ApolloHoax.net
Apollo Discussions => The Hoax Theory => Topic started by: benparry on July 16, 2018, 07:20:54 AM
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Good Morning
can i ask a question which i'm sure has an easy answer.
the first stage of Apollo launch with the F1 Rockets used 318000 gallons of LOX and 203400 gallons of Kerosene.
i have read that the mixture ratio needed was 2.27 to 1 LOX to Fuel.
shouldnt there be more LOX in there as 2.27 times 203400 is 461718 not 318000
again i'm sure i've missed something.
is there an easy answer
cheers
Ben
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Was the ratio based on mass or volume?
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Was the ratio based on mass or volume?
it was just from a chart I saw on a site. let me get it for you.
https://www.space.com/18422-apollo-saturn-v-moon-rocket-nasa-infographic.html
if you see the black rectangle directly under the picture of the rocket it says 2.27 to 1 in there
cheers Zakalwe
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I don't see the graph you referred, but from the AS-506 Post flight report
https://ia600307.us.archive.org/32/items/nasa_techdoc_19900066485/19900066485.pdf
page 5-6
1500418 kg LOX; 646854 kg Kerosene at ignition
18177 kg LOX; 14354 kg Kerosene at OECO
Thus from ignition to Outside Engine Cut Off 1482241 kg LOX burned 632500 kg Kerosene burned for an AVERAGE Ratio of 2.34.
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I don't see the graph you referred, but from the AS-506 Post flight report
https://ia600307.us.archive.org/32/items/nasa_techdoc_19900066485/19900066485.pdf
page 5-6
1500418 kg LOX; 646854 kg Kerosene at ignition
18177 kg LOX; 14354 kg Kerosene at OECO
Thus from ignition to Outside Engine Cut Off 1482241 kg LOX burned 632500 kg Kerosene burned for an AVERAGE Ratio of 2.34.
Hey bknight
if you open the link copied its about half way down in a black rectangle.
however are you saying that all of the fuel within the first stage wasn't used.
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Benparry
Note the difference. Your comparison was in gallons (volume).
Bknight's comparison was in kilograms (mass).
You might like to check the densities of liquid oxygen and kerosene.
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Benparry
Note the difference. Your comparison was in gallons (volume).
Bknight's comparison was in kilograms (mass).
You might like to check the densities of liquid oxygen and kerosene.
Hi Peter b
Sorry I am confused. If I go back to my original post if you devide the higher figure by the lower figure you don't get 2.27. However when you look at my attachment is said that a ratio of 2.27 was used. I know I am confused can you explain where I am going wrong.
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so if the first stage of Apollo launch with the F1 Rockets used 318000 gallons of LOX and 203400 gallons of Kerosene.
i have read that the mixture ratio needed was 2.27 to 1 LOX to Fuel.
shouldnt there be more LOX in there as 2.27 times 203400 is 461718 not 318000
again i'm sure i'm being silly here. can I also just ask was the whole of the fuel which was present in the first stage actually used or is it simply a case of you don't need to times it by 2.27 as not all of the fuel was used.
do I need to multiply the amount of LOX and fuel burned per second or minute by the number of minutes the burn took place for.
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I don't see the graph you referred, but from the AS-506 Post flight report
https://ia600307.us.archive.org/32/items/nasa_techdoc_19900066485/19900066485.pdf
page 5-6
1500418 kg LOX; 646854 kg Kerosene at ignition
18177 kg LOX; 14354 kg Kerosene at OECO
Thus from ignition to Outside Engine Cut Off 1482241 kg LOX burned 632500 kg Kerosene burned for an AVERAGE Ratio of 2.34.
Hey bknight
if you open the link copied its about half way down in a black rectangle.
however are you saying that all of the fuel within the first stage wasn't used.
That is correct both fuel and oxidizer were left in all the stages after engine cutoff.
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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
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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
you may have guessed by my lack of knowledge but that is totally over my head.
do you know how much of both the LOX and rocket fuel were burnt per second / minute and how many second / minutes the burn lasted.
if I can multiply them in my head I can get why the LOX or fuel shouldn't have run out lol
thanks again
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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.
