SUMMARY THE THEORY OF FLIGHT BY
BRIAN NJERU GRADE 12 STUDY NOTES
Relative airflow - ANSWER-This is the airflow that approaches the wing
directly opposite the wing's direction of motion.
Angle of Incidence - ANSWER-This is the angle at which the wing is
mounted to the fuselage. It is measured between the chord line and the
aircraft's longitudinal axis or horizontal datum line.
With the right angle of incidence (most planes have a + angle of
incidence) we can improve flight visibility, enhance takeoff and landing
characteristics, and reduce drag in level flight.
Pressure distribution around an airfoil - ANSWER-The pressure along the
surface of an airfoil is not constant.
Once could measure the different pressures at point all over an airfoil
section.
The center of pressure is the "average" of all these pressures. It is the
point through which the aerodynamic force exerts itself.
Stalling - ANSWER-That angle of attack at which any further increase in
that angle of attack will result in a decrease in lift. (15-18 degrees).
A stalling wing is still generating lift. However the lift that the wing
generates is not enough to overcome the weight.
An aircraft wing will always stall at the same angle of attack which is
determined by the design of the wing.
A wing can stall at any airspeed, weight, C of G location, etc.
Stagnation point - ANSWER-a point where the relative airflow hits the
wing and then some wind diverges over the top of the wing and the rest
underneath the wing. This small point is called the stagnation point. The
build up of wind at this point also results in an increase of lift.
There can also be a stagnation point towards the back of the wing.
,Center of pressure rules - ANSWER-1) As I increase my angle of attach,
the center of pressure moves forward.
2) As the aircraft stalls, the center of pressure moves backwards.
Change in pressure distribution - ANSWER-As the angle of attack
increases, the pressure distribution changes and center of pressure
moves forward.
When a wing stalls the center of pressure moves rearward.
Wake turbulence - ANSWER-Wake turbulence is produced by the air
moving over the wing or airfoil.
Aircraft encountering a vortex will tend to roll with it. Wing tip vortices
are greatest while developing lift.
The vertical guests encountered when crossing through a vortex can
impose structural loads as high as 10 G's.
Vortices - ANSWER-When seen from behind the aircraft, the left wing tip
vortex turns clockwise and the right wing tip vortex turns
counterclockwise.
Both travel downwards and are partly responsible for induced drag.
The heavier and slower the plane the greater the vortex.
Clean airplane - ANSWER-Means that the airplane doesn't not have
anything on it that disrupts vortices, such as landing gears.
Wake turbulence avoidance - ANSWER-On takeoff stay upwind and plan
to be airborne before the rotation point of the previous taking off
airplane and beyond the touchdown point of the previous landing
airplane.
When landing plan to touch down before the rotation point of the taking
off aircraft and after the touchdown point of the previous landing
airplane.
Ground effect - ANSWER-When an aircraft is flown low to the ground the
formation of wingtip vortices is reduced, thus induced drag is reduced.
, The closer an airfoil is to the ground the greater the performance gained
from ground effect.
The downwash is also defected more parallel to the surface.
If a plane is too heavy, the pilot might not be able to pull it out of ground
effect and stall.
In short, the vertices hitting the ground create a tiny amount of lift.
4 main forces of flight - ANSWER-Thrust, Drag, Lift and Weight.
Chord line - ANSWER-An imaginary straight line drawn through the
airfoil from the leading edge to the trailing edge.
Lift - ANSWER-Force upward which sustains the airplane in flight.
Is the component of aerodynamic forces that is perpendicular to the
relative airflow. According to Newton, the downwash is what creates lift.
Is when there is a pressure difference between the lower and upper
surfaces.
Has a vertical and horizontal component.
Acts through the center of pressure.
Is created by Bernoulli, Newtons, Euler and Navier strokes theories.
Relative Wind - ANSWER-the flow of air which moves opposite the flight
path of an airplane.
Airfoil - ANSWER-A part or surface, such as a wing, propeller blade, or
rudder, whose shape and orientation are designed to obtain a reaction
from the air through which it moves to obtain lift.
Camber - ANSWER-Curvature of the upper and lower surfaces of an
airfoil. Usually the upper surface has a greater camber than the lower.
Lift equation - ANSWER-P is air density.
V is air velocity.
S is total surface area of wing .
CL depends on the airfoil and angle of attack.
Induced drag - ANSWER-Caused by those parts of an airplane which are
active in producing lift (eg. wings).
