1. References: FTGU: pg 17- 18, 34-35
Theory of Flight
6.08 Loads and Load Factors
References:
FTGU: pg , 34-35

2. 6.08 Theory of Flight – Review
Where is the centre of pressure in straight flight, just before a stall and after a stall?
Just forward of the centre of the airfoil, near the front of the airfoil, at the back of the airfoil.
What are some factors that increase stalling speed?
Forward C of G, turns, increased weight, turbulence
What are the symptoms of a stall?
Buffeting, low airspeed, nose up attitude, stall horn, sloppy controls
When can an aircraft stall?
If the critical A of A is exceeded, at any airspeed or altitude if the critical A of A is exceeded

3. 6.08 Theory of Flight – Loads
MTPs
Definitions
Weight
Loading – Live/Dead
Load Factor
Load Factor changes
Load Factor in Turns
Forces in a turn

4. Weight is greater than lift?
6.08 Theory of Flight – Weight
What happens if…
Weight is greater than lift?
Lift is greater than weight?

5. 6.08 Theory of Flight – Loading
Gross weight of the aircraft divided by the area of lifting surfaces (wings)
2 Types
Live Load
Dead Load
= Load

6. 6.08 Theory of Flight – Loading
Dead Load
The load put on the aircraft when it is sitting on the ground. Weight due to gravity.
Live Load
Additional load due to acceleration or change in direction associated with manoeuvres in flight

7. LOAD FACTOR
Additional weight carried by the wings due to centrifugal force.
Load Factor can increase stall speed.
As Bank angle increases load factor increases

8. 6.08 Theory of Flight – Load Factor
Ratio of the actual load acting on the wings to the gross weight of the airplane
Live Load : Dead Load
In straight and level flight the load factor is 1

9. 6.08 Theory of Flight – Load Factor Changes
The load factor is increased any time the aircraft is not in straight and level flight
Due to:
Performing aircraft manoeuvre
Wind Gusts
Turbulence

10. 6.08 Theory of Flight – Load Factor Changes
Is loading a bad thing?....No but it could cause problems
1. Structural Limitation
Each aircraft is designed with a max load factor that should not be exceeded as permanent damage may occur
SGS 2-33a Max Load = 4.67 G
C152 Max Load = 4.4 G

11. 6.08 Theory of Flight – Load Factor Changes
2. Increased Stall speed
Increased load factor during manoeuvres in flight requires increased lift to maintain level flight
Critical angle of attack is reached at an increased speed
Stall speed increases
Speed to reach
critical angle of
attack
Load factor
during flight
Stall
speed

12. 6.08 Theory of Flight – Load Factor in Turns
As angle of bank is increased in a turn the load factor and amount of lift required also increases
Load factor increases exponentially with angle of bank
Angle of Bank
Load Factor
15°
1.04 G
30°
1.15 G
45°
1.41 G
60°
2 G

13. 6.08 Theory of Flight – Forces in a Turn
Lift versus drag
How do we create more lift?
Lift is divided into two components = vertical and horizontal

14. 6.08 Theory of Flight – Forces in a Turn
Vertical component  opposes weight
Horizontal component  causes airplane to turn
This horizontal component is known as centripetal force

15. 6.08 Theory of Flight – Forces in a Turn
Pulls plane into the
centre of the
turn
Resulting lift
due to added
horizontal
components
Pulls plane to
outside of
the turn

16. Centripetal versus Centrifugal Force
6.08 Theory of Flight – Forces in a Turn
Centripetal versus Centrifugal Force
Centripetal Force
Centrifugal Force
Pulls INTO the turn
Pushes AWAY from turn
Genuine force
Inertial (fictitious) force
This is the force to feel going around a corner in a vehicle. It pulls in the opposite direction of a turn.

17. 6.08 Theory of Flight – Confirmation
Fill in the blanks:
Load =
What is the difference between live load and dead load?

18. 6.08 Theory of Flight – Confirmation
Label where the centripetal and centrifugal forces are.
If this aircraft is doing a 60 degree turn, how many Gs are being produced?
When does and aircraft produce a 1G force?

19. 6.08 Theory of Flight –Loading
What we have learned…
Definitions
Weight
Loading – Live/Dead
Load Factor
Load Factor changes
Load Factor in Turns
Forces in a turn