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Whenever you want numbers about Apollo missions, your first port of call should probably be the "Apollo by the Numbers" web pages.
https://history.nasa.gov/SP-4029/Apollo_00_Welcome.htm
This old 2007 thread at a previous version of ApolloHoax provides links for every individual web page:
https://apollohoax.proboards.com/thread/1356/apollo-numbers (https://apollohoax.proboards.com/thread/1356/apollo-numbers)
Read the comments because the Nasa pages have some links that don't work, or gaps where there should be links -- hence the thread.
In the first post, page down past the individual missions to the section, "Apollo - General Information" where you'll find three pages, 18-23a to 18-23c titled "Launch Vehicle Propellant Usage".
https://history.nasa.gov/SP-4029/Apollo_18-23a_Launch_Vehicle_Propellant_Use.htm (https://history.nasa.gov/SP-4029/Apollo_18-23a_Launch_Vehicle_Propellant_Use.htm)
https://history.nasa.gov/SP-4029/Apollo_18-23b_Launch_Vehicle_Propellant_Use.htm (https://history.nasa.gov/SP-4029/Apollo_18-23b_Launch_Vehicle_Propellant_Use.htm)
https://history.nasa.gov/SP-4029/Apollo_18-23c_Launch_Vehicle_Propellant_Use.htm (https://history.nasa.gov/SP-4029/Apollo_18-23c_Launch_Vehicle_Propellant_Use.htm)
The fuel quantities there are in pounds, which might confirm what Peter B and bknight said about needing to work with mass (lbs or kg), not volume (gallons or litres).
PS This thread should probably be in the Reality of Apollo section, unless you're going to propose that the figures are hoaxed. :)
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No I am a believer I have noticed a thread in a hoax group on facebook and I confused by the figures.
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Good Morning
can i ask a question which i'm sure has an easy answer.
the first stage of Apollo launch with the F1 Rockets used 318000 gallons of LOX and 203400 gallons of Kerosene.
i have read that the mixture ratio needed was 2.27 to 1 LOX to Fuel.
shouldnt there be more LOX in there as 2.27 times 203400 is 461718 not 318000
again i'm sure i've missed something.
is there an easy answer
cheers
Ben
You're confusing units of measure - the mixture ratio is expressed in terms of mass (2.27 pounds LOX to 1 pound RP-1). "Gallon" is not a unit of mass, it's a unit of volume. LOX is denser than RP-1, so a gallon of LOX weighs more than a gallon of RP-1. IOW, you need fewer gallons to store X pounds of LOX than to store X pounds of RP-1.
This is why the tank volume ratio doesn't match the mass ratio.
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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.
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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.
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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.
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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
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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
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ah ok thanks Lurky.
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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.
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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
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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.
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30.000 HP spent to pump the fuel and LOX for each F1 engine, if I remember correctly.
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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
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tbh honest guys the answer was much simpler than I thought it would be lol
thanks again
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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.
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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!
(https://www.dropbox.com/s/jzpwpm1pc8vlq58/CartridgeComparison.jpg?raw=1)
Its all about the mass.....
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.... times velocity.
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...squared.
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.... yes
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It's actually momentum, which is just mass times velocity, as opposed to kinetic energy, which is one half mass times velocity squared. When you fire a gun, nearly all of the kinetic energy goes into the bullet but exactly equal (and opposite) amounts of momentum go into the bullet and into the gun (and whoever is holding it).
In that case, imparting kinetic energy to the bullet is the desired outcome since the bullet will, in turn, deposit that kinetic energy into its target.
A rocket is both like and unlike a gun. While the basic physics are much the same (both are heat engines) the ultimate purposes are very different. A chemical rocket first converts the energy stored in the propellants into heat energy by burning them in the combustion chamber. Then it uses a nozzle to convert that heat energy into kinetic energy of its exhaust. Unlike the gun, this is not the ultimate goal but it's necessary if you want to impart momentum to the exhaust, which in turn imparts an equal and opposite momentum applied to the rocket. That's the ultimate goal. On the other hand, the goal of a gun is to impart kinetic energy to the bullet, and the recoil is just an annoying but necessary side effect. In a rocket, the recoil is the desired effect and the kinetic energy imparted to the exhaust (and the effect on anything it happens to hit) is just the annoying cost of doing that.
Unfortunately, because momentum (which you want) goes up only linearly with velocity, while kinetic energy goes up as velocity squared, increasing exhaust velocity to achieve more impulse (thrust times time) with a given mass of propellant requires a linearly greater total amount of energy for each unit of impulse. That's the famous "tyranny of the rocket equation."