Questions tagged [liquid-fuel]

Questions regarding rocket propellant in liquid form, the main type used for chemical rockets.

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Why do methane engines require burn-off igniters?

When I was watching the flight readiness test firing of the Vulcan’s BE-4 engines, I noticed that there were igniters similar to the ROFI igniters seen on liquid hydrogen rockets. Why do methane ...
TRK's user avatar
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1 vote
0 answers
50 views

Rough values for the staytime or characteristic length of the combustion chamber of an oxygen/methanol rocket engine?

I'd like to have some idea of the staytime or characteristic length of the combustion chamber of an oxygen/methanol rocket engine. Are there sources for this, or a way to estimate it? I've tried, but ...
Kevin's user avatar
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9 votes
1 answer
436 views

Has a rocket engine with LOX as the oxidizer ever fired beyond the GEO belt?

Intuitive Machines' Nova-C lunar lander is scheduled to launch in mid-February of this year. Notably, the lander uses liquid methane as fuel and liquid oxygen as the oxidizer, and it will rely on this ...
quinnkenri's user avatar
  • 1,120
1 vote
1 answer
98 views

Multi-stage combustion products?

Okay so I've never seen anything about this before, and that's probably for a very obvious, very simple reason I am far too dim to think of, but here goes: Most combustion reactions in rocket chambers ...
AnarchoEngineer's user avatar
-2 votes
3 answers
306 views

Can Solid Rockets (Aluminum-Ice) have an advantage when designing light space-tug for LEO?

This is a new subject for Space Industry – heavy spacecraft (1200-ton) in LEO that have to burn hundreds of tons of propellant to get going to their destination. It looks inefficient to launch 7+ fuel ...
TheMatrix Equation-balance's user avatar
2 votes
0 answers
243 views

What does "pogo bleed" entail?

At around T-3:00 on every Falcon 9 countdown, we hear the following: Stage 1 pogo bleed verification I assume they are referring to pogo oscillation, but what exactly does "pogo bleed" ...
quinnkenri's user avatar
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17 votes
1 answer
2k views

Does "% Throttle" refer to fuel flow or thrust?

the question Is it possible to throttle down the thrust in a rocket engine to 1% just like in KSP? discusses the ability of liquid fuel rockets to throttle. By convention, does the “% throttle level” ...
Woody's user avatar
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1 vote
0 answers
254 views

Has combustion chamber water injection been used in RP1 rocket engine design?

Goddard’s rocket, the V2 rocket and Redstone all used water in their Alcohol fuel for combustion temperature control. To the best of my knowledge, water has not been used in RP1 fueled rockets for ...
Woody's user avatar
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-3 votes
1 answer
154 views

Rocket maximum distance [closed]

let's say I have a liquid rocket what would maximize the distance traveled by the rocket thus consume less fuel constant velocity or acceleration or why?
Peanut 's user avatar
1 vote
1 answer
64 views

Dependance of slosh mode on ratio of liquid height to tank height

If two liquid tanks of the same cross-section but different heights have the same liquid up to the same depth, will sloshing be the same or different in both tanks? I would assume they would be the ...
Reader's user avatar
  • 11
1 vote
3 answers
399 views

Propellant Density Calculation for LOX/Kero

I am trying to make sense of the equation for propellant density calculation, rho=(rw-1)/(rw/bo+1/bf). Sutton, 7th edition, gives this equation (7-2) as: $ \ \ \ \rho_{av} = \frac {\rho_o\rho_f(1+r)} {...
Mrr's user avatar
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2 votes
1 answer
219 views

What is the exhaust temperature of a liquid oxygen + liquid hydrogen vacuum engine?

Ideally the exhaust of stochiometric liquid oxygen + liquid hydrogen rocket would be fast moving chunks of ice at zero kelvin. In this way all the potential chemical energy in the fuel/oxidizer is ...
Roger Wood's user avatar
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-11 votes
1 answer
442 views

Why did the space shuttle tank look like a big orange banana [closed]

Why did the space shuttle's external fuel tank look like a big orange banana? Why that design, and how come no one makes fun of it (Other than me right now heh heh)? While we're on the subject, what'...
Deko Revinio's user avatar
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2 votes
1 answer
327 views

Is adiabatic flame temperature the same as nozzle stagnation temperature?

