Sciencemadness Discussion Board

rocket fuel for supersonic rocket motors and can take lots of weight with it

Practicaler - 5-4-2013 at 03:49

There are lots of rocket fuel most common is potassium nitrate and sucrose. And ammonium nitrate composite propellants . Basically what i wan to ask is that
1_ a rocket fuel which can make rocket motors to fly at speed at least 100m/s
2_a rocket fuel which has such a huge power that 1 kg of rocket fuel can take at least 3 kg of mass with it at speed at least 100 m/s
3_ what are your views regarding potassium nitrate an sucrose can it do such a work .

KonkreteRocketry - 5-4-2013 at 11:22

As long as the burning surface area is large enough, any fuel can do it, even the lowest efficient fuel can do that, just by making the burning surface area so large that it finishes in split of a second generating hell of a thrust.

But that may not be what you want, the best propellants are perchlorate-metal fuel-binder. High powered propellants like APCP for example, have a peak specific impulse when you mix 72% NH4ClO4, 16% Fine aluminum powder, and 12% PU, HTPB, or any liquid rubber that can be cured and turn hard, and can burned good.

If you only have nitrates, aka easiest oxidizers to find.. then. in my experience, you can give 65% KNO3, 20% Dextrose, 15% Magnesium powder, a try. The magnesium get tripple reacted with O produced by KNO3, H2O and CO2 produced by dextrose when burned with KNO3, the tripple reaction makes the propellant burn very very hot, the magnesium could reach as high as over 2200 degree Celsius when burned with CO2. The heat produced can make a lot of gas expansion and making nitrate based propellants' highest specific impulse. Note that KNSU burns only with 1400 degree celsius.

The dextrose could be replaced with Epoxy binders, if you want, but then the KNO3 ratio have to be raised to around to at least 68%. I tried Araldite, Ace, and some other, gave me a ugly 40% Carbon residue.. I personally tried a similar propellant using epoxy. For epoxies its best if you use West system 305 slow resin.

70% KNO3 5% Magnesium 16% Epoxy and 9%Sucrose. The CO2, H2O produeced by Sucrose and by Epoxy, and O by KNO3 could all react with Magnesium which in turn should have gave me a good thrust but i had some problem during ignition of this propellant, i just did this yesterday, so the whole thing burned for 7 seconds instead of 3 seconds expected, gave me a low thrust of just being able to take off at its peak. and the Long during of the hot burning magnesium has erroded my Concrete-Epoxy nozzle, severly, taking off around 2mm of thickness on all side, with some melted PVC.

I discussed about Nitrate-CO2-H2O producing fuel- and Magnesium with Richard Nakka. here is the conversation.


Richard nakka and me talking about RNX.
________________________________________________________________________________________________________________
I wrote:
I recently found a that a mixture of alcohol, toluene, and acetone, can dissolve most of the epoxy. That sounds very very interesting, because we will be able to mix KNO3 with those house hold solvents to get a much better and efficient RNX propellant ?
TZ

Richard wrote:
I don't believe that will help. The problem is that KNO3 is a low-energy oxidizer and that is why the combustion efficiency is not great. Especially since RIO has to be added to get stable combustion, which further reduces the potential.
The only realistic solution to boosting the potential of RNX is to added aluminum or magnesium. These metals are "thermics" which react with the H2O that is produced by the combustion of RNX, and greatly increase the temperature. But, a fair amount would be needed to 'self-sustain' the high temperature combustion, no less than 10-15% (experimentation would be needed). I would expect as much as 25% can be used and efficiently burned.
Richard
________________________________________________________________________________________________________________




Yup, However, All magnesium turns to MgO, that stays as a SOLID when burned, however it gives a really boost in gas expansion with its heat produced when reacted with CO2. MgO will be pushed out with no thrust gained and your nozzle might face some difficulties when MgO is passing through your throat at over mach 3, i assume thats the least exhaust velocity you need to get your rocket up over 100ms. I used a Chromium-Iron alloyed washer that actually did not melt(surprised) when i added 5% Magnesium.

However magnesium can make up for its 2 phaese flow lose, by boiiling the carbonates produced by nitrate propellant. Adding magnesium is that when it burns, it can actually boil K2CO3 which is greatly produced by KNO3, and turning it to gas. and the higher temperature could make more gas expansion i would assume the best Nitrate propellant could reach a specific impulse of around 180.

