AVRO Shackleton centre of gravity computer, made by AVRO, around 1950.
This slide rule centre or gravity computer, also known as a load adjuster, was used by the pilot or flight engineer prior to take off to calculate the centre of gravity of the AVRO Shackleton based on the load it was carrying, for example bombs, freight, passengers etc. The center of gravity affects the stability of the aircraft. To ensure the aircraft is safe to fly, the center of gravity must fall within specified limits established by the aircraft manufacturer. The Avro Shackleton, built at Woodford in Cheshire, was a British long-range maritime patrol aircraft for use by the Royal Air Force between 1951 and 1990.