When are the flaps of a Cessna Chancellor fully extended? At 45 or 15 degrees? Also, what are the range marks of its tachometer with Continental TSIO-520-NB engines?
Full flaps at 45°. Normal range of the tach is 2100 to 2700 rpm. TCM has since published a service bulletin recommending no less than 2300 rpm in cruise due to issues with crankshaft counterweights.
The numbers on the face of the tach represent the first two digits of the rpm value. When the needle points to "25" the rpm is 2500 rpm. Each small mark between the numbers represents a value of 100 rpm.
Using ymb's image:
The other gauge (manifold pressure) has numbers hatched into the panel to designate maximum manifold pressure at high altitudes. The "20" represents maximum available manifold pressure 20,000' (about 36"), for example. As the plane climbs, the maximum possible power setting falls. Those markings assume a well maintained turbo system, of course.