liquid nitrogen, alchohol

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

the rocket genuis

Active Member
Joined
Jan 11, 2011
Messages
35
Reaction score
0
i am designing a liquid fuel model rocket engine and im considering something like this for a test stand
Figure 8 Assembly drawing of small liquid-fuel rocket engine. (1) injector assembly, (2) O-ring, (3) liquid fuel, (4) gaseous oxygen (5) engine mount, (6) coolant, (7) fuel spray nozzle, (8) combustion chamber, (9) outer shell, (10) coolant.
 

Attachments

  • fig-8.gif
    fig-8.gif
    44.6 KB · Views: 41
Last edited:
Seriously, you need to read several dozen text books on liquid motor design before you attempt this.

Some formal aerospace engineering courses would be helpful as well.

BTW - Liquid Nitrogen is not an oxidizer.

Bob
 
Do you have any engineering drawings? calculated mass flow rates? operating pressures/temperatures?.....

I don't know your background, but I wouldn't attempt this project unless you are an aerospace/mechanical engineer, with lots of funding and experience. Due to cost and complexity, liquid rockets are very rarely attempted by amateurs, and outside the scope of most hobbyists.
 
Dude,

From your post history, you'd be going from E23-5T's to one of the most complex pieces of engineering possible!

It's great to read about and appreciate these feats, but you'll have a lot more fun burning the commercial loads :wink:
 
If you're planning on using liquid nitrogen + alcohol, you might want to think about changing your user name.
 
However, liquid nitrogen DOES make some darn tasty ice cream...!


[YOUTUBE]P1GDjrFNWOg[/YOUTUBE]



All the best, James
 
one its just in the BASIC and i mean the earliest stages of development. yes i have some basic courses in aerospace engineering, im working on the calculations as well and i meant liquid nitrogen or alcohol in the title im probably using LOX or most likely 99% pure hydrogen peroxide as the oxidizer
 
Seriously, you need to read several dozen text books on liquid motor design before you attempt this.

Some formal aerospace engineering courses would be helpful as well.

BTW - Liquid Nitrogen is not an oxidizer.

Bob

Bob, are you feeling ok?

That has to be the nicest post I've ever read from you in response to a classic hair brained idea.
 
And you can build all this too?


Happy sailing! :boat: fun project to watch too! (Don't let people get you down, just remember its all bout safety)
 
i have copper, brass, steel, a crap load of tools a large metal lathe, and a 1/4 inch thick steel bunker :kill:
 
thank you for the website it has some useful fuel findings. although ive already figured out how a liquid fueled rocket engine works :D
 
Last edited:
thats my online liquid fuel rocketry bible. ive been using it since day 1 since this idea popped into my head
 
im also considering a design like this.

Figure 8 Assembly drawing of small liquid-fuel rocket engine. (1) injector assembly, (2) O-ring, (3) liquid fuel, (4) gaseous oxygen (5) engine mount, (6) coolant, (7) fuel spray nozzle, (8) combustion chamber, (9) outer shell, (10) coolant.

https://gramlich.net/projects/rocket/fabrication.html


Your drawings indicate that you plan to fly what you build. If that's the case and you use this design you're going to need a really long hose because it's water cooled. If you plan to fly it with the cooling water on board the hose won't be necessary but it will most likely be too heavy to get off the ground. Of course the gaseous oxygen cylinder is also going to be too heavy so you're going to need a long hose for that too.
 
... or most likely 99% pure hydrogen peroxide as the oxidizer

Your enthusiasm is good. But, you need to take some time to learn more about the subject and as how dangerous concentrated hydrogen peroxide is. Von Braun avoided using it - which allowed him to live long enough to be remembered as a rocket genuis ...err ... genius.

-- Roger
 
Are you working in a group? In my opinion, building a liquid fuel rocket is a bit much for a single person.

