A concept for the world's biggest, longest, widest kite?

Can possibly be used for sailing straight up or down wind

Copyright © 2005 - 2016 Anders Ansar. All rights reserved. You are welcome to use pictures and words as long as you include a link to my pages.


Here the kite rises in an arc in the wind. It is controlled by the persons at the ends. The size is 22 x 0.5 m. With this size the center didn’t lift so we cheated using a string attached to the center and held by the person on the table. Smaller kites do work without this extra string, see below for possible reasons.


Abstract 

I set out to make an easy to make high performance traction kite: good  Aspect Ratio, smooth surfaces and low weight for its surface. Thinking outside the box I came up with a ribbon flown from two distant points, an arch kite. It has ultimate low weight – only the weight of the single skin material. It can not be used as the traction kites we know today. But it can be used for sailing straight up wind or down wind, the latter faster than the wind. It may also be fun as a toy or indoor kite. It can have more anchoring points than the two. Extreme span and aspect ratio is possible. A concept for the world's biggest, longest, widest kite? When using several anchoring points instead of one you enter a new field of kite design. Any ideas?

 

Background

 I came up with this idea when I set out to design the lightest and simplest traction kite:  A kite that has only single skin and no bridles (unlike e g a Para foil, multiple layers of skin and numerous bridles), no stiff parts (unlike e g Wipika, Naish, inflated sections). And not a very curved from wing tip to wing tip (like e.g.Wipika and Naish) which decreases aerodynamic efficiency plenty. 


 

This is an earlier prototype. It is a flat ribbon of plastic film. It has a wooden stick at each end. Here it rises in an arc in a light breeze. But only to some 30 degrees from the vertical, which means the lift to drag ratio is only about two.

  More about the kite pictured at the very top

At the first try it turned out the fabric folded double so I had to insert some five mm thick wooden sticks from leading to trailing edge. This was a departure from the initial idea of having no stiff parts. But weight increase was very small.

   As I wrote above the center of this kite didn’t lift, so we cheated using a line at the middle. A reason could be the cheap fabric was so elastic that  we could not steer the middle by manipulating the ends.


   Indoor kite

Here I am walking towards the camera with a kite made of thin Mylar film. You can make a larger one to be flown by two people, one at each end.  There are no battens except at the ends. The gray lines are just the tape at the broad seaming which gives the foil camber.

  

Extremely large span, 200 m?, and aspect ratios, AR, 200?, possible. A 16 men team sport?

With this design extremely large spans becomes possible, maybe the way to go for the world’s widest kite. Also high AR comes easily which could lead to a kite with low drag. But the kites I have made have not had a good lift to drag ratio, L/D ratio. They have not came anything near the vertical when viewed from the side. If they come close there may be stability problems, the kite collapsing downwards.

    If that happens you can restrain it with lines at the trailing edge. For a large kite, say 200 m long,  I can see some four people controlling each end of the kite (holding a long tube, which goes through the end of the kite). Another four holding lines, spaced at the leading edge, which pulls the kite forward. And another four holding restraining lines led to the trailing edge of the kite. A 16 men team sport.


Maximum possible size and flying height?

Wind is available well above 10000 m. For a very large kite I guess the strength and lightness of the fabric becomes the restriction. Optimal is to orientate the strength in the direction of the span. Sail makers may have some suitable material with carbon or Kevlar fibers.


I made the first kites with a cambered foil

My first kites were made of mylar and had a cambered foil, I let the material overlap a bit in an arc forward and backwards from the 1/3 cord point, from the leading edge, to get camber. I then tried the more “simple to make” flat foil and it seemed to work as well as the cambered foil.


Aerodynamic notes 

One way to go for good L/D ratio is to make it with a foil shape and  leading edge like these David Barish wings to the right.

  The vertical stabilizers are not needed on a kite with ends controlled.

   Cambered foils are unstable. One way to make them stable is to give the section a reflex at the rear end. You could get this by putting in curved battens that shapes the foil.   





See  for example  http://www.bchpa.org/newsletter/may04/barish.htm  for more information on David Barish work.


Sail with a bow kite!  Straight up wind!  Or downwind faster than the wind!   A couple of novel suggestion?

The three paragraphs below are being moved to link above.


Sail straight upwind with a bow lite!  

A new traction kite? You ask. Not as we know them today. But it can be used for traction. Equip the persons at the ends with eg ice skates (I am a skate sailor see http://home.swipnet.se/ansar/s.html), roller skates, surfboard, buggies, cars, boats ......

    Let them face the wind, kite square to the wind. They hold it quite straight. Skates pointing slightly inward from the direction of the wind. Next they turn the ends of the kite making it to raise. They will be pulled towards each other and they will be sailing straight up wind!

   When the kite has risen high the sailors turn the ends of the kite making it loose height quickly. At the same time they change course to outward from the direction of the wind, they now travel on their momentum. Soon the kite is straight again. Then they repeat the same cycle over and over again.

