Theory of Flight

1
Theory of Flight

• 6.03 Secondary Controls and
• Secondary Effects of Controls
• References
• FTGU pages 15, 28, 29

2
Review

• 1. What control surface causes roll?
• 2. What movement does the elevator create?
• 3. Which axis does yaw act around?
• 4. Name the 2 types of fuselage construction.

3
6.03 Secondary Controls andSecondary Effects of
Controls

• MTPs
• Trim
• Spoilers and Dive Breaks
• Flaps
• Secondary Effects of Controls
• Coordination

4
Trim

• Trim tab adjustable device located on the
  trailing edge of control surfaces
• Purpose alleviates pressure on the controls
• Other types of trim are bungees connected to the
  control column
• Most often only on the elevator

5
Trim
The trim tab moves in the opposite direction as
the control surface
6
Trim

• Trim in a glider
• No trim tabs
• Types
• - side trim (bungee)
• - stick trim (ratchet)

Bungee Trim
7
Spoilers Dive Brakes

• Primarily used in glider flying
• Spoilers are hinged plates on top of the wing
• disrupt the airflow over the wing to spoil the
  lift (Top)
• Dive Brakes increase drag (Bottom)

NASA applet - http//www.grc.nasa.gov/WWW/k-12/air
plane/spoil.html
8
Spoilers Dive Brakes

• Purpose allows the pilot to control the rate of
  decent during final approach and landing
• - Spoilers and dive breaks increase drag and
  decrease lift

9
Flaps

• Increases the camber of the wing
• This increases the lift and the drag
• Known as a high lift device
• Allows the aircraft to have a steeper approach
  path with a decreased stall speed
• Allows glider pilot to fly slower in a thermal

10
Flaps

• Types of flaps

11
Secondary Effects

• The air movement over control surfaces when they
  are moved causes adverse effects
• When you yaw you get Roll
• When you roll you get Adverse yaw

12
Roll from Yaw

• Roll from yaw
• When rudder is applied, the wing on the outside
  of the turn moves faster, which causes it to
  experience more lift

Faster more lift
13
Roll from Yaw
MORE LIFT
CAUSES ROLL TO THE LEFT
FASTER
YAW LEFT
14
Adverse Yaw from Roll

• When ailerons are applied the plane has a
  tendency to yaw away from the lower wing because
  of aileron drag.
• The wing that rises experiences more lift, but
  also more induced drag.

15
Adverse Yaw from Roll
Right aileron UP MORE LIFT MORE DRAG
ROLL CAUSES ADVERSE YAW
Left aileron DOWN LESS LIFT LESS DRAG
16
Coordination

• To turn the aircraft without causing unnecessary
  drag, aileron and rudder must be used.
• Using too much rudder will cause a skidding
  turn.
• Using too little (or opposite) rudder will cause
  a slipping turn.

17
Coordination

• You slip in and skid out. Think of driving and
  skidding around a corner.

18
Confirmation

• How is adverse yaw created?
• Why is there roll when an airplane is yawed?
• What is the purpose of flaps?
• Name 2 types of trim.
• What is trim used for?
• What is the difference between slipping and
  skidding?

19
Confirmation

• Draw on the airplane where the following go
• Flaps
• Spoilers
• Elevator Trim tab
• Aileron Trim tab

20
C-130 Deploying Flares