Basic Aerodynamics and Stability
Presented by: Mr Jamie Presser
Topic:
Overview of basic aerodynamics, flight controls and
effects of Centre of Gravity on stability
Definition of Controlled
Flight
Controlled Flight is:
The ability to produce movements about
the various axis that,
 Provide corrections
 Cause movement in the desired
direction
Aerodynamic Terms
Chord line:

Line running from the leading edge
point of min radius to trailing edge
Chord:
 Length of Chord line
Aerodynamic Terms
Mean camber line:
 Line running half way between upper
and lower surface of aerofoil
Camber:
 Distance between chord line and mean
camber line
Aerodynamic Terms
CoP
Chord Line
Angle
Relative Airflow
Angle of Attack
 Angle between chord line and Relative
airflow
Centre of Pressure (CoP)
 Point where all aerodynamic pressures
can be represented as a single vector
Bernoulli's Theorem
Given:
Total Pressure = P0
Static Pressure = P1
Dynamic Pressure = P2
P0 = P1 + P2
Bernoulli's Theorem
Air Flow
Restriction
P0 =
P1 +
P2
Lower static pressure
Higher static pressure
Primary Flight Controls
Thrust
Aileron
Rudder
Aileron
Elevator
Elevator
Control
movement


Primary Response = Change in Pitch
Secondary Response = Change in Speed
Ailerons
Control
Movement


Primary Response = Roll
Secondary Response = Yaw
Rudder
Control
Movement


Primary Response = Yaw
Secondary Response = Roll
Payload Aft of CoG
Payload
Aircraft balanced with
payload fitted – Nose down
tendency on release
Naturally stable
Aircraft balanced without
payload fitted – Unstable
until payload released
Unstable – Not recommended
Payload Forward of CoG
Payload
Aircraft balanced without
payload fitted – Nose down
tendency until release
Naturally stable
Aircraft balanced with
payload fitted – Unstable
when payload released
Unstable Not recommended
Payload At CoG
Payload
No change on payload release
Ideal
Predator
Global Hawk
Reaper
Heron
Shadow
Avitus - Petrel
Boeing X-37
Jindivick
Fire Scout
Any Questions?