Here's a great short film documenting the design and creation of a mechanical dragon. The hand-cranked automaton actually shoots fire!
Made by Rachel Grimmer, this was her first automaton project which she made for her medieval re-enactment group. The project included researching the history of mechanisms and automata, learning how to make an automaton, and then designing and making the dragon. In this short video, she describes the entire process.
When the crank is turned, the dragon flaps its wings, swings its tail, and blows a powder from its mouth. When blown over a nearby flame, the powder creates a dramatic fire effect. The piece incorporates a number of great mechanisms including a crank-shaft, pulleys, a skew cam, a bellows, ratchet, and a snail cam.