Author Topic: SpaceX: Merlin 1D thread  (Read 520757 times)

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 5305
  • Florida
  • Liked: 5005
  • Likes Given: 1444
SpaceX: Merlin 1D thread
« on: 08/09/2011 06:07 pm »
This tread is for the posting of new information on the Merlin 1D test article and production engine. Some discussion of the posted info is also welcome. The actual Merlin 1D production engine performance is the key to the SpaceX claims of the FH capabilities. If the 1D production engine falls too far below from the design specs, FH will not be able to perform as claimed.

Here is a summary of what we know and suspect so far:

EngineMerlin 1D (Design)Merlin 1D (Test article)Merlin 1D (Production)
SL Thrust140klbf??
Vac Thrust155klbf?(better than expected)?(expect even better)
SL isp280s??
Vac isp310s309s??
T/W160??
Chamber Pressure1420psi??
Expansion1616?16?(this shouldn’t vary much from design)
Throttle range70-100%70%-100%?70%-100%?
Engine weight 440kg???

As new information comes available an update of the table will be posted.
? – Unknown
[value]? – Possible value but unverified
[value] – Verified value
« Last Edit: 03/15/2013 08:57 pm by Chris Bergin »

Offline arnezami

  • Full Member
  • **
  • Posts: 285
  • Liked: 267
  • Likes Given: 378
Re: SpaceX: Merlin 1D Updates thread
« Reply #1 on: 08/09/2011 06:44 pm »
Good idea making this a separate thread.

One small correction: according to Tom Mueller (source: http://hobbyspace.com/nucleus/?itemid=31499 ) the chamber pressure is 1410 psi (not 1420).

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 5305
  • Florida
  • Liked: 5005
  • Likes Given: 1444
Re: SpaceX: Merlin 1D Updates thread
« Reply #2 on: 08/09/2011 07:27 pm »
Good idea making this a separate thread.

One small correction: according to Tom Mueller (source: http://hobbyspace.com/nucleus/?itemid=31499 ) the chamber pressure is 1410 psi (not 1420).

Thank you.

Corrected Design chamber pressure:

EngineMerlin 1D (Design)Merlin 1D (Test article)Merlin 1D (Production)
SL Thrust140klbf??
Vac Thrust155klbf?(better than expected)?(expect even better)
SL isp280s??
Vac isp310s309s??
T/W160??
Chamber Pressure1410psi??
Expansion1616?16?(this shouldn’t vary much from design)
Throttle range70-100%70%-100%?70%-100%?
Engine weight 440kg???

Offline baldusi

  • Senior Member
  • *****
  • Posts: 8356
  • Buenos Aires, Argentina
  • Liked: 2539
  • Likes Given: 8273
Re: SpaceX: Merlin 1D Updates thread
« Reply #3 on: 08/10/2011 01:38 am »
The SL of 280 was something that I said totally WAG. It's just adding the 5s of the 1D design over the 1C (design, not production) of 275s. The true 1C SL isp was 266s. So at least put it between brackets.

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 5305
  • Florida
  • Liked: 5005
  • Likes Given: 1444
Re: SpaceX: Merlin 1D Updates thread
« Reply #4 on: 08/10/2011 03:47 pm »
Ok so we don't have a Design to SL ISP just a reasonable guess:

EngineMerlin 1D (Design)Merlin 1D (Test article)Merlin 1D (Production)
SL Thrust140klbf??
Vac Thrust155klbf?(better than expected)?(expect even better)
SL isp280s???
Vac isp310s309s??
T/W160??
Chamber Pressure1410psi??
Expansion1616?16?(this shouldn’t vary much from design)
Throttle range70-100%70%-100%?70%-100%?
Engine weight 440kg???

When we look closely at the numbers we don't know much. The 280s SL value is resonable because we have SL Thrust, VAC Thrust, and VAC ISP from which SL ISP can be calculated.
« Last Edit: 08/10/2011 03:49 pm by oldAtlas_Eguy »

Offline Prober

  • Senior Member
  • *****
  • Posts: 10348
  • Save the spin....I'm keeping you honest!
  • Nevada
  • Liked: 721
  • Likes Given: 729
Re: SpaceX: Merlin 1D Updates thread
« Reply #5 on: 08/10/2011 08:11 pm »
My guesstimate is that your way off on the weight of the Merlin.  It should be closer to 1700-2000 pounds IMHO.
Sorry just had to do that


http://video.google.com/videoplay?docid=6461477885976703694&q=SpaceX+%28site%3Avideo.google.com+OR+site%3Ayoutube.com%29&hl=en-US


