6 ms·

Alexander Graham Bell’s Tetrahedral Kites

161 points by flannery 9y ago

jszymborski 9y ago
This one looks like a Sierpinsky Triangle :) https://c1.staticflickr.com/5/4226/35286566316_65bcda7d3f_b.jpg https://c1.staticflickr.com/5/4226/35286566316_65bcda7d3f_b....
- kmill 9y ago
  That'd be a Sierpinski tetrahedron, but it's the same idea. I think it's pretty interesting that these were made about ten years before Sierpinski described the fractals, but then again the design appeared in mosaics from much earlier: https://s-media-cache-ak0.pinimg.com/originals/52/98/75/529875deedb52ebe7adad4a29d4dea48.jpg https://s-media-cache-ak0.pinimg.com/originals/52/98/75/5298... https://s-media-cache-ak0.pinimg.com/600x315/7b/7c/06/7b7c0653e7c82e33dddf7898e70baf2c.jpg https://s-media-cache-ak0.pinimg.com/600x315/7b/7c/06/7b7c06...
  - jlg23 9y ago
    Where were those pictures taken?
    - jszymborski 9y ago
      Reverse google image sleuthing leads to a pinterest board[0] that alleges they are of the Cosmatesque style[1], which means they maybe originate from somewhere in medieval Italy? [0] https://www.pinterest.com/paulettecadic/pavements-des-cosmates/ https://www.pinterest.com/paulettecadic/pavements-des-cosmat... [1] https://en.wikipedia.org/wiki/Cosmatesque https://en.wikipedia.org/wiki/Cosmatesque
      - kmill 9y ago
        Thanks for the sleuthing. I found them myself by searching for Cosmati mosaics, since Wikipedia mentions them in the article about the Sierpinski triangle. Captions for the two images: Francesco De Comité took this photograph in the Church Santa Maria in Trastevere, Rome, Civita Castellana - Santa Maria Maggiore - Motivo detto "setaccio di Sierpinski"
- hinkley 9y ago
  'The Sierpinsky gasket makes me wanna cry.' I can't hear the name Sierpinsky without thinking of 'Mandelbrot Set' by Jonathan Coulton.
  - jszymborski 9y ago
    I hate that the part about Mandelbrot still being alive is no longer true :(
- agumonkey 9y ago
  I just thought they should be called Sierpinskites.
GnarfGnarf 9y ago
The kites were part of his exhaustive investigations into aerodynamics. There is an amazing display of his experimental propellers at the Bell Museum in Baddeck, Nova Scotia. They show how he methodically varied attributes to derive optimal pull. Well worth the visit.
VA3FXP 9y ago
It's really inspiring and impressive the stability of these kites. The weight to lift ratios are also fantastic. The linked National Geographic articles are very informative and interesting. Methinks this would make an excellent platform for a kite-antenna.
- Maarten88 9y ago
  I'm sure that kite design will be very stable in the air. But I guess the triangular wings are not very efficient and disturb each others airflow. I wonder how the tetrahedral design compares with the Cody kite design, from the same era. That design looks more efficient to me, and has been proven to scale big enough to lift people in the air. As a kid I built several small Cody kites and they fly amazingly well. We combined several and flew with up to 1km of line, hundreds of meters high. https://en.wikipedia.org/wiki/Samuel_Franklin_Cody https://en.wikipedia.org/wiki/Samuel_Franklin_Cody
  - Retric 9y ago
    "tetrahedral beings were flown both unmanned and manned during a five year period from 1907 until 1912" So, according to the article they did carry people. An important consideration is these kites where lighter per lifting area so they needed less wind and would also fall slower without wind making them somewhat safer. The added redundancy is also an important consideration. PS: It's actually fairly easy to build a kite that can lift a person in a strong wind as even a simple parachute will work. see: parasailing which can work at even 15mph. The problem is finding a design that fails safely.
- cma 9y ago
  Do SpaceX's grid fins operate on similar principles? https://i.stack.imgur.com/rnHbB.jpg https://i.stack.imgur.com/rnHbB.jpg (edit: and these: http://www.aerospaceweb.org/question/weapons/q0261.shtml http://www.aerospaceweb.org/question/weapons/q0261.shtml )
  - samstave 9y ago
    I'm sure that those are designed such to eliminate as much drag as possible while also providing steering capabilities on descent?
deleted 9y ago
[deleted]
JoeAltmaier 9y ago
Its amazing anyone thought it feasible to risk life and limb at the vagaries of the wind. Unpowered flight is fundamentally dangerous.
diggernet 9y ago
I had a tetrahedral kite growing up. That thing was amazing. It would lift off in a light breeze. And boy did it pull when the wind picked up. Great fun.
hawski 9y ago
I once built a simple box kite. It was remarkable for me how easy it was and how it could somehow perform even when there seem to be no wind. It was easier to built than a diamond kite. It was years ago and sometimes I'm thinking about building one again and placing some action camera up there. To make a few drone-like shots, but for much less money. But also because it's fun. I built mine with a few wood slats, two shopping bags, some string and glue.
- baldfat 9y ago
  I built a diamond kite with my dad and it is one of my favortie childhood memories. For some reason I have never done it with my kids yet (Finding that awesome kite paper has been elusive) but I have built dozens with kids I worked with. Such a great learning experience. http://www.my-best-kite.com/kite-paper.html http://www.my-best-kite.com/kite-paper.html
wizardforhire 9y ago
Is that a Sierpinski's triangle kite almost ten years before Sierpinski wrote about it!? Regardless truly awesome.
- gjm11 9y ago
  Yup. But (at least according to Wikipedia's article about the ST) the pattern was around -- in art -- centuries before Sierpiński!
- jgrahamc 9y ago
  Maybe, but it's not like "Sierpinski's" triangle was unknown before him. It appears far, far back in human history.
dmd 9y ago
We built one in my company's lobby a few months back! https://c2.staticflickr.com/6/5332/30663005756_793b436f73_k.jpg https://c2.staticflickr.com/6/5332/30663005756_793b436f73_k....
perilunar 9y ago
Inspired apparently by (the under-appreciated) Lawrence Hargrave's box kites: https://en.wikipedia.org/wiki/Lawrence_Hargrave https://en.wikipedia.org/wiki/Lawrence_Hargrave
amelius 9y ago
What's with that last picture?
- qubex 9y ago
  The one of them kissing? I thought that was really cute and somewhat challenges my prejudices about people of that era being repressed, cold, unemotional and reluctant to exhibit public displays of affection.
pencotts 9y ago
Let us not forget Samuel Franklin Cowdery: http://www.atlasobscura.com/articles/man-lifting-kites-cody http://www.atlasobscura.com/articles/man-lifting-kites-cody (not tetrahedral, but impressive)

