This is a Sperry Gyroscopic Artificial Horizon of the type fitted to early British Jets including: The Gloster Javelin, The Gloster Meteor, The DeHavilland Vampire and the Vickers Valliant. It has the broad arrow of the Ministry of Defence stamped on it and appears to be in serviceable condition.

An artificial horizon is used to show the pilot the attitude of the plane (i.e. whether the nose is up or down and whether the plane is banking). This might seem like something a pilot would know without an instrument, just by using his or her senses; however, when flying, if visibility is low, the senses can easily get confused by the prolonged g forces caused by turning the aeroplane. These instruments therefore are essential for flying at night or where visibility is low.

Elmer Sperry was the original inventor of the gyroscopic Artificial Horizon. He patented it in England in 1911 and went on to make most of the artificial horizons for the Royal Air Force during the Second World War. Sperry Horizons are generally considered to be among the best.

A Gloster Javelin

 This item is rare.