Cellular Kites
Note: some of the images on this page are animated
with Javascript. If your browser doesn't support Javascript you may not
get the full effect.
There are many different types of cellular kite with varying
characteristics. They range from simple box kites to highly elaborate aerial
structures, and even the simplest have an special
appeal resulting from their 3-D nature which simpler kites lack.
Hargrave Box
The Hargrave Box is the archetypal cellular kite,
invented in 1893 by
Lawrence
Hargrave. The similarity of some of the
earliest flying machines to a Hargrave Box is no coincidence.
A large Hargrave kite can generate enormous lift.
Pelham gives a plan for a
Hargrave.
Here is a picture of a
Hargrave box
flying with a rok.
Born in Greenwich, England, Hargrave emigrated to New
South Wales at the age of 16. His many experiments were aimed towards the
goal of powered flight but he refused to patent any of his findings,
preferring rather to allow anyone to build on them who could.
Traditional Box
Many people would recognise the
traditional box kite, which is more common
than the original Hargrave design. This is about the simplest form of
cellular kite and in the past, has been very popular though it's less often
seen today. It flies well in a moderate to fresh wind but only holds the
flying line at a relatively low angle. This is because it requires quite a
lot of sparing in relation to the surface area of its sail, which in any
case, is held at 45 degrees and so generates less lift. Nevertheless, this
angle acts as a dihedral which, together with the vent between the cells,
gives good stability.
Here are plans
for a traditional box kite using a kitchen garbage bag and some
dowelling. And here is a picture of a
Gibson
Girl kite - a box kite issued to allied airmen in World War II
for raising an emergency aerial in case they were downed at sea.
Improved lift can be had for a slight loss of
stability by flattening it a little, resulting in the rhomboid kite.
A traditional box can normally be transformed into a rhomboid simply by
exchanging the equal length internal cross-spars which hold it open by
two pairs of unequal length. It is instructive to demonstrate how the
flying angle increases and the stability deteriorates as the kite
becomes flatter.
Plans for a rhomboid kite are given by Eden.
Here's a
rhomboid variant flying at Dieppe in 2006.
Winged Box
The traditional box kite can be improved by adding
"wings" to provide additional lift so allowing it to rise higher on a
given length of line, as in this
picture.
This is then known (not surprisingly) as the
Winged Box Kite.
Eden also gives plans for a winged
box.
Delta Box
Alternatively, delta wings can be added to give a
delta box kite, as in this
picture of one built by Graham
Dresch.
Plans
are also available.
Pely Box
A particularly striking variant is the Pely Box, also known as the Tri-D,
which is made entirely out of identical isosceles triangles.
It gets its name from its inventor, New Zealander
Peter Lynn.
As compared with the traditional box, this design saves
the weight of two of the four longerons at the cost of some sail area.
This sketch shows a 3-cell version because, after several abortive
attempts to draw it, I got carried away. But when I built a 3-cell pely,
it turned out disappointingly unstable.
The standard 2-cell version flies without a
bridle and with the flying line attached directly to the bottom of the
front cell, although Peter Lynn has been quoted as saying that a 3-leg
bridle works better, with two legs attached to the ends of the front
longeron, and the third to the bottom of the rear cell.
Outline
plans
for a pely box are available, or you may like to consult
Eden.
Here is a
picture
of two pely boxes flying together, at Fanø 95.
Conyne
Triangular box kites can be made, but if you then
add wings, the result is the Conyne kite.
The pronunciation is disputed in kiting circles. (For what
it's worth, I pronounce it as "co" to rhyme with "snow", "nyne" as in three
threes.) But if you prefer, you can also refer to it as the French
Military Kite since it was used by the French army for reconnaissance.
It's also known as the Pilot Kite.
Silas Conyne, an American, patented it in 1902. Not only
do the box sections form a dihedral but they also result in the centre of
lift being somewhat above the attachment points of the bridle. Together,
these factors result in a very stable flying characteristic.
Here's a nice
picture
of a pair by Dan Leigh.
Moulton & Lloyd
give plans for a slightly modified conyne. They claim that shortening
the front cell a little gives even greater stability.
Plans for a standard
conyne are also available online. Here is a
picture
of one by Geert DD.
George Lawrence used a train of Conyne kites to lift cameras for
aerial photography. His most famous photograph, taken in this way, was
a panoramic view of San Francisco after the devastating earthquake and
fire of 1906. The negative was a massive 18 by 48 inches and it was
published around the world, earning him $15,000.
See it for yourself!
Delta Conyne
The Delta Conyne consists of a Conyne kite with the wings of a delta kite.
This improves the aspect ratio allowing it to fly at a higher angle.
Peter Batchelor's detailed
plans
include a photo of a large number of them flying as a train.
For greater lift, a
double delta conyne
is often made, containing two triangular box sections side by side.
Cody
Samuel Cody,
an American born in Iowa in 1867, was a highly colourful and
flamboyant character who enjoyed demonstrating his remarkable skills as a
horseman, with the lassoo, and with the gun. When his interest turned to kites,
after many experiments he settled on a winged variant of the Hargraves Box,
which has taken his name. Here are
plans
drawn from an original built by Cody himself.
Here's a
picture of a modern one by Anthony Thyssen.
When Cody arrived in England he invented much of his American
background, with the result that many of the stories about him are
fictional, not least his birth in Texas - a state he presumably thought would
have more street-cred than Iowa - and his real name was not Samuel Cody,
but Franklin Cowdery!
With a train of his kites, Cody succeeded in lifting
observers in a wicker basket, but when he approached the British military
authorities they failed to take him seriously, on account of his flamboyance.