161 points by flannery 9y ago

This one looks like a Sierpinsky Triangle :) https://c1.staticflickr.com/5/4226/35286566316_65bcda7d3f_b.jpg https://c1.staticflickr.com/5/4226/35286566316_65bcda7d3f_b....

kmill 9y ago
That'd be a Sierpinski tetrahedron, but it's the same idea. I think it's pretty interesting that these were made about ten years before Sierpinski described the fractals, but then again the design appeared in mosaics from much earlier: https://s-media-cache-ak0.pinimg.com/originals/52/98/75/529875deedb52ebe7adad4a29d4dea48.jpg https://s-media-cache-ak0.pinimg.com/originals/52/98/75/5298... https://s-media-cache-ak0.pinimg.com/600x315/7b/7c/06/7b7c0653e7c82e33dddf7898e70baf2c.jpg https://s-media-cache-ak0.pinimg.com/600x315/7b/7c/06/7b7c06...
- jlg23 9y ago
  Where were those pictures taken?
  - jszymborski 9y ago
    Reverse google image sleuthing leads to a pinterest board[0] that alleges they are of the Cosmatesque style[1], which means they maybe originate from somewhere in medieval Italy? [0] https://www.pinterest.com/paulettecadic/pavements-des-cosmates/ https://www.pinterest.com/paulettecadic/pavements-des-cosmat... [1] https://en.wikipedia.org/wiki/Cosmatesque https://en.wikipedia.org/wiki/Cosmatesque
    - kmill 9y ago
      Thanks for the sleuthing. I found them myself by searching for Cosmati mosaics, since Wikipedia mentions them in the article about the Sierpinski triangle. Captions for the two images: Francesco De Comité took this photograph in the Church Santa Maria in Trastevere, Rome, Civita Castellana - Santa Maria Maggiore - Motivo detto "setaccio di Sierpinski"
hinkley 9y ago
'The Sierpinsky gasket makes me wanna cry.' I can't hear the name Sierpinsky without thinking of 'Mandelbrot Set' by Jonathan Coulton.
- jszymborski 9y ago
  I hate that the part about Mandelbrot still being alive is no longer true :(
agumonkey 9y ago
I just thought they should be called Sierpinskites.

