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#240
by
Danderman
on 15 Aug, 2017 15:08
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#241
by
Danderman
on 15 Aug, 2017 15:10
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4 nozzles per tubo pump?
The RD-250 family engines in question have 2 nozzles and 1 turbo pump. Propellant is N2O4/UDMH
RD-250 (8D518), 3 form a RD-251 -> R-36 aka SS-18 Satan
RD-250PM, 3 form a RD-261 -> Tsyklon-2 and -3
Upper stage versions also have 2 nozzles and 1 turbo pump.
RD-252 (8D724) -> R-36 aka SS-18 Satan
RD-262 (11D26) -> Tsyklon-2 and -3
RD-253 as used on the Proton is not part of the discussion.
R-36 was SS-9, not SS-18. SS-18 does not use engines related to the SS-9 engine family (a/k/a RD-250).
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#242
by
Danderman
on 15 Aug, 2017 15:27
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Here's the original report.
http://www.iiss.org/en/iiss%20voices/blogsections/iiss-voices-2017-adeb/august-2b48/north-korea-icbm-success-3abb
I wonder how easy they will find it to cluster the RD-250s on the first stage and could it be used on the second stage as well?
Original RD-250 is 4 combustion chamber design with shared turbopumps et cetera, so all that I can see is them going to the original design as 1, 2, 3 chamber variant would be solely domestic in design and manufacture which require high quality craftsmanship which they do not have a good record of. It could that RD-250 is incorrect and that its another Soviet era engine.
The article indicates no other engine matches the description/images of that used?
This is all very shaky, since the original "RD-250" is a 2 chambered 90 ton engine, whereas HS-14 uses a single chamber engine that is much smaller. There are many former Soviet engines closer in size to the HS-14 than RD-250, perhaps not so politically correct. There are:
RD-0105 class, single chamber, 60 tons.
RD-120, single chamber 90 ton (but a good engine that could be de-scoped).
RD-0216, single chamber, 25 tons, but high ISP.
RD-0233, single chamber, 60 tons, fairly high ISP.
RD-0235, single chamber derivative of RD-0216, 10 percent more thrust.
Another possibility would be redirection of RD-216M technology from Omsk, where Cosmos launchers were manufactured until recently. It is possible the engines were manufactured there under license, as was the case in Dneprpetrovsk.
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#243
by
FutureSpaceTourist
on 15 Aug, 2017 15:37
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#244
by
Star One
on 15 Aug, 2017 15:49
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Why on Earth is he complaining about the NYT article rather than addressing his complaints towards the original report?
As they say don't shoot the messenger.
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#245
by
Danderman
on 15 Aug, 2017 15:55
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My understanding is that the engines for Cyclone (RD-250 class) were built by Yuzhmash under license from Energomash. I vaguely recall being told this during a lunch with the president of Yuzhmash. RD-171s for Zenit were still being bought from Energomash, but they made RD-120s, and their other engines, IIRC.
The NYT articles points to Yuzhmash as the source for the RD-250 by default, but AFAIK, these were also produced by Polyot in Omsk.
What is being forgotten is that Energomash is a design bureau with limited production facilities, so serial production for their engines, with the exception of RD-171, was usually conducted elsewhere.
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#246
by
Chasm
on 15 Aug, 2017 16:06
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4 nozzles per tubo pump?
The RD-250 family engines in question have 2 nozzles and 1 turbo pump. Propellant is N2O4/UDMH
RD-250 (8D518), 3 form a RD-251 -> R-36 aka SS-18 Satan
RD-250PM, 3 form a RD-261 -> Tsyklon-2 and -3
Upper stage versions also have 2 nozzles and 1 turbo pump.
RD-252 (8D724) -> R-36 aka SS-18 Satan
RD-262 (11D26) -> Tsyklon-2 and -3
RD-253 as used on the Proton is not part of the discussion.
R-36 was SS-9, not SS-18. SS-18 does not use engines related to the SS-9 engine family (a/k/a RD-250).
Ooops. Copy and paste is hard.
