15AE73 AIRCRAFT STABILITY AND CONTROL syllabus for AE

Static Longitudinal Stability and Control-Stick Fixed

Historical perspective, Aerodynamic Nomenclature, Equilibrium conditions, Definition of static stability, Definition of longitudinal static stability, stability criteria, Contribution of airframe components: Wing contribution, Tail contribution, Fuselage contribution, Power effectsPropeller airplane and Jet airplane Introduction, Trim condition. Static margin. stick fixed neutral points. Longitudinal control, Elevator power, Elevator angle versus equilibrium lift coefficient, Elevator required for landing, Restriction on forward C.G. range.

Static Longitudinal Stability& Static Directional Stability and Control-Stick free

Introduction, Hinge moment parameters, Control surface floating characteristics and aerodynamic balance, Estimation of hinge moment parameters, The trim tabs, Stick-free Neutral point, Stick force gradient in unaccelerated flight, Restriction on aft C.G.Introduction, Definition of directional stability, Static directional stability rudder fixed, Contribution of airframe components, Directional control. Rudder power, Stick-free directional stability, Requirements for directional control, Rudder lock, Dorsal fin. One engine inoperative condition. Weather cocking effect.

Static lateral dynamic & longitudinal stability and control

Introduction, definition of Roll stability. Estimation of dihedral effect., Effect of wing sweep, flaps, and power, Lateral control, Estimation of lateral control power, Aileron control forces, Balancing the aileron. Coupling between rolling and yawing moments. Adverse yaw effects. Aileron reversal. Definition of Dynamic longitudinal stability. Types of modes of motion: long or phugoid motion, short period motion. Airplane Equations of longitudinal motion.

Estimation of Dynamic Derivatives

Derivation of rigid body equations of motion, Orientation and position of the airplane, gravitational and thrust forces, Small disturbance theory. Aerodynamic force and moment representation, Derivatives due to change in forward speed, Derivatives due to the pitching velocity, Derivatives due to the time rate of change of angle of attack, Derivatives due to rolling rate, Derivatives due to yawing rate.

Dynamic Lateral and Directional Stability

Routh’s criteria. Factors affecting period and damping of oscillations. Effect of wind shear. Flying qualities in pitch. Cooper-Harper Scale. Response to aileron step-function, side-slip excursion. Dutch roll and Spiral instability. Auto- rotation and spin. Stability derivatives for lateral and directional dynamics.

Course outcomes:

After studying this course, students will be able to:

1. Apply the basic concepts of aircraft stability and control.

2. Differentiate the static longitudinal and static directional stability.

3. Estimate the dynamic derivatives.

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 2 full 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. Perkins, C.D., and Hage, R.E., “Airplane Performance stability and Control”, John Wiley Son Inc, New York, 1988.

2. Nelson, R.C. “Flight Stability and Automatic Control”, McGraw-Hill Book Co., 2007.

Reference Books:

1. Bandu N. Pamadi, `Performance, Stability, Dynamics and Control of Airplanes`, AIAA 2nd Edition Series, 2004.

2. John D. Anderson, Jr., “Introduction to flight” McGraw-Hill, International Editions, Aerospace Science Technology Editions, 2000.

3. W.J. Duncan, The Principles of the Control and Stability of Aircraft, Cambridge University Press, 2016.