Author name: Arshad Arif A.S

The propulsive efficiency of a propulsion system, such as a jet engine or a propeller, typically calculates the ratio of the useful power output (thrust) to the power input (fuel energy). The formula for propulsive efficiency is:

Typically, in a combustion process, people express the fuel-air ratio as the ratio of the mass or volume of fuel to the mass or volume of air. The formula depends on whether you’re using mass or volume measurements:

The thrust lapse rate refers to the rate at which the thrust of a jet engine decreases with increasing altitude. As an aircraft ascends to higher altitudes, the air density decreases, which affects the engine’s ability to generate thrust. The thrust lapse rate quantifies this decrease in thrust relative to the altitude climbed. Where: Talt​

The formula for engine thrust rating depends on various factors such as the type of engine (turbojet, turbofan, etc.), design specifications, and operating conditions. However, a basic formula for calculating engine thrust can be represented as: Where: T is the thrust produced by the engine. ˙m˙ is the mass flow rate of air through the

The Van der Waals equation is a modification of the ideal gas law to account for the volume occupied by gas molecules and the attractive forces between them. It is expressed as: Where: P is the pressure of the gas. V is the volume of the gas. T is the temperature of the gas. R

The propeller advance ratio is a dimensionless parameter used in aerodynamics to characterize the performance of a propeller. It describes the ratio of the forward speed of an aircraft to the rotational speed and diameter of the propeller. Where: J = Propeller advance ratio V = Airspeed (velocity) of the aircraft n = Rotational speed

The lift coefficient for a propeller is a dimensionless parameter that quantifies the lift generated by the propeller blades as they rotate through the air. It is similar to the lift coefficient for wings in aerodynamics but tailored specifically for propeller systems. Where: CL​ is the lift coefficient, T is the thrust generated by the

Torque, in physics, is a measure of the rotational force applied to an object about an axis. It is the product of the force applied to the object and the distance from the axis of rotation to the point where the force is applied, multiplied by the sine of the angle between the force vector

The formula to calculate propeller RPM (Revolutions Per Minute) depends on various factors such as engine power, propeller diameter, pitch, and airspeed. However, a basic formula to estimate propeller RPM is: Where: RPM is the propeller revolutions per minute. V is the forward speed of the aircraft in feet per second (fps). D is the