12 questions linked to/from Merlin engine stoichiometry
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### Why is the flame of the Falcon 9's 2nd stage (nearly) invisible?

During the first crewed flight of a Falcon 9 today, I watched the nozzle go from dark grey to glowing red hot, confirming that it was burning. Yet there were no visible flames. I understand this stage ...
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### What do rockets eject?

So for instance, for the space shuttle,liquid hydrogen will react with liquid oxygen to produce water vapour. Is only water vapour ejected from the rocket? Or will the ejected mass be a mix of water ...
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### Liquid fuel / Oxygen proportions

A question ive been thinking about: If an engine works of a liquid propellant(Hydrogen in this case) and LOX, is there a specific proportion required for the two chemicals to burn completely? If so ...
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### Pro/cons of burning propellant in stochiometric ratio?

Several questions and answers here speak of stochiometric ratio. I do understand it is convinient for efficiency (greater ISP). I also read somewhere (I am unable ro find again the reference, it was ...
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### What is the reason for a LACE rocket to dump fuel?

The concept of LACE sounds awesome, especially the part "fuel is hard to come by in the atmosphere but there's some oxidizer available". The inefficiency due to the heat exchange ...
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### Curves on Isp/density chart, what varies along each curve?

In an answer to this question, the brilliant diagram below was given: Each fuel has a similarly shaped curve on the chart. What does that signify? what varies along the curve?
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1 vote
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### How does one determine the optimal CH4:O2 ratio in a methane-LOX rocket engine?

The SpaceX Raptor uses a 78:22 O2:CH4 ratio. It also has combustion chamber pressures higher than any other rocket engine ever built. My questions are: What's the math / chemistry that determines ...
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### InSight Launch - Centaur Fuel Rich

During the launch of InSight today one thing sprung out to me: at T+408s the voiceover announces: Centaur slightly fuel rich. And again at ...
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### Why can I not use stoichiometry to calculate the O/F ratio of my rocket? [duplicate]

I am attempting to calculate the oxygen to fuel ratio (O/F) for my hybrid rocket engine (paraffin wax and gaseous oxygen). I know I can use the oxidizer to fuel equation to calculate this, but my ...
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### What happens in to the fuel in fuel-rich Lox-Kerosene?

This link Optimum Mixture Ratio shows a range of mixture ratios for Lox-Kerosene of 2.1 to 2.45. Its not clear to me where in this range is the stochiometric case. Some Russian designs are higher (RD-...
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### Which are more efficient: oxidizer-rich or fuel rich rocket engines?

Several internet articles claim that the high Isp of the Soviet RD-180 engine (as used in the Atlas III and V launch vehicles) was (at least partially) due to the fact the RD-180 ran oxidizer-rich, ...
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1 vote