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#40
by
Downix
on 15 Apr, 2011 17:21
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These increases are scary.
IMO unless a cheaper replacement is found this ends ACES.
$90 million extra for about 6,000 kg to LEO not happening.
This also makes the J-2X for ACES a possibility unless it suffers similar increases.
Also I just ran across a $3 million dollar replacement engine.
http://www.parabolicarc.com/2011/04/12/darma-initiative-affordable-upper-stage-rocket-engine/
THey don't list the isp at all, so it may not compare at all. The issue is, as both I and Ed keep pointing out, is lack of volume. We simply don't make enough engines to keep the price down. Projects like ACES would improve that.
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#41
by
pummuf
on 15 Apr, 2011 17:28
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... The issue is, as both I and Ed keep pointing out, is lack of volume. We simply don't make enough engines to keep the price down ...
I bet a competitor could, without the overhead and constraints of an existing design. PWR might want to start thinking like that potential competitor.
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#42
by
Downix
on 15 Apr, 2011 17:34
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... The issue is, as both I and Ed keep pointing out, is lack of volume. We simply don't make enough engines to keep the price down ...
I bet a competitor could, without the overhead and constraints of an existing design. PWR might want to start thinking like that potential competitor.
In theory, yes, if a competitor wished to invest the estimated $2 billion to develop a comparable engine for a production volume of 10/year. Investors would demand that they get repaid within 5 years, so, ($2 billion/5 years)/10 per year would mean that on top of the actual production cost, you would have to add $40 million.
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#43
by
Robotbeat
on 15 Apr, 2011 17:38
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Here is how to understand the situation.
In 1998, for example, a total of 60-62 rocket engine chamber flights were made by engines manufactured by Rocketdyne or Pratt & Whitney. They flew on five different launch vehicle systems.
In 2010, a total of only 20 rocket engine chamber flights were made by PWR engines. They flew on four launch vehicle types.
By 2013 or so, only about 12 PWR engines will fly annually on only two launch vehicle types.
This isn't just about Shuttle.
- Ed Kyle
(thanks, Ed. Good post.)
...and...
To build a theory about this one might investigate the facilities where each engine is produced, and see if SSME and RL10 have some shared overhead costs not borne by e.g. RS-68.
I would think the far safer assumption is that SSME and RS-68 have shared overhead costs (not SSME and RL-10). [...] Please correct me if you have evidence (or personal experience) that I'm wrong.
I have no affirmative proof to offer you, just two carefully couched questions: (1) Is there any evidence that any RS-68 has ever been built anywhere other than the Stennis Engine Assembly Facility, which is reportedly "capable of producing as many as 40 RS-68 engines per year?" (2) Is there any evidence that any SSME has ever been built anywhere other than Canoga Park, California?
My personal assumptions are quite obviously embedded in those questions! 
That PWR have two places where they manufacture only a handful of engines a year makes me think that PWR are thinking hard
right now about how they can consolidate to one site.
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#44
by
pummuf
on 15 Apr, 2011 17:39
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... The issue is, as both I and Ed keep pointing out, is lack of volume. We simply don't make enough engines to keep the price down ...
I bet a competitor could, without the overhead and constraints of an existing design. PWR might want to start thinking like that potential competitor.
In theory, yes, if a competitor wished to invest the estimated $2 billion to develop a comparable engine for a production volume of 10/year. Investors would demand that they get repaid within 5 years, so, ($2 billion/5 years)/10 per year would mean that on top of the actual production cost, you would have to add $40 million.
How about an existing engine, like the two mentioned in this thread.
How about an engine with lower performance that costs a fraction of the amount? How about another launch provider that's already doing this?
One thing I've realized about the US space industry is that we are willing to spend enormous amounts of money for tiny increases in isp. We will spend enormous amounts time and money optimizing a design - so much time and money that the development costs start to dwarf the manufacturing costs - When there isn't necessarily a case to do so (unless that case is to provide jobs).
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#45
by
pummuf
on 15 Apr, 2011 17:41
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That PWR have two places where they manufacture only a handful of engines a year makes me think that PWR are thinking hard right now about how they can consolidate to one site.
for how many years has PWR known that the Shuttle was retiring?
