Author Topic: SpaceX: Merlin 1D thread  (Read 520316 times)

Offline aero

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Re: SpaceX: Merlin 1D Updates thread
« Reply #420 on: 07/03/2012 05:27 pm »
Did anyone ever post the value of Bulk Density for the Merlin D?

It seems a little tricky to estimate due to the various densities given for RP-1.
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Offline charliem

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Re: SpaceX: Merlin 1D Updates thread
« Reply #421 on: 07/04/2012 05:20 pm »
Did anyone ever post the value of Bulk Density for the Merlin D?

It seems a little tricky to estimate due to the various densities given for RP-1.

This document from 1962 might give you an idea: http://atlasbases.homestead.com/Analysis_of_RP-1_Fuel_Density_-_SAWE0323.pdf

I don't think the specifications have changed much since.

Basically it says that Air Force standard RP-1 density is 807.5 kg/m3 (at 60ºF).

It also gives a formula to compensate for temperature and a composition variations. Says nothing about pressure though, so I suppose those numbers are for 1 bar.

At 76ºF, the Cape Canaveral anual average, mean density is a bit lower, 800.8 kg/m3.

Offline aero

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Re: SpaceX: Merlin 1D Updates thread
« Reply #422 on: 07/04/2012 05:53 pm »
OK, that helps. Now, do we know what the RP-1/LOX ratio is?
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Offline charliem

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Re: SpaceX: Merlin 1D Updates thread
« Reply #423 on: 07/04/2012 06:36 pm »
OK, that helps. Now, do we know what the RP-1/LOX ratio is?

I have not found any numbers for 1D but there are clues about 1C in here.

From the LOX and RP-1 tank capacities mentioned on page A-3, 15586 kg and 7159 kg, the O/F ratio should be about 2.21

For Merlin 1D it might be a different though.

Offline modemeagle

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Re: SpaceX: Merlin 1D Updates thread
« Reply #424 on: 07/04/2012 08:02 pm »
OK, that helps. Now, do we know what the RP-1/LOX ratio is?

I have not found any numbers for 1D but there are clues about 1C in here.

From the LOX and RP-1 tank capacities mentioned on page A-3, 15586 kg and 7159 kg, the O/F ratio should be about 2.21

For Merlin 1D it might be a different though.


The main chamber is probably ~2.27.  I can't find the source for that one directly so don't quote me on it, but I think I got if from a SpaceX interview or publication for the M1C and assumed that the M1D is the same. 
The tank ratio will be slightly different since the gas generator will be run fuel rich compared to the main chamber.  Although not a huge difference, but will probably account for some extra RP-1 in the tank.

The Merlin 2 presentation (I know they are not doing it as of now) had that one at a 2.4 ratio.

I may be blowing steam with my information from above, but its all I have and its what I model my engine from the information published so far.


Offline Maciej Olesinski

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Re: SpaceX: Merlin 1D Updates thread
« Reply #425 on: 07/04/2012 08:52 pm »
Not sure if anyone noticed but this can be viewed in 3d
« Last Edit: 07/04/2012 08:54 pm by placydo »

Offline ChefPat

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Re: SpaceX: Merlin 1D Updates thread
« Reply #426 on: 07/05/2012 12:52 pm »
Not sure if anyone noticed but this can be viewed in 3d
I keep a pair of 3D glasses on my desk just for pix like that. Thanks for the heads up.
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Offline billh

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Re: SpaceX: Merlin 1D Updates thread
« Reply #427 on: 08/23/2012 02:23 am »
I just noticed something interesting near the bottom of the second page in this article on smallsats:

http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_08_20_2012_p31-486488.xml

"To produce the motors, CRP uses a computer-aided design (CAD) file containing the motor's shape, and electronically divides it into layers for the 3-D printing. Space Exploration Technologies Corp. (SpaceX) uses the same technique to manufacture tiny impellers and other parts for its Merlin rocket engines from titanium powder, according to a SpaceX spokesman."
[Emphasis mine.]

I don't recall hearing before that SpaceX was using 3-D printing in their engine manufacturing. Is anybody else doing this? It sounds pretty bleeding edge. Could they really be manufacturing turbopump impeller blades that way? The required tolerances are awfully fine.

Offline Chris-A

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Re: SpaceX: Merlin 1D Updates thread
« Reply #428 on: 08/23/2012 02:26 am »
For building molds?

Offline billh

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Re: SpaceX: Merlin 1D Updates thread
« Reply #429 on: 08/23/2012 02:35 am »
That wouldn't be the most straightforward reading of it, but I suppose that's possible. I don't think the molds would be titanium. I think the blades would be titanium.

Offline Robotbeat

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Re: SpaceX: Merlin 1D Updates thread
« Reply #430 on: 08/23/2012 02:35 am »
I just noticed something interesting near the bottom of the second page in this article on smallsats:

http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_08_20_2012_p31-486488.xml

"To produce the motors, CRP uses a computer-aided design (CAD) file containing the motor's shape, and electronically divides it into layers for the 3-D printing. Space Exploration Technologies Corp. (SpaceX) uses the same technique to manufacture tiny impellers and other parts for its Merlin rocket engines from titanium powder, according to a SpaceX spokesman."
[Emphasis mine.]

