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RD-250

{{short description|Rocket engine}}

{{Infobox rocket engine

|name =RD-250 (РД-250)

|image =Rd-250.svg

|image_size =

|caption =

|country_of_origin=USSR

|date =

|first_date = December 16th, 1965

|last_date =

|designer =OKB-456

|manufacturer =PA Yuzhmash

|purpose =

|associated =R-36, Tsyklon-2 and Tsyklon-3

|predecessor =

|successor =

|status =Out of Production

|type =liquid

|oxidiser =N2O4

|fuel =UDMH

|mixture_ratio =2.6

|cycle=Gas-generator

|pumps =

|description =

|combustion_chamber=2

|nozzle_ratio =

|thrust =

|thrust_at_altitude=

|thrust(Vac) ={{convert|882|kN|lbf|abbr=on}}

|thrust(SL) ={{convert|788|kN|lbf|abbr=on}}

|throttle_range =

|thrust_to_weight=

|chamber_pressure={{convert|8.33|MPa|psi|abbr=on}}

|specific_impulse=

|specific_impulse_vacuum={{convert|301|isp|abbr=on}}

|specific_impulse_sea_level={{convert|270|isp|abbr=on}}

|total_impulse =

|burn_time =

|restarts =

|gimbal =

|capacity =

|dimensions =

|length =

|diameter =

|dry_weight ={{convert|788|kg|abbr=on}}

|used_in =R-36, Tsyklon-2 and Tsyklon-3 first stage

|references =

|notes =

}}

File:RD-250 rocket engine.jpg

The RD-250 ({{Langx|ru|Ракетный Двигатель-250|Raketnyy Dvigatel-250|Rocket Engine 250}}, GRAU index: 8D518) is the base version of a dual-nozzle family of liquid-fuel rocket engines, burning a hypergolic mixture of unsymmetrical dimethylhydrazine (UDMH) fuel with dinitrogen tetroxide ({{N2O4}}) oxidizer in a gas-generator open cycle.{{Cite web|url=https://www.russianspaceweb.com/rd250.html|title=The RD-250 engine at the center of an international storm|website=www.russianspaceweb.com|language=en|access-date=2023-01-03}} The RD-250 was developed by OKB-456 for Yangel's PA Yuzhmash ICBM, the R-36 (8K67). Its variations were also used on the Tsyklon-2 and Tsyklon-3 launch vehicles. It was supposed to be used on the Tsyklon-4, but since the cancellation of the project it should be considered as out of production.

Versions

The engine has seen different versions made:

  • RD-250 (GRAU index: 8D518): Base engine of the family. Used on the R-36. A bundle of three RD-250 form the RD-251 cluster.
  • RD-250P (GRAU index: 8D518P): Improved version of the RD-250. Used on the R-36P. A bundle of three RD-250P form the RD-251P cluster.
  • RD-250M (GRAU index: 8D518M): Improved version of the RD-250P. Used on the R-36-O. A bundle of three RD-250M form the RD-251M cluster.
  • RD-250PM (GRAU index: 8D518PM): Improved version of the RD-250M. Used on the Tsyklon-3. A bundle of three RD-250PM form the RD-261 cluster.
  • RD-252 (GRAU index: 8D724): Vacuum optimized version of the RD-250. Used on the R-36 and Tsyklon-2 second stages.
  • RD-262 (GRAU index: 11D26): Improved version of the RD-252. Used on the Tsyklon-3 second stages.

Modules

Some of these engines were bundled into modules of multiple engines. The relevant modules and auxiliary engines are:

  • RD-251 (GRAU index: 8D723): A module comprising three RD-250. Propulsion module of the R-36 (8K67) first stage.
  • RD-251P (GRAU index: 8D723P): A module comprising three RD-250P. Propulsion module of the R-36P (8K68) first stage.
  • RD-251M (GRAU index: 8D723M): A module comprising three RD-250M. Propulsion module of the R-36-O (8K69) and Tsyklon-2 first stage.
  • RD-261 (GRAU index: 11D69): A module comprising three RD-250PM. Propulsion module of the Tsyklon-3 first stage.

