15AE743 HELICOPTER DYNAMICS syllabus for AE

Introduction:

History of helicopter flight. Fundamentals of Rotor Aerodynamics; Momentum theory analysis in hovering flight. Disk loading, power loading, thrust and power coefficients. Figure of merit, rotor solidity and blade loading coefficient. Power required in flight. Axial climb, descent, and autorotation.

Blade Element Analysis:

Blade element analysis in hovering and forward flight. Rotating blade motion. Types of rotors. Concept of blade flapping, lagging and coning angle. Equilibrium about the flapping hinge, lead/lag hinge, and drag hinge.

Basic Helicopter Performance:

Forces acting on helicopters in forward flight. Methods of achieving translatory flight. Controlling cyclic pitch: Swash-plate system. Lateral tilt with and without conning. Lateral and longitudinal asymmetry of lift in forward flight. Forward flight performance- total power required, effects of gross weight, effect of density altitude. Speed for minimum power, and speed for maximum range. Factors affecting forward speed, and ground effects.

Rotor Airfoil Aerodynamics:

Rotor airfoil requirements, effects of Reynolds number and Mach number. Airfoil shape definition, Airfoil pressure distribution. Pitching moment. Maximum lift and stall characteristics, high angle of attack range.

Rotor Wakes and Blade Tip Vortices:

Flow visualization techniques, Characteristics of rotor wake in hover, and forward flight. Other characteristics of rotor wake.

Helicopter Stability and Control.

Introductory concepts of stability. Forward speed disturbance, vertical speed disturbance, pitching angular velocity disturbance, side-slip disturbance, yawing disturbance. Static stability of helicopters: longitudinal, lateraldirectional and directional. Dynamic stability aspects. Main rotor and tail rotor control. Flight and Ground Handling Qualities-General requirements and definitions. Control characteristics, Levels of handling qualities.

Flight Testing-

General handing flight test requirements and, basis of limitations.

Standards, and Specifications:

Scope of requirements. General and operational requirements. Military derivatives of civil rotorcraft. Structural strength and design for operation on specified surfaces. Rotorcraft vibration classification.

Conceptual Design of Helicopters:

Overall design requirements. Design of main rotors-rotor diameter, tip speed, rotor solidity, blade twist and aerofoil selection, Fuselage design, Empennage design, Design of tail rotors, High speed rotorcraft.

Course outcomes:

After studying this course, students will be able to:

1. Apply the basic concepts of helicopter dynamics.

2. Compute the critical speed by using various methods.

3. Distinguish the turborotor system stability by using transfer matrix and finite element formulation.

Graduate Attributes :

• Engineering Knowledge.
• Problem Analysis.
• Design / development of solutions
• Interpretation of data

Question paper pattern:

• The question paper will have ten questions.
• Each full question consists of 16 marks.
• There will be 2full questions (with a maximum of four sub questions) from each module.
• Each full question will have sub questions covering all the topics under a module.
• The students will have to answer 5 full questions, selecting one full question from each module.

Text Books:

1. J. Gordon Leishman, Principles of Helicopter Aerodynamics, Cambridge University Press, 2002.

2. George H. Saunders, Dynamics of Helicopter Flight, John Wiley & Sons, Inc, NY,1975. VISVESV

Reference Books:

1. W Z Stepniewski and C N Keys, Rotary Wing Aerodynamics, Dover Publications, Inc, New York, 1984.

2. ARS Bramwell, George Done, and David Balmford, Helicopter Dynamics, 2nd Edition, Butterworth-Heinemann Publication, 2001.

3. John, M. Seddon and Simon Newman, Basic Helicopter Aerodynamics, Wiley, 2011.

4. Gareth D. Padfield, Helicopter Flight Dynamics, 2nd Edition, Wiley, 2011.