August 17, 2017 -- Now this should be said to the partly nonsensical statements in the media about the North Korean engine:

• The engine is undoubtedly an Energomash RD-250 (type of turbopump is the best proof; position of the TP is typical of this Glushko engines serie, outline and dimensions of the combustor are identical; thrust is comparable: vac 2 x 41 t. Both are engines with open gas generator cycle. Who wants to know something about the engine, look here: R-16 missile engine derivative
• We now also have a detail from the TP that can be seen in a North Korean video. That should be the proof that they build the engine itself.
• Meanwhile Ukraine's state space agency has cofirmed my analysis from Sept. 2016 that the rocket engine used to launch North Korea's most recent intercontinental ballistic missile is the same as the type of engine used by Ukraine-made space vehicles (UPI Aug. 16).
• The engine was not acquired recently by North Korea, probably already illegal in the time of the disintegrating Soviet Union. Many depots and museums were unattended. I believe that in this period North Korea has illegal acquired many Soviet rocket technology (old SLBM's and LLBM's).
• So the Ukrainian government or Pivdenmash (Yushmash) were not involved in the RD-250 transfer and are thus falsely accused.
•  The tested engine (one combustor) is specially made for the HS-12 and HS-14. The turbopump operates in the throttle mode (possibly reducing the rotation).
• North Korea will no longer operate the project HS-10 and HS-13 after failures with the SLBM engine 4D10. Probably in 2014, they have decided to use the stored RD-250 clone for new military missiles. However, they have used a lot of time for cloning, I believe this without any other help.
• After the launch tower has been extended considerably on the Sohae Launch Center, it is to be assumed that the complete engine is planned for a new larger carrier rocket, which we will soon see. Three twin-combustors of this engine are probably needed for this carrier rocket.