Static Stability and Dynamic Stability
B
D
E
C
A
A and C : Stable (Statically)
B : Statically Unstable
A: Dynamically also Stable
C: Dynamically Unstable
E: Neutrally Stable
Static Stability: Initial tendency of the system
Dynamic Stability: Behaviour wit

Topic : Introduction to Aerodynamic Fundamentals
What is an airfoil?
An airfoil is a device that
can produce circulation in
its vicinity without itself
actually rotating
-F. W. Lanchester
Topic : Introduction to
Aerodynamic Fundamentals
What is an airfoil

AERO3630 Lecture on : Thin Airfoil Theory
The concept is:
Describe a shape mathematically
How?
using singular function(s)
AERO3630 Lecture on : Thin Airfoil Theory
Assumptions:
Ideal Flow (Potential Flow)
Incompressible flow
Further assumptions:
Low angle

Topic : Compressible flow
Remind yourself that the objective in
subsonic flow consideration is to :
KEEP FLOW ATTACHED
STOP FLOW SEPARATION
Topic : Compressible flow
Transonic flow?
It is essentially a mixed flow
On the wing sections, some parts
remain su

AERO3630 Lecture on : Lifting Line/Finite Wing Theory
You are now starting to learn how to
determine lift on a wing (3D)
Start from where you left off in Thin Airfoil
Theory
Imagine the wing is made up of infinitesimal
airfoil sections spanning a distance

Topic : Dimensional Analysis
Dimensional analysis is an analytical tool that
helps us organise empirical information about
a fluid flow:
It helps us to simplify the relationship
between things we want to know about a flow
and the constraints we impose upo

Topic: Preparing For Experiments
Significance of some
important Nondimensional numbers
Remind yourself how you go
about making these nondimensional numbers
;
Topic: Preparing For Experiments
Topic: Preparing For Experiments
Topic: Preparing For
Experiment

Topic: Application of Potential flow Concept
Let us recall the main variables:
Velocity, V
Density,
Pressure, p
Temperature, T
Viscosity (dynamic),
Topic: Application of Potential flow Concept
Let us make some initial assumptions about the variables:
Ve

Topic 3 : Modelling
Once you have performed dimensional analysis and
obtained non-dimensional groups the next task is
prepare for physical experimentations using wind
tunnels.
So you have to prepare an engineering model for testing. An engineering
model i

AERO3630 Aerodynamics
Flow Visualisation Experiment
AERO3630 Aerodynamics
Flow Visualisation Experiment
Aim
The overall aim of this experiment is to learn how the aerodynamic forces acting on a body in a flow
can be manipulated.
Methodology
The methodolog

AERO3630 Aerodynamics
Potential Flow Experiment
AERO3630 Aerodynamics
Potential Flow Experiment
Aim
The overall aim of this experiment is to demonstrate the significance and limitations of the concept of
potential flow by examining the pressure distributi

AERO3630 Aerodynamics
Airfoil Pressure Distribution Experiment
AERO3630 Aerodynamics
Airfoil Pressure Distribution Experiment
Aims
The overall aim of this experiment is to learn how the lift force on a body moving in a fluid can be
determined.
Methodology

AERO3630 Aerodynamics
Airfoil Drag Experiment
AERO3630 Aerodynamics
Airfoil Drag Experiment
Aims
The overall aim of this experiment is to learn how the total drag experienced by a body moving in a
fluid can be determined.
Methodology
Two different methods

AERO3630 Aerodynamics
AF10 Air Flow Bench
AERO3630 Aerodynamics
AF10 Air Flow Bench
The AF10 Air Flow Bench is modular in design with an interchangeable open test section allowing a
variety of different hands-on experiments to be performed as seen in Figu

Lecture on Aerodynamics in relation to AERO3630:
Topic: Introduction to Aerodynamic Fundamentals
Aerodynamics is a subject of intellectual beauty,
composed and drawn by many great minds over the
centuries
-J. D. Anderson, Jr.
faculty of engineering
Topic:

Topic: Technical Assessment
Now that you have learnt about the sources of equations to
create mathematical model for flow analysis and the tools of
investigation, let us now concentrate what are most
important parameters we should be concerned with.
Let u

Review Questions for Statics:
1. Define stability? Distinguish between the static, dynamic and neutral stability by
taking a suitable example.
2. Apply the above definitions for an aircraft in flight and hit by a gust and discuss
its behaviour.
3. Define

Equations of Motion of the Aircraft
Mathematical Modelling of the Aircraft
Newtons Second Law of motion:
Relate the summation of external forces and moments to the
linear and angular accelerations of the system or body
Newtons Laws valid in the Inertial F

Equations of motion of Longitudinal Dynamics
u + g Cos 0 = Xu u + Xw w + Xw w + Xqq + Xee
w +g Sin 0 - U0 q = Zu u + Zw w + Zw w + Zq q + Zee
q = Mu u + Mw w + Mw w + Mq q + Mee
=q
complete linearized set of equations for the longitudinal
dynamics
The var

AUTOPILOTS FOR LONGITUDINAL DYNAMICS
Definition: AutoPilot
Self Pilot, Automatic Pilot
Pilot: Depending upon the situation, whoever who decides the
steering of the aircraft
Steering : Decides the path the aircraft to follow
Command : The input that goes t

Equations of Motion for the lateral dynamics:
The three equations unutilized during the longitudinal dynamics are;
Y = m(V + UR WP)
L = Ix P - Ixz R + QR (Iz Iy) PQ Ixz
N = Iz R IxzP + PQ (Iy Ix) + QR Ixz
Three non-linear equations, coupled
The equilibriu

Effect of Variation of Stability Derivatives
1.
2.
3.
4.
Wind tunnel Tests
Numerical packages
Different Flight Regimes
Control Effectiveness
a. Damping and Frequency of Dutch Roll
b. No effect on Roll or Spiral Mode
Dihedral Effect
a. Spiral Mode
b. No si

Review Questions for Statics:
1. Define stability? Distinguish between the static, dynamic and neutral stability by
taking a suitable example.
2. Apply the above definitions for an aircraft in flight and hit by a gust and discuss
its behaviour.
3. Define

1. Show that the poles of the aircraft are the same as the eigenvalues of the matrix A
(the system dynamic matrix).
2. What do you infer from the above two questions?
3. Discuss qualitatively the transfer functions of an aircraft.
4. What are short period