Tachometer Chronograph
Chronograph Functions index
Timing to 1/5 second.
Timing up to 30 minutes.
Timing telephone conversations.
Tachometer scale (Q)
The tachometer scale is calibrated to show the speed of a moving object, such as a vehicle, over a known distance. The standard length on which the calibration is based is always shown on the dial, e.g.1,000, 200 or 100 meters, or in some cases, one mile. As the moving vehicle, for instance, passes the starting-point of the measured course whose length corresponds with that used as the basis of calibration, the observer releases the chronograph hand and stops it as the vehicle passes the finishing-point. The figure indicated by the hand on the tachometer scale represents the speed in kilometers or miles per hour. (see number 9).
On the tachometer scale of the chronograph illustrated opposite, the speed of an aircraft flying above a runway 10000 meters long is shown to be 700 kilometers per hour.
Q = Tachometer scale