Tom Clancy's Hunt for Red October and Red Storm Rising. I think most people usually don't consider Tom Clancy to be a science fiction writer, but these two boo

Tom Clancy's Hunt for Red October and Red Storm Rising. I think most people usually don't consider Tom Clancy to be a science fiction writer, but these two books (his best two by far, FWIW) both feature speculative technology central to the story. Red October features a magneto-hydrodynamic drive for a submarine; MHD drives work for real in the small scale but without great superconductors it doesn't scale well to work for a full scale military submarine. In Red Storm Rising there are F-19 stealth jets based off rumors of the F-117. They get a few things wrong (smooth continuous curves instead of flat facets, poor stealth from below, armed with anti-aircraft missiles, etc) but on the whole they were reasonably grounded speculation. If you're not convinced, here is a longer argument for Red October (the film) being hard science fiction: https://qntm.org/october https://qntm.org/october