Liquid Fuel Rockets

[TariqMujahid]

I've searched this board pretty thoroughly, and only found topics on Solid Fuel rockets, like a mix of AN and Al and charcoal etc...

On the internet, i've found some plans for building a liquid fuel rocket booster. It uses a fuel of Hydrogen Peroxide (i think 30%, but i cant find the website anymore) and Gasoline. That's well and good, but the plans cost $25. As NBK2000 pointed out, yes, i do have a hairstring budget and i don't feel like spending that much money. Why am i bothering with this then, you ask? For knowledge; i doubt i'll be building a rocket booster in the near future. Perhaps someone else has bought the plans and is willing to share the knowledge with us?

Anyhow, if you don't know how a liquid fuel rocket works, here's how: It pumps the pressurized fuel into a combustion chamber, where it is burned (duh), and the pressurized gasses are released from the nozzle and thus propel the rocket.

My "improvised" or "ghetto" version of this rocket would be to use a PVC pipe as the main body. It would be divided into 3 sections: The main fuel tank, the combustion chamber, and the area connecting the Combustion Chamber and Fuel Tank. The Fuel Tank and Combustion chamber would be of equal width, but the connecting piece would be narrower. The Fuel Tank would be pressurized right before launching the rocket using a CO2 cannister perhaps, thus pushing the fuel into the Combustion chamber to be burnt.

My problem is- if i use a CO2 cannister to pressurize the fuel, could that cause the PVC pipe to explode? Also, what would be a good liquid fuel to use? The fuel must include an Oxidizer, in my case Hydrogen Peroxide, and something else that burns nicely. Thanks

[Ctrl_C]

Another solution is H₂O₂ over a silver catalyst. It reacts violently, producing hot gases. Silver however is expensive and you would need to make some sort of screen out of it. Hydrogen Peroxide can be distilled to save money.

[TariqMujahid]

As a substitute for silver, i've heard of Iron Oxide being used and yielding very similar results. Silver is expensive, which is why i'd prefer the Iron Oxide.

Silver is a catalyst in the reaction, right? So simply putting silver in Hydrogen Peroxide shouldn't cause the reaction you speak of right away...shouldn't you have to apply heat to the mixture? I'd prefer this, because it seems a lot safer than having a binary rocket fuel. Then again, the whole idea of an improvised liquid-fuel rocket doesn't seem all that safe to begin with..

You say Hydrogen Peroxide can be distilled? My method of purifying it was to freeze the drug-store version or hardware store version and separate the H2O2 from the H2O that is mixed in with it. For rocket fuels, it is ideal to have 90% H2O2. Could freezing or distillation be used to bring the H2O2 up to this concentration?

[James]

I remember seeing a couple of tables that I think might be relevent.
<table border=0>
<tr><td>H₂+O₃</td><td>607</td><td>H₂+O₂</td><td>450-460</td></tr>
<tr><td>CH₄+O₂</td><td>385</td><td>jp5 + H₂0₂</td><td>330</td></tr>
<tr><td>H₂0₂</td><td>160</td><td>Kerosene+O₂</td><td>355</td></tr>
</table>
but check out Analog July 1996, and something called 'The Starflight Handbook'

<small>[ April 06, 2002, 11:19 PM: Message edited by: James ]</small>

[Machiavelli]

This one might be helpful:
<a href="http://www.gramlich.net/projects/rocket/" target="_blank">http://www.gramlich.net/projects/rocket/</a>
"HOW to DESIGN, BUILD and TEST SMALL LIQUID-FUEL ROCKET ENGINES"

[vulture]

Why use silver if you can use copper, brass, manganese dioxide and potassium permanganate as a catalyst?

And I don't think 30% hydrogen peroxide is gonna work. You'll need at least 60%.

