Using a lifter kite as a low aspect ratio power kite

[PierreB]

This pilot kite is more or less circular, and has also a correct L/D ratio of 2.4.

Below is a link of a publication: Aerodynamics of a circular planform wing: the L/D ratio looks to be about 3.

https://iopscience.iop.org/article/10.1088/1757-899X/488/1/012005/pdf

See also http://naca.central.cranfield.ac.uk/reports/1935/naca-tn-539.pdf, and

https://www.boatdesign.net/attachments/frisbee-aerodynamics-aiaa-2002-3150-pdf.69553/

[Rodread]

Where do you get the 2.4 L/D figure for the Peter Lynn pilot @PierreB ?
The short summation on it’s performance has normally been
It flies high even in low winds, pulls hard, but has stability issues.

Also with the 3 following links in the post above… They’re rigid aircraft. They’ll have to remain relatively small as AWES, unless being arrayed into a larger meta kite.
Do you have a suggested arraying method for energy capture with this class of wing?

[PierreB]

@Rodread

Where do you get the 2.4 L/D figure for the Peter Lynn pilot @PierreB ?

I get the 2.4 L/D by the link I mentioned

@PierreB

2.4

This link leads to the message below:

Can you share your experience with your lifters?

Just an update. IMHO high flying kites are generally more useful than downwind kites. So I am interested in L/D and such. I measured this the other day. [image] I added a hollow tail to calm down left-right motion. 67 degrees should mean a L/D ratio of 2.4. I believe this is quite good for a Pilot type kite, in particular one that flies in very little wind and pulls like nothing else. High wind needs to be solved for this kite though

That said, I don’t know if we speak about the same pilot kite.

@Rodread

Also with the 3 following links in the post above… They’re rigid aircraft. They’ll have to remain relatively small as AWES, unless being arrayed into a larger meta kite.

Indeed, it is just an indication.

@Rodread

Do you have a suggested arraying method for energy capture with this class of wing?

I try to see if there are some possibilities.

[Rodread]

Thanks @PierreB
Is there a way you propose that we can group the working of these single line Low AR kites?
I experimented a bit with running the main tether line through the top skin of the Peter Lynn lifters but the control was horrible. Whenever the lower kites tried to align with their apparent wind they would run into the tight through line and collapse their skin inflation.
Stacking through more rigid frames is more promising as can be seen in many dragon stacks or small kite stacks on a single line.

Being able to rotate and work against the line going through (or around outside) the kite element (kixel) seems key

[PierreB]

After discussion with Dave Santos I see that some of his ideas are interesting. An almost round pilot kite can have a L/D ratio of 2.4, which is not too bad for a very low aspect ratio. In crosswind use that leads to (2.4)² = 5.76, while a Nasa Parawing has a L/D ratio of about 2.8, leading to about 8, while a classic power kite has a L/D ratio of about 4 or 5, leading to about 16 or 25. Certainly the difference is important but some advantages of a low wing loading can occur, such like less wear, more regular efficiency, and the (mentioned by Dave) possibility of an iso-kite being able to fly in any directions without turn I mentioned in Reversible kite - #5 by Rodread topic for thin wings. These features could facilitate a full use of the swept area.

Now the question is how far it can scale. Then how building a network keeping the initial features of one unit.

@Rodread

Is there a way you propose that we can group the working of these single line Low AR kites?

I don’t think stacked kites are good for a crosswind use because the top kite covers a greater distance than the bottom kite.

I would rather see a network side by side, or if possible a network of side by side units making a single whole to facilitate both building and maneuver.