This repository contains a six-degrees-of-freedom (6-DOF) nonlinear flight dynamics simulation of the F/A-18 aircraft, implemented in MATLAB/Simulink.
The model is specifically developed for low angle-of-attack (low-AoA) flight regimes, where the aircraft aerodynamics can be reasonably approximated using polynomial and linear aerodynamic derivatives.

The primary objective of this project is to provide a control-oriented and analysis-friendly simulation framework suitable for:

• Aircraft trimming
• Linearization
• Stability and control analysis
• Flight control system (FCS) development
• Academic and educational studies in flight dynamics

• Valid for low angle of attack
• No deep-stall or post-stall aerodynamics
• No high-AoA vortex-dominated effects

• Aerodynamic coefficients are modeled using polynomial fits and linear coupling terms
• Aerodynamic data is sourced from:

Sinha, N. K., & Ananthkrishnan, N.
Advanced Flight Dynamics with Elements of Flight Control

This ensures the model remains physically interpretable and mathematically tractable, making it suitable for trimming and linearization in Simulink.

The following parameters correspond to the F/A-18 configuration used in the simulation:

The product of inertia $I_{xz}$ is not provided in the reference text. For the low-angle-of-attack, symmetric F/A-18 configuration considered in this simulation, the aircraft is assumed to be mass-symmetric about the body $x\text{-}z$ plane. Therefore,

Ixz = 0

This assumption is standard in control-oriented flight dynamics models and is consistent with the formulations in Sinha & Ananthkrishnan.

The simulation computes external forces and moments acting on the aircraft from:

• Lift coefficient (CL)
• Drag coefficient (CD)
• Side-force coefficient (CY)
• Rolling moment coefficient (Cl)
• Pitching moment coefficient (Cm)
• Yawing moment coefficient (Cn)

These coefficients are functions of:

• Angle of attack (alpha)
• Sideslip angle (beta)
• Control surface deflections (aileron, elevator, rudder)

• Thrust modeled using a generic, control-oriented thrust model
• Suitable for trim and flight-control studies
• Engine spool dynamics and afterburner effects are neglected

• Body-fixed reference frame
• North–East–Down (NED) inertial frame
• Standard Newton–Euler rigid-body equations of motion
• Euler angles used for attitude representation

The model structure allows direct integration with:

• State-space representations
• Linearized plant models
• Control law architectures (PID, LQR, etc.)

This simulation framework is intended for:

• Aircraft trimming and equilibrium analysis
• Linearization and small-disturbance modeling
• Flight control system design
• Academic teaching and learning
• Research-oriented flight dynamics experimentation

This model does not include:

• High-angle-of-attack aerodynamics
• Post-stall or departure dynamics
• Flexible body effects
• Engine spool dynamics
• Inlet distortion or afterburner modeling

As such, it should not be used for:

• High-fidelity performance prediction
• High-AoA maneuvering or departure studies
• Real-time pilot-in-the-loop certification simulations

• MATLAB (R2021a or later recommended)
• Simulink
• Simulink Control Design (for trimming and linearization)

1. Sinha, N. K., & Ananthkrishnan, N.
   Advanced Flight Dynamics with Elements of Flight Control
   CRC Press

2. Stevens, B. L., Lewis, F. L., & Johnson, E. N.
   Aircraft Control and Simulation
   Wiley

This project is developed as part of an advanced flight dynamics and control study, with emphasis on:

• Physical intuition
• Mathematical clarity
• Control-oriented modeling

The goal is not maximum fidelity, but maximum insight.