Why does nobody use Liquid-Propellant rockets?

madcow rocketry
the model rocket show
Advertise with us
The Rocketry Forum

Help Support The Rocketry Forum:

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

Thanks for sharing.

Did you do anything special to create redundancy in the vent/purge procedure? I lose sleep worrying the purge valve will freeze or there will be a power loss to the motor leaving a pressurized bomb with no way to return to a safe state.

Im only guessing but I suppose your main valve plus your purge valve creates a redundant mechanism.

-->MCS

.
 
MCS said:
Hey Eric,

Thanks for sharing.

Did you do anything special to create redundancy in the vent/purge procedure? I lose sleep worrying the purge valve will freeze or there will be a power loss to the motor leaving a pressurized bomb with no way to return to a safe state.

Im only guessing but I suppose your main valve plus your purge valve creates a redundant mechanism.

-->MCS

.
Click to expand...

The vent valves all fail safe (open) when the Helium pressure drops and the LOX tank has an additional pressure release vent that was set for about 50psi above operating pressures. So if for some reason the valve cant be opened the safety vent would kick in before the tank could overpressure. All tanks where proof pressure tested to at least 2x operating pressures. The lox vent valve and safety release where also plumbed up toward the top of the vehicle away from the LOX tank allowing the gas to warm up some before reaching the valve. The valves where all LOX cleaned and designed for that service.

Eric
 
Last edited:
[email protected], this is absolutely awe-inspiring. This is where all of us AP guys wanna be someday. Personally, I'd have to go back and finish the engineering degree I never got, and find a whole bunch of other guys that know what the hell they're doing. There's no room for mistakes with this stuff...
 
cerving said:
[email protected], this is absolutely awe-inspiring. This is where all of us AP guys wanna be someday. Personally, I'd have to go back and finish the engineering degree I never got, and find a whole bunch of other guys that know what the hell they're doing. There's no room for mistakes with this stuff...
Click to expand...

You certainly have to have respect for the energetic nature of the fuels when combined. A book like [Rocket Propulsion Elements] is a good place to start for those with interest. All the engine design basically was derived from that book. It's an engineering book so it's not light reading.

A few more photo's of the vehicle. I'll stop hijacking the thread :)

The image below shows the vehicle un-skinned. Tanks, valves, etc are visible here:
R1.jpg

This is an image looking into the engine. The boat tail hadn't been fitted yet. The red pneumatic lines for valve control can be seen.
R2.jpg

This is the main helium distribution section. The big blue regulator on the left drops the 3500psi helium down to tank pressure. The smaller black regulator replaces the external control gases once pressurized. The valve on the right is the LOX vent valve. The lox tank is at the bottom of the vehicle. A couple pressure sensors and the remote helium fill valve can be seen.
R3.jpg

Some engine data from the last full up static test performed prior to building the flight vehicle.
EngineData1.jpg

Eric
 

Attachments

  • EngineParams.JPG
    EngineParams.JPG
    48.1 KB · Views: 82
Last edited by a moderator:
I think this is an ambitious idea. I applaud your initiative.

I have research a little and would think the main problem with a liquid propellant besides safety is the cost. It has been said before. H2O2 with oxygen and alcohol seem to be the most affordable.

Hydrocarbons are an idea, but they tend to be explosive - look up napalm. It tends to stick to everything. They also need to be cooled to remain mostly liquid, unless you use Kerosine or Diesel.
 
So Let's Talk Hydrogen Peroxide

I see quite a few varying opinions on use of this oxidizer and monopropellant on this thread. My background consists of handling hundreds of thousands of pounds of H2O2 and supervising employees who did the same - without any injuries, I might add.

90% hydrogen peroxide offers similar density impulse as liquid oxygen but without the cryogenic issues. In addition, anhydrous peroxide can offer similar Isp as LOX. There are tankage advantages as well: lined composites work very well with H2O2 with the attendant weight savings.

From a development perspective, I've seen Beal Aerospace go from a 250 lbf monopropellant engine to 5,000 lbf biprop, then to a 30,000 lbf vac engine, all the way to a 810,000 lbf monster. This development took place in only three years and at a fraction of the cost of what a turbopump LOX/RP-1 engine would have.

H2O2 engines allow for a very rapid engine development timeline and at the same time, mitigates program risks. While as a starving graduate student in 2001 I was able to fabricate and successfully fire a 200 lbf hybrid. This engine burned UHMW poly and 99% H2O2 - and it met the performance margins, first time around. Cost: under $1000 including the gas money to drive to the test stand in another state.

Handling H2O2 can be safely done when certain rules are followed. This is no different than LOX. My company's customers have many hours of manned flight time on H2O2 monopropellant engines, along with a host of governmental R&D efforts.
 
Greetings and welcome to the list.

Im curious where you source higher concentration peroxide. Armadillo with thier deep-ish pockets gave-up peroxide because the chemical became impossible to source in any usable quantity. A few guys at FAR operate a remote still. Im at a loss to find quantity beyond these projects.

-->MCS

.
 
Truth in advertising: I run X-L Space Systems.

The issue with Armadillo was a matter of timing; I had two paths to take due to my age at the time. One was to earn a commission in the armed forces, the other to continue running X-L. I chose to enter active duty and did that for 5 years and then returned to X-L. That was in 2007.

My company offers drum quantities of 90% - 99% to qualified customers.

M. Carden
 
It is too bad H2O2 is outside the bounds of EX, which makes finding launch sites more difficult.

