Airspeed Indicator 450+ Knots Mk 9L Ref 6A/4721 RAF KC-97 This is a late WWII-era

This is a late WWII-era Wheel and Flap Position Indicator

000 of these instruments were made at the A

The knob at the top of the indicator is actually a hex key used to adjust deviations in readings on the Master Compass

B-25 Mitchell

which pioneered the way for future designs of aerial refueling aircraft

Airspeed Indicator 450+ Knots Mk 9L Ref 6A/4721 RAF KC-97 This is a late WWII-eraThis is an excellent example of a post WWII era Air Speed Indicator Mark 9L, Ref 6A 4721, as used in the British RAF fighters Supermarine Spitfire and Seafire. Air speed from 0 270 Knots is indicated by a clockwise rotating pointer, starting at the 6 o'clock position, along the outer perimeter scale. As the aircraft passes 270 Knots, air speed is indicated along the inner scale up to 450 Knots, with gradations up to 500 Knots. The indicator measures