Towards a crosswind version of Kiwee?

[gordon_sp]

My apologies for my false statements about the orientation of the device during crosswind motion. I was confusing crosswind movement with crosswind force which is exactly opposite.
If the lifter kite is moved in a figure-of-eight by means of a kite steering unit, what will happen to the sheaves of the cable drive? Will the reorientation cause the axes of the sheaves to tilt from the horizontal position? Will the cable rub against the wall of the sheave causing friction losses and reduced life?

[kitefreak]

A pilot lifter can support a turbine that swings like a pendulum off the main-line. Just a small steering input at the vane can initiate large swings. The lifter will fly a tiny inverse figure-8 to the sweeping turbine’s large pattern. Add an elastic bungee leader to the pilot if needed to damp disturbance from the swinging elements. OAIPC

Cableway loop sheaves twist in relation to each other quite a lot without problems. The ground sheave can also be made to follow the flying sheave’s tilting. Fairleads and close block tolerance prevent most trouble. Line twist is not a problem for braided line.

Rope driving worked well historically, even with vegetable fiber ropes. Rapid wear suggests design failure. Proper sizing, conservative loading, and elastomer coating on the sheave can provide very long service.

Here is the old bible of rope-driving, more vital than ever, to AWE R&D. Lots of good data easily extrapolated to UHMWPE specs-

Rope-driving: a treatise on the transmission of power by means of fibrous...

[PierreB]

I would like to point out a paradox. Kiwee ​​is the only airborne wind turbine on the market and yet scientific studies on this device and the rope drive transmission shine by their absence.

And the potential is significant as a lot of structures can be envisaged for static as well as crosswind AWES, and at almost any scales.

[tallakt]

Did I miss a power curve plot? Do you have one to share?

[PierreB]

Some indications of the current Kiwee are on

Can you share your experience with your lifters?

For kiwee one flight angle is depending on wind speed. Flight angle at 10m/s windspeed is greater Than 60deg. At that speed, our theoretical extracted power is around 240 watts (by memory). Our measured extracted power is around 210 watts. Wind turbine Drag is about 70 newton. Thing is, the farthest you are from Betz, the less power you produce and also the less drag. Right now we are really cloth from Betz. Maybe rod is not that cloth. Thus he has less drag… Rod ? Another difference, kiwee…

and on

Can you share your experience with your lifters?

Yes à little more than 1 m2. Regarding lifter surface area, as soon as you have consistent wind, kiwee can operate with a 2m2 pilot kite. If the wind is weaker, we need a 4 m2. That is why we choose 4 m2 pilot. 60 degree is not a really high value in consistent winds, more of a common one. 210W is the propeller value. You have to had right angle efficiency and belt transmission efficiency in the calculus if you want to look at power production. For flight angle concern, only propeller charact…

I have not more but the data above are enough to extrapolate in crosswind conditions if a device with efficient enough rope drive transmission is built.

[Kitewinder]

I don’t have power curve tallak. Kiwee is not a traditionnal wind turbine. you don’t use it to lower your bill. you just use it for the power it delivers. And that varies of course a lot with windspeed.
Blade diameter is 1 meter roughly . I guess you can figure out everything just with that number.
Regarding kiwee, we wil have a donwload able firmware on our website so that customer will be able to upload it trough bluetooth with smartphone. How cool is that ? ( amazing to me, it means I can deliver a first firmware version and upgrade it with time )
olivier