R-36 aka SS-9 Scarp
R-36
M aka SS-18 Satan
-----
I think that someone in NK took a hard look at the RD-215/RD-250 class/type/style engines, said "Works for me" and then went on to implement their own version.
How certain is the propellant identification? N2O4/UDMH vs. AK-27/UDMH
There are some ideas that the NK Scud-D / Scud-ER / Hwasong-7 introduced AK-27/UDMH over the usual AK-27/Kerosene. That would give NK much time to build experience with high energy propellants.
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#247
by
Star One
on 15 Aug, 2017 16:51
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How are NK paying for these engines with so many sanctions on them, surely by now these are having an impact even on the elite?
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#248
by
russianhalo117
on 15 Aug, 2017 17:05
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How are NK paying for these engines with so many sanctions on them, surely by now these are having an impact even on the elite?
natural resource trade with other countries. NK is the largest supplier of its coal to China and Russia which funds majority of NK's government operations. Other funding reserves are kept abroad in places like Switzerland and the Isle of Man. With the coal China doesn't have the means to produce steel and power industrial cities. As China builds more nuclear reactors and domestic energy to fuel its high demand, the need for NK coal drops and is being replaced with NK's developing metals trade.
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#249
by
Star One
on 15 Aug, 2017 17:37
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How are NK paying for these engines with so many sanctions on them, surely by now these are having an impact even on the elite?
natural resource trade with other countries. NK is the largest supplier of its coal to China and Russia which funds majority of NK's government operations. Other funding reserves are kept abroad in places like Switzerland and the Isle of Man. With the coal China doesn't have the means to produce steel and power industrial cities. As China builds more nuclear reactors and domestic energy to fuel its high demand, the need for NK coal drops and is being replaced with NK's developing metals trade.
Thanks. Said like that makes sanctions sound slightly futile.
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#250
by
Danderman
on 15 Aug, 2017 21:24
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Note that the Soviet Union required 4 RD-250 class engines to produce an IRBM, and 6 for their ICBM.
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#251
by
Steven Pietrobon
on 16 Aug, 2017 05:04
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KJU Inspects KPA Strategic Force The Movie
Only two rocket related images from that video.
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#252
by
K210
on 16 Aug, 2017 09:50
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https://documents-dds-ny.un.org/doc/UNDOC/GEN/N17/024/94/PDF/N1702494.pdf
Link seems to be broken.
http://www.un.org/ga/search/viewm_doc.asp?symbol=S/2017/150
This is the primary link, from which you can choose the document language.
This report seems to be making a lot of assumptions to back the point that the engine tested in september 2016 and march 2017 by NK is the RD-250. First of all i think the engine tested in march of this year and september of last year are different engines. One is probably for the first stage of a new SLV while the other is for ballistic missles as we have seen over the past few months.
The RD-250 is a closed cycle engine whereas both engines tested by north korea were clearly open cycle. Also it would not make a lot of sense for north korea to jump from gas ganerater engine straight to oxidiser rich staged combustion cycle engines as even countries with decades of experience with rocket engines like china often run into problems.
The report also points out how difficult it is to reverse engineer a rocket engine and end up with a engine identical to the original. However it is worth pointing out that this has been pulled off before. ISRO for example developed their first gen cryogenic engine CE-7.5 by reverse engineering the russian RD-56 engine. China i believe developed their early engines modeled after soviet designs.
What i think has happened is that NK at some point in time has come across blueprints for old soviet engines. They have probably taken the basic design and adapted it for their own needs much like a handful of other countries.
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#253
by
Star One
on 16 Aug, 2017 11:02
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https://documents-dds-ny.un.org/doc/UNDOC/GEN/N17/024/94/PDF/N1702494.pdf
Link seems to be broken.
http://www.un.org/ga/search/viewm_doc.asp?symbol=S/2017/150
This is the primary link, from which you can choose the document language.
This report seems to be making a lot of assumptions to back the point that the engine tested in september 2016 and march 2017 by NK is the RD-250. First of all i think the engine tested in march of this year and september of last year are different engines. One is probably for the first stage of a new SLV while the other is for ballistic missles as we have seen over the past few months.
