Author Topic: SpaceX: Merlin 1D thread  (Read 232749 times)

Offline modemeagle

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Re: SpaceX: Merlin 1D Updates thread
« Reply #440 on: 10/01/2012 07:26 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.



I am not OldAtlas_Eguy, but here is my estimated data.

Sea Level - 168 seconds - 87,253 lbf
Design - 336 seconds - 174,674 lbf (used in my simulation to change ISP by altitude)
Vacuum - 345 seconds 179,310 lbf

Estimated nozzle exit pressure is 0.74 psi.  Flow seperation at sea level would be very bad and probably kill the isp lower then 168 seconds estimated.


* Estimated data by MODEMEAGLE

Offline WHAP

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Re: SpaceX: Merlin 1D Updates thread
« Reply #441 on: 10/02/2012 03:55 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.

Why are people sure Elon meant 80 tonnes when he wrote 80 tons?
« Last Edit: 10/02/2012 03:56 PM by WHAP »

Offline kch

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Re: SpaceX: Merlin 1D Updates thread
« Reply #442 on: 10/02/2012 04:09 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.

Why are people sure Elon meant 80 tonnes when he wrote 80 tons?

They're "seeing" what they want to see -- it happens a lot.

Offline Robotbeat

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Re: SpaceX: Merlin 1D Updates thread
« Reply #443 on: 10/02/2012 04:10 PM »
As long as it is within 10 percent or so, I doubt he cares.
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Offline oldAtlas_Eguy

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Re: SpaceX: Merlin 1D Updates thread
« Reply #444 on: 10/02/2012 04:39 PM »
South Africa after 1977 was fully metric only, so this is the measument system environment in which Elon Musk grew up. He left South Africa in 1988. The default "ton" definition to someone who used only metric and very little English measurments would be the metric ton.

http://ukma.org.uk/south-african-experience

So the interpretation of metric ton for this tweet has a foundation.

Offline modemeagle

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Re: SpaceX: Merlin 1D Updates thread
« Reply #445 on: 10/02/2012 05:01 PM »
My numbers are about a year old and based on scaling the M1D with a vacuum optimized nozzle.  If I was within 10% of the final data then I figured I was doing good.  I also used lower thrust data in my simulations and found FH could reach orbit with almost 70% of my estimated data.

Offline iamlucky13

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Re: SpaceX: Merlin 1D Updates thread
« Reply #446 on: 10/02/2012 11:48 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

I asked in the general thread, but my question was buried in the big long argument about T-shirts...  ::)

...what's the big ring around the base of the nozzle? The regen manifold is visible separately above it, so I know it's not that.

Offline go4mars

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Re: SpaceX: Merlin 1D Updates thread
« Reply #447 on: 10/02/2012 11:57 PM »
It also could be read the other way...  That they tested it at 80.  Not that it's rating is for 80. 
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Offline modemeagle

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Re: SpaceX: Merlin 1D Updates thread
« Reply #448 on: 10/03/2012 12:07 AM »
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

I asked in the general thread, but my question was buried in the big long argument about T-shirts...  ::)

...what's the big ring around the base of the nozzle? The regen manifold is visible separately above it, so I know it's not that.
If you look in the background you will see a flex below the turbo pump.  Notice the dark streaks in the exhaust.  Compare it to the F-1 and the only conclusion is the turbo pump exhaust is pumped into the nozzle.

Offline neilh

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Re: SpaceX: Merlin 1D Updates thread
« Reply #449 on: 10/03/2012 12:18 AM »
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

I asked in the general thread, but my question was buried in the big long argument about T-shirts...  ::)

...what's the big ring around the base of the nozzle? The regen manifold is visible separately above it, so I know it's not that.

This is a totally random uneducated guess, but would the ring make sense as a mounting point for a retractable nozzle?
Someone is wrong on the Internet.
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Offline MP99

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Re: SpaceX: Merlin 1D Updates thread
« Reply #450 on: 10/03/2012 07:11 AM »
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

I asked in the general thread, but my question was buried in the big long argument about T-shirts...  ::)

...what's the big ring around the base of the nozzle? The regen manifold is visible separately above it, so I know it's not that.

If you look in the background you will see a flex below the turbo pump.  Notice the dark streaks in the exhaust.  Compare it to the F-1 and the only conclusion is the turbo pump exhaust is pumped into the nozzle.

Isn't the turbo-pump exhaust shown at the left of the pic, rather than being diverted into the nozzle? This would need to remain separate if v1.1 us is going to use the same roll control as v1.0.

cheers, Martin

Offline modemeagle

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Re: SpaceX: Merlin 1D Updates thread
« Reply #451 on: 10/03/2012 10:15 AM »
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

I asked in the general thread, but my question was buried in the big long argument about T-shirts...  ::)

...what's the big ring around the base of the nozzle? The regen manifold is visible separately above it, so I know it's not that.

