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Author
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Topic: Position of LOX & Kerosene tanks on Saturn V
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collocation
Member Posts: 387
From: McLean, VA
Registered: Feb 2004
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posted 03-23-2006 03:11 PM
   
Like to know if there were any specfic reason/s to have the LOX tank on top of the Kerosene tank on the first stage of the Saturn, was it to cool the Kerosene |
ivorwilliams
Member Posts: 69
From: Welwyn Garden City, UK
Registered: Jan 2005
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posted 03-23-2006 06:40 PM
I'm no expert but I would have thought that having a LOX tank so close to the engines would have been a bit risky! |
bruce
Member Posts: 917
From: Fort Mill, SC, USA
Registered: Aug 2000
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posted 03-23-2006 08:50 PM
Here's a diagram of the Saturn V that shows the position of the LOX and Kerosene tanks.
http://history.nasa.gov/SP-4206/p405.jpg The http://history.nasa.gov site has a lot of great related info on the Saturn V. Hope this helps. Bruce |
LT Scott Schneeweis
unregistered
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posted 03-23-2006 10:49 PM
quote:
Originally posted by collocation:
Like to know if there were any specfic reason/s to have the LOX tank on top of the Kerosene tank on the first stage of the Saturn, was it to cool the Kerosene
Actually the engineers when to great lengths to ensure the RP1 was not frozen..there LOX lines supplying oxidizer to the F1 engines from the (LOX) tank traversed the fuel tank and each line was encapsulated with an outer insulative pipe filled with air. The rational for placing the RP1 tank at the base was predicated on RP1's higher density. ------------------
Scott Schneeweis
URL http://www.SPACEAHOLIC.com/ |
Duke Of URL
Member Posts: 1316
From: Syracuse, NY
Registered: Jan 2005
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posted 03-24-2006 10:22 AM
They put the LOX tank near the cream cheese tank to keep it cool.[This message has been edited by Duke Of URL (edited March 24, 2006).] |
nasamad
Member Posts: 2141
From: Essex, UK
Registered: Jul 2001
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posted 03-24-2006 02:41 PM
Just a guess to add to the answers above but the delivery lines from the upper tank actually passed through the lower tank. Seeing as the RP1 tank was smaller than the LOX, it would enable the lines to be shorter if the RP1 was at the bottom. Just my 2p.......Adam |
collocation
Member Posts: 387
From: McLean, VA
Registered: Feb 2004
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posted 03-24-2006 03:28 PM
Yes, I have detailed cross section of the Saturn and the lines do go through the lower thank, but I think the density answer was probably the most logical, wieght did matter, get rid the most wieght the quickest |
Jurg Bolli
Member Posts: 994
From: Albuquerque, NM
Registered: Nov 2000
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posted 03-24-2006 04:20 PM
KSC has a marvelous old cut-out model of a Saturn that shows the plumbing very well. The model is old and very large but extremely informative. It is on its side in the Saturn V center.
Although I don't know the answer to the original question I am with Scott on this and suspect that the density was the main reason, if not the only one.
Jurg |
spacecraft films
Member Posts: 802
From: Columbus, OH USA
Registered: Jun 2002
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posted 03-24-2006 06:31 PM
Our Saturn V DVD set has some footage in the Quarterly Reports that shows quite clearly how the pieces of the tankage went together....The LOX lines went right through the RP-1 tank. Mark
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Stephen Clemmons
Member Posts: 108
From: Wilmington, NC, New Hanover
Registered: Aug 2004
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posted 03-25-2006 05:13 PM
Scott, your'e pretty close. It had to do with the weight, balance and density. Most rocket engines use a three to one ratio. three parts oxygen to one part fuel.
LOX weighs 3.5 Lbs per gallon, RP1 weighs 8.0+.
If the fuel tanks were on top, it would become top heavy after a few seconds because the oxygen was being consumed much faster, creating a serious weight and balance problem. Another problem was a dangerous trait of gaseous Oxygen (GOX), which I'll explain.
Going all the way back to the early rocket boosters, all were configured with the tell-tale LOX vent valve at the top of the stack, just under the payload.
It was located here so prevailing winds could carry off the oxygen vapors above the landscape.
Since GOX is very cold, it also has a bad habit of settling around the base of the booster.
Theorically, with a 100% GOX Atmosphere in and in and around the engines and engine compartment, the boat-tail could catch on fire at engine start.
This was probably the key to the whole thing because they didn't want the GOX venting off down near the engine compartment. By having the vents at the top of tank and stack, this eliminated that problem.
Incidently, On the Atlas ICBM they wanted the Fuel at normal ambiant temp and the Oxygen Super Cooled way below _-297 deg to give them what was known as a soft start, the ability of the engines to come up to max thrust without setting off a shock wave on the airframe from a normal abrupt start when the main pumps hit mainstage.
This was accomplished by running the last portion of LOX (2000 Gallons) through coils in a Liquid Nitrogen Tank called the slugger. This cooled the LOX that loaded in the bottom of the tank to -320 degrees. This was the last LOX to load just before liftoff and provided a super cool head at the LOX pumps just before the vent valve closed. This decrease in temperature gave a delayed combustion cycle as engine was slower to come to full thrust, but only by miliseconds, just enough to prevent a system shock. This resulted in a smooth take off. On the Saturn V, Gaseous Oxygen was captured at least for the most part by ducts on the Umbilicals and routed to the dump area during loading, This was a large pit dug outside the inner perimeter road where it could dissipate Hydrogen was definitely vented from the top of the tower.
Hope this helps out.
Just so this post is not boring, this was an actual event at one of the launches. We were in the final stages of preparation for launch of Apollo 8, just hours away from launch.
The security guards was making a final check of the inner perimeter to make sure we didn't have visitors hiding in the bushes like on one of the Gemini Launches. (two college students wanted to watch a launch up close and hid in the brush. They were discovered just before launch less than 1/4 mile away.) We had been loading fuel and Hydrogen for a full week and was now loading liquid oxygen. The disipation area on the far side of the inner perimeter road was covered with what the guards thought was heavy fog, common at the Cape. They didn't realize that this was pure 100% GOX.
They were not aware of the characteristics of oxygen and drove into the area. Because of the hot exhaust and engine oils, their vehicle immediately caught on fire. They managed to get off a message that their truck was on fire. Next to arrive was another security vehicle and it caught on fire. It was followed by a fire truck and it also burst into flames.
Everyone walked out but the vehicles burned down to almost nothing.
Needless to say, that was the last time anyone went into this pit during loading operations.
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