I am trying to understand whether these two concepts are in fact, the same parameter. The way I see it, the adiabatic flame temperature is the highest temperature achieved by stoichiometric combustion ...
MRR's user avatar
  • 21
8 votes
4 answers
4k views

What are the advantages and disadvantages of using either liquid hydrogen or liquid methane based rocket fuels?

I am working on a near-hard scifi story that mainly involves travel across a single widely populated solar system. I imagine that realistically there will probably be a wide variety of ship designs, ...
TitaniumTurtle's user avatar
8 votes
1 answer
2k views

What is the purpose of the shrouds surrounding these rocket engines?

While researching the purpose of some rocket engine components, I came across several images of perforated shrouds surrounding the combustion chambers of rocket engines. I was highly curious about ...
Angel Sachse's user avatar
1 vote
0 answers
33 views

Relative location of RP1 and LOX tanks in Saturn V [duplicate]

In Saturn V, the 2nd and 3rd stages had their fuel tank located above the LOX tank, but in the first stage, the LOX tank was located above the fuel tank. Is it because the individual stages had their ...
Niranjan's user avatar
  • 3,758
4 votes
1 answer
458 views

Is N2O a practical monopropellant?

N2O has been worked with very early on in the 40s and now again is seeing a resurgence. Is this interest merited, disregarding its apparent non-toxicity, and how well does it perform in an engine/...
R. Hall's user avatar
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7 votes
1 answer
708 views

Is it more expensive to send a chemical rocket from surface of Earth to an orbit or from this orbit to Mars?

I was trying to understand how cost-effective it would be to use an ion engine to power a mission. But since these propulsion systems cannot be used to leave Earth's gravitational field due to their ...
Ryan's user avatar
  • 459
4 votes
2 answers
2k views

Starship: Methane and Oxygen can't both be liquid, except in a narrow temperature range. Is this a problem for interplanetary voyages?

On an extended spaceflight in Starship, the liquid propellant and oxidizer will tend towards the same temperature. The tanks can be refrigerated by boiling off contents, but your mileage may vary ...
Woody's user avatar
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4 votes
0 answers
110 views

Is Lucy fueled with hydrazine and liquid oxygen?

On Sept. 18, propulsion engineers finished filling Lucy’s fuel tanks with approximately 1,600 pounds (725 kilograms) of liquid hydrazine and liquid oxygen, which make up 40% of the mass of the ...
Uwe's user avatar
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4 votes
1 answer
362 views

Can the cryogenic expansion of liquid oxygen and liquid hydrogen be used to pump a rocket engine?

A common fuel amongst rockets is that of the combination of cryogenic liquid hydrogen and liquid oxygen. I looked at the design of a simple rocket using this cocktail that is the propellant and found ...
Steve Mucci's user avatar
6 votes
1 answer
772 views

Does anyone know the stay time, or what characteristic length should be used, for a LOX/LCH4-fuelled rocket engine?

Just what it says on the tin. I need to know either the "stay time" (Ts) or characteristic length (L*) that would be used to figure combustion chamber dimensions used with a LOX/LCH4-...
JDKelley's user avatar
  • 301
14 votes
1 answer
3k views

Why can solid rockets be both the skinniest and most spherical launch vehicles while liquid fuel rockets have a more limited range of aspect ratios?

Question: Why can solid rockets be both the skinniest and most spherical launch vehicles while liquid fuel rockets have a more limited range of aspect ratios? Are there fundamental engineering ...
uhoh's user avatar
  • 149k
1 vote
1 answer
288 views

Comparison of rocket engines using LH2 & LOX as propellants

I am a bit confused - If it is correct that RL 10 and LR 87-LH2 both were developed in 1950 by Aerojet, and both used LOX and LH2 as the propellants, if so, then why was there a huge difference in ...
Niranjan's user avatar
  • 3,758
2 votes
1 answer
215 views

What expansion ratio is the best for mars surface level engines?

