Reference RPM for tachometer time
The Reference RPM for tachometer time is the RPM for Max Rated Power at Sea Level, so its 2700RPM.
172N with Lycoming O-320-H2AD, Max Rated Power is at 2700 RPM
172R (180HP)/S with Lycoming IO-360L2A, Max Rated Power is at 2700 RPM
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