Penny Farthing bicycle. Ford Nucleon (nuclear powered steam car) Boat Car 1977 GM made a Coal Dust Powered Car Concrete Battelships when we had a shortage of iron Coal Powered Iron Steam Balloon Tsar Tank - huge tank that looks kind of neat.
Several of those, I've heard of, and know the reasons for their failures. You've seriously never heard of penny-farthing bicycles? They were quite common, for a while. The front wheel had to be big, in order to get the necessary speed and stability from direct pedals; but this created issues with safely mounting and controlling it. It very rapidly became obsolete, once chain-drive made it possible to achieve the necessary speed with a smaller drive wheel. At the dawn of the Atomic Age, some engineers at Ford imagined that nuclear reactors would eventually be small enough and safe enough to use to power cars. The Nucleon was their idea of what a nuclear-powered car would be like. Of course, they never produced a working model, as there never came to be a suitable reactor available to power it. I think they produced a number of non-working mockups. The Amphibicar might have been a good idea, but it was rather badly made, tended to leak and rust, and was generally unreliable.
^^^ I saw the clip of that bike you mention. I wouldn't feel comfortable sitting up so high on a bike. God bless you always!!! Holly