Disk Speed Indicator Mk XV for use with Norden Sight Eurofighter Typhoon It is dated 1949

It is dated 1949

including*:

including heavy bombers B-17

but requires the correct electrical input to function properly

The difference between zero and the north-indicating pointer is the aircraft's direction of travel with respect to magnetic north

Disk Speed Indicator Mk XV for use with Norden Sight Eurofighter Typhoon It is dated 1949The Disk Speed Indicator Mk XV was used by WWII US Army Air Force and Navy bombardiers to verify and calibrate the disk speed of the Norden Bomb Sight during flight before initiating the bomb run. 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. With the bomb sight switched on, the bombardier would affix the top axle to the small female receptacle