MUSEUM "WAALSDORP"

Air Acoustics

	From the first world war until the 30's air acoustics played an important role in the air defence. Air vehicles carrying a weapon could not be located from the ground e.g. at night time or under cloudy conditions. As radar was still to be discovered, vision had to be supplemented by hearing using the sound of the engines. Early listening equipment First assignment Investigations Equipment "Waalsdorp" Equipment "Colonies" Use of the equipment Transport of angle values Co-ordination of equipment with the step system Listening cage Miniaturised listening equipment		Example of a large listening ear to observe the sound of approaching airships or aeroplanes. This equipment was used in Japan. Photo from the Illustrated London News of September 5th, 1936. (full size 54 KB)