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#46
by
Downix
on 15 Apr, 2011 17:42
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... The issue is, as both I and Ed keep pointing out, is lack of volume. We simply don't make enough engines to keep the price down ...
I bet a competitor could, without the overhead and constraints of an existing design. PWR might want to start thinking like that potential competitor.
In theory, yes, if a competitor wished to invest the estimated $2 billion to develop a comparable engine for a production volume of 10/year. Investors would demand that they get repaid within 5 years, so, ($2 billion/5 years)/10 per year would mean that on top of the actual production cost, you would have to add $40 million.
How about an existing engine, like the two mentioned in this thread.
How about an engine with lower performance that costs a fraction of the amount? How about another launch provider that's already doing this?
One thing I've realized about the US space industry is that we are willing to spend enormous amounts of money for tiny increases in isp. We will spend enormous amounts time and money optimizing a design - so much time and money that the development costs start to dwarf the manufacturing costs - When there isn't necessarily a case to do so (unless that case is to provide jobs).
You said a competitor. Those engines are not competitors, they don't have the isp to match the RL-10. Even the close Russian engine PWR sells does not match the RL-10. To use those you would require more fuel, and reduce your payload. PWR is really in a situation where to compete, you must develop, but the act of developing will make you uncompetitive.
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#47
by
Downix
on 15 Apr, 2011 17:42
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That PWR have two places where they manufacture only a handful of engines a year makes me think that PWR are thinking hard right now about how they can consolidate to one site.
for how many years has PWR known that the Shuttle was retiring?
Enough to get it down to two. They used to have more.
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#48
by
Lurker Steve
on 15 Apr, 2011 17:46
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How many engines does PWR have in development right now ?
The majority of the J-2X work is funded by NASA.
Do they have anything else going on ?
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#49
by
Downix
on 15 Apr, 2011 17:49
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How many engines does PWR have in development right now ?
The majority of the J-2X work is funded by NASA.
Do they have anything else going on ?
NGE for the USAF, RS-68A for ULA.
And that's about it.
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#50
by
edkyle99
on 15 Apr, 2011 17:52
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How many engines does PWR have in development right now ?
This is a key point. During the 1990s, rather than compete and innovate, Rocketdyne withdrew from the Atlas IIAR competition to build the engine that ultimately would power today's Atlas V.
A few years ago, Orbital decided to develop a new rocket. There was no U.S. propulsion competitor able to offer a first stage engine. Subsequently, Orbital decided to buy a liquid upper stage for that new rocket. Ditto on the U.S. propulsion offerings.
These two rockets are going to account for a big percentage of total U.S. launches in coming years. That is market share, and technological prowess, ceded, without a fight, by U.S. propulsion companies.
- Ed Kyle
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#51
by
Jim
on 15 Apr, 2011 18:16
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This is a key point. During the 1990s, rather than compete and innovate, Rocketdyne withdrew from the Atlas IIAR competition to build the engine that ultimately would power today's Atlas V.
That was because they didn't think they could handle RS-68 and Altas IIAR development at the same time.
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#52
by
Bernie Roehl
on 15 Apr, 2011 18:22
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These two rockets are going to account for a big percentage of total U.S. launches in coming years.
- Ed Kyle
Perhaps. Perhaps not.
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#53
by
mrryndrsn
on 15 Apr, 2011 18:29
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... The issue is, as both I and Ed keep pointing out, is lack of volume. We simply don't make enough engines to keep the price down ...
I bet a competitor could, without the overhead and constraints of an existing design. PWR might want to start thinking like that potential competitor.
In theory, yes, if a competitor wished to invest the estimated $2 billion to develop a comparable engine for a production volume of 10/year. Investors would demand that they get repaid within 5 years, so, ($2 billion/5 years)/10 per year would mean that on top of the actual production cost, you would have to add $40 million.
How about an existing engine, like the two mentioned in this thread.
How about an engine with lower performance that costs a fraction of the amount? How about another launch provider that's already doing this?