What expansion ratio is the best for mars surface level engines? For launches from Earth, first stage nozzles are much shorter than second stage nozzles because of Earth's high sea-level pressure. For ...
Achillebckr's user avatar
4 votes
1 answer
232 views

Can rocket engines which use hypergolic propellants be augmented with LOX for increased efficiency?

Hypergolic rocket engines typically use NTO and hydrazine based propellants. Wikipedia page on Liquid Rocket Propellants shows N2O4 and N2H4 at 1.36 ratio to have 286s Isp at sea level. My question is ...
Ashvin's user avatar
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4 votes
1 answer
348 views

Was liquid ozone + fluorine ever tested as an oxidizer? Ever with jet fuel?

Searching for ozone layer circa 1957 I got Theoretical Rocket Performance of JP-4 Fuel with Mixtures of Liquid Ozone and Fluorine, NACA RM E56K14, Issue 58, Volume 63, Vearl N. Huff, Sanford Gordon. ...
uhoh's user avatar
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4 votes
1 answer
98 views

Can kerolox or SRB soot particles grow too large too quickly; not accelerated in expanding exhaust leading to a loss of mass-specific impulse?

In this answer to Is methyl silane CH6Si ever considered as fuel in rocketry? I argue that there's no huge loss in mass-specific impulse (Isp) when producing sand (and by extension soot) in the ...
uhoh's user avatar
  • 149k
12 votes
1 answer
3k views

Why is an inflatable balloon inside a fuel tank not used to prevent fuel from "sloshing around"?

After seeing all the Starship failures, having something with a membrane keep things in place seems like an obvious solution. Has it been considered or tested - or do we simply lack a material that is ...
Dagelf's user avatar
  • 517
4 votes
1 answer
559 views

Why are propellant tanks filled from the bottom?

It seems that the norm is to (fast-) fill fuel and oxidiser tanks from the bottom. For example, on this drawing of the Saturn S-IC stage you can see the LOX and RP-1 fill valves at the bottom of the ...
Ludo's user avatar
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3 votes
0 answers
244 views

Injector design - LOX vs nitrous oxide

What will be the main design differences between using liquid oxygen and liquid nitrous oxide as oxidizer in a bi-propellant rocket engine? What liquid/gas properties (vapor pressure etc.) play the ...
Kozuch's user avatar
  • 1,453
3 votes
1 answer
2k views

Open source liquid rocket engine

Is there an open source bi-propelant liquid rocket engine that would have all the documentation, computations, test results and 3D design files (CAD) freely accessible?
Kozuch's user avatar
  • 1,453
0 votes
1 answer
967 views

Highest Isp achieved with nitrous oxide as oxidizer

What is the highest Isp achieved on orbital rocket for an engine that used nitrous oxide as oxidizer? Both hybrid and liquid engines can be considered. Not considering nitrous oxide monopropellant ...
Kozuch's user avatar
  • 1,453
4 votes
1 answer
1k views

If high-test peroxide is most stable when pure, why are most uses of it in rocketry at lower concentrations?

Per the Wikipedia article for High-test peroxide: Hydrogen peroxide becomes more stable with higher peroxide content. For example, 98% hydrogen peroxide is more stable than 70% hydrogen peroxide. ...
DodoDude700's user avatar
2 votes
2 answers
414 views

Is there a "green" hypergolic propellant?

Is there any such thing as a non-cryogenic, liquid, "green" hypergolic bipropellant, where green means environment friendly and non-toxic?
Kozuch's user avatar
  • 1,453
4 votes
1 answer
241 views

What is the products of a catalyzed reaction between Hydrogen Peroxide and Ethanolamine with Copper(II) Chloride?

I found this article about Hypergols, specifically H2O2. It mentions in table 3 and in the body of the paper that they found that Ethanolamine with Copper Chloride reacted vigorously. In my search for ...
Enzo's user avatar
  • 51
0 votes
0 answers
123 views

Liquid fueled suborbital rockets?

