8 replies to this topic

[myinisjap]

i have always wanted to make a liquid fuel rocket but have no clue where to start any info would help

[karlfoxman]

i have always wanted to make a liquid fuel rocket but have no clue where to start any info would help

Well i admire your wanting to get involved with them, must be pretty hard to build one. I remember looking at this ages ago and i found it very interesting. I have never attempted to build one but i have build a KJ66 gas turbine. Anyway here is the URL liquid fuel rocket design

Good luck!!

[Andrew]

liquid fuelled rocket engines (big ones and small ones, development, manufacture and operation without a licence) were outlawed in the UK a very long time ago, about 60 odd years ago. You might want to check up on the most up to date legislation before you go using it to power a rocket.

Anyway, putting the dampeners aside; the basic principle of liquid fuelled rocket engines is to pump two chemicals that react with each other (to yield lots of gaseous product and preferably with a negative enthalpy change), as quick as you can into a combustion chamber. The exhaust gases are then fed into a nozzle; in order to gain control over thrust direction while maximising the thrust itself. The chamber itself needs to be extremely strong.

There are 7 main considerations about a rocket engine, you need to make.
1. Combustion chamber; needs to be strong.
2. Fuel; your choice of fuel system will determine almost every other aspect.
3. Fuel storage; many factors need consideration here.
4. Fuel pumps; need to be able to shift large volumes of fuel while still maintaining a very high pressure.
5. Nozzle; optimum shape size are critical.
6. Plumbing; rocket engines get bloody hot, gas micro-tube made from copper will just melt without adequate cooling.
7. Cooling; as mentioned before, this is a very important factor in design.

In terms of fuel systems, at the absolute best end, you can have liquefied hydrogen for a fuel and liquefied oxygen for the oxidiser. The energy density of this fuel system is 30 times higher than that of petrol (per unit weight), which makes it a preferred method for getting into space.

There are a lot of mid range fuel systems that are commonly used, one that is not used any more (mostly because it kills the planet etc.) is hydrazine and nitrogen tetraoxide. These two chemicals only need to look at each other and they explode. You need no primary ignition; all you need to do is pump them into the chamber.

At a novice end, you have the likes of the V2 rocket fuel and torpedo oxidiser. Ethanol and hydrogen peroxide make a quite good combination. You first pass the H2O2 over a catalyst (vanadium pentoxide, copper and silver are all good) to decompose it into steam and oxygen, the alcohol can go straight into the chamber. You need to heat both the fuel, and the steam/O2 mix, before stuffing them into the chamber, a common technique is to use the heat of the exhaust gas to heat the fuel.

[JamesH]

liquid fuelled rocket engines (big ones and small ones, development, manufacture and operation without a licence) were outlawed in the UK a very long time ago, about 60 odd years ago. You might want to check up on the most up to date legislation before you go using it to power a rocket.

I was under the impression that only solid rocket motors required a licence.

[Damp Squib]

I was under the impression that only solid rocket motors required a licence.

As far as I know they are the only restriction is where you launch a rocket with a specific altitude and location,if you think about it you can wheel an oxy\ace torch wherever you want to so theres no reason you cant wheel a rocket motor,peroxide is legal,oxygen,petrol,nitrous.

They do have an experimental catagory at launches,AFAIK the only motor you can use are non solid experimental motors

The law is unclear in this country where rockets are concerned,the jist of it is they dont want morons firing rockets through peoples windows but dont want to completely put the nail in the coffin on experimental rocketry,if steve bennet of hadnt filled a tube with sugar and nitrate a few years ago there wouldnt be a Starchaser industry or a space technology course at Salford university

I live by the my own rules,do it safely,dont endanger anyone but yourself,dont damage anyone elses property,dont make loud noises near neighbours

I will guarantee you wont be arrested for launching a rocket in a field there is no law or regulation regarding the activity apart from your own safety judgement, if you hurt someone or damage something its your ass-a great motivator for safety ,I also highly doubt anyone would check to see if you have an estes in your airfame

SAFETY,SAFETY,SAFETY

My two cents

[Andrew]

One of the biggeys, is ATC and aviation regulations. In this country's air space, you land a heafty fine for going supersonic, a large rockets (100kg+) is more than capable of achieving this.One of the biggeys, is ATC (Air Traffic Control) and aviation regulations. In this country's air space, you land a hefty fine for going supersonic (piloted or not), a large rocket (100kg+) is more than capable of achieving this, in fact several 14kg solid fuel SAMs are capable of going supersonic. The energy density of liquid fuel systems far surpasses that of solid fuels, making it even easier to reach faster speeds and higher altitudes.

Also, any flying object that goes above 300 feet in the Traffic controlled zone (this covers most of England and Scotland) needs to be licensed and have prior consent from ATC.

I agree, as far as the occasional launch to ? thousand feet from the middle of a large field will probably not get you arrested, but it could! ATC do not take kindly to UFOs, certainly not UFOs that look like SAMs on the radar.

You will probably get away with a ground test of a rocket engine, of most proportions, even massive ones, most police would not give it a second thought if everything was as safe as houses.

Safety is a big issue, one of the more agreeable parts of Damp Squib?s view is that you need to think safety all the time.

However, there are plenty of laws and regulations, do not kid yourself. You could come a cropper even if you do not damage anything or anyone.

[Damp Squib]

Andrew you obviously know much more about the regulations than me 'I'm not being sarcastic ',are you sure about launching anything above 300 feet needing a license\permit?,the model rockets I fly are just warmed up at 300 feet with estes D's,surley the airframes and motors coudnt be sold without showing the license?

Any links to the version of regs you have would be much appriciated

safety at least you agreed with part of my post ,I respect your honesty,my post was geared more toward my moral view on experimental rocketry in the UK,I would love to see the reg sheet pertaining to liquid fuel motors I'm a little tired to start searching for it now,if anyone has a quick hyperlink that would be great

[myinisjap]

no need to worry about the laws in UK im in the US

[Andrew]

The outlawing of liquid fuel rocket engine development has a lot to do with the Second World War, and subsequently the Cold War. It was decided a very long time ago that the UK will not pursue this type of technology on any scale. These regulations are of coarse now historical, and I too would like to see how they, it they do at all affect anyone today, especially amateurs. The old laws still prevent the likes of SSTL from running their own launch vehicle program. They routinely use ex-soviet ICBM to launch satellites.

The 300ft rule is to do with the control of air space and air traffic, specifically aimed at planes and helicopters, but it applies to all air traffic; I have an incling that it is now 1000ft. The controlled zone is a complicated thing. I suspect Google would find a map quite easily. It would be interesting to find out how high you can go, when outside the air traffic controlled zone, before you need a licence from the Gov, if at all any is needed.

I personally live right in the middle of the zone, near heathrow, so no fun for me.