« Last Edit: 08/11/2011 01:13 am by Prober »
2017 - Everything Old is New Again.
"I fear all we have done is to awaken a sleeping giant..." --Isoroku Yamamoto

Offline baldusi

  • Senior Member
  • *****
  • Posts: 8356
  • Buenos Aires, Argentina
  • Liked: 2539
  • Likes Given: 8273
Re: SpaceX: Merlin 1D Updates thread
« Reply #6 on: 08/10/2011 08:28 pm »
My guesstimate is that your way off on the weight of the Merlin.  It should be closer to 1700-2000 pounds IMHO.
That say that it did 160:1 T/W. May be oldAtlas_Eguy should add that item to the list?

Offline jongoff

  • Recovering Rocket Plumber/Space Entrepreneur
  • Senior Member
  • *****
  • Posts: 6807
  • Lafayette/Broomfield, CO
  • Liked: 3987
  • Likes Given: 1684
Re: SpaceX: Merlin 1D Updates thread
« Reply #7 on: 08/10/2011 08:38 pm »
My guesstimate is that your way off on the weight of the Merlin.  It should be closer to 1700-2000 pounds IMHO.

Nope Prober, I'm pretty sure he's actually really close there.  Merlin 1D actually took a fair bit of weight out of the 1C, though they may have had to add some weight back in when they upped the thrust.  But yeah, I'm pretty sure they didn't double the weight.  :-)

~Jon

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 5305
  • Florida
  • Liked: 5005
  • Likes Given: 1444
Re: SpaceX: Merlin 1D Updates thread
« Reply #8 on: 08/10/2011 09:02 pm »
Since the weight value shown is a calculated value and was not a stated value attributed to Mueller but was calculated from two values that were stated it is listed as a reasonable value but unverified.

VAC Thrust / T/W  =  engine weight
155,000lbf / 160:1 = 968.75lb or 440kg

The one item of unknown here is it is not known whether the T/W is referencing SL or VAC. VAC being the worst case and one normally used so that was assumed.

Offline Prober

  • Senior Member
  • *****
  • Posts: 10348
  • Save the spin....I'm keeping you honest!
  • Nevada
  • Liked: 721
  • Likes Given: 729
Re: SpaceX: Merlin 1D Updates thread
« Reply #9 on: 08/10/2011 09:29 pm »
Since the weight value shown is a calculated value and was not a stated value attributed to Mueller but was calculated from two values that were stated it is listed as a reasonable value but unverified.

VAC Thrust / T/W  =  engine weight
155,000lbf / 160:1 = 968.75lb or 440kg

The one item of unknown here is it is not known whether the T/W is referencing SL or VAC. VAC being the worst case and one normally used so that was assumed.


The Fastrac engine was just shy of 2000lbs.  Sorry don't see that many published weight savings.
2017 - Everything Old is New Again.
"I fear all we have done is to awaken a sleeping giant..." --Isoroku Yamamoto

Offline baldusi

  • Senior Member
  • *****
  • Posts: 8356
  • Buenos Aires, Argentina
  • Liked: 2539
  • Likes Given: 8273
Re: SpaceX: Merlin 1D Updates thread
« Reply #10 on: 08/10/2011 09:54 pm »
Since the weight value shown is a calculated value and was not a stated value attributed to Mueller but was calculated from two values that were stated it is listed as a reasonable value but unverified.

VAC Thrust / T/W  =  engine weight
155,000lbf / 160:1 = 968.75lb or 440kg

The one item of unknown here is it is not known whether the T/W is referencing SL or VAC. VAC being the worst case and one normally used so that was assumed.


The Fastrac engine was just shy of 2000lbs.  Sorry don't see that many published weight savings.

Fastac
Thrust (v): 60klbf
isp (v): 315s
Weight: < 2000lb
T/W > 30:1


Merlin 1D
Thrust (v): 155klbf
isp (v): 310s
Weight: 970lb
T/W: 160:1

Not much improvement, eh? I would trade 1.6% isp for that T/W difference.
« Last Edit: 08/10/2011 09:56 pm by baldusi »

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 5305
  • Florida
  • Liked: 5005
  • Likes Given: 1444
Re: SpaceX: Merlin 1D Updates thread
« Reply #11 on: 08/11/2011 01:12 am »
Since the weight value shown is a calculated value and was not a stated value attributed to Mueller but was calculated from two values that were stated it is listed as a reasonable value but unverified.