One thing I've realized about the US space industry is that we are willing to spend enormous amounts of money for tiny increases in isp. We will spend enormous amounts time and money optimizing a design - so much time and money that the development costs start to dwarf the manufacturing costs - When there isn't necessarily a case to do so (unless that case is to provide jobs).
You said a competitor. Those engines are not competitors, they don't have the isp to match the RL-10. Even the close Russian engine PWR sells does not match the RL-10. To use those you would require more fuel, and reduce your payload. PWR is really in a situation where to compete, you must develop, but the act of developing will make you uncompetitive.
The rd-0146 does indeed match the performance of the rl-10 used on Atlas, in terms of thrust and Isp. It's heavier, but the mixture ratio is better (6:1). At least that's what it says on the P&W web site (
http://www.pratt-whitney.com/StaticFiles/Pratt%20&%20Whitney%20New/Media%20Center/Assets/1%20Static%20Files/Docs/pwr_RD-0146.pdf).
Murray Anderson
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#54
by
jimgagnon
on 15 Apr, 2011 18:32
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Wonder if Pratt and Whitney would be interested in selling RocketDyne? As their engine production volume is declining, instead of milking RocketDyne for all its worth perhaps they would be interested in selling to one of their customers. ULA?
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#55
by
Jim
on 15 Apr, 2011 18:35
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These two rockets are going to account for a big percentage of total U.S. launches in coming years.
- Ed Kyle
Perhaps. Perhaps not.
They will, the "Perhaps. Perhaps not" is applicable to Spacex.
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#56
by
Jim
on 15 Apr, 2011 18:36
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The rd-0146 does indeed match the performance of the rl-10 used on Atlas, in terms of thrust and Isp. It's heavier, but the mixture ratio is better (6:1).
There is no "better" when it comes to mixture ratio.
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#57
by
Robotbeat
on 15 Apr, 2011 18:43
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The rd-0146 does indeed match the performance of the rl-10 used on Atlas, in terms of thrust and Isp. It's heavier, but the mixture ratio is better (6:1).
There is no "better" when it comes to mixture ratio.
If it has the same Isp but more oxygen (i.e. a little closer to stoic), you get a greater bulk density and lower tank mass. I don't know if that's the case for the engine in question, but that's what a "better" mixture ratio would be.
EDIT: A hydrolox engine with the same Isp but a (O:F mass) mixture ratio of 6:1 would have lower tank mass than a hydrolox engine with a 5.85:1 ratio (which is what some say the RL-10B2 has, though I don't have a good source). Assuming the inlet pressures are the same.
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#58
by
Downix
on 15 Apr, 2011 18:58
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#59
by
Robotbeat
on 15 Apr, 2011 19:14
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The rd-0146 does indeed match the performance of the rl-10 used on Atlas, in terms of thrust and Isp. It's heavier, but the mixture ratio is better (6:1).
There is no "better" when it comes to mixture ratio.
If it has the same Isp but more oxygen (i.e. a little closer to stoic), you get a greater bulk density and lower tank mass. I don't know if that's the case for the engine in question, but that's what a "better" mixture ratio would be.
EDIT: A hydrolox engine with the same Isp but a (O:F mass) mixture ratio of 6:1 would have lower tank mass than a hydrolox engine with a 5.85:1 ratio (which is what some say the RL-10B2 has, though I don't have a good source). Assuming the inlet pressures are the same.
No, it does not have the same isp. It has the same isp as one model of the RL-10, but that model is not the only one.
Check it here:
http://www.pratt-whitney.com/StaticFiles/Pratt%20&%20Whitney%20New/Media%20Center/Assets/1%20Static%20Files/Docs/pwr_RD-0146.pdf
isp 451
Compare to the RL-10 in the Delta IV:
http://www.pw.utc.com/StaticFiles/Pratt%20&%20Whitney%20New/Products/Pratt%20&%20Whitney%20Rocketdyne/1%20Static%20Files/pwr_rl10b-2.pdf
isp 465
Again,
I never claimed it had the same Isp, but you do realize the 465s is for the RL-10B2, which has the extensible nozzle extension and which I believe are being converted to the fixed nozzle version with less Isp (as used on the Atlas V), so the demand may be for an engine with ~451s Isp.