I don't recall hearing before that SpaceX was using 3-D printing in their engine manufacturing. Is anybody else doing this? It sounds pretty bleeding edge. Could they really be manufacturing turbopump impeller blades that way? The required tolerances are awfully fine.
Yeah, I think other people are doing it that way. the tolerances are good enough for blade shape (though I wouldn't be surprised if they did another polishing step or something like that). And no, I don't think it's just for molds, though it's possible they can't use it for the most strenuous parts of the rocket engine (which might want single-crystal fancy alloys or something like that).
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Offline go4mars

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Re: SpaceX: Merlin 1D Updates thread
« Reply #431 on: 08/23/2012 05:11 am »
I don't recall hearing before that SpaceX was using 3-D printing in their engine manufacturing....Could they really be manufacturing turbopump impeller blades that way?
I've seen their machine and what it makes.  It was explained to me as a good way to have engineers fast-track parts.  Make it on your computer, hit print, then walk over in a little while and see if it fits/works.  Make adjustments as necessary.  Just little stuff (at least back when I was in there).  Really cool. 
« Last Edit: 08/23/2012 05:12 am by go4mars »
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Offline Prober

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Re: SpaceX: Merlin 1D Updates thread
« Reply #432 on: 08/23/2012 02:33 pm »
I just noticed something interesting near the bottom of the second page in this article on smallsats:

http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_08_20_2012_p31-486488.xml

"To produce the motors, CRP uses a computer-aided design (CAD) file containing the motor's shape, and electronically divides it into layers for the 3-D printing. Space Exploration Technologies Corp. (SpaceX) uses the same technique to manufacture tiny impellers and other parts for its Merlin rocket engines from titanium powder, according to a SpaceX spokesman."
[Emphasis mine.]

I don't recall hearing before that SpaceX was using 3-D printing in their engine manufacturing. Is anybody else doing this? It sounds pretty bleeding edge. Could they really be manufacturing turbopump impeller blades that way? The required tolerances are awfully fine.

Boeing was doing some of this when they owned Rocketdyne.
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Offline docmordrid

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Re: SpaceX: Merlin 1D Updates thread
« Reply #433 on: 08/25/2012 07:00 am »
3D metal printing has become a 'really big deal' recently with the development of laser / plasma sintering of the layers, fusing theclayers into a solid part.

The quality is very high, as was evidenced last year in Europe when a woman received a pronted titanium jaw prosthesis. Thing is, the process can be used with many alloys and metal ceramics. Times, they are a changin'
DM

Offline MP99

Re: SpaceX: Merlin 1D Updates thread
« Reply #434 on: 09/30/2012 10:47 pm »
Copied from the "general" thread:-
First picture of the Merlin 1D-Vac:

https://twitter.com/elonmusk/status/252528724602400768
Quote
Elon Musk ‏@elonmusk
Now test firing our most advanced engine, the Merlin 1D-Vac, at 80 tons of thrust. pic.twitter.com/HGK1joVQ

Does this match the expected thrust for M1D vac?

cheers, Martin

Online ugordan

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Re: SpaceX: Merlin 1D Updates thread
« Reply #435 on: 09/30/2012 10:50 pm »
Sounds high, but if you take published M1d thrust and Isp numbers and assuming it uses the same chamber and has the same mass flow as regular M1d, that seems to work out to about 343 sec Isp. Pretty much the target for the original MVac.

Offline GBpatsfan

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Re: SpaceX: Merlin 1D Updates thread
« Reply #436 on: 09/30/2012 10:57 pm »
Copied from the "general" thread:-
First picture of the Merlin 1D-Vac:

https://twitter.com/elonmusk/status/252528724602400768
Quote
Elon Musk ‏@elonmusk
Now test firing our most advanced engine, the Merlin 1D-Vac, at 80 tons of thrust. pic.twitter.com/HGK1joVQ

Does this match the expected thrust for M1D vac?

cheers, Martin
From SpaceX website Merlin Engine(presumably M-1D) Vacuum Thrust:   161,000 lbf

Offline Zed_Noir

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Re: SpaceX: Merlin 1D Updates thread
« Reply #437 on: 09/30/2012 11:40 pm »
Copied from the "general" thread:-
First picture of the Merlin 1D-Vac:

https://twitter.com/elonmusk/status/252528724602400768
Quote
Elon Musk ‏@elonmusk
Now test firing our most advanced engine, the Merlin 1D-Vac, at 80 tons of thrust. pic.twitter.com/HGK1joVQ

Does this match the expected thrust for M1D vac?

cheers, Martin
From SpaceX website Merlin Engine(presumably M-1D) Vacuum Thrust:   161,000 lbf

Think that's for the regular version of the Merlin 1-D.

Offline oldAtlas_Eguy

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Re: SpaceX: Merlin 1D Updates thread
« Reply #438 on: 10/01/2012 05:09 pm »
Thanks for the update.

Updated table to show the possible Test article? vac thrust value for 80mt.

EngineMerlin 1DVAC (Design)Merlin 1DVAC (Test article)Merlin 1DVAC (Production)
Vac Thrust174klbf?176klbf??
Vac isp348s?(an educated WAG)??
T/W160???
Chamber Pressure1410psi???
Expansion??>117?(this was the MVAC value)
Throttle range70-100%???
Engine weight >440kg???
Costs<M1CVAC?-?

There are still a lot of unknowns but this is the best validation of the estimates we have had so far.

Offline Prober

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Re: SpaceX: Merlin 1D Updates thread
« Reply #439 on: 10/01/2012 06:45 pm »
Old Atlas, know I shouldn't be thinking this but....

What would you get if the 1.1D Vac was fired at SL?   That F12 is still bugging me. 

Edit:   good place to learn something anyhow.


« Last Edit: 10/01/2012 06:45 pm by Prober »
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