VAC Thrust / T/W  =  engine weight
155,000lbf / 160:1 = 968.75lb or 440kg

The one item of unknown here is it is not known whether the T/W is referencing SL or VAC. VAC being the worst case and one normally used so that was assumed.


The Fastrac engine was just shy of 2000lbs.  Sorry don't see that many published weight savings.

Fastac
Thrust (v): 60klbf
isp (v): 315s
Weight: < 2000lb
T/W > 30:1


Merlin 1D
Thrust (v): 155klbf
isp (v): 310s
Weight: 970lb
T/W: 160:1

Not much improvement, eh? I would trade 1.6% isp for that T/W difference.

For full comparison

Merlin 1C
Thrust (v): 108klbf
isp (v): 304s
Weight: 1030lb
T/W: 105:1


Offline ArbitraryConstant

  • Senior Member
  • *****
  • Posts: 2014
  • Liked: 628
  • Likes Given: 311
Re: SpaceX: Merlin 1D Updates thread
« Reply #12 on: 08/11/2011 07:25 pm »
There is very little public information that I am aware of, but I'm curious about the performance we might expect of a MVac 1D.

My speculation is that the expansion nozzle probably can't grow that much, when the improved expansion ratio is the source of some of the 1D's improved ISP.

How much of the ISP improvement comes from the higher chamber pressure versus greater expansion?

Offline mlorrey

  • Member
  • Senior Member
  • *****
  • Posts: 2173
  • International Spaceflight Museum
  • Grantham, NH
  • Liked: 23
  • Likes Given: 5
Re: SpaceX: Merlin 1D Updates thread
« Reply #13 on: 08/12/2011 02:19 am »
This in an avleak article:
http://www.aviationweek.com/aw/generic/story.jsp?id=news/awst/2011/08/08/AW_08_08_2011_p27-354586.xml&headline=SpaceX%20Plans%20To%20Be%20Top%20World%20Rocket%20Maker&channel=defense
Quote
Revealing several new details of the 1D, Tom Mueller, propulsion engineering vice president, says the engine is designed to produce 155,000 lb. vacuum thrust and have a chamber pressure at “the sweet spot” of roughly 1,410 psia. “We’ve also increased the nozzle expansion ratio to 16 [compared with 14.5 on the Merlin 1C],” says Mueller, who adds that the initial engine “is doing better than we hoped.” The engine is designed for an Isp (specific impulse) of 310 sec. and has a thrust-to-weight ratio of 160:1. “We took structure off the engine to make it lighter. The engine we shipped [for test] to Texas was a development engine and hopefully the production engines will be even better,” he says.

The 1D design incorporates many lessons learned from the earlier Merlins and is of a simpler design with an increased fatigue life. “We’ve added the ability to throttle between 70% and 100%. Currently we have to shut off two engines during ascent, and on this we will be able to throttle them all,” he says. The development will also provide the basis for a 1D-Vac version intended for the second stage of the planned Falcon Heavy. “There are no plans to build a 1E. It’s going to be a 1D with the same turbopump.”
VP of International Spaceflight Museum - http://ismuseum.org
Founder, Lorrey Aerospace, B&T Holdings, ACE Exchange, and Hypersonic Systems. Currently I am a venture recruiter for Family Office Venture Capital.

Offline ArbitraryConstant

  • Senior Member
  • *****
  • Posts: 2014
  • Liked: 628
  • Likes Given: 311
Re: SpaceX: Merlin 1D Updates thread
« Reply #14 on: 08/12/2011 03:10 am »
This in an avleak article:
http://www.aviationweek.com/aw/generic/story.jsp?id=news/awst/2011/08/08/AW_08_08_2011_p27-354586.xml&headline=SpaceX%20Plans%20To%20Be%20Top%20World%20Rocket%20Maker&channel=defense
Quote
Revealing several new details of the 1D, Tom Mueller, propulsion engineering vice president, says the engine is designed to produce 155,000 lb. vacuum thrust and have a chamber pressure at “the sweet spot” of roughly 1,410 psia. “We’ve also increased the nozzle expansion ratio to 16 [compared with 14.5 on the Merlin 1C],” says Mueller, who adds that the initial engine “is doing better than we hoped.” The engine is designed for an Isp (specific impulse) of 310 sec. and has a thrust-to-weight ratio of 160:1. “We took structure off the engine to make it lighter. The engine we shipped [for test] to Texas was a development engine and hopefully the production engines will be even better,” he says.

