World War II Database

1.  David Stubblebine says:
25 Feb 2023 09:46:01 PM

Note the label indicating the Jack Switches. This is a component of the ballast dropping mechanism that is rarely discussed in detail but it was ingenious in design. When the barometers registered that the balloon’s altitude had fallen below a prescribed height, an electric signal would blow out two adjacent black-powder plugs in the large lower ballast ring which released a ballast bag filled with sand. The ignition of the blow out plug would light a timed fuse burning toward the smaller ring above. When the fuse set off a blowout plug in the smaller ring, the spring-loaded ‘J’ shaped hook of the jack switch would snap upwards and close the electrical circuit for the next set of ballast bags (those are fuse cords leading to the upper ring, not wires). The fuses and jack switches did two things: 1) they isolated each blow out plug circuit so all the ballast bags did not drop at once; and 2) the fuses created a time lag between one ballast bag being dropped and the next one being armed, allowing the balloon the time needed to regain some altitude after releasing the ballast. Burning fuses were cleverly used as timing devices at several places in the Fu-Go balloon design.