Liquid Propulsion questions

Discussions of motors from single-use and RMS solid propellants to hybrid propellants

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OfficiallyVC
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Liquid Propulsion questions

Postby OfficiallyVC » Mon Aug 22, 2016 1:47 pm

Hey there,
As a science and rocketry nerd, I have always wanted to make my own liquid engine, like a very small scale fireable SSME. The problem I have is not the making of the engine, but the legality of making it.

What sort of laws and regulations do I have to take into account for the making of a small scale SSME engine (under 20cm long altogether).
It would not be attached to a rocket, only a piece to put up, however is functional as a motor.

I live in the ACT, however travel over the border into NSW for rocketry purposes.

Thanks, nick
Programs: Citadel Project (rockets), in igne et aere (planes), VXEP (Very eXperimental Engine Project), CMAP (Custom Miniaturized Avionics Project);
Motors: VXEP 1-3;
Completed Rockets: Alpha III, Sarkate 1;
Projects in Progress: Citadel 1-4, Sarkate 2-3

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Re: Liquid Propulsion questions

Postby SpaceManMat » Mon Aug 22, 2016 2:14 pm

You want to build a small rocket motor using cryogenic liquid hydrogen and liquid oxygen?

I'm no expert but I don't beleive that the small size will make this any easeir or less dangerious.

Handeling of cryogenic liquids is particualy critical and especially liquid oxygen which is extremely dangerious, prety much anything organic will explode in its presence - things like grass or tar, even metals etc.

I imagine you would need to start contacting government bodies to figure out how to certify for handeling these first.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 13,647 feet
Fastest Flight: Mach 1.55
Largest Motor: CTI 1115J530 IM
Current Project: X Wing

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OfficiallyVC
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Re: Liquid Propulsion questions

Postby OfficiallyVC » Mon Aug 22, 2016 7:13 pm

I assumed I would have to do something along the lines of that, however I just wanted to make sure, and gather tips and even more information from the community here.
Programs: Citadel Project (rockets), in igne et aere (planes), VXEP (Very eXperimental Engine Project), CMAP (Custom Miniaturized Avionics Project);
Motors: VXEP 1-3;
Completed Rockets: Alpha III, Sarkate 1;
Projects in Progress: Citadel 1-4, Sarkate 2-3

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OverTheTop
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Re: Liquid Propulsion questions

Postby OverTheTop » Mon Aug 22, 2016 7:47 pm

Hi Nick. Hmm. Liquid propellant engine. Lots to learn :)

FYI, here is some reading you might like, since you have an interest in that area:

"History of Liquid Propellant Rocket Engines", Sutton
http://arc-test.aiaa.org/doi/book/10.2514/4.868870

"Ignition" (more on the history of hypergolics, free!)
https://library.sciencemadness.org/libr ... nition.pdf

Since you are into the SSME, have you seen the article?:
"27,000 Seconds in Hell" by Air & Space magazine. See if you can find a copy of it somewhere. A great read on the development of the SSME.
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Re: Liquid Propulsion questions

Postby SpaceManMat » Mon Aug 22, 2016 8:44 pm

OverTheTop wrote:Hi Nick. Hmm. Liquid propellant engine. Lots to learn :)

FYI, here is some reading you might like, since you have an interest in that area:

"History of Liquid Propellant Rocket Engines", Sutton
http://arc-test.aiaa.org/doi/book/10.2514/4.868870

"Ignition" (more on the history of hypergolics, free!)
https://library.sciencemadness.org/libr ... nition.pdf

Since you are into the SSME, have you seen the article?:
"27,000 Seconds in Hell" by Air & Space magazine. See if you can find a copy of it somewhere. A great read on the development of the SSME.


Really liked Ignition, the article about SSME sounds like it would be great too.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 13,647 feet
Fastest Flight: Mach 1.55
Largest Motor: CTI 1115J530 IM
Current Project: X Wing

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OverTheTop
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Re: Liquid Propulsion questions

Postby OverTheTop » Mon Aug 22, 2016 8:52 pm

Really liked Ignition, the article about SSME sounds like it would be great too.


