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Will KNO3 potasium nitrate disolve in methonal and later burn

  1. Mar 28, 2007 #1
    I wish to make a ground small test rocket motor using liquid fuel with 1lb of thrust

    Its to complex make air injections or LOX

    The solid fuel guys use KNO3 with sugar and melt it to make solid fuel

    I prefer to make a surface device such as model car go with a liquid fuel option if it is possible

    Stephen ...... a non chemistry type of experimenter
  2. jcsd
  3. Mar 28, 2007 #2


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    It would be very dangerous to premix your oxidant and fuel together. You'll put your eye out!

    A safer liquid would be 70% hydrogen peroxide used as a monopropellant. Pump the peroxide into a combustion chamber that contains some platinum gauze and it will decompose into oxygen and steam.
  4. Mar 29, 2007 #3
    The project is dependent on being able to get locally available fuels

    The project is dependent on being able to get locally available fuels at reasonable prices in my location in Europe

    The highest peroxide available is 25% and that costs like $20 a 100cc

    Other source from hairdressers which can be thinned down are nearly impossible to get as they for security reasons as they use 60% and has terrorist implications so its a lot of troble just for a few shots at 100cc a pop

    Methonal and KNO3 is readily available at reasonable prices

    The mixing would be done on site of use within minutes and not stored if not used

    The other options to use LOX is again also complicated with cryogenic issues and although $40 for the 2 cubic feet not to expensive the rental of the bottle the deposit and then making of suitable taps and so forth to extract into tanks some 50grams of LOX

    The solid fuel rockets is the cheapest with sugar and KNO3 but they are violent massive burst of short runs 1 to 3 seconds with most power in the first 1/3 of the run time or similar short runs issues
    I want less power more evenly spread out over 5 to 10 seconds

    Other mono props like nitromethane wil only work at 371 bars and thats only good for massive engines of 100kg plus size and the fuel costs are 20times greater than methonal

    Ram jets and pulse jets are too big for this type of project as they are more suited to run for five minutes

    Given access to H2O2 probably do that but all attempts to get the stuff are just non starters
    Also I don't want to spend a fortune
    Also 70% is a problem for having lots of protective gear also as it is hazardous to living cells

    If it was dangerous to pre mix the methonal and KNO3 I can arrange that there are two tanks

    The methonal would be allowed to run into the tank with KNO3
    I would be a suitable distance like 30 metres (100) feet away with my Radio control to my car and using my lap tops WiFi to give close visual from a 2.4ghz camera

    Then I would light up the glow plug and inject the mix into the chamber

    If it works then great
    If it go kapow well its an old model car anyway

    The real question is how risky is the premixxed propellant and
    will it dissolve to be a useful propellant and what ratio mix is needed and so forth

    I figure rather than go down the the mix it 4 fun road it would be cheaper to ask others who might know what the issues are


    PS cant find the vidio of this but the myth busters built a real car JATO using sugar KNO3 and did 150mph on the desert lake bad following behind in a helecopter


    also this utube links show two cars launched with what I think are solid fuel rockets

    and mayby I should make this model car and make it go faster


    or make this rocket flying laptop a reality
    Last edited by a moderator: Sep 25, 2014
  5. Mar 29, 2007 #4


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    Instead of using oxygen, you could use nitrous oxide. The Mythbusters used this type of rocket on a program that tested the plausibility of a civil war era rocket. They used a paraffin/nitrous oxide rocket that they built from steel! It flew about a thousand yards.


    My favorite quote from that eposode:

    "They brought in a rocket scientist consultant: Steve Harrington, CEO Flometrics and San Diego State professor.

    Harrington: "Unfortunately in the rocket science world there aren't that many women and they are hunted to extinction.""

  6. Mar 29, 2007 #5


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    If you find that KNO3 doesn't dissolve in methanol (it should), you could switch over to ammonium nitrate. It will definitely dissolve and can be made from ammonia and nitric acid. Methanol might be too volatile for safe use. You can use biodiesel or kerosene as the fuel. If it burns too energetically, add more fuel to slow it down or cut it with baby powder to make a paste. Add some epoxy to it an you have a solid rocket.
  7. Mar 29, 2007 #6
    Thanks useful info

    The basic idea I want to use is KISS and local easy to get materials with the least problems for ignition and safety issues without to spend too much money