Practicaler - 6-4-2013 at 03:07

I have potassium nitrate and painting grade aluminum powder and I also do have potassium chlorate and benzoic acid and sodium benzoate . . . Well konkrete rocketry will you please tell me what is the best fuel that can be madr with potassium nitrate sucrose and aluminum. OR with potassium chlorate or potassium permangante or sodium nitrate or anything which can be used to do my work i dont have any any access to perchlorates but nitrate are in plenty for me. Chlorate supplyis also limited . Basically i want to make such a rocket which can Carey at least 3kg of load with it

KonkreteRocketry - 6-4-2013 at 10:34

Quote: Originally posted by Practicaler  
I have potassium nitrate and painting grade aluminum powder and I also do have potassium chlorate and benzoic acid and sodium benzoate . . . Well konkrete rocketry will you please tell me what is the best fuel that can be madr with potassium nitrate sucrose and aluminum. OR with potassium chlorate or potassium permangante or sodium nitrate or anything which can be used to do my work i dont have any any access to perchlorates but nitrate are in plenty for me. Chlorate supplyis also limited . Basically i want to make such a rocket which can Carey at least 3kg of load with it


Chlorate burns too fast and is instable, try not take so much load with it, 3kg is kind of... over load.

If you ever make a nitrate rocket, use this.

60% KNO3
30% Sucrose
10% Magnesium.

48 KNO3 + 5 C12H22O11 = 24 K2CO3 + 24 N2 + 55 H2O + 36 CO2

The H2O, CO2, and N2 burned from the sugar and KNO3 will burn with magnesium violently.

Mg + N = Mg2N3

Mg + CO2 = CO + MgO

Mg + 2H2O = Mg(OH)2 + H2

Mg + O = MgO

Those reactions from magnesium will BOOST the nitrate propellant by a lot, boiling off the K2CO3 also. This is the highest specific impulse ever made by KNO3.


Practicaler - 7-4-2013 at 06:50

Making magnesium powder is a big trouble for me but getting aluminum powder is much easy. Will it do my work . In my knowledge Al doesn't react with nitrogen

KonkreteRocketry - 7-4-2013 at 07:05

Quote: Originally posted by Practicaler  
Making magnesium powder is a big trouble for me but getting aluminum powder is much easy. Will it do my work . In my knowledge Al doesn't react with nitrogen


in nitrates, both aluminum and magnesium dont turn into gas in its oxidized state, but magnesium is more reactive so use magnesium for nitrates.

KonkreteRocketry - 10-4-2013 at 09:26

Check this, i did this static test 2 days ago. I could have reached a maximum speed of 82 meters /s with this.

I added 5% Magnesium to KNSU, surprisingly , the specific impulse i got from my calculation was 169. a typical KNSU would produce 130 max. I had a delaval nozzle though.

https://www.facebook.com/photo.php?v=10152738867955707



[Edited on 10-4-2013 by KonkreteRocketry]

Trotsky - 11-4-2013 at 02:09

I've had good luck with rocket candy produced using 7% Al and 10% AN. My KN was somewhat more coarse than I would have liked, but the AN was ultrafine.

I had problems getting it to ignite, though. I ended up sticking a small bit of straight KNSU into the nozzle and ignited that, which had no problems getting the primary charge going.

I experimented with KMnO4+Paraffin and KMnO4 + Epoxy motors with varying amounts of AN, charcoal and Al added. With paraffin it was impossible to get an even distribution and even consistency. Paraffin-based motors were sub-par to garbage, but it was kind of fun, and the flame had a neat color. In retrospect, though, it was stupid as I was inhaling neurotoxic Mn fumes at dangerous levels.

Thebrain - 11-4-2013 at 17:27

How big a payload are you looking at? One thing to consider is that the larger your payload, the more fuel you'll need. And fuel is heavy too. It will cut into your payload capacity.

Antiswat - 13-4-2013 at 05:17

i believe also golden powder could be used, but im not entirely sure, you would ofcourse need to press it..
burns quite fast and ignites really fast..
i had decreased the burn speed of golden powder with mixing it 1:1 by volume with 60:40 KNO3 Sugar
meaning..
6g KNO3 4g ascorbic acid
6g KNO3 4g sugar
if i had better location for playing with rockets i would most likely do it, my idea would be making a goldenpowder-blackpowder type, also i have found out that golden powder can be made with KClO3, so pretty surely also KClO4, tho its very insoluble.. other perchlorates like NaClO4 if possible to get perhaps?
mixing metal powder into the golden powder seems to make it worse, but perhaps the idea of the metal powder reacting with the gas produced could make a difference..

as konkreterocketry states i agree, you need to think about the rocket's design mostly.. the more burn area the better

abit more interesting as i see it is kicking off the rocket as used in military weapon systems.. ive heard this being talked about as ''softlaunch'' or something, where the projectile/rocket is first shot off as in a mortar, with little force, but this needs fins to work properly, as it stabilizes the rockets flight alot, apparently also. then a proper timing with rocket fuel initiation..
for things like this golden powder could be used or crimson powder, lovely stuff, havent tried anything else but heating some in a capped aluminium tube, made a not so impressive bang and a decent shot tho it went through what covered up one end of the tube, it shows potential..

Vikascoder - 8-5-2013 at 08:20

What fuel is used in rpg launcher. You could try that for your work I think in RPG most probably ammonium perchlorate and aluminum is used .