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iGGiE

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Pondering the idea of hybrids it occured to me that in all hybrid engines the fuel is a solid and the oxidiser is allways gas/liquid (as far as i am aware).
This made me wonder if it would be possible to create a hybrid with a solid oxidiser and a gaseous/liguid fuel.

Anybody else thought about or tried this one??



iGGiE
 

sandman

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Hmmmm, That is interesting.

Maybe Kno3 Potasium nitrate as the oxidiser and kerosine. A lot easier to deal with.

I don't know enough about chemestry to help...but interesting.

sandman
 

iGGiE

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im going to look into the idea further. i need to look at possible oxidiser and fuel combinations, then perhaps do a couple of experiments.

If all goes well i will post any results here.

iGGiE
 

rstaff3

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Have you done an internet search? There are lots of people building all sorts of amateur rocket motors. You should also join the aRocket and chemRocket email lists if you are serious about this.
 

vjp

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Originally posted by sandman
Hmmmm, That is interesting.

Maybe Kno3 Potasium nitrate as the oxidiser and kerosine. A lot easier to deal with.
Or may KNO3 (or straight AP) with gaseous propane? Radio Shack used to sell micro propane cylinders (they might have been butane - not sure) for their small micro torches. They were about the same size as the little nitrous cylinders that the micro hybrid folks use.

This way, you could use existing hybrid hardware.

Down side - you're back to using restricted substances, if you go the AP route. OTOH, you can find KNO3 at Wal-Mart.
 

BlueNinja

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This sounds like a cool idea! If you use AP for oxidizer, it would probably produce A LOT of thrust mixed with the kerosene or whatever you use. Wouldn't KNO3 be at walmart in the foods department as saltpeter? Or am I thinking about something else potassium?
 

rstaff3

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I'm a chemistry cripple and would rather not dabble with compositions that are not well documented. Flamable liquids can be quite dangerous.

Note that Ratt works is making a Tribid that also injects alcohol IIRC. I think it has been flown at a Tripoli EX meet as a manufacturer's demo.
 

rocwizard

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I have been going over this idea for some time now, but haven't figured out how i should go about testing it yet. So far, here is what i have come up with: AP suspended in either epoxy or HTPB for the oxidizer grain, and JP4 presurized with helium for fuel. the motor would operate similarly to the AT hybrid system as far as ignition.

Still gotta work all the numbers first though. not to mention how to put it all together
 

MarkABrown

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Originally posted by iGGiE
This made me wonder if it would be possible to create a hybrid with a solid oxidiser and a gaseous/liguid fuel.

Anybody else thought about or tried this one??



iGGiE
This is called a reverse hybrid and quite a few people have tried it. You should check out the arocket mailing list and it's archives to see what success others have had with this configuration. I don't suppose I need to say it but, BE CAREFUL messing with things if you don't know what chemistry is involved in the reactions!
 

benjarvis

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Yeah, as has been said.... reverse hybrids have been done for almost as long as, if not just as long as normal hybrids...

Some of the reasons that they're not so popular is that solid oxidisers are harder to cast into a grain (and keep structurally stable during combustion) than fuels... also given the fact that most ox/fuel ratios have a greater percentage of oxidiser than fuel it kinda makes less sense to have all of the plumbing and tankage for a lower volume of fuel than for a larger volume of oxidiser... if that makes sense?

Basically... it's technically harder, and has no real advantages


Ben
 
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