Gerald
 
They used it in the space shuttle boosters because they needed high thrust+2 minute duration with fairly specific requirements. It's really just easy and expendable. And they also wanted to be able to recover the boosters and reuse most of it (most liquid boosters are left in the ocean).
 
edwinshap1 said:
They used it in the space shuttle boosters because they needed high thrust+2 minute duration with fairly specific requirements. It's really just easy and expendable. And they also wanted to be able to recover the boosters and reuse most of it (most liquid boosters are left in the ocean).
Click to expand...

Yep, exactly.
 
MCarden said:
Truth in advertising: I run X-L Space Systems.

The issue with Armadillo was a matter of timing; I had two paths to take due to my age at the time. One was to earn a commission in the armed forces, the other to continue running X-L. I chose to enter active duty and did that for 5 years and then returned to X-L. That was in 2007.

My company offers drum quantities of 90% - 99% to qualified customers.

M. Carden
Click to expand...

Ah.. the pieces now fit.

What is the practicality of sending a single digit number of drums to FAR from XL??

-->MCS

.
 
I've sent lots of drums that way before. Usually, the consignee meets up with the delivery truck outside of FAR and guides them in.
 
Guys, wasn't there a company back in the late 80's/early 90's that marketed a liquid fueled rocket? I seem to recall the company was named something like Solara???
I think one of the liquid components was gasoline.
My memory is a little sketchy. Does this ring any bells with folks???
 
Greg Young said:
Guys, wasn't there a company back in the late 80's/early 90's that marketed a liquid fueled rocket? I seem to recall the company was named something like Solara???
I think one of the liquid components was gasoline.
My memory is a little sketchy. Does this ring any bells with folks???
Click to expand...
Yes! Systeme Solaire -- the engine was the SS67B[somethingROCKETlikePROBABLYwithanX?] and yes, was peroxide/gasoline IIRC. It was advertised a lot in HPR. Probably vaporware; if not when you bought it, then definitely when you lit it-- octane is a terrible liquid rocket propellant highly prone to hard starts.

Sidebar-- this is the most hard-start-esque smiley I could find: :puke:
 
Thanks David, that was the name I was trying to recall!
I wonder if anyone on the forum actually purchased one and attempted to fly it?
 
CoyoteNumber2 said:
I saw one launch attempt. The motor/engine did not ignite and the rocket lifted off under pressure from the decomposing potassium permanganate catalyst, arcing over and impacting the ground a short distance away. When we picked up the wreckage, the H2O2 residue bleached our fingertips pure white.
Click to expand...
Wow, so the hardware actually existed? Awesome! And kinda scary too :eyepop:
 
[email protected] said:
You certainly have to have respect for the energetic nature of the fuels when combined. A book like [Rocket Propulsion Elements] is a good place to start for those with interest. All the engine design basically was derived from that book. It's an engineering book so it's not light reading.

A few more photo's of the vehicle. I'll stop hijacking the thread :)


Hijacking the thread? your info keeps me looking and interested.Mr. Bob
Starlight Dude
Countyline Hobbies
Grovertown, IN.
Click to expand...
 
Last edited by a moderator:
There is a way to get liquid rocket motor performance in a small rocket. Many of the complexities of a liquid biprop come from the difficulties, complexities and vagaries of starting and managing two liquid systems. By printing a container for liquid fuel, along with fuel metering features, The Aerospace Corporation made a small liquid motor that flies like a hybrid.

https://www.aerospacemanufacturinganddesign.com/article/3d-printed-liquid-fuel-rocket-motor/
 
Thunderbolt said:
There is a way to get liquid rocket motor performance in a small rocket. Many of the complexities of a liquid biprop come from the difficulties, complexities and vagaries of starting and managing two liquid systems. By printing a container for liquid fuel, along with fuel metering features, The Aerospace Corporation made a small liquid motor that flies like a hybrid.

https://www.aerospacemanufacturinganddesign.com/article/3d-printed-liquid-fuel-rocket-motor/
Click to expand...

Interesting. Is the container working as an eductor to allow the liquid fuel to be metered into the flow of liquid oxidizer? Is the container also consumed?
 
I had the opportunity to visit Copenhagen Suborbitals a little while ago. It was fascinating to see their liquid fuel rockets. But it is in a different league! If I had deep pockets and lots of time, it would be kind of fun to dive into the realm of liquid rocketry, but reality slaps me and says "NO, Not LOX." If you ever make it to Denmark, I would recommend you visit them and see how they work with liquid fuel...
 
Revolution Aerospace is working to make liquids for amateur users as a COTS system on methanol and nitrous oxide. Their primary source of updates are from Reddit, but this post was pretty insightful. Hopefully they can make it safe and reasonably affordable.
 
Steve Shannon said:
Interesting. Is the container working as an eductor to allow the liquid fuel to be metered into the flow of liquid oxidizer? Is the container also consumed?
Click to expand...

The fuel container is printed plastic and is also consumed as fuel. The exact internal workings have not been fully described.
 

Similar threads

the_mell0nator
UTK Rocket Man
Replies
15
Views
812
Hobie1dog
Hobie1dog
Z
High altitude liquid rocket
3 4 5
Replies
131
Views
6K
cerving
cerving
S
Adam Laakmann's Rocket Facts LinkedIn posts #1 - #10
Replies
8
Views
919
John Kemker
John Kemker
tfish
Gas Pipe...rockets
Replies
25
Views
2K
tfish
tfish
SolarYellow
Bogus sim files posted online - why?
2 3
Replies
76
Views
3K
NateB
NateB

Latest posts

Back
Top