Comparison

class="wikitable" style=""

|+ RD-250 Family of Engines

Engine

! RD-250

! RD-250P

! RD-250M

! RD-250PM

! RD-252

! RD-262

GRAU

| 8D518 || 8D518P || 8D518M || 8D518PM || 8D724 || 11D26

Module

| RD-251 || RD-251P || RD-251M || RD-261 || N/A || N/A

Module GRAU

| 8D723 || 8D723P || 8D723M || 11D69 || N/A || N/A

Development

| 1962-1966 || 1967-1968 || 1966-1968 || 1968-1970 || 1962-1966 || 1968-1970

Propellant

| colspan="6" style="text-align: center;"| N2O4/UDMH

Combustion chamber pressure

| colspan="4" style="text-align: center;"| {{convert|8.336|MPa|psi|abbr=on}}

|colspan="2" style="text-align: center;"|{{convert|8.924|MPa|psi|abbr=on}}

Thrust, vacuum

| {{convert|881.6|kN|lbf|abbr=on}} || {{convert|881.6|kN|lbf|abbr=on}} || {{convert|881.6|kN|lbf|abbr=on}} || {{convert|881.7|kN|lbf|abbr=on}} || {{convert|940.8|kN|lbf|abbr=on}} || {{convert|941.4|kN|lbf|abbr=on}}

Thrust, sea level

| {{convert|788.5|kN|lbf|abbr=on}} || {{convert|788.5|kN|lbf|abbr=on}} || {{convert|788.5|kN|lbf|abbr=on}} || {{convert|788.7|kN|lbf|abbr=on}} || N/A || N/A

I{{sub|sp}}, vacuum

| {{convert|301|isp|abbr=on}} || {{convert|301|isp|abbr=on}} || {{convert|301|isp|abbr=on}} || {{convert|301.4|isp|abbr=on}} || {{convert|317.6|isp|abbr=on}} || {{convert|318|isp|abbr=on}}

I{{sub|sp}}, sea level

| {{convert|270|isp|abbr=on}} || {{convert|270|isp|abbr=on}} || {{convert|270|isp|abbr=on}} || {{convert|269.6|isp|abbr=on}} || N/A || N/A

Length

| {{convert|2600|mm|in|abbr=on}} || {{convert|2600|mm|in|abbr=on}} || {{convert|2600|mm|in|abbr=on}} || N/A || {{convert|2190|mm|in|abbr=on}} || {{convert|2190|mm|in|abbr=on}}

Diameter

| {{convert|1000|mm|in|abbr=on}} || {{convert|1000|mm|in|abbr=on}} || {{convert|1000|mm|in|abbr=on}} || N/A || {{convert|2590|mm|in|abbr=on}} || {{convert|2590|mm|in|abbr=on}}

Dry weight

| {{convert|728|kg|lb|abbr=on}} || {{convert|728|kg|lb|abbr=on}} || {{convert|728|kg|lb|abbr=on}} || N/A || {{convert|715|kg|lb|abbr=on}} || {{convert|715|kg|lb|abbr=on}}

Use

| R-36 (8K67) 1st stage || R-36P (8K67P) 1st stage || R-36-O (8K67-O)
and Tsyklon-2 1st stage || Tsyklon-3 1st stage || R-36, R36P, R-36-O,
Tsyklon-2 2nd stage || Tsyklon-3 2nd stage