Dinitrogen oxide (also called laughing gas) is used as a double based propellant together with organic fuels. Shouldn't be too hard too find it or you can make it by heating ammoniumnitrate. However, the liquifying is all yours... <img border="0" title="" alt="[Wink]" src="wink.gif" />

[Azazel]

i would presume this rocket would be hard to construct on a low budget due to size constraints vs material costs.
I love topics like this however there are so many things to consider. here are some things i have picked up along the way in concern to making such a rocket. I must admit that i am not quite sure as to what the h2o2 fuel would actually perform like... anyways

From what i know so far, is that for a rocket with liquid propellent there are many factors which are relevent to the thing actually working. One major concern is the quality of the fuel itself. It must be able to travel through an injection system effectively so as not to create any inconsistansies within the system. There must be 2 injection systems by the way which exert high pressures by filling the combustion chamber with an oxidiser and the fuel. Now...
The parts to outline -
2 injection systems are required
1 liquid oxygen is needed
1 Fuel sorce is needed

Now when taking these into consideration the rocket would actually be quite large... or larger than most would expect. Remember there would be 2 sections to house the seperate fuels, and then 2 injectors pumping away constantly. The injectors, im not too sure where you could get these from. If your have a good understanding of mechanical engineering you may know how to extract these efficienty from a fuel injected engine. But thats just an idea. Apart from that you must work out what suitable volume combustion chamber is needed. Could be alot of maths in working that out and to tell you the truth i have no clue as to what you even need to take into concern in regards to that. I think you would need to know how much hot gasses are created so you can determine combustion chamber size. Remember equast gases will choke the combustion reaction if they dont escape but the injectors pumping in product fuels should compensate for this. The combustion chamber must also be equiped with an igniter system.
I have heard of alcohol and petrol [not too sure what type but i would assume from the generalisation it refers to common car type fuels, but i dont know if these burn fast enough ] being used as fuel types.

I could go on for ages my friend but it would take a long time...

However hard it may sound this would make an excellent project. One which may produce excellent results. Nothing better than being proud for what you made. best of luck

[Anthony]

I don't think liquid fueled rockets are really suitable for the kind of things we tend to do. I get the impression that liquid fueled motors have a much poorer power/weight ratio than solid motors. The fuel just doesn't seem to pack enough energy per unit weight. The motors are controlable though, you can turn them off/on and throttle them, something you can't do with a solid fueled motor, but in our applications I don't think this advantage outweighs the benefits.

[Bitter]

Military missiles use solid propellent, so why argue with that ? They can't be wrong can they ?

[RTC]

The V2 rocket's use h2o2.

[Anthony]

I think cruise missiles (tomahawks) use some kind of gas turbine... with a solid booster to get them off of the launch pad anf up to a decent air speed though.

[TariqMujahid]

I'm interested in Liquid-Fueled rockets not as a weapon; but simply for learning and trying something new. Maybe the military does use solid propellants, but that's not what i'm interested in. If i want solid propellants, i can buy rocket engines from the hobby store. Of course it is a difficult project and i doubt with my limited budget ($7 and a $20 gift certificate to a mall), i'll be building one any time soon. It's fun to talk about though, and give myself and some other good minds something to ponder about.

[HOOPS123]

Check out project "R.U.S.H."
<a href="http://www.rocketguy.com/oldhome.html" target="_blank">http://www.rocketguy.com/oldhome.html</a>

[nbk2000]

Russian ICBMs use liquid fuels because they're more powerful and controlable. US ICBMs use solid fuel because they're less maintainence, and store for years. Cruise missles use solid-fuel booster rockets to get them up to flight speed before the gas turbine kicks in.

I'd have to stick to solid fuel for any improvised weapon. Liquid propellants are dangerous.

[cutefix]

The engine design for liquid fuel rockets is more sophisticated.It was very popular during the rocket development years after the second world war,as was led by von Braun in White Sands.However,for practical reasons,during the latter years,miniaturization of missile components,and improvement of guidance,favored the compactness of solid fueled rocket design.There were fewer accidents related to storing of hypergolic rocket fuels which led to deadly accidents that occured with the Titan liquid fueled rockets.previously.Even Russia spent so much time to "copy" the Minutemen ICBM solid fuel propulsion system.This development by the US made them superior in missile technology,that was envied by China and Russia.
I think only aspiring nuclear capable countrries like India,Pakistan,and even North Korea still favores the obsolete technology of liquid fuel rocket propulsion.

<small>[ April 09, 2002, 08:27 PM: Message edited by: cutefix ]</small>

[Arkangel]

Tariq, for a variation, you could have a go at a steam powered rocket. Can't remember if it was on the forum I saw some info, but the one I saw most detail on was powering a car. Have a search around, they are simple and powerful.