It was a great read. 27000 seconds was life the motors were expected to work to. That's a long time (7.5 hours :shock: ) at the temperatures and pressures they operate at. Two fuel pumps per engine, 75000 horsepower, EACH :shock:
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"Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)

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Re: Liquid Propulsion questions

Postby jhurst7 » Mon Aug 22, 2016 9:05 pm

If you just want to build a liquid-fuel engine, you'd probably want to use non-cryogenic fuels such as Kerosene (RP-1) and Nitrous Oxide as Kerosene is liquid at room temperature and Nitrous Oxide could probably be maintained in a liquid state with less effort than LOX. Also, you'd probably be able to change the design of the SSME and be able to use external electric pumps instead of a Staged Combustion Cycle. This would reduce the complexity of it all. Anyway, that's just my two cents.
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Re: Liquid Propulsion questions

Postby High Impulse » Mon Aug 22, 2016 10:38 pm

This is also some good reading.

http://www.cientificosaficionados.com/l ... ohetes.pdf

I looked into doing a similar thing a while back, but was cut short quite quickly when I realised the hazards... Anything at any decent internal pressure posses some serious risks, even when dealing with slightly less dangerous fuels.
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Re: Liquid Propulsion questions

Postby strud » Tue Aug 23, 2016 6:44 am

Hi Nick

I don't believe the main issues for your project will be legal ones.

My understanding of the legal issues surrounding devices such and pyro and rocket motors are the manufacture of a mixture containing both oxidiser and fuel.

Both hybrid and liquid motors do not mix these until the time of combustion.

What is regulated are pressure vessels. However if the pressure vessel is not being operated in a place of work or near others I also believe that entities such as workcover/worksafe etc have no interest.

So the real problem as I see it is the problem of scaling down a turbopump driven liquid motor.....

Turbopumps at 'normal' scale are super hard ie amateurs don't make them (someone prove this statement wrong ?)

Turbopumps at miniature scale would be SUPER hard.

What might be more possible is a small scale electric pump.

There are a lot of people on the web who have made small scale liquid motors so finding resources to work off might be ok.

You will likely need to invest a fair bit of money into workshop equipment, which isn't a bad thing :-)

Good luck

Oh, bear in mind that you will not be able to operate this at any of the clubs active on this forum since no insurance policy on earth will cover you.

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Re: Liquid Propulsion questions

Postby OverTheTop » Tue Aug 23, 2016 7:22 am

What might be more possible is a small scale electric pump.

I was thinking that might be achievable too. Rocket Lab in NZ has a nice rocket that runs on two electric (BLDC) motors. About 50 horsepower each I believe. According to someone there in the know, this is about the upper limit for electric turbopumps currently.
The good thing with electric pumps is that the pump speeds are controlled entirely by software, rather than by burning fuels. Much easier to control mass flows and mixtures.
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Re: Liquid Propulsion questions

Postby OfficiallyVC » Thu Aug 25, 2016 7:55 am

I just wrote a 600 word(ish) reply, but then my internet crashed, and I lost it, so a reply will be up this afternoon.
Programs: Citadel Project (rockets), in igne et aere (planes), VXEP (Very eXperimental Engine Project), CMAP (Custom Miniaturized Avionics Project);
Motors: VXEP 1-3;
Completed Rockets: Alpha III, Sarkate 1;
Projects in Progress: Citadel 1-4, Sarkate 2-3

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Re: Liquid Propulsion questions

Postby SpaceManMat » Thu Aug 25, 2016 8:47 am

strud wrote:Hi Nick

I don't believe the main issues for your project will be legal ones.

My understanding of the legal issues surrounding devices such and pyro and rocket motors are the manufacture of a mixture containing both oxidiser and fuel.

