Aircraft performance and stability

The course is divided into two parts:

1. Performance  (2 ECTS), taught by Prof. Marinus (RMA)

This part covers:

• Fundamentals: Finite wing theory, wing properties, control surfaces, flow separation, drag, and propulsion systems

• Performance concepts: Conventions, aerodynamic forces, governing equations

• Steady flight: Symmetric flight, parameters affecting performance curves, climb performance, descent performance, gliding

• Accelerated flight: Accelerated straight and level flight, takeoff and landing, load factor, turning flight, accelerated climbs, total energy, flight envelope

• Flight instruments

2. Stability and Control (2 ECTS) ; Taught by Prof. Coussement (ULB)

This part includes:

• Stick-fixed and stick-free longitudinal static stability; lateral static stability

• General dynamical equations of motion

• Small disturbance theory and linearized equations

• Aerodynamic derivatives

• Dynamic stability:

  • Longitudinal modes: phugoid and short-period oscillation

  • Lateral modes: spiral mode, roll convergence, Dutch roll

• Aircraft response to control inputs

• Introduction to closed-loop control design

At the end of the course, the student is expected to be able to:

• Describe the performance characteristics of an aircraft

• Calculate key performance parameters

• Evaluate the longitudinal static stability of an aircraft, including the static margin

• Compute the longitudinal and lateral modes of motion of an aircraft

• Identify and explain the major aerodynamic mechanisms associated with each aerodynamic derivative

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Cours pré-requis

The course combines theoretical lectures with guided exercise sessions. Lectures provide the foundational concepts in performance and stability, while the exercise sessions allow students to apply these concepts through practical problem-solving, numerical computations, and case studies.

Références, bibliographie et lectures recommandées

• B. Etkin et L. D. Reid: Dynamics of flight. Stability and Control, Wiley, 1995. B.N. Pamadi: Performance, Stability, Dynamics and Control of airplanes, AIAA Education series, 1998 T.R. Yechout et al.: Introduction to aircraft flight mechanics. Performance, static stability, dynamic stability and classical feedback control, AIAA Education series, 2003.
• Anderson, J. Introduction to flight, 3rd ed. McGraw-Hill, New York (USA), 1989.
• Pamadi, B. Performance, Stability, Dynamics, and Control of Airplanes, 3rd ed. AIAA education series. American Institute of Aeronautics & Astronautics, 2015.
• Phillips, W. Mechanics of flight. John Wiley & sons, Hoboken (USA), 2004.

Recommended references. 

Cumpsty Nicholas 'Jet propulsion';

Stengel Robert 'Flight Dynamics';

Yechout Thomas 'Introduction to aircraft flight mechanics'

 

Contacts

Service d'Aero-Thermo-Mécanique - CP 165/41 - Axel Coussement (axel.coussement@ulb.be)

Campus

Solbosch

Méthode(s) d'évaluation

• Examen écrit
• Examen oral

Examen écrit

• Question ouverte à développement long
• Question ouverte à réponse courte

Examen oral

The stability evaluation can be converted from a written exam to an open book oral exam at the discretion of the professors. This will be communicated after the deliberation of the Jury. 

Construction de la note (en ce compris, la pondération des notes partielles)

The final mark is composed of the following components:

• Written test on Performance (theory & exercises): 50%
• Written test on Stability and Control (theory & exercises): 50 % 

A 10/20 or higher obtained in one part during the first exam session may be carried over to the second session, upon student request and subject to the professor’s approval. No partial grades are carried over from one academic year to the next.

Langue(s) d'évaluation

• anglais