The NK-33 engines were originally built for the Soviet Moon Rocket, the N-1. (Under the designation of NK-15, and NK-15V for the high altitude version). This design was a direct result of a blazing row between the Chief Designer, (Sergey Korolev), and the best rocket engine designer, Valentin Glushko. Glushko wanted to use propellants which Korolov considered far too dangerous. So Korolev turned to Nikolai Kuznetsov, who up until that point had only designed engines for jet aircraft. Large rocket engines are notoriously difficult to design, due to combustion instability, so they were pretty much forced into a large number of smaller engines.
Many consider this a key reason for the failure of the N-1 program.
During the development of the N-1 the engines were not restartable, which made it almost impossible to test them properly before using them. With no less than 30 of them on the first stage, the odds of one failing were fairly high, so the plan was to use a system called KORD to shut down the opposite engine if one stopped working, thus preserving the symmetry of the thrust.
By the end of the program though, they were extremely good, and achieved a remarkable level of thrust to weight, (plus they were restartable). The engines are still being deployed today, being used for an upgraded Soyuz core stage, (Soyuz 2-1-V), and also to drive US rockets.
As far as my graphics are concerned, building models of the engines was part of the work I did for the book “N-1 for the Moon and Mars”, part of the CGI models for the N-1 rocket. I find rocket engines extremely tricky to model, the mass of densely packed pipes make it seriously difficult to see the structure in most cases, let alone to model it.
Since the book was finished, I have been working on an improved model of the N-33 engines, starting with a mesh I bought as a template, which had a lot of the tricky parts done well. I then set about adding more details.
Here’s the current state of the project:
And a shot with a human figure for scale.