GnarfGnarf 9y ago

The kites were part of his exhaustive investigations into aerodynamics. There is an amazing display of his experimental propellers at the Bell Museum in Baddeck, Nova Scotia. They show how he methodically varied attributes to derive optimal pull. Well worth the visit.

VA3FXP 9y ago

It's really inspiring and impressive the stability of these kites. The weight to lift ratios are also fantastic. The linked National Geographic articles are very informative and interesting. Methinks this would make an excellent platform for a kite-antenna.

Maarten88 9y ago
I'm sure that kite design will be very stable in the air. But I guess the triangular wings are not very efficient and disturb each others airflow. I wonder how the tetrahedral design compares with the Cody kite design, from the same era. That design looks more efficient to me, and has been proven to scale big enough to lift people in the air. As a kid I built several small Cody kites and they fly amazingly well. We combined several and flew with up to 1km of line, hundreds of meters high. https://en.wikipedia.org/wiki/Samuel_Franklin_Cody https://en.wikipedia.org/wiki/Samuel_Franklin_Cody
- Retric 9y ago
  "tetrahedral beings were flown both unmanned and manned during a five year period from 1907 until 1912" So, according to the article they did carry people. An important consideration is these kites where lighter per lifting area so they needed less wind and would also fall slower without wind making them somewhat safer. The added redundancy is also an important consideration. PS: It's actually fairly easy to build a kite that can lift a person in a strong wind as even a simple parachute will work. see: parasailing which can work at even 15mph. The problem is finding a design that fails safely.
cma 9y ago
Do SpaceX's grid fins operate on similar principles? https://i.stack.imgur.com/rnHbB.jpg https://i.stack.imgur.com/rnHbB.jpg (edit: and these: http://www.aerospaceweb.org/question/weapons/q0261.shtml http://www.aerospaceweb.org/question/weapons/q0261.shtml )
- samstave 9y ago
  I'm sure that those are designed such to eliminate as much drag as possible while also providing steering capabilities on descent?

deleted 9y ago

[deleted]

JoeAltmaier 9y ago

Its amazing anyone thought it feasible to risk life and limb at the vagaries of the wind. Unpowered flight is fundamentally dangerous.

diggernet 9y ago

I had a tetrahedral kite growing up. That thing was amazing. It would lift off in a light breeze. And boy did it pull when the wind picked up. Great fun.

hawski 9y ago

I once built a simple box kite. It was remarkable for me how easy it was and how it could somehow perform even when there seem to be no wind. It was easier to built than a diamond kite. It was years ago and sometimes I'm thinking about building one again and placing some action camera up there. To make a few drone-like shots, but for much less money. But also because it's fun. I built mine with a few wood slats, two shopping bags, some string and glue.

baldfat 9y ago
I built a diamond kite with my dad and it is one of my favortie childhood memories. For some reason I have never done it with my kids yet (Finding that awesome kite paper has been elusive) but I have built dozens with kids I worked with. Such a great learning experience. http://www.my-best-kite.com/kite-paper.html http://www.my-best-kite.com/kite-paper.html

wizardforhire 9y ago

Is that a Sierpinski's triangle kite almost ten years before Sierpinski wrote about it!? Regardless truly awesome.

gjm11 9y ago
Yup. But (at least according to Wikipedia's article about the ST) the pattern was around -- in art -- centuries before Sierpiński!
jgrahamc 9y ago
Maybe, but it's not like "Sierpinski's" triangle was unknown before him. It appears far, far back in human history.

dmd 9y ago

We built one in my company's lobby a few months back! https://c2.staticflickr.com/6/5332/30663005756_793b436f73_k.jpg https://c2.staticflickr.com/6/5332/30663005756_793b436f73_k....

perilunar 9y ago

Inspired apparently by (the under-appreciated) Lawrence Hargrave's box kites: https://en.wikipedia.org/wiki/Lawrence_Hargrave https://en.wikipedia.org/wiki/Lawrence_Hargrave

amelius 9y ago

What's with that last picture?

qubex 9y ago
The one of them kissing? I thought that was really cute and somewhat challenges my prejudices about people of that era being repressed, cold, unemotional and reluctant to exhibit public displays of affection.

pencotts 9y ago

Let us not forget Samuel Franklin Cowdery: http://www.atlasobscura.com/articles/man-lifting-kites-cody http://www.atlasobscura.com/articles/man-lifting-kites-cody (not tetrahedral, but impressive)