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• Sequencer Firing Debugging
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  The good news is electronics always obeys the laws of physics so there is a reason why things don't work. My first guess is you have a power dipping problem. Are you using a fresh alkaline (good) or an old or carbon (bad, bad) 9 volt battery? Put a volt meter on the battery and see if the voltage drops. Test your circuit with a regulated power supply. Do you still see the same problem?

  Posted by Teazer on September 13, 2010 at 12:39:50 Pacific Time

• Sequencer timing failure
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  I've finished my igniter sequencer but I'm having a problem. If I omit the transistors and use resistors and leds, everything works fine. When I use the transistors and lamps or the transistors and igniters, once the first one goes, the second one lights almost imediately after. When using lamps, the first bulb shines bright while the second glows dim. The second is ignoring the clock pulse. Any ideas what could be wrong?

  Posted by brushyfork on September 10, 2010 at 17:05:25 Pacific Time

• HHO vs HHCl
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  It just occurred to me that if you use salt instead of baking soda as your electrolyte you will get a mix of Hydrogen and Chlorine gas instead of H2 and Oxygen. Since Igniting a mix of H2 and Cl produces much more energy than igniting HHO you can increase the amount of water in each bottle (stage) which should result in longer flights. Caveat: Chlorine gas is toxic so don't inhale much and it takes less energy (less heat) from a spark to ignite an HHCl mixture. Furthermore, the product of burned H2 and Chlorine is hydrochloric acid (muriatic acid). But I'm sure if you've taken the proper precautions for handling pure H2/O2 mixtures then you should be safe enough even with chlorine replacing the O2. Keep baking soda handy anyhow since thats a good first aid treatment for contact with acids...So, GO, set a record or something! That's what I'm gonna try to do tomorrow ;)
  

  Posted by lotusdiver on June 20, 2010 at 07:20:10 Pacific Time

• Question about the schematic...
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  Hi guys! I'm midway through the construction of the circuit, and was wondering how important it is that the 0.01 uF capacitor be an electrolytic one? I'm trying to use a ceramic button style cap, and I can't get my circuit to work (which may be entirely due to my crap breadboarding skills). And if I do need an electrolytic 0.01 uF cap, wgere do I find it? I can't find any at Digikey or Mouser or Newark (at least none whee I don't have to order like 500 and pay $$$ and wait six weeks).
  
  Thanks!
  
  Corey Richter

  Posted by kebo26 on May 07, 2010 at 11:53:01 Pacific Time

• Question about the schematic?
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  I have built the circuit and it appears to sequence correctly. The question that I have is where do the arrows lead back to coming off the top side of the igniters. Is it just back to ground?

  Posted by Bubbajoe on April 28, 2010 at 22:41:24 Pacific Time

• Hydrogen-oxygen bottle rocket?
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  Help, (please) I think that this HHO rocket,may be beyond my abillities. Too late to turn back now, this is the approved science fair project my son has started. All I need to do is build and launch this puppy.(note no small dogs will be hurt, in the making or launching of this rocket) Question #1, Make:Volume 20, page 93 set up,says use clear silicone sealer, page 94, 1d.1e. and 1f. say glue with silicone sealer. should I use silicone glue or sealer, product name, thank you.
  

  Posted by MiCkEy/tD on April 07, 2010 at 16:14:19 Pacific Time

• 10 Question
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  1) Using steel wool as an ignitor won't affect the flight will it.
  2) Could anything be change in the HHO to positively affect the flight (like using H2O2 to create the gas or adding CO2)?
  3) How many times can you reuse the water for the gas. Or can it be used infinite number of times?
  4) Why does the water turn brown? Is it iron oxide, if so whered the iron come from.
  5) Will the bottle weaken at a rapid rate as you test over and over, or can it withstand several consecutive tests?
  6) If you only use air and HHO shouldn't it still fly as long as it has something to push against? The only problem would be the possible breaking of the bottle.
  7) Is there a possibility of the bottle melting because of the explosion?
  8) When adding baking soda, the more the better?
  9) What is the best way to test the rockets thrust without using a ballistic pendulum
  10) If you want test the efficiency of a mixture would it be better to test distance/height/time or thrust itself.

  Posted by Callidus on February 15, 2010 at 12:03:47 Pacific Time

• What is probable PSI generation?
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  With 1/3, 1/3, 1/3 mixture, what is the likely psi generation per second?
  
  I want to restrict the nossle, but also want to keep the max psi under 80 psi.
  
  Assuming a positive delta per second to psi for the ignition and a negative delta per second to psi for the thrust output, what can be expected on a standard bottle.
  
  I don't mind doing research on this, but don't know the topics to start with to determine the psi/second generated from oxyhydrogen ignition in a contained volume.
  
  I don't think the energy generated is the key factor, I think that the volume expansion is the key factor.
  
  For the combusion PSI, is there a conversion model based upon the ideal gas law: PV = kNT?
  
  I have no idea what formulas are involved for expanding gas exiting a chamber...
  
  I picked up a Make mag while browsing magazines. It's the best thing that happened to me for years.
  
  
  

  Posted by rwagnon on January 13, 2010 at 22:43:44 Pacific Time

• Safer generator
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  My son and I have been working with a single-stage version for a science fair project. I didn't like the idea of working around water carrying those kinds of currents, so we modified it (of course ;) ). From the top of the funnel, we ran a clear vinyl hose hose out of the 5 gal bucket and into a neighboring one. Once filled with gas, this hose serves to isolate the water in the gas generator from the water in the rocket fill bucket... and putting a small hose clamp on the tube means you can even generate gas and "store" it in the tubing for a little bit (waste not, want not). This allow you to very precisely mix any ratio of HHO/Air/Water you want... ideal for a science fair project.
  
  We also modified the ignitor, using two very small alligator clips to hold the rocket ignitors. Much easier to replace, and more reliable.
  
  So far, 8.1 second flights are easy (without a parachute)... but the video of a dusk take-off is spectacular. This summer we'll try the multi-stage approach, but for now I think I need to make a ballistic pendulum to thrust test this puppy.

  Posted by brdavis on January 09, 2010 at 16:56:39 Pacific Time

• Single Stage?
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  How would you create a single stage without the having to build the entire circuit so you can do several tests, and still add rest of the circuit to do the two-stage as a "finale"? Should I just build all the circuit and just no add the second stage?

  Posted by Callidus on January 08, 2010 at 18:34:16 Pacific Time

• Chemistry?
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  I'm curious about the chemistry of this rocket. The article hinted a little bit about the electrolysis and the need to add sodium bicarbonate as an electrolyte. But can anyone add some insight as to why the water molecule will decompose when there is a voltage potential between the two electrodes? And can anyone offer a little more detail on what the voltage and amperage needs to be at to induce electrolysis? Thanks!

  Posted by Compgeek on November 08, 2009 at 17:07:33 Pacific Time