Fuel

[bknight]

You are referencing volume as Peter indicated.  Mass is the appropriate property to use.  Look at the rocket equation:

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

Only MASS is used in the equation, therefore your comparison should be mass, not volume

again excuse my denseness.

if the burn lasted 2 minutes which I read then that's 120 seconds. I read that the first stage used 20000 kg per second so that's 2400000.

but above it was said that at ignition it only had 646000 kg's

again am I wrong.

The burn rate seems about right for five engines but the center engine was shut down at 135.0 while the outboard engines continued to burn until 1.61.63 (or 2:01.63).


I posted average ratios because I don't know if they changed the ration during the 1st stage.

Edited to correct time.

[bknight]

Ben Those willfully ignorant individuals on YT and FB are spouting nonsense to get a reaction from others.  They don't know the real numbers that lead to reality of Apollo.  It is ok to get sucked into discussions, but remember Apollo did happen and the data is out there Kiwi gave you an excellent reference as did I.  BTW there are post mission reports on all missions, just change the link to point to the mission you might want to reference.  tim is right in the same boat as the rest, he may be posting in the particular thread you are asking about.  Just keep posting the real data, not the beliefs of a few individuals, you will preserver.

[benparry]

Ben Those willfully ignorant individuals on YT and FB are spouting nonsense to get a reaction from others.  They don't know the real numbers that lead to reality of Apollo.  It is ok to get sucked into discussions, but remember Apollo did happen and the data is out there Kiwi gave you an excellent reference as did I.  BTW there are post mission reports on all missions, just change the link to point to the mission you might want to reference.  tim is right in the same boat as the rest, he may be posting in the particular thread you are asking about.  Just keep posting the real data, not the beliefs of a few individuals, you will preserver.

oh I know that for sure. this isn't tim its a different group. the guy mentioned 2.27 but as I now understand that is volume not mass.

the links above i'm gonna check out. if I can find the amount of fuel burnt per second and multiply that by how long the burn lasted that should be good.

[benparry]

ok after checking out Kiwis links (many thanks for that) I think I've cracked it.

Apollo 11 burned for 168 seconds and in total burnt 3.2 million lb's of LOX and and 1.4 million lb's of Fuel.

does that sound about right.

can i also just ask that it says before burn the amount of LOX was 3305786 and the fuel was 1424889.
is there a way to calculate if those figures are consistent with the gallons mentioned right at the start. is there a calculation to see. i know that the densities are different but is there a way to cross reference them.

cheers

Ben

[Northern Lurker]

ok after checking out Kiwis links (many thanks for that) I think I've cracked it.

Apollo 11 burned for 168 seconds and in total burnt 3.2 million lb's of LOX and and 1.4 million lb's of Fuel.

does that sound about right.

can i also just ask that it says before burn the amount of LOX was 3305786 and the fuel was 1424889.
is there a way to calculate if those figures are consistent with the gallons mentioned right at the start. is there a calculation to see. i know that the densities are different but is there a way to cross reference them.

cheers

Ben

Do you want African or European gallons? Liquid Oxygen and RP1 have both different densities and storage temperatures. If you want to convert to gallons (or litres) you need to account the effect of temperature to volume into your equations. That's why both aviation and rocketry calculate their fuels by weight. Also note that you will have different LOX/RP1 ratio depending on whether you use mass or volume.

Lurky

[benparry]

ah ok thanks Lurky.

[smartcooky]

1 US Gal of Lox = 4.32 kg > 318000 US Gal of Lox = 1,372,287 kg
1 US gal of Kerosene = 3.03 kg > 203,400 US Gal of Kerosene = 615,962 kg

1,372,287 / 615,962 = 2.23

That is pretty close to your 2.27

Temperature will affect the density, so will barometric pressure.

[benparry]

1 US Gal of Lox = 4.32 kg > 318000 US Gal of Lox = 1,372,287 kg
1 US gal of Kerosene = 3.03 kg > 203,400 US Gal of Kerosene = 615,962 kg

1,372,287 / 615,962 = 2.23

That is pretty close to your 2.27

Temperature will affect the density, so will barometric pressure.

ah ok many thanks for that. cheers guys

[JayUtah]

Do you want African or European gallons? Liquid Oxygen and RP1 have both different densities and storage temperatures.

...and volume flow rates, etc.  The only time rocketry really deals in propellant volume is for mechanical design of the tanks.  All else is either mass in the traditional units of mass for whichever system of units you use, or mass in the units of chemical reckoning for stoichometrics, energy chemistry, and so forth.  When we talk about propellant amounts, assume mass unless told differently.

If you want to convert to gallons (or litres) you need to account the effect of temperature to volume into your equations.

And viscosity for liquids, if the mechanics of propellant flow enter the picture.  Pumping these liquids at these rates is informally akin to pumping pancake syrup through a bicycle pump.  Keep in mind just the propellant pump for the F-1 develops more horsepower than the entire engines of some high-performance jets.

That's why both aviation and rocketry calculate their fuels by weight.

And automotive.  Your car has a mass airflow sensor, not a volume airflow sensor.

Also note that you will have different LOX/RP1 ratio depending on whether you use mass or volume.

Yup, the volume ratios really have no use except when designing the rocket's airframe and planning the sizes of the propellant tanks.

[Allan F]

30.000 HP spent to pump the fuel and LOX for each F1 engine, if I remember correctly.

[Zakalwe]

30.000 HP spent to pump the fuel and LOX for each F1 engine, if I remember correctly.

55,000 BHP (41MW).

https://en.wikipedia.org/wiki/Rocketdyne_F-1#Design

[benparry]

tbh honest guys the answer was much simpler than I thought it would be lol
thanks again

[raven]

Even as basically a laywoman, it makes complete sense to me why volume would not be a good way to measure fuel amounts with a rocket. Why? Because of Newton's Third Law, is what. It's all about throwing mass one way to go the other, and, while extra volume does  complicate things, particularly in an atmosphere, drag is a drag, in the end, it's basically about throwing  out the end opposite the way you want to go either as much as possible, or as fast as possible, or both. So fuel volume doesn't tell you as much as mass.
At least that's my understanding. Corrections, as always,  are welcome.

[smartcooky]

Even as basically a laywoman, it makes complete sense to me why volume would not be a good way to measure fuel amounts with a rocket. Why? Because of Newton's Third Law, is what. It's all about throwing mass one way to go the other, and, while extra volume does  complicate things, particularly in an atmosphere, drag is a drag, in the end, it's basically about throwing  out the end opposite the way you want to go either as much as possible, or as fast as possible, or both. So fuel volume doesn't tell you as much as mass.
At least that's my understanding. Corrections, as always,  are welcome.

That is essentially the reason why a .22 cal handgun doesn't have much recoil, but a .44 magnum can damage your wrist and remodel your face if you don't hold it right! 



Its all about the mass.....

[Allan F]

.... times velocity.