In aircraft design, the term “flat engines” typically refers to horizontally opposed engines with a flat or boxer configuration. The density of a flat engine is not a relevant parameter, as density is a property of materials or substances, not engines.Density is usually measured in units such as kilograms per cubic meter (kg/m³) or pounds per cubic foot (lb/ft³), and it represents the mass of a substance per unit volume.
- ρ = Density of the fluid (in kilograms per cubic meter, kg/m³)
- P = Pressure of the fluid (in pascals, Pa)
- R = Specific gas constant for the fluid (in J/(kg·K))
- T = Temperature of the fluid (in kelvin, K)