Flight Mechanics - From Theory to Certification of Aircraft

This lesson is our first contact with the Flight Mechanics world. And as for everything else, we need to define some references from which we will build our knoledge upon.

In this lesson we will derive the Equations of motion of a 3D rigid body (the airplane). We will review Newton's second law for translational and rotational motion and end up with our state vector that will define the aircraft position, linear velociteis, angular velocities and attitude for a given time.

One of the most important forces that dictate the behavior of the aircraft are the Aerodynamic forces. In this lesson we will review the basics of aerodynamics and derive our forces and moments coefficients that will be essential in the analysis of the aircraft's motion.

Let's check how the atmosphere can be modeled and the effects of the anemometric system of the aircraft, leraning the differences between the indicated/calibrated airspeed and the true airspeed.

This lesson we will start creating our first simulink library, the Atmospheric one. The anemometrics and ISA model we learned are going to be implemented in Simulink. The version of Matlab 2016a is the one used. But if you follow the step-by-step instructions you can use any version.

Now it's time to implement our forces and moments computations through the Equations of Motion library, let's start by the first subsystem: Forces and Moments.

The next subsystem of the Equations of Motion library is the Body Rates.

In this lesson we will continue working on the Equations of Motion library, now it's time for the Euler Angles subsystem.

The last subsystem of the Equation of Motion  library is with regards to trajectory data. The trajectory angle gamma and the track angle of the aircraft will be calculated as well as the ground speed.

Finally, we will finish the Equations of Motion library.

In this lesson we will edit the Atmospheric library to insert the wind effect, calculate the angle of attack and the sideslip angle.

This lesson is a quick one. We are going to create the Propulsion library with the generic model we studied in the Section 1.

Now we start to work on our last library, the Aerodynamics one. In this lesson we'll introduce the inputs and the CL calculation.

The other coeffcients will be proposed as a challenge in task 3.

Now that all coeffcients have been calculated we have to convert them from the stability axis to the body axis. After that we will transform the coefficients in forces and moments. Additionally, for the moments which have been derivied in relation to a standard position of 25% of the mean aerodynamic chord (%mac), we will correct them and account for the actual CG position (x_cg, y_cg and z_cg) of the aircraft.

This is the last lesson of this section. We will combine all the previous libraries and create the Aircraft (ACFT) model.

- Understanding the trim script

- Longitudinal trim

- Lateral trim

Time varying simulations starting from a trimmed condition.

In this lecture you'll learn how to use matlab optimizer functions "fmincon"and "fminsearch" to adjust the aerodynamic derivatives and have a model that matches flight test results. Two examples are provided, one for the dutch roll maneuver and a straight stall test.

In this lecture you'll learn how to read USB Joystick inputs in Simulink and Export the data to a flight simulation tool such as Flight Gear.

Download Flight Gear before this class on the following link:
https://www.flightgear.org/download/

• Introduction to the Subpart B 14 CFR FAA Part 25 requirements

• Introduction to Advisory Circulars as means of compliance

• Examples of compliance demonstration

• Examples of Flight Tests conducted during a certification campaign.

This section we are going to cover the basic principles of fly-by-wire aircraft, its advantages and most common control laws.