    Nitros Hybrid is problem to get nitros

    only local supply is small bottles for whipped cream suspect 16 grams per bottle at $0.80 cent a bottle and minimum ten pack or $8

    It makes a pure nitros solution to costly as nitros hybrids need 9 parts nitros to one part propellant such as parrifin wax etc

    The preference for methonal is that with a model car glow plug system it can ignite the fuel and then the glow plug will keep the flame going without complicated heavy spark ignition systems even though the fuel is 4 times the cost of diesel or twice that of bio deisel

    Also I can get the fuel methonal easy in the LHS

    The ammonia nitrate solution would be a more distant second choice as it is often mistaken for a explosive project especially if I use diesel which this rocket project isn't hopefully :smile:

    Hopefully KNO3 will dissolve and supply sufficient oxygen

    methonal needs some 9 parts for air less than petrols 12 parts for air

    I might have to figure how to gang together a few 16 gram nitros bottles with the dissolved KNO3 to have a complete burn

    useful idea for solid fuels in the future projects

    My preference for bigger projects the future in rockets that fly is to follow the sugar KNO3 route from www.inverseengineering.com or http://www.nakka-rocketry.net
    as that looks affordable for one off shots
    and the fuel isn't to toxic or unstable or expensive
    wish I had the desert like they got as the places I would go would be swampy lands in stickville with little chance for recovery of rockets and not have any risks from bopping the local sheep or goats when the chutes fail and keep me in the clear from the no model rocketry close to the city limits rules

    anyway that the future

    The best site I found for liquid solutions is www.armadilloaerospace.com and that is the main inspiration that Liquid is the preferable for many solutions

    But I do also want to try out in the immediate now Liquid options to have experience in all types and the small liquid types could make good side thrusters if the rocket went off course from vertical and that would need instant precision firring in pulses something the solids cant do or could make nicer rocketry for reusable crafts if I can rig a more steerable chute or similar

    Also I really don't want to have any unnecessary incidents as wrecked equipment will delay the testing process

    I also don't want to start with big rockets so 0.5 or 1 lbs be sufficiently small to start with

    Thanks any new ideas let me know of to get KNO3 and mix a few cc in a safe place with suitable protection if it dosnt pan out

    Last edited: Mar 29, 2007
  8. Mar 29, 2007 #7
    The nitrous / fuel rocket will work but if your looking just for the cool of it. I built a pulse jet with a mason jar, wire, a piece of sink drain and car dry gas (methanal?). I only got a little thrust but it sounded awsome.
    I have a short low res clip on my file store. http://home.mindspring.com/~dave.mcdonald1/
    It's called pj 2.wmv

    The problem with the nitrous is the initial heat needed to start decomposition. Mythbusters used black powder as a starter. That could be serious.
  9. Mar 29, 2007 #8
    pulsar motors and RAM motors are something else for the future...

    pulsar motors and RAM motors are something else for the future...

    but they have a lot of noise like 150 dbs:surprised
    and eat gobs of fuel like 500cc 4/5 pint a minute to produce 85newtons ~8kg push and are

    and they are often big motors for their push power for example 85newtons is ~two foot long
    if your only looking for a few seconds of power

    I already have a lot of experience in my model plane club with helping out the pulsar guys and jet turbine bunches who visit the model plane club doing demos

    I am more familiar with liquid propulsions systems so I prefer to experiment on small solutions in that mode as I have a lot of complementary stuff like tanks fitting etc

    Another piece of info I want to figure is can I transfer the nitrous oxide gas in the small bottles into one larger tank easily like say I could with LPG liquid propane gas which I transfer frequently for home brew turbine projects .

    The problem is in Europe the info on rocketry is very limited as it not so popular to do as USA but funny the regulations are often more easier in most of Europe outside UK than USA so swings and roundabouts really

    But chemicals are a big deal to get

    often need all sorts of licenses just for routine fuels like hydrogen peroxide H2O2


    PS liked the vidio
    what link supply's that method to make that solution
    It would be a good learner for the model plane club juniors to learn some motor principles some of whom only do electric because they cant tune the motors

    The starting the nitros motors is not so difficult I figure but the start times can vary from instant to 15 seconds so making it very difficult to use in precise work

    The solid fuels are similar start issues but the Russians in the space program seem to use them to cushion the capsules landing in the desert as they land on land so on big solids precision might be possible but I could be wrong on that detail
    Last edited: Mar 29, 2007
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