truly based on jets, by which, presumably, they meant self-contained gas turbines.) They found it was not powerful enough to lift a person off the ground, and was expensive to build. The plans specified a Rotax 503 ultralight engine, but they intended to use the more powerful and lighter Rotax 583 engine before a similar lighter unnamed engine was substituted. In fiction The concept of jet packs appeared in popular culture, particularly science fiction, long before the technology became practical. Perhaps the first appearance was in pulp magazines. The 1896 novel The Country of the Pointed Firs mentions a "fog-shaped" man hovering low with a "the look of a pack on his back" who "flittered away out o' sight like a leaf the wind takes with it". The 1928 cover of Amazing Stories featured a man flying with a jet pack. When Republic Pictures planned to produce a superhero serial using its renowned "flying man" scenes as used in The Adventures of Captain Marvel, the character of Captain Marvel was tied up in litigation with the owners of the character of Superman. For its postwar superhero serial, Republic used a jet pack in King of the Rocket Men. The same stock special effects were used in other serials. While several science fiction novels from the 1950s featured jet packs, it was not until the Bell Rocket Belt in the 1960s that the jet pack caught the imagination of the mainstream. Bell's demonstration flights in the U.S. and other countries created significant public enthusiasm. Jet packs were featured in two episodes ("Turu the Terrible" and "The Invisible Monster"), of the original Jonny Quest (1964-1965) animated television series, and are seen at the end of the closing credits. In 1965 a Bell Rocket Belt appeared in the James Bond movie Thunderball when James Bond played by Sean Connery used a jet pack in the pre-title sequence to escape the villains and rendezvous with his French contact. The pack was piloted by Gordon Yaeger and Bill Suitor. In the Irwin Allen television series Lost in Space (1965-1968), a jet pack was used by members of the Jupiter 2 expedition on several occasions. In 1966 the plot of the 21st book in the Rick Brant series titled Rocket Jumper was based on a hydrogen peroxide fueled jet pack. The book included a relatively detailed description of the design including the use of a platinum-metal