RAF Flying Training Manual, Part 1-Landplanes, 1940 T-33 It is specified for measuring

It is specified for measuring altitude up to 15 Km

The disk speed is the parameter which determined the duration of flight between sighting of the target and automatic release of the aircraft's ordnance

It appears to have once been installed

The Aeroplane Spotter was a British weekly newsletter full of information regarding military aircraft of the RAF

The glass sight is intact

RAF Flying Training Manual, Part 1-Landplanes, 1940 T-33 It is specified for measuringHere is a WWII era Flying Training Manual, Part 1 Landplanes, published in 1940 by the British Royal Air Force Air Ministry, Air Publication 129, and updated in 1941. The manual is full of basic flight instruction information about flying landplanes (vs seaplanes) as well as more advanced lessons such as instrument flight, formation flight, as well as flying from aircraft carriers. It also includes information about the technology of the aircraft,