Another modification, the HeS 10, placed a complete HeS 8 engine inside a larger nacelle, and expanded the intake impellor to be larger than the engine. The HeS 10 appears to have been the first example of what would today be called a turbofan engine.
Another modification, the HeS 10, featured a complete HeS 8 engine within a larger nacelle and an enlarged intake impeller bigger than the engine. This design is considered the first instance of a turbofan engine.