Slide 1 : 4.06 Theory of Flight - Drag
Slide 2 : Lift acts 90 degrees to what?
The chord
As lift increases what happens to drag?
It increases
Define Centre of Pressure
The point in an airfoil where the average pressure of a wing lies
Define Angle of Attack
The angle at which the airfoil meets the relative airflow
Slide 3 : MTPs
Drag
Types of Drag
Wing tip vortices
Streamlining
Flying for Range and Endurance
Best angle versus best rate
Slide 4 : Drag
Is the resistance an airplane experiences in moving forward through the air
Slide 5 : There are 2 main types of Drag
Parasite Drag– This drag is further broken down
Form drag
Skin Friction
2. Induced Drag
Slide 6 : Parasite Drag
Drag of all those parts the airplane which DO NOT contribute to lift
This drag is hard to eliminate but it can be minimized
Landing gear
Antennas
Struts
Wing tip fuel tanks
Slide 7 : Form Drag
Drag created by the for or shape of the body as it resists motion through the air
Slide 8 : Skin Friction
The tendency of air flowing over the body to cling to its surface
What causes it to resist motion?
Ice on the wings
Dirt build up
Slide 9 : Induced Drag
Caused by those parts of an airplane which are active in producing lift
Cannot be eliminated Lift Drag
Slide 10 : Induced drag can be reduced with a high aspect ration
Slide 11 : Over the top of the wing the airflow goes inward
Under the bottom of the wing the airflow moves outward This creates a swirling motion off the wing tip called a vortex Due to the pressure changes
Slide 12 : The less drag you have…
Flying a glider: the further you can fly
Flying an airplane: the less fuel you use
Therefore streamlining is important
A design device by which a body is shaped to minimize drag
Slide 13 : An aircraft will glide further if you optimized the lift / drag ratio
The airspeed that gives the best lift to drag ratio is called “Gliding for Range” Why would this be useful?
Slide 14 : An airspeed slightly less than best range will allow the aircraft to stay in the air the longest amount of time
This is called gliding
for maximum endurance Why would this be useful?
Slide 15 : Distance travelled versus time
Affected by wind
The speed which gives the most horizontal distance for a given time Why would this be useful?
Slide 16 : Altitude gained versus time
Not affected by wind
The speed which gives the most altitude for a given time Why would this be useful?
Slide 17 : Fill in the diagram
Is it possible to eliminate induced drag? Why or why not?
Slide 18 : What is the difference between maximum glide and maximum endurance
Is an aircraft’s best rate speed affected by wind?
What are some ways to minimize drag?