HELICOPTER FLIGHT MECHANICS

Course objectives

The course covers fundamental aerodynamics concepts on the rotor, rigid blade dynamics for an articulated rotor and helicopter control and performance in various flight conditions. EXPECTED LEARNING OUTCOMES Knowledge and understanding; Upon completion of the course, the student will be able to: - Describe, having understood the main phenomenological aspects, the basic elements of aeromechanics and dynamics of the articulated rotor - Illustrate and compare the main methodologies for mathematical modeling of the helicopter - Describe how equilibrium flight conditions (trim) of the helicopter are established and illustrate how state and control variables change as functions of flight speed - Illustrate methods for determining the helicopter performance data - Describe the main systems of the helicopter: rotor, motor, transmission, flight control system - Describe the dynamic stability characteristics of helicopters - Interpret and illustrate technological and design developments in rotary-wing and/or hybrid aerial vehicles. Applying knowledge and understanding) Upon completion of the course, the student will be able to: - Apply the concept of the optimal rotor to the design of the blade - Develop and use a simple mathematical model of the machine aimed at studying performance - Determine state and control variables in trimmed flight as flight speed varies. Making judgments Upon completion of the course, the student will be able to: - Tackle problems of average complexity that require planning and coordinating activities, using appropriate computational tools, and writing technical reports within set deadlines. Communication skills Upon completion of the course, the student will be able to: - Conduct collaborative activities as part of group work - Expose the results of activities conducted in groups in the form of presentations and/or technical reports. Learning skills By the end of the course, the student will have gained an understanding of the present and future role of rotary-wing machines, including new systems for urban air mobility (UAM), and the ability, at a basic level, to formulate and solve problems related to helicopter aeromechanics through both the application of software applications and the independent development of computational codes.

Channel 1
GUIDO DE MATTEIS Lecturers' profile

Program - Frequency - Exams

Course program
Rotorcraft components: main rotor, tail rotor, fuselage, engine, rotor transmission, control system. Basic mechanics of rotor systems, flapping, lagging and feathering motions. Rotor aerodynamics in hovering and axial flight, actuator disc theory and blade element theory. Vertical descent and vortex ring state. Figure of merit, blade tip loss, ground effect. Rotor wake models. Rotor aerodynamics if forward flight, induced velocity, blade element theory, force and torque coefficients, flapping coefficients. Helicopter trim in axial and advancing flight, longitudinal and lateral equilibrium conditions. Performance analysis, engine performance and power losses, required power. Hover performance, forward flight performance, climb in forward flight. Analysis of mission. Autorotation, performance estimation in autorotative forward flight, rotor speed decay, Height-Velocity diagram. Introduction to stability and controllability, speed stability, angle of attack stability, dihedral effect.
Prerequisites
Formulation of the cardinal equations of the rigid body. Fundamentals of wing section aerodynamics. Knowledge of methods for the analysis of aircraft performance. Basic concepts on aircraft static stability and controllability. Basic concepts on linear algebra and Laplace transform. Principal elements in aircraft dynamic stability and Handling qualities.
Books
Official textbook - A.R.S. Bramwell, G. Done, D. Balmford, Bramwell's Helicopter Dynamics, Second Edition, Butterworth-Heinemann, Oxford, 2001.
Teaching mode
The course is divided into lectures and exercises during which problems of greater complexity are solved in small groups. There will also be seminars on applications of the knowledge acquired in the course to technical problems specific to the labour market.
Frequency
Although not compulsory, attendance at classes and participation in activities in small groups of students is recommended.
Exam mode
TESTING TOOLS The assessment is done by an oral test that involves three questions covering all topics of the lectures. The final grade is expressed as the average of the marks obtained in the evaluation of each of the questions. The duration of the exam is between 30 and 45 minutes. In order to successfully pass the examination, it is strongly recommended to have carried out the course assignments, writing the related reports. ASSESSMENT METHODS The examination requires that the student is able to integrate the skills acquired in the course and apply them in more complex, open-ended problems. A typical exam consists of: verifying the general comprehension of course arguments; verification of ability to understand and use the mathematical modeling of aeromechanical characteristics of rotorcraft; verification of understanding of the main dynamic characteristics of helicopter and rotor; verification of knowledge of methods of performance analysis; verification of knowledge of the vehicle main systems and sub-systems; verification of ability to analyze the stability and response to commands. EVALUATION CRITERIA Minimum knowledge (rated between 18 and 20); average knowledge with sufficient communication skills (21-24); good ability to apply knowledge with adequate communication skills (25-27); ability to apply knowledge to problems of some complexity, to demonstrate in-depth understanding of the course arguments with good communication skills and critical thinking; ability to demonstrate good attitude to reasoning by also proposing original solutions (28-30 with honors).
Bibliography
- J.G. Leishman, Principles of Helicopter Aerodynamics, Cambridge Aerospace Series, Cambridge University Press, 2000 - W. Johnson, Rotorcraft Aeromechanics, Cambridge University Press, 2013 - G.D. Padfield, Helicopter Flight Dynamics, Blackwell Science Ltd., Oxford, 1996 - R.W. Prouty, Helicopter Performance, Stability and Control, Krieger Publishing Company, Florida, 1986
Lesson mode
The course is divided into lectures and exercises during which problems of greater complexity are solved in small groups. There will also be seminars on applications of the knowledge acquired in the course to technical problems specific to the labour market.
  • Lesson code1011234
  • Academic year2025/2026
  • CourseAeronautical engineering
  • CurriculumModellistica e analisi per la progettazione aeronautica (percorso valido anche per il conseguimento del doppio titolo con Georgia institute of technology and Georgia tech Lorraine o per il doppio titolo Italo-portoghese )
  • Year2nd year
  • Semester1st semester
  • SSDING-IND/03
  • CFU6