Original Circoflex Kite Plan
Back to Circoflexi Information
Prolog
This plan was first recieved, htmlized, and placed on the internet on 15 May
1997. It is direct copy of the plan as written by Tom Oostveen, one of the
co-inventors of the Circoflex.
Unfortunatly about a month latter (27 June 1997), I recieved an email from Tom
Oostveen, who requested that the plan be removed from the internet for the
moment until he can review it. I did this moving the plan to a secret URL and
emailing this URL to anyone who formally requests the link from me by
email.
Since then Tom never returned my emails, or anyone elses. After attempts
over a full year with help by Peter Peters in the Netherlands, no further contact with Tom has been
recieved.
Requests for the then secret URL for the english version of the plan have been
regualar (4-5 each week) during this period.
Finally both Peter Peters and myself agree, enough is enough! The French
Version has been available since the plan was first published in european
kite flying magazines. Also a simple and cryptic version has also been printed
in a second edition of {...insert book name here...}.
As such it is only right that an english internet version be made available.
So on 27 of November 1998, after more than a year of being offline, the plan
is again available. and you see it before you.
For more information of this and other circoflex kites please, have a look at
my Circoflex Kite Information Pages. You may also like to
have a look at my Anthony's Kite Workshop.
-- Anthony Thyssen
What is a Circoflex
The Circoflex is a ring shaped kite that consists of a strip off fabric 750
x 50 cm. ( or 1000 x 60 cm), a seam of 2 cm at front containing only the
construction material, a reinforced fiber ring of 750 cm (or 1000 cm) 3 or
3.6 mm and a seam at the back containing a 2mm line to ply the fabric into
a curve that increases the wind pressure in the construction. The Circoflex
has 12 bridles that join in groups of 7 and 5, interconnected with a string
to adjust the flight angle.
Reactions to the Circoflex
Lots of remarks and Questions during the experimental lifting sessions and
the first official lift in Dieppe shows that the shape of the Circoflex
object, stimulates creative thinking
- A natural scientist passing by: "Sir, this object really starry me
thinking, I don't understand the principal yet".
- "How does it fly, where are the spars"?
- "Does it pull? Oh, no, it's just like a delta. "
- "To my opinion it's a revolution in kite design ".
- "The sled kite, was because of it's simplicity the kite of the seventies..
I suppose this will be the kite of the year 2000".
- "Nice kite, what a pity I didn't invent it myself".
- "Could you also join the rings or fly different kites or different sizes on
one line".
- "it seems you are fully addicted to rings. "Lord of the Rings" translated
in Dutch means 'addicted to rings',
- "it's that simple, I don't understand why it wasn't invented before".
- "Could it be built with carbon fibre?"
- "Could it be made like a spinning wheel or like a turbine with a
propeller inside ".
- "Ah, well you just should be struck by the idea ".
- "What is it? It's no kite, I can see no string. It's not a balloon
either, it can't be a UFO because it is fully open".
- "It's no kite, its just an object of art". .
- "I have never seen something remarkable like this before!"
- "How is it possible that this one fibre ring construction flies ? "
- "Is it possible to fly it without the fibre ring ? "
Experimental Circoflex
How to fly a windsock as a kite. In 1993 we had to fly a windsock but
we had a lot of trouble lifting the kite Which we had to fly over a huge
river standing on a breakwater. This motivated us to experiment, in
order to fly the windsock independently as a kite. This windsock was
not constructed traditionally as a conus, which provides too much drag
and too little lift, but like a tube with a 6 metre circumference, 7
meter long, with a fibre rod in the entrance and with a rope in the seam
at the end of the tube. This rope was pulled about 30 cm shorter than
the 6 metres at the entrance.
In order to test the influence of circumference and length on flight
characteristics an 8 metre circumference tube 4.5 metres long was
constructed in spinnaker nylon. This turned out to fly even better
titan the long tube. This was the start of the challenge to experiment
with variation of length and circumference. We initially developed a
Circoflex 750 and Circoflex 1000 (750 and 1000 cm) circumference
version.
The experimental versions of the Circoflex were made out of taped high
density plastic or Mylar The twelve point bridle was just towed around
the fibre not to the fabric, this spreads the pressure on the surface of
the material. The first step in shortening the 4,5 m length version
became 1.50 cm, the next Circoflex experimental versions were 1.20; 1.00
and 0.80; and finally 0.60 metres. A balanced aesthetic relation
between circumference and length turns out to be 50-55cm for the
Circoflex 750/50. But we even flew a Circoflex 750/35 cm version which
also flies in low stable sea-winds, but the proportion of length and
diameter is less balanced in our opinion. The Circoflex 1000/60 is best
with 60cm length.