The RD-250 is a closed cycle engine whereas both engines tested by north korea were clearly open cycle. Also it would not make a lot of sense for north korea to jump from gas ganerater engine straight to oxidiser rich staged combustion cycle engines as even countries with decades of experience with rocket engines like china often run into problems.
The report also points out how difficult it is to reverse engineer a rocket engine and end up with a engine identical to the original. However it is worth pointing out that this has been pulled off before. ISRO for example developed their first gen cryogenic engine CE-7.5 by reverse engineering the russian RD-56 engine. China i believe developed their early engines modeled after soviet designs.
What i think has happened is that NK at some point in time has come across blueprints for old soviet engines. They have probably taken the basic design and adapted it for their own needs much like a handful of other countries.
Kind of ignoring the advanced manufacturing and materials needed by just saying oh they knocked them up from some old blueprints they found lining around.
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#254
by
Kryten
on 16 Aug, 2017 11:18
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The RD-250 is a closed cycle engine whereas both engines tested by north korea were clearly open cycle. Also it would not make a lot of sense for north korea to jump from gas ganerater engine straight to oxidiser rich staged combustion cycle engines as even countries with decades of experience with rocket engines like china often run into problems.
There's consensus that NK have tested and flown the 4D10 ORSC engine, so they have at least some grasp of that technology already. Also, are you sure RD-250 is closed-cycle? Norbert Bruegge's site lists all engines in that family as GG.
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#255
by
WulfTheSaxon
on 16 Aug, 2017 17:36
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https://www.reuters.com/article/us-northkorea-missiles-intelligence-idUSKCN1AV2CKNorth Korea likely has the ability to produce its own missile engines and intelligence suggests it does not need to rely on imports, U.S. intelligence officials said on Tuesday.
The assessment disputes a new study by the London-based International Institute for Strategic Studies that said that the engines for a nuclear missile North Korea is developing to hit the United States likely were made in factories in Ukraine or Russia and probably obtained via black market networks.
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#256
by
Danderman
on 16 Aug, 2017 20:17
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The RD-250 is a closed cycle engine whereas both engines tested by north korea were clearly open cycle. Also it would not make a lot of sense for north korea to jump from gas ganerater engine straight to oxidiser rich staged combustion cycle engines as even countries with decades of experience with rocket engines like china often run into problems.
There's consensus that NK have tested and flown the 4D10 ORSC engine, so they have at least some grasp of that technology already. Also, are you sure RD-250 is closed-cycle? Norbert Bruegge's site lists all engines in that family as GG.
The RD-250 family are gas generator engines:
http://www.b14643.de/Spacerockets/Specials/R-16_missile_engine_derivative/index.htmRD-253 is closed cycle, but not related to RD-250.
Chris Bergan has posted the Yuzhnoye response here:
https://forum.nasaspaceflight.com/index.php?topic=43583.msg1713332#msg1713332
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#257
by
Danderman
on 16 Aug, 2017 20:20
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The report also points out how difficult it is to reverse engineer a rocket engine and end up with a engine identical to the original. However it is worth pointing out that this has been pulled off before. ISRO for example developed their first gen cryogenic engine CE-7.5 by reverse engineering the russian RD-56 engine. China i believe developed their early engines modeled after soviet designs.
When ISRO designed their cryogenic engine, they had working examples of LH2 engines and access to Russian engineers continually.
When China designed their initial rocket engines, they had working examples of Soviet engines and access to Soviet engineers.
When NK designs their engines, they probably don't have working examples, nor easy access to Russian engineers. For example, although they may have access to some Makayev engineers, they don't have access to Isayev engineers, and Isayev is the engine designer, not Makayev.
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#258
by
WulfTheSaxon
on 17 Aug, 2017 01:14
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#259
by
Danderman
on 17 Aug, 2017 01:54
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From the end user perspective (meaning those serving as potential targets of a NK ICBM), there isn't a lot of difference between a 40 ton RD-250 engine and a 4D10 that has been upgraded from 25 tons and 2 extra verniers installed.