Possible technological transfer to North Korea

Several experts think that technology from the RD-250 engine could have been transferred to North Korea from Russia. This transfer would explain the rapid progress of North Korea in the development of two new missiles: the intermediate-range Hwasong-12 and the intercontinental ballistic missile (ICBM), Hwasong-14. Due to complexity of the technology involved in this type of engine, modifications or reverse engineering seem difficult to achieve. Thus it is believable that complete hardware could have been bought on black market and directly shipped to North Korea, by Russia or Ukraine.{{Cite web|url=http://www.iiss.org/en/iiss%20voices/blogsections/iiss-voices-2017-adeb/august-2b48/north-korea-icbm-success-3abb|title=The secret to North Korea’s ICBM success|website=www.iiss.org|language=en|access-date=2017-08-15}} Conversely, there is analysis[http://www.atlanticcouncil.org/blogs/ukrainealert/north-korean-missile-engines-not-from-ukraine North Korean Missile Engines: Not from Ukraine], Mariana Budjeryn & Andrew Zhalko-Tytarenko, Atlantic Council, 2017-09-12 (made by two Ukrainian authors) suggesting an alternative mechanism for North Korea to receive R-36 missile engines, or an entire missile, from USSR or Russia.

See also

{{Portal | Space}}

References

{{reflist|30em|refs=

{{cite web |url=http://www.astronautix.com/engines/rd250.htm |archive-url=https://web.archive.org/web/20020826013159/http://astronautix.com/engines/rd250.htm |url-status=dead |archive-date=August 26, 2002 |title=RD-250 |website=Encyclopedia Astronautica |access-date=2015-06-20}}

{{cite web |url=http://www.astronautix.com/engines/rd251.htm |archive-url=https://web.archive.org/web/20020626222322/http://www.astronautix.com/engines/rd251.htm |url-status=dead |archive-date=June 26, 2002 |title=RD-251 |website=Encyclopedia Astronautica |access-date=2015-06-20}}

{{cite web |url=http://www.astronautix.com/engines/rd252.htm |archive-url=https://web.archive.org/web/20020531043521/http://www.astronautix.com/engines/rd252.htm |url-status=dead |archive-date=May 31, 2002 |title=RD-252 |website=Encyclopedia Astronautica |access-date=2015-06-20}}

{{cite web |url=http://www.astronautix.com/engines/rd261.htm |archive-url=https://web.archive.org/web/20020627063538/http://www.astronautix.com/engines/rd261.htm |url-status=dead |archive-date=June 27, 2002 |title=RD-261 |website=Encyclopedia Astronautica |access-date=2015-06-20}}

{{cite web |url=http://www.astronautix.com/engines/rd262.htm |archive-url=https://web.archive.org/web/20021028223251/http://astronautix.com/engines/rd262.htm |url-status=dead |archive-date=October 28, 2002 |title=RD-262 |website=Encyclopedia Astronautica |access-date=2015-06-20}}

{{cite web |url=http://www.kosmonavtika.com/lanceurs/tsiklone/tech/2.html |title=Tsiklone - Le premier étage |trans-title=Tsyklon - The first stage |first=Nicolas |last=Pillet |publisher=Kosmonavtika.com |language=fr |access-date=2016-07-04}}

{{cite web |url=http://www.kosmonavtika.com/lanceurs/tsiklone/tech/3.html |title=Tsiklone - Le deuxième étage |trans-title=Tsyklon - The second stage |first=Nicolas |last=Pillet |publisher=Kosmonavtika.com |language=fr |access-date=2016-07-04}}

{{cite web |url=http://www.npoenergomash.ru/netcat_files/File/Table_of_Engines.docx |title=NPO Energomash list of engines |publisher=NPO Energomash

|url-status=dead |archive-url=https://web.archive.org/web/20141107202512/http://www.npoenergomash.ru/netcat_files/File/Table_of_Engines.docx |archive-date=7 November 2014}}

}}

External links

  • [http://www.yuzhmash.com/production/index/rengines?id=24 Yuzhmash official information on the RD-261.]
  • [https://web.archive.org/web/20020826013159/http://astronautix.com/engines/rd250.htm Encyclopedia Astronautica information on RD-250 base engine.]

{{Rocket engines}}

Category:Rocket engines of the Soviet Union

Category:Rocket engines using hypergolic propellant

Category:Rocket engines using the gas-generator cycle

Category:Energomash rocket engines

Category:Yuzhmash rocket engines