Kek. Perfect.
@Liquidxlax
Aircraft were in common use in 1928, and an engineer's education does not stop with their matriculation. If he was still in our world through the early 40's Aircraft were so common that they were used in sporting events.
Diesel-electric Submarines, IC engines, rudimentary fluid and aerodynamics were a thing, enough to get the Dalahni started at least. If he knows enough to build radios from scratch then he knows enough to give people a hundred year jump on their EE development.
Comp-B, TNT, Napalm and other explosive advancements alone woukd make life difficult for an enemy of whoever posessed that knowledge. The fact that the brain-eater managed to develop Sarin sugests he's already up to or nearly at modern chemistry standards.
Face it, this dude is a nightmare and Clark is a supertanker full of nightmare fuel.