Professor Fergusson (Cedric Hardwicke) is the proud builder and owner of a hot air balloon called the Jupiter. The Jupiter has a large red and white striped balloon suspended over a unicorn shaped gondola. The balloon works on a closed system that keeps the gas inside. The craft has more maneuverability than other hot air balloons and is piloted by the Professor’s assistant, Jacques (Fabian). Professor Fergusson performs a test run for Royal Geographic Society members Sir Henry Vining (Richard Haydn) and Mr. Chiddingfold (Ronald Long). Fergusson is looking for backing to explore the eastern side of Africa. While trying to show the balloon’s maneuverability he manages to scare the crap out of his passengers. After the hair-raising ride the Royal Geographic Society refuses to fund the Professor’s project.
Cornelius Randolph (Raymond Bailey) owns a chain of newspapers in America. He comes forward with the funding needed for the Professor’s project provided his reporter and nephew, Donald O’Shay (Red Buttons) goes along to document the trip. O’Shay is a slightly brash American and a bit of a troublemaker. In an effort to kill two birds with one stone, his uncle decides that sending his nephew along gives him a good story and, hopefully, keeps O’Shay out of trouble.
Just prior to takeoff, however, Fergusson is called to a meeting with the Prime Minister (Herbert Marshall). The Prime Minister tells Fergusson that a slave trading expedition has been sent to the western side of Africa hoping to plant the slave traders’ flag and make the western part of the country slave trading. He then commissions the professor and his ship to fly to the west and plant a British flag thereby keeping the western part of Africa slavery free. The Prime Minister decides to send with him the very same Sir Henry Vining as the crown’s representative.
Fergusson goes to Zanzibar to pick up O’Shay, who happens to be causing a riot in the slave tents by trying to save one of the women being sold, Makia (Barbara Luna). The gang makes a hasty retreat, and Makia manages to stow away in the crow’s nest of the balloon. At a stop in the city of Hezak O’Shay once again causes trouble by saving an American, Susan Gale (Barbara Eden), who was captured by the slave trader Ahmed (Peter Lorre). The slave trader, who happened to steal some of the local sultan’s treasure, climbs aboard the balloon and ends up stuck flying across Africa with the rest of the explorers.
With their numbers complete, the crew of the Jupiter head towards the west coast of Africa finding trouble everywhere they go in the race to claim Africa for the British.
“5 weeks in a balloon” was released in 1962 and was directed by Irwin Allen. It is an American fantasy adventure film with romantic and science fiction aspects. The movie was loosely based in the 1863 Jules Verne novel of the same name.
The film is dotted with stock footage montages of animals in herds. There is a lot of the usual Irwin Allen fluff, but the special effects were rather impressive, and the cinematography nicely done. The cast was also great. Visual effects included models of the balloon as well as a full-size gondola with a unicorn head that was hung from a crane. Although it set in Africa, the film was shot in California. Balloonist expert Don Piccard was the film's technical advisor. The chimpanzee called “The Duchess” was played by a chimp named Chester.
The balloon in the movie was called the Jupiter. It seems that Irwin Allen was fond of the name, so he called the spaceship in the television program “Lost in Space” the Jupiter 2.