Skypull completes a fully autonomous flight with its Technical Demonstrator

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Well done Skypull… Peaking briefly around the 1kW
Would be good to see data for more than 55 sec of test before claiming you’ll be making a SP300 25kW market demonstrator by mid 2021
SP300 I wonder what the 300 is.

Very cool sliding winch, undoubtly to support vertical axis rotation

Can anyone explain to me why the Skypull kite is rectangular with a cross in the middle?

I think the format is meant to be arrayable
So to scale there might be a 4x2 set of boxes.
Also it interperets well from quad-copter control.
I presume it’s also mixed mode props/turbine blades with more emphasis on prop than makani had … Because it’s a non conductive tether and the props look to be spinning coming back to restart the extraction loop - that’s going to require on-board power sourcing.
Great to see some variation in yoyo

Got to get rid of the bendy fishing rod though.
Line abrasion
What next harnessing salmon power?
Very 1860s Boston

There is an explain of the design on :

The Skypull drone has a double wing design to maximize lift with reduced wingspan. Additionally, each wing is made of a multi-element airfoil that maximizes lift and minimizes drag for best flying efficiency, similar to the wing of a commercial airplane during take-off and landing. The original patented design “box wing” guarantees increased strength, reduced weight and high resistance to fatigue. Hence, the Skypull drone represents a revolutionary design for optimized flying efficiency and maximum lift, for high capacity (MW) airborne wind energy production.

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I guess it reminded me of the look of the Joby energy box sections wing

Indeed, and also KiteKRAFT wing

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I guess my question would be: how could a design deviating so much from a bird or an airplane be the most efficient design. I get a biplane with two wings or a slotted wing, but to me this design seems awkward and prone to low efficiency from the getgo, befor you meet the thousand cuts of design for real life.

Typical sawtooth yoyo curve (see the video at 1:22) with wide figure-eight path leading to various power zones in the flight window: high peak power, low average power during reel-out phase, very low average power during the full cycle also due to the time and the energy consumption during reel-in phase (not shown on the video).

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The output data on the screen behind Florians head at ~1:30 on the Kitecraft video is much smoother looking.
Yes their craft has extraneous looking string and struts which maybe haven’t mastered a low tech AWES but they have a very fast acting high tech solution which has to be watched in slow motion to be appreciated.

The KiteKRAFT wing is a flygen. I think the variations on the propeller are more smoothed compared to those of a yo-yo system where the winch more or less stops in each change of direction of the kite as it occurs close to the edge of the window of flight, where the pull is lower. Perhaps a flywheel could smooth better such variations.

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