Aerospace Engineering: Wing Flaps and Rudder

Wing Flaps

• One purpose of wing flaps is to enable the pilot to make steeper approaches to landing without increasing airspeed.
• Another purpose of wing flaps is to relieve the pilot from maintaining continuous pressure on the controls.
• Wing flaps increase wing camber and angle of attack, enabling steeper approaches to landing.
• Trim tabs, not wing flaps, help relieve control pressures.
• Wing area usually remains the same, except for specialized flaps increasing wing area.

Flaps During Approach and Landing

• Flaps increase lift and induced drag, enabling the pilot to decrease the angle of descent without increasing the airspeed.
• Flaps increase lift at slow airspeeds, allowing for touchdown at a lower indicated airspeed.

Rudder Purpose

• The rudder controls yaw, which is rotation about the airplane's vertical axis.
• Ailerons (not the rudder) control overbanking tendency in steep turns.
• Ailerons correct for the tendency of outside wings to travel faster and lift more, opposing overbanking tendency.
• Roll is movement around the longitudinal axis and is controlled by ailerons.

Primary Flight Control Surfaces

• The three primary flight control surfaces are the ailerons, the elevator, and the rudder.
• Flaps are not a primary flight control surface.
• The stabilator or elevator is a primary flight control surface.
• Ailerons are also a primary flight control surface.

Airplane Aerodynamics

• The four forces acting on an airplane in flight are lift, weight, thrust, and drag.
• Lift opposes weight.
• Thrust opposes drag.
• Lift is produced by wings opposing weight.
• Thrust is generated by the engine/propeller.
• Drag results from air resistance as the airplane moves.

Angle of Attack

• Angle of attack is the angle between the wing's chord line and the relative wind.
• The chord line is a straight line from leading edge to trailing edge.
• Relative wind is the direction of airflow relative to the wing.
• Angle of attack is not dependent on the airplane's longitudinal axis.
• The angle of attack at which an airplane wing stalls remains the same regardless of gross weight.

Airplane Turn

• The horizontal component of lift causes an airplane to turn.
• The vertical component of lift opposes weight and controls vertical, not horizontal movement.
• Centrifugal force is not part of the turning force.
• Inherently stable aircraft are easier to control than inherently unstable aircraft.

Compass Turning Error

• In the Northern Hemisphere, a magnetic compass will normally indicate a turn toward the north if an airplane is accelerating while on an east or west heading.
• Compass readings are accurate in straight-and-level, unaccelerated flight.
• The compass will not be accurate during turns.

Pitot-Static System

• Airspeed indicator is inoperative if the pitot tube is clogged.
• Altimeter and vertical speed indicator will be inoperative if the static vents are clogged.
• The pitot system is part of the airspeed indicator.
• The static system is part of the altimeter and vertical speed indicator.

Airspeed Indicator

• The red line represents the never-exceed speed (the highest speed).
• Maneuvering speed and turbulent speed are not directly indicated on the airspeed indicator.

Density Altitude

• Density altitude is the pressure altitude corrected for non-standard temperature.
• Density altitude is the same as pressure altitude at standard temperature.

Engine Overheating

• To aid in cooling an engine that is overheating during a climb, reduce the rate of climb and increase airspeed.

Abnormal Combustion

• Use of lower fuel grade for an airplane engine will most likely cause detonation.

Aviation Fuel

• Substitutions for aircraft fuel should use higher octane if recommended octane is unavailable.

Explore the essential functions of wing flaps and rudders in aircraft control. This quiz covers the purposes of wing flaps during landing approaches and the role of rudders in managing yaw. Test your understanding of these critical aviation concepts.