aircraft Modeller, September, 1972, pages 20 and 21, whereby a motorless control line model is flown in the wind by making the device 90 sweep out a tipped orbit with the high side of the kite upward as for an autogyro rotor. In this mode of flight, power could be collected from a propeller and dynamo in a manner shown in FIG. 1 or, by attaching the tether cable 20 to a large crank 92 pivoted about fixture 94 on the ground.

Superfluous link:The Drag and Shape of Control Lines in Flight

Senior Boeing Engineer, Chris Carlin, was a key mentor to many of us in AWE a decade ago. His long and heroic career was full of major aerospace research, like developing large scale wind turbine reliability, and flying full size airliners as drones, for fiery crash tests.

Perhaps Carlin’s most valuable lesson to AWE R&D was to seek Engineering Similarity Cases to heuristically assess feasibility, and to reuse engineering methods. In AWE, this started with study of giant industrial trawling nets, as mega-kite analogues.

Finding Similarity Cases continues to help us find ways forward in AWE. The latest is a USP3987987fig5 Similarity Case, Reaction Ferries, rigged similarly as a cross-current paravane at MW scale. Reaction Ferries have been around for centuries, and prove the fig5 cable-rig works quite well, at a substantial scale-

Its a close match, but most fig5 rigs are flatter than the original patent artist depicted-

image

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Reaction ferry similarity case is not US3987987figure 5 because pulling is on a single moving anchor, a little like the rope-drive of your colleague @Windy_Skies, or rather NTS linear track, or rather the sketch below:
Reaction ferry similarity case

Of course Similarity Cases are always partial matches to a novel concept. Having reviewed many photos of Reaction Ferries, rarer cases use a single tether, but most are bridled directly to a pulley traveling on a cross-line. These are the closest similarity cases to fig5.

All Reaction Ferries have the essential property of tacking paravanes in cross-current motion, just as fig5 is a tacking kite in crosswind motion. Rigging details vary, but the essence is quite similar, and two anchors set crosswise is the common form.

Any cableway gondola moving between two pylons is also a fig5 similarity case. There is no mysterious parasitic limitation on power by static tension. In fact, a higher static cableway tension, up to a point, is the most efficient basis for the dynamic tension of tensile work.

Consider a bicycle chain drive as a fig5 rigging similarity case. Wikipedia-

" Efficiency: A bicycle chain can be very energy efficient: one study reported efficiencies as high as 98.6%.(https://en.wikipedia.org/wiki/Bicycle_chain#cite_note-Spicer-4) The study, performed in a clean laboratory environment, found that efficiency was not greatly affected by the state of lubrication…Higher chain tension was found to be more efficient: “This is actually not in the direction you’d expect, based simply on friction”."

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Some cases of reaction ferry use several tethers instead of a single tether, both moving on the fixed transverse cable, unlike the device on the figure 5, unlike a bicycle chain, both being not similarity cases in regard to reaction ferry.

Pierre, Sorry if you are unable to see any similarity in these cases. The heuristic reasoning must therefore seem very mysterious. Never give up trying.

kPower can rig fig5 variants by single or multiple lines, and still distinguish key topological constants as a similarity basis for cases like reaction ferries.

Dave,
I indicated a reaction ferry similarity case. The figure5 is not this as it describes a static force equilibrium. However some flexibility allows a little force transfer from the kite as it moves the vertex horizontally.

Agreed, you see a similarity case with NTS, but not with fig5.

I see both similarity cases, and fig5 is the topic here.

The problem with kite tacking on single line to reverse track direction is the phase delay to cross the static zone. Fig5 topology does not have this problem; it tacks and develops traction immediately.

Here is a video of a system based on Fig. 1a or 5.


As the kite on the video is 2 m² and the wind speed is 5 m/s, assuming a L/D ratio of 4, a rough calculation in pumping (yo-yo) mode would give a mechanical power of about 350 W during reel-out phase, so about 175 W in average, and less in electrical power, but likely more than the given value of 100 W. However said value of 100 W is higher than I expected. And as already mentioned this cannot face all wind directions.
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Baptiste also shared info on LinkedIn https://www.linkedin.com/posts/baptiste-labat-01751138_kiteborne-nano-system-test-1711-2018-activity-6663749398582951937-vw2Y

Glad to see, after all these years, someone bothered to try a “crosswind kite-power” system using “a power-kite”.

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