The 1D design incorporates many lessons learned from the earlier Merlins and is of a simpler design with an increased fatigue life. “We’ve added the ability to throttle between 70% and 100%. Currently we have to shut off two engines during ascent, and on this we will be able to throttle them all,” he says. The development will also provide the basis for a 1D-Vac version intended for the second stage of the planned Falcon Heavy. “There are no plans to build a 1E. It’s going to be a 1D with the same turbopump.”
Hm... that article leans towards the position that the new engine is LH2.

Maybe it was just on the back burner until the design for Merlin 1D was finalized?
« Last Edit: 08/12/2011 03:11 am by ArbitraryConstant »

Offline krytek

  • Full Member
  • ****
  • Posts: 535
  • Liked: 2
  • Likes Given: 0
Re: SpaceX: Merlin 1D Updates thread
« Reply #15 on: 08/12/2011 07:05 am »
Gwynne said SpaceX will make 100 engines total in 2011.
I'm quite at a loss here, considering the COTS-2 mission will consume only 10 engines, what will they do with the remaining 90 units? They're producing almost an order of magnitude more engines than they are consuming.

So that leads to a big question, has there been any indication Spacex is planning to sell rocket engines to any other entities?

Offline Confusador

  • Full Member
  • **
  • Posts: 294
  • Liked: 191
  • Likes Given: 381
Re: SpaceX: Merlin 1D Updates thread
« Reply #16 on: 08/12/2011 07:22 am »
Gwynne said SpaceX will make 100 engines total in 2011.
I'm quite at a loss here, considering the COTS-2 mission will consume only 10 engines, what will they do with the remaining 90 units? They're producing almost an order of magnitude more engines than they are consuming.

So that leads to a big question, has there been any indication Spacex is planning to sell rocket engines to any other entities?

I'd want more context for that to know what she meant.  If she's counting Dracos, then each Dragon mission uses 28.  Assuming they built the engines for a couple of those, plus the MDA flight (that's still on the books, right?), plus some 1D and Super Draco development engines... 100 sounds pretty reasonable.
« Last Edit: 08/12/2011 07:23 am by Confusador »

Offline Pedantic Twit

  • Full Member
  • *
  • Posts: 102
  • Liked: 7
  • Likes Given: 0
Re: SpaceX: Merlin 1D Updates thread
« Reply #17 on: 08/12/2011 07:47 am »
I'd want more context for that to know what she meant.  If she's counting Dracos, then each Dragon mission uses 28.

The Falcon 9 User's Guide also includes 4 Dracos on the 2nd stage, making the total 32 for every Falcon 9 + Dragon flight.

Offline MikeAtkinson

  • Full Member
  • ****
  • Posts: 1980
  • Bracknell, England
  • Liked: 784
  • Likes Given: 120
Re: SpaceX: Merlin 1D Updates thread
« Reply #18 on: 08/12/2011 08:54 am »
There is very little public information that I am aware of, but I'm curious about the performance we might expect of a MVac 1D.

My speculation is that the expansion nozzle probably can't grow that much, when the improved expansion ratio is the source of some of the 1D's improved ISP.

How much of the ISP improvement comes from the higher chamber pressure versus greater expansion?

The increase in MVac 1D will all come from increased expansion ratio (to a first approximation). As the exit area probably won't increase, the throat will be decreased. Merlin 1D increased expansion from 14.5 to 16, again probably by a reduction in throat area.

Higher chamber pressure allows more mass to be squeezed through the throat (hence increasing the thrust), a smaller throat area decreases the mass (hence decreasing the thrust). So for an upper stage engine it is a balancing act between thrust and Isp. Usually Isp is more important, but increasing the area ratio quickly provided diminishing returns.

The optimum is probably different for MVac 1D than the old MVac. It is impossible with the information at hand to compute exactly what that optimum will be.

Offline ChefPat

  • Full Member
  • ****
  • Posts: 1055
  • Earth, for now
  • Liked: 125
  • Likes Given: 1022
Re: SpaceX: Merlin 1D Updates thread
« Reply #19 on: 08/12/2011 12:27 pm »
Gwynne said SpaceX will make 100 engines total in 2011.
I'm quite at a loss here, considering the COTS-2 mission will consume only 10 engines, what will they do with the remaining 90 units? They're producing almost an order of magnitude more engines than they are consuming.

So that leads to a big question, has there been any indication Spacex is planning to sell rocket engines to any other entities?
Maybe they're just ramping up for their ambitious Launch Manifest?
Playing Politics with Commercial Crew is Un-American!!!

Tags:
 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1