Results from the creation of lift.
BRIAN NJERU GRADE 12 STUDY NOTES
Relative airflow - ANSWER-This is the airflow that approaches the wing
directly opposite the wing's direction of motion.
Angle of Incidence - ANSWER-This is the angle at which the wing is
mounted to the fuselage. It is measured between the chord line and the
aircraft's longitudinal axis or horizontal datum line.
With the right angle of incidence (most planes have a + angle of
incidence) we can improve flight visibility, enhance takeoff and landing
characteristics, and reduce drag in level flight.
Pressure distribution around an airfoil - ANSWER-The pressure along the
surface of an airfoil is not constant.
Once could measure the different pressures at point all over an airfoil
section.
The center of pressure is the "average" of all these pressures. It is the
point through which the aerodynamic force exerts itself.
Stalling - ANSWER-That angle of attack at which any further increase in
that angle of attack will result in a decrease in lift. (15-18 degrees).
A stalling wing is still generating lift. However the lift that the wing
generates is not enough to overcome the weight.
An aircraft wing will always stall at the same angle of attack which is
determined by the design of the wing.
A wing can stall at any airspeed, weight, C of G location, etc.
Stagnation point - ANSWER-a point where the relative airflow hits the
wing and then some wind diverges over the top of the wing and the rest
underneath the wing. This small point is called the stagnation point. The
build up of wind at this point also results in an increase of lift.
There can also be a stagnation point towards the back of the wing.
,Center of pressure rules - ANSWER-1) As I increase my angle of attach,
the center of pressure moves forward.
2) As the aircraft stalls, the center of pressure moves backwards.
Change in pressure distribution - ANSWER-As the angle of attack
increases, the pressure distribution changes and center of pressure
moves forward.
When a wing stalls the center of pressure moves rearward.
Wake turbulence - ANSWER-Wake turbulence is produced by the air
moving over the wing or airfoil.
Aircraft encountering a vortex will tend to roll with it. Wing tip vortices
are greatest while developing lift.
The vertical guests encountered when crossing through a vortex can
impose structural loads as high as 10 G's.
Vortices - ANSWER-When seen from behind the aircraft, the left wing tip
vortex turns clockwise and the right wing tip vortex turns
counterclockwise.
Both travel downwards and are partly responsible for induced drag.
The heavier and slower the plane the greater the vortex.
Clean airplane - ANSWER-Means that the airplane doesn't not have
anything on it that disrupts vortices, such as landing gears.
Wake turbulence avoidance - ANSWER-On takeoff stay upwind and plan
to be airborne before the rotation point of the previous taking off
airplane and beyond the touchdown point of the previous landing
airplane.
When landing plan to touch down before the rotation point of the taking
off aircraft and after the touchdown point of the previous landing
airplane.
Ground effect - ANSWER-When an aircraft is flown low to the ground the
formation of wingtip vortices is reduced, thus induced drag is reduced.
, The closer an airfoil is to the ground the greater the performance gained
from ground effect.
The downwash is also defected more parallel to the surface.
If a plane is too heavy, the pilot might not be able to pull it out of ground
effect and stall.
In short, the vertices hitting the ground create a tiny amount of lift.
4 main forces of flight - ANSWER-Thrust, Drag, Lift and Weight.
Chord line - ANSWER-An imaginary straight line drawn through the
airfoil from the leading edge to the trailing edge.
Lift - ANSWER-Force upward which sustains the airplane in flight.
Is the component of aerodynamic forces that is perpendicular to the
relative airflow. According to Newton, the downwash is what creates lift.
Is when there is a pressure difference between the lower and upper
surfaces.
Has a vertical and horizontal component.
Acts through the center of pressure.
Is created by Bernoulli, Newtons, Euler and Navier strokes theories.
Relative Wind - ANSWER-the flow of air which moves opposite the flight
path of an airplane.
Airfoil - ANSWER-A part or surface, such as a wing, propeller blade, or
rudder, whose shape and orientation are designed to obtain a reaction
from the air through which it moves to obtain lift.
Camber - ANSWER-Curvature of the upper and lower surfaces of an
airfoil. Usually the upper surface has a greater camber than the lower.
Lift equation - ANSWER-P is air density.
V is air velocity.
S is total surface area of wing .
CL depends on the airfoil and angle of attack.
Induced drag - ANSWER-Caused by those parts of an airplane which are
active in producing lift (eg. wings).
Results from the creation of lift.
