Hello Everyone,
I know this is my first post in this name here however I have had my eye in this forum for many years. I would post this in the EX forum however not US Citizen so I will be very basic with this.
For hybrid oxidisers I know its not illegal (In Australia at least) to have H2O2 as a oxidiser. Personally I like using this over N2O as a oxidiser. I have a strong supply of H2O2 90% and the cost is about the same. Obviously this is not used as a mono prop (Hence Hybrid) mixed with a wax/glue grain. Again to refrain from talking about EX my question is below.
Would it be possible for TRA or NAR in either a forum like TMT to be able to certify a H2O2 oxidiser hybrid motor? Also for the Hybrids available currently I wonder why they chose N2O over H2O2. Availability is a plus however my belief is H2O2 is better fuel.
Let me know what you all think. Again if this post is out of bounds I am sorry.
The only hybrid oxidizer allowed by NAR and TRA is nitrous oxide. There is no law prohibiting an amateur rocketeer from using H2O2 as an oxidizer but unless you can somehow acquire surplus hi-test peroxide, >90%, you will not find any commercial manufacturer that will sell anything stronger than 50% to a non-government propulsion user. I know because our company does propulsion research and FMC came to our facility and would only provide 50% peroxide. They did the same thing to Armadilllo Aerospace, and everyother company I am aware of. And if it were commercially available at substantially higher than the ~$1.50/pound commercial wholesale price.
Nitrous oxide is only reactive under normal contitions when heated to over ~350C where it starts to thermally decompose. There are a few catalysts that can cause a lower temperature but those catalysts are quite expensive. Peroxide on the other hand, is highly reactive, and sometomes explosive, even at room temperature. It will even decompose in storage, and if the container is not vented, the container will eventually explode. Bill's video show some of the reactivity, but an early Armadillo Aerospace video on the reactivity of peroxide with common materials is a classic. The leather shoes that continue to reiginte several times after the flames are extinguished is indicative of how difficult peroxide can be to handle.
Nitrous oxide is a liquified gas under its own vapor pressure. Peroxide has a vapor pressure lower than water so it needs to be pressurized either by a puimp or compressed gas both of which add complexity to an rocket motor when compared to nitrous.
The gold standard oxidizer for a professional hybrid is actually liquid oxygen which is 100% oxygen. 100% peroxide will provide 47% oxygen by weight, 90% peroxide delivers 42% oxygen and 80% delivers only 38% oxygen whereas while nitrous will supply always 36% oxygen by weigh. The 50% peroxide that is relatively easy to obtain delivers only 24% oxygen, so it is much less efficient that nitrous.
To be useful in a rocket motor, you need a catalyst to crack the liquid peroxide so it liberates the oxygen as a gsa. The catalyst bed and the gas pressurization system add weight to the rocket. The pressurization and catalyst systems are not needed with nitrous as it enters the motor as a gas. In practice with small amateur rocket motors no performance gain would be expected using peroxide after doing a complete system analysis.
There is no extrodinary hazards handiing nitrous in the field. A spill will not starts a fire or explosion. A peroxide spill will start a fire in a launch field most of the time, and possibly an explosion if it contacts a catalytic material or something hot.
I do not envision any circumstance where NAR or TRA would certify a peroxide hybrids simply due to the high probability of fire or explosion during the handling and use of the peroxide.
Bob
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