Simulation Architecture

R2026b

Step 2 of 3 in 1903 Wright Flyer Longitudinal Flight Simulation

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This section describes the structure of the Simulink^® model and explains how each subsystem contributes to the simulation. Use this architecture to integrate aerodynamic forces, pilot commands, and environmental effects into a unified dynamic model. The architecture consists of the Airframe subsystem, the Environment subsystem, and the Pilot subsystem, each of which models a critical aspect of the Wright Flyer dynamics.

Airframe Subsystem

The Airframe subsystem simulates the rigid-body dynamics of the Wright Flyer, including elevator angle of attack, aerodynamic coefficients, aerodynamic forces and moments, and the three‑degrees‑of‑freedom equations of motion. This subsystem forms the core of the simulation by computing how the aircraft responds to aerodynamic and propulsive inputs.

The Airframe subsystem consists of these parts:

• The Elevator Angle of Attack subsystem computes the effective elevator angle by combining the aircraft angle of attack with the canard geometry. This calculation determines the aerodynamic contribution of the elevator and provides input to the Pilot subsystem.

  

• The Aerodynamic Coefficients subsystem contains aerodynamic data sets and equations that define the lift, drag, and moment coefficients. Prelookup blocks interpolate stored aerodynamic tables to compute coefficients as functions of angle of attack, pitch rate, and elevator deflection. These coefficients determine the aerodynamic forces and moments acting on the airframe.

  

• The Forces and Moments subsystem converts aerodynamic coefficients into body-axis forces and moments. It computes lift, drag, and pitching moment, transforms them into body axes, and adds propeller thrust. These forces and moments depend on dynamic pressure, reference geometry, and airframe parameters.

  

• The 3DOF (Body Axes) block integrates the equations of motion to compute the aircraft linear and angular motion. It also converts between the original model axis system and body axes. Parameters for the 1903 Flyer include English units, fixed mass type, initial velocity of 47.26 ft/s, initial attitude based on incidence and angle of attack, initial position of [0 –0.1], initial pitch rate wfq, mass computed from weight and gravity, and inertia defined by wf_inertia.

  3DOF (Body Axes) Block Parameters

  

Environment Subsystem

The first and final flights of the Wright Flyer occurred on December 17, 1903. Orville and Wilbur Wright chose an area near Kitty Hawk, North Carolina, situated near the Atlantic coast. Wind gusts of more than 25 miles per hour were recorded that day. After the final flight on that blustery December day, a wind gust caught and overturned the Wright Flyer, damaging it beyond repair.

The Environment subsystem of the Wright Flyer model contains a variety of blocks from the Environment sublibrary of the Aerospace Blockset™ software, including wind, atmosphere, and gravity, and calculates airspeed and dynamic pressure. The Discrete Wind Gust Model block provides wind gusts to the simulated environment. The other blocks are

• The Incidence & Airspeed block calculates the angle of attack and airspeed.

• The COESA Atmosphere Model block calculates the air density.

• The Dynamic Pressure block computes the dynamic pressure from the air density and velocity.

• The WGS84 Gravity Model block produces the gravity at the Wright Flyer's latitude, longitude, and height.

  

Pilot Subsystem

The Pilot subsystem controls the aircraft by responding to both pitch angle (attitude) and angle of attack. If the angle of attack differs from the set angle of attack by more than one degree, the Pilot subsystem responds with a correction of the elevator (canard) angle. When the angular velocity exceeds +/- 0.02 rad/s, angular velocity and angular acceleration are also taken into consideration with additional corrections to the elevator angle.

Pilot reaction time largely determined the success of the flights [1]. Without an automatic controller, a reaction time of 0.06 seconds is optimal for successful flight. The Delay of Pilot (Variable Transport Delay) block recreates this effect by producing a delay of no more than 0.08 second.