Preliminary Endurance For Jet Aircraft Calculator

Preliminary Endurance Formula:

\[ PE = \frac{LD_{max} \times \ln\left(\frac{W_i}{W_f}\right)}{c} \]

Maximum Lift-to-Drag Ratio:

Weight at Beginning of Cruise:

Weight at End of Cruise:

Power Specific Fuel Consumption:

kg/s/W

Preliminary Endurance:

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1. What is Preliminary Endurance?

Preliminary Endurance of Aircraft is the maximum length of time that an aircraft can spend in cruising flight. It's a crucial parameter in aircraft performance analysis and mission planning.

2. How Does the Calculator Work?

The calculator uses the Preliminary Endurance formula:

\[ PE = \frac{LD_{max} \times \ln\left(\frac{W_i}{W_f}\right)}{c} \]

Where:

\( PE \) — Preliminary Endurance (seconds)
\( LD_{max} \) — Maximum Lift-to-Drag Ratio
\( W_i \) — Weight at Beginning of Cruise Phase (kg)
\( W_f \) — Weight at End of Cruise Phase (kg)
\( c \) — Power Specific Fuel Consumption (kg/s/W)

Explanation: The formula calculates the maximum endurance time based on the aircraft's aerodynamic efficiency, weight change during cruise, and engine fuel consumption characteristics.

3. Importance of Preliminary Endurance Calculation

Details: Accurate endurance calculation is essential for mission planning, fuel management, and determining the operational capabilities of jet aircraft. It helps in optimizing flight profiles and ensuring mission success.

4. Using the Calculator

Tips: Enter maximum lift-to-drag ratio, weights at beginning and end of cruise phase, and power specific fuel consumption. All values must be positive, and initial weight must be greater than final weight.

5. Frequently Asked Questions (FAQ)

Q1: What is maximum lift-to-drag ratio?
A: Maximum lift-to-drag ratio is the highest ratio of lift force to drag force that an aircraft can achieve, representing optimal aerodynamic efficiency.

Q2: Why use natural logarithm in the formula?
A: The natural logarithm accounts for the exponential relationship between fuel consumption and endurance time in jet aircraft.

Q3: What is power specific fuel consumption?
A: Power specific fuel consumption is a measure of engine efficiency, defined as the weight of fuel consumed per unit power per unit time.

Q4: How does weight affect endurance?
A: Higher initial weight and lower final weight (more fuel burned) generally result in longer endurance, but the relationship is logarithmic.

Q5: Are there limitations to this calculation?
A: This is a preliminary calculation that assumes constant aerodynamic efficiency and may need adjustment for specific flight conditions and aircraft configurations.