Engine RPM field

TM 9-2320-211-20-3-2

(4) Engine RPM field. The engine rpm is recorded on the blue side of the

chart. The readings are recorded at the same time as the readings on the green side.

The engine rpm field (Fig. 20-6) is divided by seven circles. Each circle is equal to

500 rpm. The base line is recorded just above the inside time scale and the 3500 rpm

circle is just below the outside time scale. The base line is recorded as soon as the

chart is put into the tachograph and is only recorded with the engine off. The rpm

recording is made up of vertical arcs. The circle at the top of the arcs shows the

top rpm of the engine at the time shown on the time scale.

Figure 20-6. Engine RPM Recordings