Author Topic: SpaceX: Merlin 1D thread  (Read 492321 times)

Offline hrissan

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Re: SpaceX: Merlin 1D Updates thread
« Reply #520 on: 12/18/2012 05:16 pm »
Thanks for the new picture.

You can see the faint exhaust from the GG even though it is very clear. The better the mixture ratio for the GG the clearer the exhaust.

Maybe they use an O2 sensor like a car engine to manipulate the GG mixture ratio right to the edge. That would give better performance for the GG and the Merlin engine in general.
Stohiometric combustion is very hot and will destroy the turbine. Running oxygen rich gives very aggressive (though not so hot) exhaust and will destroy the turbine. They usually run fuel rich and select ratio according to the maximum temperature the turbine can safely endure.

Can this be Merlin 1D running on Methane? :)

Offline Robotbeat

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Re: SpaceX: Merlin 1D Updates thread
« Reply #521 on: 12/18/2012 05:30 pm »
Or, they're just piping the exhaust into the engine.
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Offline cambrianera

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Re: SpaceX: Merlin 1D Updates thread
« Reply #522 on: 12/18/2012 05:36 pm »
My two cents:
-startup pic,
-GG not yet ignited, spinning with compressed gas (the faint exaust oldAtlas_Eguy noticed)
-green reflex visible only on the frame because the green plume is already expanding some meters down the hole.

Overall, nice pic. Good details of new arrangement of turbopump (RP1 pump clearly visible), clear view of new reaction rod (opposite side of the turbopump), some wirings removed (probably sensors for development).
Oh to be young again. . .

Offline meekGee

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Re: SpaceX: Merlin 1D Updates thread
« Reply #523 on: 12/18/2012 06:17 pm »
The green color is weird.  All I can say, FWIW, is that the color of the inner ring matches very well the color of the grass outside, visible on the middle right.
« Last Edit: 12/18/2012 06:19 pm by meekGee »
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Offline cambrianera

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Re: SpaceX: Merlin 1D Updates thread
« Reply #524 on: 12/18/2012 06:34 pm »

Stohiometric combustion is very hot and will destroy the turbine. Running oxygen rich gives very aggressive (though not so hot) exhaust and will destroy the turbine. They usually run fuel rich and select ratio according to the maximum temperature the turbine can safely endure.

Can this be Merlin 1D running on Methane? :)

I agree completely on turbine feed.
About running on Methane.... ;D
Oh to be young again. . .

Offline butters

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Re: SpaceX: Merlin 1D Updates thread
« Reply #525 on: 12/18/2012 06:41 pm »
Isn't that an M1DVac? My understanding is that the M1D GG exhausts to ambient, whereas the M1DVac GG exhaust is ducted into the nozzle extension.

Offline cambrianera

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Re: SpaceX: Merlin 1D Updates thread
« Reply #526 on: 12/18/2012 06:52 pm »
Isn't that an M1DVac? My understanding is that the M1D GG exhausts to ambient, whereas the M1DVac GG exhaust is ducted into the nozzle extension.
This is the only pic we have of M1DVac; nozzle is really larger and different (obviously missing the radiatively cooled extension)
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Offline corrodedNut

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Re: SpaceX: Merlin 1D Updates thread
« Reply #527 on: 12/18/2012 06:56 pm »
You can see in the previously released video (at about .11 sec on the clock) that there is a momentary lack of visible exhaust just after startup:



« Last Edit: 12/18/2012 07:06 pm by corrodedNut »

Offline douglas100

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Re: SpaceX: Merlin 1D Updates thread
« Reply #528 on: 12/18/2012 11:03 pm »
Isn't that an M1DVac? My understanding is that the M1D GG exhausts to ambient, whereas the M1DVac GG exhaust is ducted into the nozzle extension.

Then how do they do roll control?
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Offline Robotbeat

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Re: SpaceX: Merlin 1D Updates thread
« Reply #529 on: 12/18/2012 11:52 pm »
Isn't that an M1DVac? My understanding is that the M1D GG exhausts to ambient, whereas the M1DVac GG exhaust is ducted into the nozzle extension.

Then how do they do roll control?
Perhaps they'll just use thrusters.

