Step 5: Building the Blimp Frame

Start with the blimp's frame, made of balsa. Mine was 6" x 12", which left me with a lot of space where I want put more things later. You could probably get away with 6" x 6". Anyway, once you've cut that out, glue a balsa beam ( mine were 1/4" wide) underneath the flat piece, one at the front and one at the back, in a direction perpendicular to the grain. The fibers of the balsa wood can and will split apart if you don't do this. You can see these beams in the "head-on" views.

Now you need legs for your blimp. I had the Apollo moon lander in mind when I did mine, and trust me, they're worth it -- they protect your precious equipment from impact damage, and balsa is so light that the weight added is practically negligible. Mine are 6" long, at an angle of about 45 degrees below horizontal. Cut / file the ends of each leg so that when the 'foot' is flat on the ground, the leg is at 45 degrees, and the 'top foot' is parallel to the horizontal. Now glue each leg into place so that they stick out to the sides, with the feet more or less flat (you're going to glue cotton balls to them, so it doesn't need to be perfect).

You'll need triangular supports for the legs, otherwise they'll bend out and snap under weight. Cut them to the same angle as the legs, with each of the smaller sides 1" long, and glue them onto the legs and the larger frame. Your blimp should be able to stand up now, so glue some cotton balls to the feet for soft landings.

One more thing to add in this step: the battery box. The battery is by far the heaviest component, so you want it to be exactly centered. Measure the dimensions of your battery, then use these to measure from the sides and sketch a box in the center. Make sure your battery fits before you glue the balsa, and leave a small gap for the wires to poke out.

You blimp looks awesome, only the code is without any doubt the most incomprehensible code I have ever seen! I can't make heads or tails from it. Could you explain the how te code works? I really like the 433 MHz set I got, but I haven't found a clear code that I can adapt to my homemade rover. <br> <br>Thom
Darn, I have been trying to figure out your code for quite some time, IT-IS-SO-SIMPLE, I have tried to use virtualwire but then I can't use the servo library (they hate each other). Thanks for sharing it!
when I first read the title I accidently read &quot;Hydrogen bomb.&quot;
Nice work on this project! I had the same 433 Rx Tx units and could never get them to communicate properly! Definitely one of the best troubleshooting sections I've read!
this soo reminds me of the hindenburg. tho to be fair, hydrogen had nothing to do with the explosion. zinc paint(?!) was the problem. <br>very cool project. <br>tho 433mhz might not be legal in USA, but even a toy car with arduino could work
You are my hero. I have tried filling a smaller blimp with hydrogen in the same way, but using only very small amounts of lye (five attempts with no success). I would love to build a setup like this some day, especially one using a hydrogen fuel cell for power. One question: does the water buffer remove any steam or water vapor from the hydrogen entering the envelope? I always worried about getting water in it. Thanks for a very informative 'ible.
You're right to be worried about water vapor. It will only be a problem if you let the reaction get too hot, which will make it start steaming or even boil if it gets out of hand. If you make sure it doesn't get more than a little warm ( I dunno, 75 deg F), the water vapor will be negligible. If you're really worried about it, you could try running the gas through a percolator to cool it down before it enters the envelope (meaning some of the vapor would condense out). The buffer I have is mainly to prevent any water in liquid form that bubbles up from getting close to the envelope. Don't give up on lye!
Awesome. Love the chemistry lab details and the troubleshooting section.

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