However, at least one kite academic has thrown in a little doubt, saying 'the idea was already around'.
But hey, I'm an Aussie like Hargrave, and hence really like the idea of an Aussie helping to lead the way like this! At least Hargrave's writings provide a clear starting point in history for the construction and flight of cellular kites, and box kites in particular.
Lawrence Hargrave was much more than a kite-maker. His list of accomplishments include being an...
- Engineer. Starting with an engineering apprenticeship in 1867
with the Australasian Steam Navigation Company (Sydney), Hargrave
worked as an engineer on several expeditions undertaken by others.
- Explorer. Hargrave transitioned from engineer to an explorer in his own right, during later expeditions.
- Astronomer. Not his strongest point, but in 1878 Hargrave
became an assistant astronomical observer at Sydney Observatory, and
held the post for 5 years.
- Inventor. Mainly in fields related to flight, Hargrave worked
on airfoils, box kites of course, and - are you ready for this? - the
rotary engine! Even some early jet engines, powered by kerosene.
- Aeronautical pioneer. Like others in his time, Hargrave
studied the flight of birds and made great efforts to crack the
challenge of controlled, heavier-than-air flight.
On that last point, I can remember reading a lot about early
aviation when I was just a young lad. It turns out Lawrence was in
contact with most of the famous people whose names were dotted
through those books. For example, Octave Chanute, Otto Lilienthal,
B.F.S. Baden-Powell, Alexander Graham Bell, Percy Pilcher, and William
Eddy. There's even a photo of Hargrave and Bell together.
However, this site is strictly about kites, so let's focus now on Lawrence Hargrave's intense kite-building period during 1893!
Before the final perfected design, which you can see in that photo, Lawrence Hargrave went through a lot of ideas and model-making. In fact, quite a number of rubber-powered flying models preceded the more well-known kite experiments!
The final Hargrave Box design
The final Hargrave kite had a number of refinements. The cross
braces were shaped to an airfoil section to reduce drag. Just like the
stream-lined wing braces of some modern light aircraft. A cord running
vertically down the center of each cell could be adjusted to tension up
the whole cell, thus keeping the sail panels taut.
Two long spars, one above the other, provided a rigid 'backbone'
for the kite. Like many modern kites of considerable size, this box kite
could be dis-assembled and rolled up for transportation.
However, the kite had no bridle, just a simple single-point
attachment to the underside of the front cell. Hey, it works fine on
very rigid kites! You just have to make sure the towing point is at the
Going Round In Circles
Lawrence Hargrave's progression of ideas started with tubular
concepts. The first such design had each cell looking a bunch of short
tubes stuffed into a single bigger tube. 6 smaller short tubes to be
precise. A long spar connected 2 identical cells. Hargrave flew a paper
model of this kite and was pleased with the results. Maybe it wasn't
such a great lifter, but at least it was very stable. The cellular kite
Next, the smaller tubes were done away with, and the result was 2
large diameter but short length tubes mounted either end of a long
spar. This circular type design is still made from time to time, by box
kite enthusiasts. You could say it is like a traditional square box
kite, but with an infinite number of sides! And of course, just a single longitudinal spar instead of 4.
The Book Case Phase
There followed a rather elaborate design with many flat panels.
Each cell looked rather like a book-case with the back panel removed.
Four 'shelves' with vertical dividers resulted in 16 square sub-cells in
both main cells. Again, a long spar joined the 2 cells, with a single
bridle line attached to the spar. No doubt it flew, but what a complex
thing to build!
With the next design after the flying book-cases :-) the
appearance of the 2 cell designs started to hint at the final box kite
configuration. As in the photo up there. The number of 'shelves' was
reduced by one, in each cell. Also, most of the vertical panels
disappeared, leaving just the ones on the far left and right sides.
Now, the kite was essentially 1 Hargrave box kite piggy-backing
another. In other words, 4 horizontal lifting surfaces in each cell,
plus the 2 vertical surfaces capping the wing tips. Perhaps there were
some problems with the long spar bending, so a 2-point bridle was used
on this kite.
Classic Lawrence Hargrave Box Kites
From here on, several more kites were made, which featured just 2 lifting surfaces per cell. Also, the chord (distance from front to rear edges) of the horizontal panels was extended a lot. Each of these kites looked much like the one in the photo.
Lawrence Hargrave was experimenting with proportions. He was trying hard to arrive at the most lifting ability possible, without
sacrificing too much stability or adding too much weight. For example,
he scaled up one version to compare its figures with a wing flown some
years earlier by Otto Lilienthal. It turned out Hargrave's design had a
much lower wing loading. In other words, less weight per unit of lifting
At this stage, Lawrence Hargrave was starting to consider how
such a kite could be propelled as a free-flying aircraft. He shared his
ideas freely with other experimenters, and even had some influence on
the inventions of the Wright brothers.