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#20
by
edkyle99
on 16 Oct, 2012 16:20
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Hi guys,
I was wondering hor the RP1 and LOX are fueled in the launcher ?
I only see what seems to be air conditionned and electrical connections betweek the tower and the launcher..
Cheers !
cyril
First stage LOX and kerosene fill and drain are, or were, done via. ducts that extended to the "Universal Boat Tail" base of the stage. This is due in part to the Thor heritage of Delta, which led to an original design that could be fueled quickly on an erector from the missile's aft end. The boat tail design was subsequently modified and beefed up for Long Tank Thor-Agena and Delta, and the fill drain lines were moved slightly to exit at the absolute base of the vehicle to provide room for strap-on solids.
The connections are hard to see in images, because the exterior propellant lines appear to run sort of inside the launch stand supports and because the connectors appear to be hidden behind spring loaded "doors" that are almost always closed in rare images of the base of the rocket.
- Ed Kyle
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#21
by
phred
on 17 Oct, 2012 13:10
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The heating of the Delta fuel increases the total energy of the system
The heat capacity of kerosene is like 2010 Joules per kilogram, which means that for a temp increase of say 16C, the additional energy would be 32,000 Joules per kg. But the heat of combustion is 43 megajoules per kilogram, so the increase is pretty small.
Could it be that the performance increase comes from the lowering of the viscosity, making the propellant pumps feed at a higher rate?
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#22
by
Jim
on 17 Oct, 2012 13:40
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The heating of the Delta fuel increases the total energy of the system
The heat capacity of kerosene is like 2010 Joules per kilogram, which means that for a temp increase of say 16C, the additional energy would be 32,000 Joules per kg. But the heat of combustion is 43 megajoules per kilogram, so the increase is pretty small.
Could it be that the performance increase comes from the lowering of the viscosity, making the propellant pumps feed at a higher rate?
nope
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#23
by
Liryc
on 18 Oct, 2012 13:35
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Hi guys,
I was wondering hor the RP1 and LOX are fueled in the launcher ?
I only see what seems to be air conditionned and electrical connections betweek the tower and the launcher..
Cheers !
cyril
First stage LOX and kerosene fill and drain are, or were, done via. ducts that extended to the "Universal Boat Tail" base of the stage. This is due in part to the Thor heritage of Delta, which led to an original design that could be fueled quickly on an erector from the missile's aft end. The boat tail design was subsequently modified and beefed up for Long Tank Thor-Agena and Delta, and the fill drain lines were moved slightly to exit at the absolute base of the vehicle to provide room for strap-on solids.
The connections are hard to see in images, because the exterior propellant lines appear to run sort of inside the launch stand supports and because the connectors appear to be hidden behind spring loaded "doors" that are almost always closed in rare images of the base of the rocket.
- Ed Kyle
Thanks Kyle,
I had a feeling that the 1st stage was filled from the aft bay.
I found this photo but the studs emerging from the "support arms" seem very small to me...
What about the upper stages ?
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#24
by
Liryc
on 18 Oct, 2012 13:36
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Hi guys,
I was wondering hor the RP1 and LOX are fueled in the launcher ?
I only see what seems to be air conditionned and electrical connections betweek the tower and the launcher..
Cheers !
cyril
First stage LOX and kerosene fill and drain are, or were, done via. ducts that extended to the "Universal Boat Tail" base of the stage. This is due in part to the Thor heritage of Delta, which led to an original design that could be fueled quickly on an erector from the missile's aft end. The boat tail design was subsequently modified and beefed up for Long Tank Thor-Agena and Delta, and the fill drain lines were moved slightly to exit at the absolute base of the vehicle to provide room for strap-on solids.
The connections are hard to see in images, because the exterior propellant lines appear to run sort of inside the launch stand supports and because the connectors appear to be hidden behind spring loaded "doors" that are almost always closed in rare images of the base of the rocket.
- Ed Kyle
Thanks Kyle,
I had a feeling that the 1st stage was filled from the aft bay.
I found this photo but the studs emerging from the "support arms" seem very small to me...
What about the upper stages ?
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#25
by
Jim
on 18 Oct, 2012 13:47
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Thanks Kyle,
I had a feeling that the 1st stage was filled from the aft bay.
I found this photo but the studs emerging from the "support arms" seem very small to me...
What about the upper stages ?
The propellant lines are not visible in that photo. That is only the launch mount.
Delta second stage uses storable propellants and are filled days before the final countdown and while in the MST using drag on lines
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#26
by
TrueGrit
on 18 Oct, 2012 19:08
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To improve overall stage impulse due to combustion efficiency improvements with hotter RP1... Just like how solid motor performance can change with temperature. Hint: You don't actually burn liquid propellant, but first vaporize it and its the gaseous vapor that burns. And its significant enough that Atlas does track account for the differences and predicted the RP1 propellant temperatures prior to flight.
As for the "jelling" issue... That limits how long LOx can be onboard to prevent the RP1 in the feedline which runs down the middle of the LOx tank from being chilled too much. RP1 isn't heated to help that... And as was noted the 3/4 solid missions early load RP1 and end up with ambient RP1.
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#27
by
Liryc
on 19 Oct, 2012 11:48
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The propellant lines are not visible in that photo. That is only the launch mount.