Which suborbital (sounding, balistic, amateur or else) rockets use or used liquid fuel? I could find (with help from A. Rumlin) New Shepard - Blue Origin - RP-1 Spica - Copenhagen Suborbitals - ...
Joe Jobs's user avatar
  • 2,610
6 votes
2 answers
11k views

Rocket fuel cost to launch 1 kg to orbit

I have 2 questions about the cost of liquid rocket fuel to launch (anything) to LEO orbit. Let's assume we use fuels used in commercial spaceflight today (probably LOX+LH2 or LOX+RP-1 etc.). What is ...
Kozuch's user avatar
  • 1,453
5 votes
1 answer
177 views

Is there a distinct flame-front in a liquid-fuelled rocket combustion chamber?

Liquid fuel and liquid oxidizer are injected at high pressure through small orifices into the 'top' of a rocket's combustion chamber. The intention is that these mix quickly and then burn completely ...
Roger Wood's user avatar
  • 3,854
1 vote
2 answers
148 views

How many times is a single rocket engine tested?

When a rocket engine is loaded into a test stand is it tested once before removal or is it allowed to cool and then tested again. Is every liquid-fueled rocket motor that flies to space first tested ...
BobTheAverage's user avatar
3 votes
3 answers
747 views

Can liquid rocket engines have the same thrust as solid rocket engines?

Take the Vega rocket launcher for example. Its first three stages are solid rocket engines and burn at a relatively short time. If I were to change its first stage into a liquid rocket engine, can ...
Miguel's user avatar
  • 103
1 vote
1 answer
183 views

What is the effect of calorific value of fuel on the specific impulse of a rocket engine?

What is the effect of calorific value of a fuel on the specific impulse of a rocket engine? Other things remaining the same, and if it is possible to use both, will the same fuel provide the same ...
Niranjan's user avatar
  • 3,758
3 votes
1 answer
302 views

Dinitrogen tetroxide decomposes to nitrogen dioxide at room temperature, but rockets that use it are usually said to use N₂O₄ and not NO₂ - why?

To the best of my understanding, both dinitrogen tetroxide and nitrogen dioxide are usable and perform quite similarly as oxidizers, but rockets that use either are almost always said to use ...
DodoDude700's user avatar
6 votes
5 answers
2k views

Using of the rocket propellant for engine cooling

Why does liquid space propellant make a good engine coolant? I was researching the regeneratively cooled nozzle and combustion chamber on the Merlin 1D when I found this out. I do know that the pipes ...
user242559's user avatar
4 votes
0 answers
258 views

Why didn't propylene fly? (Vector—yes, Vector—is back)?

Ars Technicha's Rocket Report: SLS has technical problems, Vector—yes, Vector—is back links to Vector restarting operations under new ownership which says: One thing they did wrong was the technology ...
uhoh's user avatar
  • 149k
4 votes
1 answer
232 views

Concerns/challenges with LOX as a regenerative coolant

What are the fundamental issues that make LOX as a regenerative coolant difficult to work with or less ideal than using fuels as a coolant instead in small scale engines (<7000lbs of thrust/ ...
YuccaWorks's user avatar
4 votes
1 answer
143 views

How to experimentally determine the degree of atomization of the propellants mixing in a fuel injector?

When validating a fuel injector design on a test stand using liquid water to simulate a liquid-liquid fuel injector(the one i'm working with currently is a pintle design but I suppose one could ...
Jorge Mercado's user avatar
14 votes
4 answers
4k views

Do the SpaceX Falcon-9 rockets use foam insulation similar to the Space Shuttle? Is it still a potential problem?

The Space Shuttle used polyurethane and polyisocyanurate foams for insulation. A chunk of foam breaking off during launch resulted in the Space Shuttle Columbia disaster. Do all chemically-fueled ...
Kurt Hikes's user avatar
3 votes
1 answer
146 views

At which pressure does a liquid fueled rocket start producing supersonic flow?

In a compressed-tank LOX+ethanol (or similar liquid fuel) rocket: How much should the tank or combustion chamber pressure (which should be the same) be to have a significant exhaust velocity increase ...
Sartem Cacartem's user avatar