100 Most Valuable Old-School DIY Blueprints (yup, all analog and all free)
Vintage Projects offers 100+ free plans for building all sorts of fun DIY projects spanning musical instruments, archery, boats, motorbikes, go carts, science experiments, telescopes, tractors, radios, and more.
Instructions include a homemade paddle boat (more like a bicycle boat), a "pocket-sized" motorbike that can fit in your school locker, and even an electric-powered submarine for underwater exploration (perhaps a precursor for Tao Xiangli's fully functional sub).
These retro plans may not be for your average do-it-yourselfer... plan on truly building it from the ground on up.
Sampling of the 100+ projects below.