LH/LOX rocket engines

[Nine Tailed Fox]

Can't wrap my head around how it's exhaust is water vapor from combustion(?) and still produce crazy amounts of thrust.. 

[The Flying Sloth]

Just like splitting a water molecule in an endothermic reaction (absorbs energy) makes hydrogen (fuel) and oxygen, when a spark ignites that mixture it creates water vapour in a very exothermic reaction (releases energy) again. 

[Sophia_Borjia]

Most of gas from car tail pipe is also water, mixed with co2 and a lot of toxic trace compounds.

2 H2 + O2 = 2 H2O and a lot of heat.  Water is basically hydrogen ash.

Don't under estimate steam, making steam for some use is how most nuclear reactors operate.  Just big advanced steam engines.

[GoldenLag]

11 minutes ago, Nine Tailed Fox said:

Can't wrap my head around how it's exhaust is water vapor from combustion(?)

because that is what you get when you react hydrogen and oxygen gas together. 

12 minutes ago, Nine Tailed Fox said:

still produce crazy amounts of thrust.. 

the lighter the exhaust, the better specific impulse (efficiency).

 

and per kilogram of hydrogen and oxygen, there are few other reactions that give more energy. 

 

 

 

doesnt matter what the exhaust is, just the weight of it. 

[Roswell]

12 minutes ago, Nine Tailed Fox said:

Can't wrap my head around how it's exhaust is water vapor from combustion(?) and still produce crazy amounts of thrust.. 

It's just basic chemistry. They're using the two elements that compose water as propellant

 

6 minutes ago, VegetableStu said:

chemistry (2H + O = H2O (i forgot how to do the energy equation ,_,) ) and physics (For every (giant tank of) action, there is an equal and opposite (giant tank of) reaction)

Close!

 

2H₂ + O₂ = 2H₂O + Energy

 

[GoldenLag]

1 minute ago, yaboistar said:

- there's a good reason they use it as a takeoff performance booster on some engines like those on the B52

well its non-toxic. so its very nice for boosters, even if you need a ton of fuel as steam rockets have terrible specific impulse. 

 

other than its being scolding hot, its safe. very nice on runways where you probably want to have a clean exhaust product.