Here is a static test fire of a liquid engine built by a college group that i am involved in.

https://www.youtube.com/watch?v=U6w6LnCI5zQ

As you can see, this was run without a cooling jacket, which turned the copper nozzle throat red hot. So a cooling jacket was made, and will pump in either the fuel or oxidizer (i forget which - i havent looked at it for a while) around the nozzle. Coolant will work for static test, but probably not practical for flying, if that is your eventual goal.

Some other final observations:

- Cost: This rocket motor that we made cost in excess of $20,000. Unknowingly how much more without the access to the tools/machines/facilities already in place

- The bolt hole patterns and other work were done on a CNC mill. IDK if its possible to do it with just a lathe. Outsourcing stuff will add cost quickly.

- Back to the group thing. This took around 10 senior engineers a year to develop, lead by one of the best students our school has seen in a while. Now our group is doing the programming of the servo actuated valves for flight, which is being heavily assisted by a few electrical engineers. Again, an insane amount of knowledge/expertise.

- I would stay away from LOX/cryogenics. Despite all this, the engine above does not run on cryogenic fuel/oxidizer. That is a whole 'nother ballgame.



I'm not trying to scare you, just caution you about what you are getting into. Good luck with the endeavor.
 
Last edited:
You're waaaay outside of high power rocketry....
And you'll need all kinds of approvals to fly it and it will never happen at a regular launch, and I doubt even at a INDY launch (think spaceport, dude)
I used quite a bit of LN add LO in the service, trust me you don't want to mess with it without some formal training (then how you gonna get it?)
why don't you try hybrids to satisfy your need for engineering motors???
 
Seriously, you need to read several dozen text books on liquid motor design before you attempt this.

Some formal aerospace engineering courses would be helpful as well.

BTW - Liquid Nitrogen is not an oxidizer.

Bob

It doesn't have to burn to make thrust........

I would try compressed air and water first.
 
It doesn't have to burn to make thrust........

I would try compressed air and water first.
True. You can get quite a bit of thrust by vaporizing liquid nitrogen...

The good news is liquid oxygen is fairly hard to get, and 99% peroxide is virtually impossible to buy.

I do admire his enthusiasm, but hope he does a lot more reading and learning before he tries anything. 1/4" thick steel may not be enough. The MIT bunker for undergraduate propulsion projects has 1 foot thick reinforced concrete walls with an an 8" thick steel door.

Bob
 
True. You can get quite a bit of thrust by vaporizing liquid nitrogen...

The good news is liquid oxygen is fairly hard to get

<< SNIP!>>

Bob

Alas! This isn't the case. Pulmonary disease patients normally get their O2 in liquid form these days. My mother had emphysema at the end of her life, and I used to sleep next to a canister of LOX on visits. (It was a bit unsettling, I admit, but she was my Mom, after all!)

Even if a prescription is required, all you have to do is know somebody.

Regards,
-LarryC
 
Alas! This isn't the case. Pulmonary disease patients normally get their O2 in liquid form these days. My mother had emphysema at the end of her life, and I used to sleep next to a canister of LOX on visits. (It was a bit unsettling, I admit, but she was my Mom, after all!)

Even if a prescription is required, all you have to do is know somebody.

Regards,
-LarryC

There are also some aircraft that use LOX -> Gas converters for supplemental oxygen, so you can find it in the aviation industry.
 
for the 3rd time its in a very early design phase, ITS NOT DESIGNED TO FLY ITS JUST GOING ON A TEST STAND. and im looking at this design now
 

Attachments

  • fig-8.gif
    fig-8.gif
    44.6 KB · Views: 31
This is definitely a Marlin Perkins moment, I'll stand (way) back and watch through the binoculars....

Kew-el if it works, and I hope that you can pull it off. Bad, Bad, Bad juju if it fails though
 
Your enthusiasm is good. But, you need to take some time to learn more about the subject and as how dangerous concentrated hydrogen peroxide is. Von Braun avoided using it - which allowed him to live long enough to be remembered as a rocket genuis ...err ... genius.

-- Roger

No, he lived long because his failures just burned german grunts.
 
Back
Top