Construction:
The only construction needed is a ring of fibre or reinforced fiber
which can be folded for transport into 4 small rings, together with the
fabric ready to fly when it unfolds in a second (1000cm into 4 rings or
250cm circumference, diameter about 80cm). For more than 4 to 5
Beaufort winds or when scaling up the size, carbon fiber could be
applied. At the end of the ring is another 'construction' existing of
2mm nylon line in the seam of 2-2.5cm. This line brings about the
effect of a curve causing the air pressure in the construction to
maintain the ring shape. It should be about 20-25cm less in
circumference than the fiber ring.
One important feature: a weight of about 35gr should be taped or taped
by Velcro. The weight should be spread evenly over 30-35cm inside the
bottom of rite kite in the middle of the hours 5 to 7, some 8 to 10cm
before the end seam. As a weight, balls of lead, used in the seams of
curtains should be fastened to the sail. Instead of the lead balls, a
zipper could be stitched at the bottom. This functions not only as a
weight but as a device to build up the Circoflex easily.
When using nylon, the fiber ring can also be taken out the construction
for transport. Stitch a ring on both sides of the zipper on front seam.
Spread out the nylon, put a tent pole through each of these rings and
the fibers can easily be put into the seam, This is even more important
with an upsized Circoflex when using carbon fiber
Bridles
The bridles should be connected to nylon tape stitched directly to the
seam before stitching the seam itself. The rings should be pointing to
the center of the fiber ring. When the seam is too wide the bridles
pulling on the fabric via the tapes and on the rings will cause a
smaller ring in the front (a kind funnel shape) which disturbs the
flying characteristics. When the lines in case of Mylar and high
density plastic will be knotted directly to the fiber ring, the seam
should also be rather small. Via the openings in the fabric where the
bridle lines are knotted an air flow may pass and blow up the seam with
the same consequences for the flight characteristics. When the lines
are connected directly to the fiber, an extra check is needed after
unfolding the four wise fold Circoflex. While folding, the fibers turn,
and the lines will turn too and may become shorter..
The 12 bridle points are evenly spread over the fiber ring like on a
clock. It is also easier to communicate when the ring is not fully in a
circle share and some Adjustments need to be made, The bridles of
9,10,11,12,1,2,3, should be connected to one ring. The bridles of
4,5,6,7,8, should be knotted to another ring. In between these rings a
line 20-25cm will be connected in order to adjust the third ring to
which the kite line is fastened. The length of the lines are in the
table. As a rule of thumb: when the kite has the tendency to turn to
the left the bridle at the opposite should be repositioned. The ring
Should have an ideal round circle shape.
Fabrics
Because of the evenly spread pressure on the ring surface and the taping
of the seam around the fiber ring, light material like high density
plastic and Mylar can be applied. Other fabrics like tyvek, nylon,
ripstop nylon and polyester can be used.
Experimenting is going on to apply fabrics that let some wind pressure
pass in high winds.
Patterns and special designs
The simple Mylar silver/gold version is so appealing to people that they
don't understand what is up there. Even more when flown with very thin
bridles and line. As in all kites large patterns and not too many different
colors will emphasize it's shape.
Esherpatterns, Mondriaan, Indian and African .simple patterns can inspire
the constructor. Special Circoflex kites have seen constructed for night
flight. A black version with over 30 LED's with 9 programs, the other also
black with silver .Mylar and over 100 reflecting tape streamers at the end.
Further experimentation
- The Circoflex can be upscaled. We are constructing a 20 and a 36 meter
version.
- The Circoflex can be put in trains by connecting the bridle ring of
first kite with a line of about three metres to the bridle ring of the
second kite.
- A smaller ring could be constructed inside the larger ring by connecting
the smaller kite to the 12 extra lines connected to the center of the
biggest kite.
- Rings could be interconnected and flown with multiple bridle lines.
- With a carbon fiber ring a construction like a bicycle spoke system
could be made. One the axle, turning objects could be added.
Recieve Date: 9 May 1997
Html Created: 15 May 1997
Plan returned: 27 November 1998
Original Author: Helmut Schiefer
Co-inventor: Ton Oostven
HyperText: Anthony Thyssen,
<anthony@cit.gu.edu.au>