Theory of Flight - 608 Dukes - Home
Transcript of Theory of Flight - 608 Dukes - Home
Theory of Flight
6.03 Secondary Controls and
Secondary Effects of Controls References:
FTGU pages 15, 28, 29
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.
6.03 Secondary Controls and
Secondary Effects of Controls
• MTPs:
– Trim
– Spoilers and Dive Breaks
– Flaps
– Secondary Effects of Controls
– Coordination
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
Trim
• Trim in a glider – No trim tabs
• Types
- side trim (bungee)
- stick trim (ratchet)
Bungee Trim
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/airplane/spoil.html
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
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
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
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
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.
Adverse Yaw from Roll
Left aileron DOWN LESS LIFT LESS DRAG
Right aileron UP MORE LIFT MORE DRAG
ROLL CAUSES ADVERSE YAW
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”.
Confirmation
1. How is adverse yaw created?
2. Why is there roll when an airplane is yawed?
3. What is the purpose of flaps?
4. Name 2 types of trim.
5. What is trim used for?
6. What is the difference between slipping and skidding?
Confirmation
Draw on the airplane where the following go:
• Flaps
• Spoilers
• Elevator Trim tab
• Aileron Trim tab