If you look in the background you will see a flex below the turbo pump.  Notice the dark streaks in the exhaust.  Compare it to the F-1 and the only conclusion is the turbo pump exhaust is pumped into the nozzle.

Isn't the turbo-pump exhaust shown at the left of the pic, rather than being diverted into the nozzle? This would need to remain separate if v1.1 us is going to use the same roll control as v1.0.

cheers, Martin
I could be wrong, been know to happen from time to time.
« Last Edit: 10/03/2012 10:26 AM by modemeagle »

Online MATTBLAK

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Re: SpaceX: Merlin 1D Updates thread
« Reply #452 on: 10/03/2012 10:20 AM »
A rare admission around here!
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Offline ugordan

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Re: SpaceX: Merlin 1D Updates thread
« Reply #453 on: 10/03/2012 11:14 AM »
Isn't the turbo-pump exhaust shown at the left of the pic, rather than being diverted into the nozzle? This would need to remain separate if v1.1 us is going to use the same roll control as v1.0.

Not necessarily. F9 US has to have cold gas RCS anyway for coast period attitude control, prop settling, etc. You don't need GG exhaust for roll control if you're confident the engine operation itself won't introduce large roll torques (although this assumption can bite you in the rear), bigger than RCS can handle and/or deplete the propellant.

MVac already demonstrated that any roll torques it produced were fairly small and yet the lower regen part of the nozzle was tube-wall design which makes the exhaust swirl a little. M1D flavor should be free from even that effect so it should impart very little roll torque.

Offline Crispy

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Re: SpaceX: Merlin 1D Updates thread
« Reply #454 on: 10/03/2012 11:43 AM »
How does the shape of the regen channels affect the motion of the exhaust? I can understand how acceleration of propellant flow through the channels can create a torque, but how can it influence the exhaust?

Offline corrodedNut

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Re: SpaceX: Merlin 1D Updates thread
« Reply #455 on: 10/03/2012 11:58 AM »
...the lower regen part of the nozzle was tube-wall design...

I'm not sure about that. It seems that both Merlin C and D Vac are solely channel wall. Although the new MvacD extension has yet to be seen, assuming they are the same, there's no active cooling on the nozzle extentions, aside from the new GG exhaust injector.

edit: wrong picture, fixed.
« Last Edit: 10/03/2012 12:03 PM by corrodedNut »

Online meekGee

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Re: SpaceX: Merlin 1D Updates thread
« Reply #456 on: 10/03/2012 02:51 PM »
I could be wrong, been know to happen from time to time.

I don't think you're wrong this time. There's what appears (to me) to be insulation on the lower conduit. My guess is that this is done to prevent cooling of the flowing gasses, which would have created unrealistic test conditions.
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Offline cambrianera

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Re: SpaceX: Merlin 1D Updates thread
« Reply #457 on: 10/03/2012 07:21 PM »

If you look in the background you will see a flex below the turbo pump.  Notice the dark streaks in the exhaust.  Compare it to the F-1 and the only conclusion is the turbo pump exhaust is pumped into the nozzle.

I agree with you; for sure the manifold has sensors (thermocouples?) for something flowing inside.
Also it seems tapered from left of the image to the right.

I second also Ugordan's conclusions about roll control, considering that SpaceX has data from three flights to validate their models.

Offline ugordan

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Re: SpaceX: Merlin 1D Updates thread
« Reply #458 on: 10/03/2012 07:40 PM »
It seems that both Merlin C and D Vac are solely channel wall.

Hmm, you're probably right.

Offline iamlucky13

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Re: SpaceX: Merlin 1D Updates thread
« Reply #459 on: 10/03/2012 08:57 PM »

If you look in the background you will see a flex below the turbo pump.  Notice the dark streaks in the exhaust.  Compare it to the F-1 and the only conclusion is the turbo pump exhaust is pumped into the nozzle.

I agree with you; for sure the manifold has sensors (thermocouples?) for something flowing inside.
Also it seems tapered from left of the image to the right.

I second also Ugordan's conclusions about roll control, considering that SpaceX has data from three flights to validate their models.

I agree on the roll control...requirements could certainly be within the limits of a reasonable cold gas system.

I can't say the "only conclusion" however is that they're mixing the turbopump exhaust in the nozzle extension. That was the answer that jumped out at me most immediately when seeing the big ring and the darker exhaust but a couple things surprise me about this;

1.) The current nozzle extension is apparently fine just being radiatively cooled niobium.

2.) It's a relatively substantial difference between the vacuum and atmospheric configurations of the -1D.

3.) It doesn't taper around the circumference like the scrollcase manifold on the F-1, which isn't necessarily required, but would help distribute the exhaust evenly.

4.) I haven't previously heard any rumors about switching to cold gas roll control on the upper stage, except in connection with brand new engines like Raptor. On the other hand, I briefly forgot the 2nd stage already has a cold gas system, so it's not like it would be completely new...

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