1978 Cessna 172N N3291E
The Skyhawk N, or Skyhawk/100 as Cessna termed it, was introduced for the 1977 model year. The "100" designation indicated that it was powered by a Lycoming O-320-H2AD, 160 horsepower (119 kW) engine designed to run on 100 octane fuel, whereas all previous engines used 80/87 fuel. Unfortunately, this engine proved troublesome and it was replaced by the similarly rated O-320-D2J to create the 1981 172P.
The 1977 N model 172 also introduced rudder trim as an option and standard pre-selectable flaps. The price was USD$22,300, with the Skyhawk/100 II selling for USD$29,950.
The 1978 model brought a 28-volt electrical system to replace the previous 14-volt system. Air conditioning was an option.
The 1979 model N increased the flap extension speed for the first 10 degrees to 115 knots (213 km/h). Larger wing tanks increased the optional fuel to 66 US gallons (250 l).
The N remained in production until 1980 when the 172P or Skyhawk P was introduced.