... besides, they don't ALWAYS do roll control... ;)
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Offline meekGee

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Re: SpaceX: Merlin 1D Updates thread
« Reply #530 on: 12/19/2012 12:31 am »
You can see in the previously released video (at about .11 sec on the clock) that there is a momentary lack of visible exhaust just after startup

It's when they shift gear
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Offline Lars_J

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Re: SpaceX: Merlin 1D Updates thread
« Reply #531 on: 03/14/2013 11:03 pm »
The '11 years of SpaceX' video had a close-up of a Merlin 1D: (production version?)

https://www.youtube.com/watch?v=ujX6CuRELFE&feature=youtu.be

It certainly looks less complicated (on the outside at least) than the M1C.
« Last Edit: 03/14/2013 11:08 pm by Lars_J »

Offline billh

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Re: SpaceX: Merlin 1D Updates thread
« Reply #532 on: 03/14/2013 11:32 pm »
It certainly looks less complicated (on the outside at least) than the M1C.

Well, of course, they're still building it.

Offline Lars_J

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Re: SpaceX: Merlin 1D Updates thread
« Reply #533 on: 03/14/2013 11:33 pm »
It certainly looks less complicated (on the outside at least) than the M1C.

Well, of course, they're still building it.

No, it isn't just that. Compare the 1C with the 1D (an image from earlier in the thread) - Now imagine that engine without the test sensor and wiring for that:

From the '11 years' thread:
A couple of interesting images.

If someone wants to splice those two factory floor images and the 3 interstage images together, be my guest. I don't have the software for doing it.

your shot0033 - that's a Merlin 1D I think? It looks...smooth.

I was wondering what that was myself. It almost doesn't look like metal. Is it a training model for teaching engine assembly?

Look at the image below - The M1D has a different, less shiny surface texture.
« Last Edit: 03/14/2013 11:35 pm by Lars_J »

Offline bubbagret

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Re: SpaceX: Merlin 1D Updates thread
« Reply #534 on: 03/15/2013 12:29 am »
Look at the image below - The M1D has a different, less shiny surface texture.
That was an old test picture. Here is the "M1D" test article on the right compared to a more recent engine on the left. Notice the old M1D picture more resembles an M1C with a sandwich nozzle. The thrust mounts, turbo and throat are considerably changed on the new engine.
« Last Edit: 03/15/2013 12:31 am by bubbagret »

Offline Lars_J

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Re: SpaceX: Merlin 1D Updates thread
« Reply #535 on: 03/15/2013 12:43 am »
Yes, the turbopump exhaust is different, and a bunch of the early test sensor wires are gone. That left engine certainly is a very good match for the image from the new '11th anniversary' video..
« Last Edit: 03/15/2013 12:48 am by Lars_J »

Offline simonbp

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Re: SpaceX: Merlin 1D Updates thread
« Reply #536 on: 03/15/2013 04:25 pm »
Look at the image below - The M1D has a different, less shiny surface texture.
That was an old test picture. Here is the "M1D" test article on the right compared to a more recent engine on the left. Notice the old M1D picture more resembles an M1C with a sandwich nozzle. The thrust mounts, turbo and throat are considerably changed on the new engine.

Yeah, 1D does look a lot cleaner. And with a shorter turbohead and mount, which I guess was part of the motivation for the redesigned thrust structure on v1.1.

Anyone when the first v1.1 is supposed to arrive at VAFB, thus allowing our first glimpse at the actual flight hardware?

Offline guckyfan

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Re: SpaceX: Merlin 1D Updates thread
« Reply #537 on: 03/15/2013 04:39 pm »
Does the turbopump exhaust really go into the engine bell? That left picture looks like it.

Offline Jason1701

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Re: SpaceX: Merlin 1D Updates thread
« Reply #538 on: 03/15/2013 04:41 pm »
Does the turbopump exhaust really go into the engine bell? That left picture looks like it.

No, the pipe that appears to come out of it is actually behind. M1DVac probably does, though.

Offline pippin

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Re: SpaceX: Merlin 1D Updates thread
« Reply #539 on: 03/15/2013 04:57 pm »
M1DVac does? Ho do they do roll control then?

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