• Have you entered ???
    LAUNCH LAB ROCKETRY GIVEAWAY

9 General Categories of Rocket Propellant

The Rocketry Forum

Help Support The Rocketry Forum:

Bruce

Well-Known Member
Joined
Feb 21, 2019
Messages
259
Reaction score
42
If there are 3 states of matter (not counting plasma) and 2 components to rocket propellant, then doesn't that mean that there could be 3 squared or 9 general categories of rocket propellant?

Fuel-----Oxidizer----Common Name
____________________________________________
Gas-----Gas
Gas-----Liquid
Gas-----Solid
Liquid--Gas
Liquid--Liquid------Liquid Propellant
Liquid--Solid
Solid---Gas
Solid---Liquid-------Hybrid Propellant
Solid---Solid--------Solid Propellant

So, other than the 3 obvious ones, have any of the other 6 been tried?
 

rocket_troy

Well-Known Member
Joined
Sep 9, 2013
Messages
197
Reaction score
70
All the Solid<->Liquid varieties have been tried. Gas is typically not a practical option due to density.

TP
 

Bruce

Well-Known Member
Joined
Feb 21, 2019
Messages
259
Reaction score
42
That makes sense about using gasses. Probably anything that a gas could do, a liquid (under high pressure) could do better.

So that leaves only Liquid Fuel with Solid Oxidizer. I'd like to read more about this type of motor. Does anyone have any links?
 

Rocket501

Well-Known Member
TRF Supporter
Joined
Feb 9, 2018
Messages
213
Reaction score
105
It's sometimes called a reverse hybrid. They tend to be pretty bad overall. Some common combinations include jet fuel and typical solid prop oxidizers. The solid elements tend to be overly brittle, combustion efficiency is poor, ISP is lower, O/F ratios poor and overall it's usually just a bad idea. Gas-solid blends are still hybrids, gas-liquids are considered liquid rocket engines. As far as I know, all of these combinations have been tried with the possible exception of gaseous fuel and solid oxidizer.
 

rocket_troy

Well-Known Member
Joined
Sep 9, 2013
Messages
197
Reaction score
70
Sorry no links, but I can point you to someone who has definitely done them: Mr Anthony Cesaroni. Apparently they worked okay.

TP
 

Bruce

Well-Known Member
Joined
Feb 21, 2019
Messages
259
Reaction score
42
I'm trying to visualize how a "Reverse Hybrid" might work. Is there a big chunk of solid oxidizer in the case and liquid jet fuel is pumped in?

Or perhaps could you do it more like a liquid-liquid motor and have the solid oxidizer in pellet form and somehow bring the pellets one at a time into the combustion chamber without affecting the chamber's pressure? Something like a revolving door?
 

manixFan

Not a rocket scientist
Joined
Feb 15, 2009
Messages
2,014
Reaction score
991
Location
TX
There are monopropellant gas ion thrusters:


And there are several liquid monopropellants such as Hydrazine and Hydrogen Peroxide. So using your chart they would just be:

Gas------Ionized Monopropellant
Liquid---catalyzed Monopropellant


Tony
 
Last edited:

Rocket501

Well-Known Member
TRF Supporter
Joined
Feb 9, 2018
Messages
213
Reaction score
105
It's the first one. The second one tends to be too much hassle and mass to be worth the bother.
 

rocket_troy

Well-Known Member
Joined
Sep 9, 2013
Messages
197
Reaction score
70
I'm trying to visualize how a "Reverse Hybrid" might work. Is there a big chunk of solid oxidizer in the case and liquid jet fuel is pumped in?
Generally yes. I'll PM you with more details regarding the solid part.
 

AeroTech

Lifetime Supporter
TRF Lifetime Supporter
Joined
Dec 17, 2009
Messages
447
Reaction score
831
From the Hybrid History portion of the AeroTech 54mm Hybrid Instruction Manual:

"March, 1992: Under the direction of Gilbert Moore, the Utah section of the AIAA creates a consortium of four northern Utah universities to provide students with education and experience in hybrid rocket propulsion. Unity IV, their first hybrid project, uses GOX and HTPB. The rocket crashes shortly after liftoff due to a leak caused by ignition of combustible grease in a pressure gauge receptacle and the subsequent ejection of the gauge."