Nevertheless, they were so impressed by his shooting skills that they offered
him a post as a shooting instructor, which he declined. Only after crossing
the English Channel in a 13ft boat drawn by one of his kites did they express
interest. In subsequent experiments during 1904-5, Sapper Moreton was lifted
to the incredible height of 2600ft!
The military associations of this
kite have lead to it often being referred to as the Cody War kite.
There exists on the net a highly informative page of
photos and plans
of an original cody kite recently sold at Sotheby's.
Waldof
An enduring fascination with 3-dimensional structures led Peter Waldron
of Worcestershire, England, to investigate ways of making kites with
the greatest sail area and minimum weight possible. He called his first
success in 1977, "Professor Waldof's Box Kite" - a 6-sided winged
double box. Whether coined by himself or invented by another, he seems to
have relished the unofficial title "Professor Waldof", as well as the
common mis-spelling "waldorf", and association with the type of salad
of the same name.
The Waldof Box was only the first of a series of spectacular creations,
including the Waldof Conic, and Superstar, as shown in the sketch.
(Rest your mouse on it and look at the status line at the bottom
of your browser to identify the variants.)
The Conic has the advantage over the Box that if there are any small
inaccuracies in the sizes of the panels, tension can redistribute
itself throughout the structure instead of causing some panels to go
slack. Here's a
photo
of one from kitestore.com.
I think it's also more elegant, but the Superstar has been described
as the most refined of the three.
Here are the plans
for the one I built, and a
picture of it in flight.
As well as linking several Waldof Boxes together into a huge assemblage
like a space station, other creations were the
Waldof Star - a 3-dimensional 8-pointed structure,
and the Magic Box - a small winged box, easily assembled for flight by
springing it open like an umbrella.
Snowflake
Another spectacular multicellular kite is the
snowflake, or facet. As with some of the more complicated cellular
kites, it has an external frame rather than spars running through the
middle. The frame is often hexagonal,
(Morgan has a picture of one such)
but there are advantages in making it
circular, as in the sketch. Despite its appearance it's actually quite
easy to make, as it simply consists of 15 squares of fabric, 3 large and
6 each of two smaller sizes, in the ratio 3:2:1. See if you can work it out.
If each square is a single colour, you get a kaleidoscopic effect, but it's
often made in a concentric colour scheme. Pass your mouse over it to see
which you prefer.
I built one 2m in diameter which always attracts attention, and I wrote up the
plans
in case you fancy building one too. Here's a
picture
of it flying with a couple of windsocks (purely for visual effect), and
someone's shark in the background.
Tumbling Star
Other multicellular kites exist, in fact an almost
endless variety could
be constructed by anyone with good 3-D visualisation.
Some, like the snowflake, use external sparing, whilst others, like the
waldof, have spars running through them diametrically.
Those having significant front to back length are stable fliers but
others are less so and tumble if given slack line.
The philosophy "if you can't fix it, feature it" is appropriated by such
"tumbling stars", which can wrap themselves up in
their own line when given slack, and then unwind themselves again when
pulled taught.
Morgan gives plans for one.
Here is a
tumbling star
by Anthony Thyssen.
If the tumbling star fascinates you but you couldn't contemplate
building one, consider the dancing cube. This is like just one box of
a traditional box kite. Without the second
cell and the gap between them, it's unstable, but because of that, great
fun to fly! Carolyn Weir has compiled some simple
plans
using ripstop nylon. Alternatively, commercial versions are available
quite cheaply, not only cubes, but triangular prisms and cylinders,
known as the Triad and the Pop-can.
Circoflex
Finally, to return to a simple structure, the
circoflex consists of no more than a ring (like a wedding ring, or a
very short section of pipe), with a flexible spar in the leading edge to
maintain the shape. A line running through a pocket in the trailing edge
is tightened to reduce the trailing edge diameter by 2% or so, and
a multi-legged bridle is attached to the spar to hold it at an angle to
the wind.
The circoflex was invented by Helmut Schieffer and Ton Oostveen, both of the
Netherlands, who introduced it at the Dieppe Festival in 1996 to great
acclaim. For several years it was probably the most discussed single
line kite on rec.kites.
Circoflexes are often built from mylar film (familiar as shiny foil
gift-wrap) in sizes of several metres in diameter. Mylar tends to
crease, but this only adds to the spectacular effect as the light glints
on it. With a thin, barely visible bridle and flying line, this
unidentified flying object always causes a stir among onlookers as it hangs
almost motionless in the air, wobbling like a jelly in any slight gusts.
If you don't have a sewing machine but want to build something that'll turn
heads wherever you take it, this is definitely the kite for you, especially
if you're handy with the sticky tape!
The original plans are in French, but Anthony Thyssen has an
English version
for 7.5 and 10m circumference models
He also has a collection of pointers to a considerable number of
photos of circoflexes.
Here is just one of them - a
silver circoflex
flying over a rocky outcrop in Leicestershire. Few kites look
more like something from outer space!
The circoflex is sometimes confused with the
bol, but the two are
actually quite different. In particular, the circoflex has a
bridle with unequal length legs to hold it at an angle to the wind and
so generate lift. It also has an almost constant diameter from the leading
edge to the trailing edge.
Return to the
-
Continue the
Copyright © 1999 Philip Le Riche
[Home]
[Single-line]
[Flat]
[Bowed]
[Cellular]
[Sled]
[Parafoil]
[Rotating]
[Dual-line]
[Triple-line]
[Quad-line]
[Catalogue]
[Terminology]
[Materials]
[Uses]
[Knots]
[Classroom]
[Bibliography]
[Curator]