[TariqMujahid]

Hydrogen Peroxide + Silver, from what i've heard, produces adequate amounts of steam for propulsion... What happens, is the reaction causes Oxygen to form and be expelled through the nozzle very quickly. At the same time, being an exothermic reaction, a lot of heat is developed and the H20 that is then in the combustion chamber is converted to steam and aids in the propulsion. Still, it requires the very pure H202, which can be hard to come by.

[Anthony]

If you want steam propulsion but don't want to mess around with high conc H2O2, it can also be made from tap water :) You need a pressure vessel full of water and attached to the exhaust is a valve which can be opened remotely. You heat the water, possibly via an emersion element on board, or more simply (and lighter) with an external gas burner. Once the tank is pressurised and the water super-heated, you open the exhaust valve, the pressure in the tank drops rapidly and the water flash boils, shooting large amounts of steam out of the exhaust.

Same sort of concept as an air/water rocket in that you leave everything on the ground.

Range might well be quite limited though, but the fuel is cheap.

[Arkangel]

A frangible disc is often the valve, located just inside the nozzle

[BoB-]

Pyro valves are much simpler to design than frangible barrier valves, basically a small pyro charge slams a piston forward aligning the vent holes, opening the valve. Its intstantanious, reusable, and its what pro liquid rockets use.

Heres some links for you;

<a href="http://www.rocketryonline.com/" target="_blank">http://www.rocketryonline.com/</a> -Online rocket mag.

<a href="http://www.uoguelph.ca/~antoon/websites/rock.htm" target="_blank">http://www.uoguelph.ca/~antoon/websites/rock.htm</a> -rocketry webring.

<a href="http://www.tripoli.org/" target="_blank">http://www.tripoli.org/</a> -Online model rocketry fanclub.

[Azazel]

and plus why would a nation want to waste money on a weapon which can be oposed by a safer system, which has simpler parts, needs only maintenance on the warheads b/c rocket body has expiry date, and is safer to store...

i think a really awesome project would be to design a solid fuel rocket about the size of a car. The maths behind that would be awesome. If you managed to get it all right after all of the test flights [and thousands of dollars] im sure you would be quite proud.

has anyone here come up with an idea to control a rocket from ground ??? i was thinking along the lines of model airplane r/c... im not too sure on the distance these things work on though... can anyone help me out here

[nbk2000]

The SALT treaties limited the number of ICBMs each country could have.

The US missles have superior accuracy, so we could use smaller warheads.

The russians weren't as accurate, so they needed larger warheads, which required more lift. That means liquid fuel rockets which have superior fuel weight/power ratios. Plus, they used larger missles so each one could carry more warheads. I thinks some of the SS-2x series carried almost 30 nukes each. <img border="0" title="" alt="[Eek!]" src="eek.gif" />

[TariqMujahid]

To put any sort of guidance system onto a rocket is illegal in the US...however, no one here cares about that. =)

The model airplane idea isn't a bad one; but you'd have to get the rocket aligned onto the target at the beginning of the flight so it doesn't drift out of range on you. To do this, you would simply attatch different servos (sp?) onto the fins of the rocket to guide it. The servos would be controlled by a remote control on the ground. Apparently, you can have servos that attatch video to it too...of course, this will cost money.

One of the big problems with this though is keeping the rocket stable. The rocket may tend to twist, so that "UP" on your remote control is no longer "UP", etc. I've heard a suggestion from somewhere else of using a gyroscope to keep it stable?

This is getting off topic though; i think it's worthy of a new forum post, provided it hasn't been mentioned before. We're talking about Rocket Guidance in a section about Liquid Rocket Fuels =).

[BoB-]

If you've got a R/C model airplane, you dont need a missle, you've already got a stable guided aerial vehicle.

The weak propeller that drives most of them could never carry an effective explosive charge, heres where a liquid fueled rocket comes in, it should serve as the main engine. In effect a mini cruise missle.

It could also be launched straight up with the aid of a few model rocket engines.

[Azazel]

yea but i aint bin laden man... i aint gona go arming an RC model plane with H.E... its too disrespectfull