Sunday, March 21, 2010

Unidentical twins: Carbon and Steel



Carbon fiber fascinates me. The stability and the low weight, plus the cool look, is just amazing.

But so far my carbon fiber models have been rather small, even tiny. Small slingshots are lightweight no matter what they are made from, so the advantage of the carbon fiber is not so great for small frames.

So I decided to design a larger frame model, based on my "compass" design. But I used 16 mm tubes in addition to pieces of the 5 mm board.

The "heart" of the design is formed by the board, which extends into the tubes a bit. This means that the glue does not "carry the load", the slingshot shoots with no glue at all. The glue just prevents shifting. You can see the construction by looking at my "blueprint", the outlined parts are made from carbon fiber boards.

In order to compare it with steel, I made a similar one from 16 mm steel tube. The steel one ain't heavy at all, just 340 gramms, not too bad for such a big frame. But the carbon fiber one is 60 gramms only!

Both slingshots are strong enough for my toughest bands. Of course they have a low fork and 10 cm effective fork width (measured from the middle of the bands).

The attachment method works well, too! Clean, smooth over the top style.

Here is the video:

http://www.youtube.com/watch?v=mrYxetJ6o6U

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