 

jsdemar

Well-Known Member
Joined
Dec 31, 2009
Messages
2,631
Reaction score
643
"Ignition!: An Informal History of Liquid Rocket Propellants", by John Clark
 

dhbarr

Amateur Professional
Joined
Jan 30, 2016
Messages
7,220
Reaction score
1,642
"Ignition!: An Informal History of Liquid Rocket Propellants", by John Clark
tl;dr -- Tsiolkovsky already thought of it and the Germans probably tried it
 

CoyoteNumber2

Original San Diego High Power Rocketry
Joined
Jan 30, 2009
Messages
644
Reaction score
139
Wouldn't it be fun if we could use double-base propellants?
 

Bruce

Well-Known Member
Joined
Feb 21, 2019
Messages
259
Reaction score
42
Wouldn't it be fun if we could use double-base propellants?
I'm not sure that using double base propellants would be of any advantage.

It looks like the concept was explored up through at least WW2. One example would be the Tiny Tim air to ship missile,

https://wiki.warthunder.com/Tiny_Tim

It used a double base propellant, Balistite,

https://en.wikipedia.org/wiki/Ballistite

which was developed by Alfred Nobel in the late 19th century.

The propellant was of the high thrust / short duration type and my understanding (correct me if I'm wrong) was that these types of propellant being powder based were limited by how tightly they could be compressed. Even the most highly compressed powder based propellants still had some voids surrounding the particles which had the undesirable property of increasing the burning surface area.

The breakthrough was castable propellant which was invented by Jack Parsons. He introduced asphalt as a binder. This allowed solid propellant to be produced with a minimum of voids. The binder also acted as the fuel, so only an oxidizer needed to be mixed with it simplifying everything. Asphalt was later replaced by the rubber-like compounds used in most solid fuels today.

I've only found the above info by web surfing and am certainly no academic historian. Any corrections would be gladly accepted!
 

Ez2cDave

Well-Known Member
TRF Supporter
Joined
Jan 18, 2009
Messages
4,522
Reaction score
1,345
There are TWO more types of "propellant" . . .

( 1 ) Tri-Brid - Essentially a motor that operates as a traditional Hybrid ( Liquid Oxidizer / Solid Fuel ) BUT with a Secondary Liquid Fuel ( Alcohol, for example ), injected under pressure, during combustion. "Back in the day", there was AT LEAST one manufacturer ( RATTworks ) that did this.

http://www.rattworks.net/research_tribrid.html

http://www.privatedata.com/byb/rocketry/exp/hybrid/ratt_tribrid/index.html


( 2 ) Monopropellant - 100% Hydrogen Peroxide, for example.

Dave F.
 

Rocketjunkie

Addicted to APCP
Joined
Jan 19, 2009
Messages
4,395
Reaction score
604
The Nike motors use a double base propellant. Useful to the military as they don't leave an obvious target of the launcher.
 

Bruce

Well-Known Member
Joined
Feb 21, 2019
Messages
259
Reaction score
42
There are TWO more types of "propellant" . . .

( 1 ) Tri-Brid - Essentially a motor that operates as a traditional Hybrid ( Liquid Oxidizer / Solid Fuel ) BUT with a Secondary Liquid Fuel ( Alcohol, for example ), injected under pressure, during combustion. "Back in the day", there was AT LEAST one manufacturer ( RATTworks ) that did this.

http://www.rattworks.net/research_tribrid.html

http://www.privatedata.com/byb/rocketry/exp/hybrid/ratt_tribrid/index.html


( 2 ) Monopropellant - 100% Hydrogen Peroxide, for example.

Dave F.

If we're going to include those, we'll have to add Steam as well!

Maybe it is a monopropellant, but Steam was used for nearly all of the private manned rocket flights - Evel Knieval, Mike Hughes and Eddie Braun. Johnny Knoxville being the sole private manned rocket pilot to use the more conventional solid propellant...
 
Top