Mysterious engine picture found in the files
An intriguing image of what appears to be the Pratt & Whitney J58 engine was found in the game files, leading to speculation about its connection to the in-game engine design of Raketa
Discovery
There is an image of an engine located within the game files, with a quick reverse search it appears to be the Pratt & Whitney J58 (click to read the Wiki Article).
(Original Image located within the Game Files)
(Reverse image search results)
(Screenshot of another designer sharing a similar photo of the same engine)
Confirmation
However, despite the presence of this image of the J58 and it's apparent inspiration for Raketa's turbine engines, they are not in fact J58s as confirmed by one of the Game Devs in a public message inside the official Discord server.
(Public Post made by MikeRTV concerning the Raketa)
(In-game image of Raketa's engine bay)
Conclusion
In summary, Raketa’s engines are actually derived from the TV3-117 helicopter engines used in the Mi-24 "Hind." While they may resemble the SR-71’s J58 engines at a glance, there’s no substantial evidence to support that they are J58s. Raketa’s engines lack the external piping characteristic of the early "turbo-ramjet" design found in the J58, which diverts air around the compressors and directly into the combustion chamber and afterburner, a feature functional only at speeds above Mach 3, which the game does not support. Additionally, Raketa’s engine exhausts are diverted upwards instead of directly backward, a typical feature of helicopter engines to prevent interference with the tail rotor by redirecting exhaust away from it. Ultimately, Raketa’s engines are not J58s but seem to take design inspiration from them for visual effect.