   In order to have a reasonable long cycle the kite must not be to short. For example a 100 m long kite will pull in each end some 7 m before it has risen to around its maximum practical height. If the sailors move upwind 5 meters for every meter they are pulled inwards they move 35 m when pulled in 7 m. If they travel at 5 m/s the traction cycle will take 7 seconds - long enough to be handled by humans I believe.

   To get this working you need a kite with good lift to drag ratio - a kite that rises to around 10 degrees from the vertical, when viewed from the side, ends of kite in line. That angle corresponds to a  lift to drag ratio of about 6, if I got it right (tan 10 = 5.88).

 

Sail straight downwind, faster than the wind!

It is also possible to sail straight downwind, faster than the wind, I believe,with the same technique. First the sailors have to gain forward speed, e g by skating, until they feel wind in their faces. Then they can initiate the cycles described above.

The easiest way to test this type of sailing may be to take a Para glider and run a pair of long lines,  50 - 100 m, from each wing tip to the sailors.


You develop

The idea of using multiple anchoring points opens up for new designs not possible with the usual kite anchored at one point.

What is next? It is up to you! Any suggestions of designs?

 

 


Have you seen The world's fastest skate sail, 120 km/h (75 MPH)? The stand inside wing skate sail.

   It has not really been used on land yet. It can probably beat buggies and land yachts. (I beat the large Skeeter ice boat when sailing in the USA.) Building instructions available.




Man shrinks luggage to 1 oz, 30 gram.  Or longer a version at: http://sites.google.com/site/travelulcomp/

Is also equipped for more comfortable in hot weather.

 

When I was almost finished with this page I found the same type of kite at:

http://www.ssk-kerpen.de/sport-seiten/ssk-kit_bild.htm    Have you seen it somewhere else?

A kind Dutch man sent me the URL below with photos of a 440 feet arch kite. Very impressive!

http://www.kitelife.com/archives/issue33/carolina-kf03/

Another kind reader send me another URL of a windbow

http://users.argonet.co.uk/users/parsons/windbow.jpg

  

Things from my desk. Sailing boats I have raced. My humble abode.



My design Course Racing Wing Skate Sail 
I think I was first to show that 
skate sailing in wings is much faster that its predecessor with the sailor standing to leeward of a fabric sail. Top speed is some 75 MPH, 120 km/h. That is 30% faster than its  predecessor. 
Photo:The wing 
 hangs on the shoulders and I wear ice skates. 
Wind is very light, you can hardly feel it in your face, still speed is some 40 km/h, 25 MPH, or some 6 times faster than the wind. 
Some 100 have been built world wide. I have designed, built and raced some twenty of these wings.

 


My design High Speed Wing Skate Sail. Sailor in wing -  100 mph?, 160 km/h?
This is a small area wing sail and should therefore be able to reach higher speeds before you are overpowered.
  With this wing overpowering should come around 100 mph, 160 km/h. 
Wing still in modification and testing phase and - right high speed conditions are very rare - about once a year: Snow free, smooth, absolutely safe thickness and wind over 20 knots, 10 m/s. and thick.  

My skate sailingpage

My Speed sailing projects  



Boats that I have sailed and raced
I have owned and raced: A C-class sailing canoe (local Swedish design.) An Elvström Trapetz two man dinghy. A Star Boat. Two Tornado Catamarans, once an Olympic class. Two Laser dinghies.When I showed my first Tactical Compass, Ansar 1,  to sailors I was engaged as tactician on a 6 m R-yacht and a very successful Scampi Half Ton Class, Lady Luck.
Photo. Camping trip in a Laser Dinghy 
This was on large Lake Saimaa in Finland for half a month with a friend in his dinghy.
You can click on the photo and on the enlargement see an Ansar 1 compass mounted behind the mast.
 
 
Freelance photography and writing. E.g. my E-Book: 100 steps to Ultra Light  Luggage and Less Heat Stress
Photo: No-Bag-Travel. All in the pockets! Two weeks in Romania.
After decades of traveling light on the world's hot roads in sixty countries, several circumnavigations, minimizing, testing and eliminating gear - finding ways to manage without, I announce this website:
My E-Book: Pack light. Less heat stress.


 


My Tactical Compasses for Sail Racing.
Wind shifts At-A-Glance

Animation: The position of the central pointer gives you the wind shift information At-A-Glance! Wind is in from the right. 
The compasses has been bought by famous sailors like Iain Murray, Australia. Peter Norlin, Sweden.

My Tactical compasses



The view from my humble abode in central Stockholm, Sweden. Beyond the water, a canal, is the Karlberg Palace. 
The canal is connected to the oceans. There is a public jetty just outside my abode so you can arrive by boat for a visit. 
The castle dates back to the end of 1640.


(My note: Latest version of this table is here, 13 Feb 2017)

Back to Skate sailing index.    To my Home page.

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Copyright © 2009-2017 Anders Ansar. All rights reserved. You are welcome to use pictures and words, uncommercially, as long as you include a link to my pages.

Written June 2005. Modified Feb. 2017

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