Landing Ground Run Calculator

Landing Ground Run Formula:

\[ Landing Ground Run = (Normal Force \times Velocity at Touchdown Point) + \left(\frac{Weight Of Aircraft}{2 \times [g]}\right) \times \int_{0}^{Velocity at Touchdown Point} \frac{2 \times Velocity of Aircraft}{Reverse Thrust + Drag Force + Reference Of Rolling Resistance Coefficient \times (Weight Of Aircraft - Lift Force)} \, dx \]

Normal Force:

Velocity at Touchdown Point:

m/s

Weight Of Aircraft:

Velocity of Aircraft:

m/s

Reverse Thrust:

Drag Force:

Reference Of Rolling Resistance Coefficient:

Lift Force:

Landing Ground Run:

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1. What is the Landing Ground Run Equation?

The Landing Ground Run equation calculates the distance an aircraft requires to come to a complete stop after landing on a runway. It accounts for various forces including normal force, reverse thrust, drag force, and rolling resistance.

2. How Does the Calculator Work?

The calculator uses the Landing Ground Run equation:

\[ Sgl = (Fnormal \times VTD) + \left(\frac{Waircraft}{2 \times [g]}\right) \times \int_{0}^{VTD} \frac{2 \times V_{\infty}}{VTR + D + \mu_{ref} \times (Waircraft - L)} \, dx \]

Where:

\( Fnormal \) — Normal Force (N)
\( VTD \) — Velocity at Touchdown Point (m/s)
\( Waircraft \) — Weight Of Aircraft (kg)
\( V_{\infty} \) — Velocity of Aircraft (m/s)
\( VTR \) — Reverse Thrust (N)
\( D \) — Drag Force (N)
\( \mu_{ref} \) — Reference Of Rolling Resistance Coefficient
\( L \) — Lift Force (N)
\( [g] \) — Gravitational acceleration (9.80665 m/s²)

Explanation: The equation calculates the stopping distance by considering the initial kinetic energy and the work done by various decelerating forces during the landing roll.

3. Importance of Landing Ground Run Calculation

Details: Accurate landing ground run calculation is crucial for aircraft performance analysis, runway length requirements, safety assessments, and operational planning. It helps ensure that aircraft can safely stop within available runway distances under various conditions.

4. Using the Calculator

Tips: Enter all values in appropriate units. Normal force, velocities, weight, and forces must be positive values. The rolling resistance coefficient is typically a small positive value (0.002-0.02 for aircraft tires on concrete).

5. Frequently Asked Questions (FAQ)

Q1: What factors affect landing ground run distance?
A: Landing speed, aircraft weight, reverse thrust effectiveness, braking efficiency, runway surface condition, wind, and temperature all affect landing distance.

Q2: How does reverse thrust contribute to stopping?
A: Reverse thrust redirects engine exhaust forward, creating a decelerating force that helps slow the aircraft without relying solely on wheel brakes.

Q3: What is typical rolling resistance for aircraft?
A: Typically 0.02-0.03 for dry concrete, but can vary significantly with runway conditions (wet, icy, contaminated).

Q4: How does lift affect landing ground run?
A: As the aircraft slows down, lift decreases, increasing the normal force on wheels and improving braking effectiveness.

Q5: Why is numerical integration used in this calculation?
A: The integral accounts for the continuously changing forces and velocities during the landing roll, providing a more accurate distance calculation than simplified average-value methods.