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March 23rd, 2006 - Adventures in Engineering
The wanderings of a modern ronin.

Ben Cantrick
  Date: 2006-03-23 07:49
  Subject:   Nontoxic hypergolic liquid bipropellant rockets.
Public
  Mood:der uber-nerd


Specifically, our non-toxic hypergolic miscible fuel is comprised of three parts: a colloidal transition metal oxide, a low-molecular weight alcohol, and a sensitizing agent. The metal oxide rapidly decomposes 98% hydrogen peroxide into hot molecular oxygen, steam, and heat. The heat and oxygen that are generated rapidly combust the alcohol while the sensitizer destabilizes the hydrogen peroxide and provides additional fuel combustion value. The sensitizer is added to modify the local pH and to increase the polarity of the alcohol, which makes larger portions of the metal catalyst soluble.

http://roger.ecn.purdue.edu/~rusek/papers/nawcbiprop.html

Found this while I was looking for ways to make a PMFF/nitrous hybrid engine hypergolic. The neat trick here is that they dissolve some metal ions in the alcohol, so when you spray the alcohol and peroxide together, the peroxide instantly flames up due to catalyst action. Nice.

Isp is around 270s with the correct butanol isomer(s). That's very nearly as good as hydrazine. The fuel to oxidizer ratio kinda sucks at 4:1, but you can use methanol instead at about 2.5:1 and still get 260s. It's a pretty good small rocket system. The propellants are pretty non-toxic, reasonably dense, and liquid at room temperature. Ignition is fast and highly reliable. Peroxide distillation rigs used to be quite risky, but some smart guy figured out that you could distil under vacuum and now they're quite safe if built right.


(This is the part where everyone except willow_red just smiles, nods, and proceeds to ignore me. Okay, everyone? On three: One, two, THREE! (Smile) (Nod) (Wander away))
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Ben Cantrick
  Date: 2006-03-23 20:04
  Subject:   [Digg] 4GB hard drive about the size of a postage stamp.
Public
"Mounting dimensions are 0.94×1.26-inches, with a thickness of 0.197-inches. The drive uses 0.12-Watts in standby and 0.60-Watts during write operations. Running on 3.0-Volts over the 0° to 70°C temperature range, it has one platter, two heads, and a 3600rpm rotational speed."
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