Both hybrid and liquid motors do not mix these until the time of combustion.

What is regulated are pressure vessels. However if the pressure vessel is not being operated in a place of work or near others I also believe that entities such as workcover/worksafe etc have no interest.

So the real problem as I see it is the problem of scaling down a turbopump driven liquid motor.....

Turbopumps at 'normal' scale are super hard ie amateurs don't make them (someone prove this statement wrong ?)

Turbopumps at miniature scale would be SUPER hard.

What might be more possible is a small scale electric pump.

There are a lot of people on the web who have made small scale liquid motors so finding resources to work off might be ok.

You will likely need to invest a fair bit of money into workshop equipment, which isn't a bad thing :-)

Good luck

Oh, bear in mind that you will not be able to operate this at any of the clubs active on this forum since no insurance policy on earth will cover you.


Had the thought that maybe modern car fuel pumps for injector systems might be capable of the sort of pressures required. They are getting extremely high pressures out of them these days. Definitely worth a look.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 13,647 feet
Fastest Flight: Mach 1.55
Largest Motor: CTI 1115J530 IM
Current Project: X Wing

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Re: Liquid Propulsion questions

Postby OfficiallyVC » Thu Aug 25, 2016 9:44 am

Hey there all,
Thankyou for the replies and *very* helpful information,
Firstly, thanks for the very interesting and enlightening articles to read and use as sources in the making of the engine.
Sadly, i couldn't find the "27,000 seconds in hell" article, so i may just buy an air and space description.
Secondly, jhurst7, I took the advice on the RP-1 and NOx instead of LOx & LH, thanks for that, making it easier (slightly) to manage.
Also, I will take the advice on teh electric pumps into mind, although i don't really know where to get one (or two).
Thirdly, High Impulse, thanks for the warning on internal pressures within the engine, i will take that into account when building and testing everything.
Also strud, thankyou for the advice on the legal side of the motor, that will clear up some of my worries about it.
Also, I agree with your point that the turbopumps will be really hard to build, so instead i am thinking about using electric pumps, making it simpler.
I will start searching for people who have done projects like what i am doing, so i can see if there are any tips for making motors.
I think investing in workshop equipment is a really good idea, and i am frankly looking forward to working on this, as it will be quite fun.
And on the insurance point, i'll have to be really careful around the rocket, even more than i planned.
OverTheTop, With the electric pumps, would you be able to provide a link to the rocket lab website showing them? Because that would be very, very helpful.
Also, having a regulator within the pumps would be very helpful with controlling and tailoring the engine.
Lastly, SpaceManMat, thanks for the input on the car fuel pump as an injector system, I didn't actually think of that, and that would be very good instead of building my own.

Overall, thanks for all the help,
I will update this thread whenever i have other questions, or with progress reports.
Hopefully this pans out well,
~Nick
Programs: Citadel Project (rockets), in igne et aere (planes), VXEP (Very eXperimental Engine Project), CMAP (Custom Miniaturized Avionics Project);
Motors: VXEP 1-3;
Completed Rockets: Alpha III, Sarkate 1;
Projects in Progress: Citadel 1-4, Sarkate 2-3

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OverTheTop
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Re: Liquid Propulsion questions

Postby OverTheTop » Thu Aug 25, 2016 11:12 am

Rocket Lab website:
http://www.rocketlabusa.com/
It is probably a bit thin on details for the Rutherford motor system. They don't have a huge amount of detail available.
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"Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)

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Re: Liquid Propulsion questions

Postby SpaceManMat » Thu Aug 25, 2016 6:23 pm

Found this 14 bar (200 psi) fuel pump on eBay.

Your going to need to figure out your required pressure and flow rate before you choose a pump.

http://www.ebay.com.au/itm/SPA-Turbo-14 ... 3641.l6368
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 13,647 feet
Fastest Flight: Mach 1.55
Largest Motor: CTI 1115J530 IM
Current Project: X Wing


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