1. Uncontrolled copy not subject to amendment
Principles of Flight

2. Principles of Flight
Learning Outcome 4: Be able to apply the principles of flight and control to gliders

3. REVISION

4. Questions What effect does a Trailing Edge Flap have on the Stalling
Speed?
Higher.
Lower.
c. The same.
d. No difference.

5. Questions One type of Leading Edge Flap is: Plain. Slot. c. Split.
d. Kruger.

6. Questions What are some of the High Lift Devices on the Leading
Edge called?
a. Plain Flaps.
b. Ailerons.
c. Slats.
d. Split Flaps.

7. GLIDING

8. Gliding
Objectives:
List and describe the Forces acting on Glider during
balanced flight.
State the effect of Wind on the distance travelled
over the ground.
Explain the effects of Airbrakes on Glide Performance.
Understand the ‘Gliding Angle’ (Angle of Attack).

9. Gliding What are the Forces acting on a Powered Aircraft? Lift Thrust
Drag
What forces are present in S&L Flt?
Where do these forces act through? Show Centre of Gravity CG.
Could show CG using an odd shaped object
Weight
Are these forces in Balance for Straight & Level Flight?

10. Gliding What would happen if we had NO Thrust? Lift Thrust Drag Weight
What forces are present in S&L Flt?
Where do these forces act through? Show Centre of Gravity CG.
Could show CG using an odd shaped object
Weight
What do we need to do to overcome the Drag?

11. Gliding Lift Drag Weight What forces are present in S&L Flt?
Where do these forces act through? Show Centre of Gravity CG.
Could show CG using an odd shaped object
Weight

12. Gliding Lift Drag Weight What forces are present in S&L Flt?
Where do these forces act through? Show Centre of Gravity CG.
Could show CG using an odd shaped object

13. Gliding Speed The car can ‘coast’ down the hill with no engine. How?
GRAVITY
Can we use ‘Gravity’ to fly a Glider?

14. Gliding Speed A Glider uses Gravity to Descend.
The Airflow over the Wing
produces Lift.
How do we Control the Speed?

15. Gliding Lift If the Nose is raised, What will happen? Speed
What forces are present in S&L Flt?
Where do these forces act through? Show Centre of Gravity CG.
Could show CG using an odd shaped object
Speed
Lift and Speed reduce.
The Rate of Descent also reduces!

16. Gliding Lift If the Nose is lowered, What will happen? Speed
What forces are present in S&L Flt?
Where do these forces act through? Show Centre of Gravity CG.
Could show CG using an odd shaped object
Speed
Lift and Speed increase.
The Rate of Descent also increases!

17. Gliding
Remember:
If you fly too slowly Lift will be lost and the Glider will Stall.
If you fly too fast the Rate of Descent will be High.

18. Gliding How far will a Glider travel?
The flatter the Gliding Angle, the further the
distance over the ground.
The steeper the Gliding Angle, the shorter the
What is the BEST Angle to Fly?

19. Lift/Drag Ratio α CL CD α 0°

20. Lift / Drag Ratio Less Lift More Drag Usual Angles of flight CL CD
Angle of attack
Most efficient
Less Lift
More Drag

21. Speed to Fly? DRAG IAS VIMD We know the best Angle to fly, but what
TOTAL DRAG
We know the best Angle to fly, but what
is the Best Speed to Fly?
DRAG
Discuss briefly the components, but emphasise the form drag part.
This is discussing variation of airspeed and drag.
Not important if they don’t get this.
VIMD
ZERO LIFT DRAG
LIFT DEPENDENT DRAG
IAS

22. Gliding The Pilot’s Notes will give information on Gliding Speeds.
For Example:
A Viking Glider’s angle is about 1 in 35.
Therefore, from a height of 3,280 ft (1 kilometre),
In Still Air,
It will travel about 35 kilometres.

23. Effect of Wind What will happen when flying at the same Airspeed
and Angle of Attack?

24. Effect of Wind What will happen when flying at the same Airspeed
and Angle of Attack?
Still Air
Headwind
Tailwind

25. Effect of Airbrake When ‘Opened’ what happens to the Drag?
The Drag Increases.
What Must be done to maintain Airspeed?
Lower the Nose.

26. Effect of Airbrake

27. Effect of Airbrake =Steeper Descent +Shorter Ground Distance
Airbrake In
Airbrake Out
=Steeper Descent
+Shorter Ground Distance

28. Airbrakes

29. Any Questions?

30. Gliding
Objectives:
List and describe the Forces acting on Glider during
balanced flight.
State the effect of Wind on the distance travelled
over the ground.
Explain the effects of Airbrakes on Glide Performance.
Understand the ‘Gliding Angle’ (Angle of Attack).

31. Questions Name the Forces Acting on a Glider in Normal Flight.
a. Force, Weight and Lift.
b. Drag, Weight and Thrust.
Drag, Weight and Lift.
Drag, Thrust and Lift.

32. Questions How does a Glider Pilot Increase the Airspeed?
a. Operate the Airbrakes.
b. Lower the Nose by pushing the Stick Forward.
Raise the Nose by pulling the Stick Back.
Lower the Nose by pulling the Stick Back.

33. Questions A Viking Glider descends from 1640 ft (0.5 km).
How far over the ground does it Travel (in still air)?
a kms.
b. 35 kms.
70 kms.
8.75 kms.

34. Questions When flying into a Headwind, the distance covered
over the ground will:
a. Be the same.
b. Decrease.
Increase.
Take you to Burger King.