Delta second stage uses storable propellants and are filled days before the final countdown and while in the MST using drag on lines
Just found some photos where I think these feeding lines may appear !
What do you think ?
I also realized that one of the "support pins" was smaller than the others. Any idea what's the different with the other supports ?
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#28
by
Liryc
on 19 Oct, 2012 11:51
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+ this smaller "support pin" has hydraulic jacks at his bottom, seems to be some sort of retractable system...
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#29
by
Jim
on 19 Oct, 2012 12:13
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+ this smaller "support pin" has hydraulic jacks at his bottom, seems to be some sort of retractable system...
For clearance during liftoff
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#30
by
Liryc
on 19 Oct, 2012 12:15
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That's what I thought at the beginning but why would they do this only on 1 of the support pins ?
(and why is this one smaller)
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#31
by
Jim
on 19 Oct, 2012 12:17
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Just found some photos where I think these feeding lines may appear !
What do you think ?
I also realized that one of the "support pins" was smaller than the others. Any idea what's the different with the other supports ?
The black square item is just a covering over the vernier thruster. The other item is turbopump exhaust.
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#32
by
Jim
on 19 Oct, 2012 12:24
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That's what I thought at the beginning but why would they do this only on 1 of the support pins ?
(and why is this one smaller)
To clear the turbopump exhaust duct
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#33
by
Liryc
on 19 Oct, 2012 13:13
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Argh... you're right.
very interresting !
Still can't understand where are the feeding lines interfaces on the launcher (and on the ground too)
They are hiding it very well
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#34
by
Jim
on 19 Oct, 2012 14:47
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Argh... you're right.
very interresting !
Still can't understand where are the feeding lines interfaces on the launcher (and on the ground too)
They are hiding it very well
Look at the middle photo that I posted. You can see one of the lines. It is red.
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#35
by
Liryc
on 19 Oct, 2012 15:02
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Yeah i see the red line (the pic is tiny, do you have it slightly larger ?)
So as I can see the red line doesn't go through the support pins right ?
(I saw some holes on the support masts and thought they would support the feeding lines)
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#36
by
Robotbeat
on 27 Dec, 2014 03:48
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The heating of the Delta fuel increases the total energy of the system
The heat capacity of kerosene is like 2010 Joules per kilogram, which means that for a temp increase of say 16C, the additional energy would be 32,000 Joules per kg. But the heat of combustion is 43 megajoules per kilogram, so the increase is pretty small.
Could it be that the performance increase comes from the lowering of the viscosity, making the propellant pumps feed at a higher rate?
nope
Can you show your work or provide a citation?
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#37
by
Damon Hill
on 28 Dec, 2014 08:19
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I seem to recall that Proton loads its (hypergolic) propellants from the base for the first three stages. Possibly a common pair of pipes with valves on each stage to fill/drain tanks sequentially. The Proton's pad interface is visible on the core oxidizer tank's base which plugs into a receptacle with all liquid, gas and electrical connections. I don't know quite how the fourth stage is loaded, as it may use kerosene and LOX depending on the model selected for the mission.
Also simplifies first stage tank construction by eliminating internal domes to separate the fuel and oxidizer, which should save weight and wasted internal volume. Proton's a pretty elegant system and was way sophisticated for its time.
Zenit may be similar; I think there's a support mast for the third stage and payload. I haven't read any details for other Russian launchers apart from the R-7/Soyuz family, but given their military derivation I suspect they're similar.
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#38
by
Liryc
on 28 Dec, 2014 11:52
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I don't know quite how the fourth stage is loaded, as it may use kerosene and LOX depending on the model selected for the mission.
The proton upper stage (breeze-M) uses UDMH/N2O4 and is fueled in a separate building (outside the integration building) before transfer to the launch pad.
You can see it on the left side of the integration building here :
http://wikimapia.org/#lang=fr&lat=46.061469&lon=62.923862&z=17&m=bAs for the blocks DM-2/DM-2M (which use lox-kero as propellant), they must be fueled on the launch pad. And given the absence of external mast or umbilicals on the launch pad, I guess they might have either internal or external fueling lines going up on the launcher. (to be confirmed)[/quote]
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#39
by
russianhalo117
on 29 Dec, 2014 17:39
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Propforce - 2/11/2006 1:13 PM
Just talked to my Delta II propellant guru ....
You were right, the RP is heated to increase the overall vehicle performance. Even though this reduces propellant density thereby reducing the total RP-1 loading, it still provides an overall vehicle delta-vee advantage.
This practice is opposite of what Atlas II and Sealaunch were doing, from what I understand. Both were chilling their propellants to maximize mass loading.
Now why the difference approach, that's a good question...
My guess would be that the differing approaches have to do with the fact that the Atlas and Zenit engines, which provide all or most of the liftoff thrust, are optimized for thrust while the Delta II engine, which provides less than 20% of the liftoff thrust on the "79XX" models, leans more toward vacuum optimization. Or, from another perspective, it is because the Atlas and Zenit engines burn a much higher fraction of total vehicle mass in fuel than the Delta II engine does, so fuel density is relatively more important for Atlas and Zenit while that extra bit of specific impulse is relatively more important for Delta II.
- Ed Kyle
I asked my grandfather and he said that they heated the RP-1 even in the early Thor and Delta days long before SSRMs were added later in the early Delta Letter series.
