Mixture

The engine performance charts do not factor in mixture setting, assuming that the pilot will keep the mixture near optimal. Any effects the mixture has on the power or behavior of the engine can be modeled as corrections.

An important effect of mixture setting is the rate of fuel consumption. The rate of fuel burn is given by:

$$\dot m_f = -(F/A)\dot m_{th}$$ (76)

where (F/A) is settable with the mixture control. Of course, a flight simulator uses a negative sign because it is interested in the actual fuel weight, which decreases as the fuel burns.