p.10
Trim Systems and Their Functions
How does a trim tab affect the elevator's movement?
A trim tab positioned up forces the elevator down, causing the tail to move up and the nose to move down.
p.10
Secondary Flight Controls: Flaps and Spoilers
What is the effect of leading edge flaps on an aircraft?
They increase both C_L-MAX and the camber of the wings.
p.3
Primary Flight Controls: Ailerons, Elevator, and Rudder
What design features limit flight control surface deflection?
Control-stop mechanisms and limited movement of the control column or rudder pedals.
p.11
Secondary Flight Controls: Flaps and Spoilers
What is the purpose of an antiservo tab?
To streamline the control surface and make the stabilator less sensitive by opposing the pilot's force.
p.11
Secondary Flight Controls: Flaps and Spoilers
What are balance tabs used for in aircraft?
To decrease excessively high control forces by counterbalancing air pressure against the primary control surface.
p.3
Primary Flight Controls: Ailerons, Elevator, and Rudder
What axis does the aileron control?
The longitudinal axis (roll).
p.11
Trim Systems and Their Functions
What is a ground adjustable tab?
A nonmovable metal trim tab on the rudder that is bent on the ground to apply a trim force.
p.12
Primary Flight Controls: Ailerons, Elevator, and Rudder
How is the jackscrew operated in small aircraft?
Cable operated with a trim wheel or crank.
p.3
Primary Flight Controls: Ailerons, Elevator, and Rudder
What is the purpose of design limits on flight control surfaces?
To prevent the pilot from inadvertently overcontrolling and overstressing the aircraft.
p.1
Mechanical Flight Control Systems
What are the basic components of mechanical flight control systems?
Rods, cables, pulleys, and sometimes chains.
p.7
Primary Flight Controls: Ailerons, Elevator, and Rudder
What is the purpose of an elevator down spring?
To supply a mechanical load to lower the nose when aerodynamic efficiency is inadequate due to an aft CG condition.
p.12
Autopilot Systems and Their Integration
What are common features of an autopilot system?
Altitude and heading hold.
p.1
Mechanical Flight Control Systems
Why are mechanical flight control systems still in use today?
Because the aerodynamic forces are not excessive in certain aircraft.
p.12
Autopilot Systems and Their Integration
What does a single-axis autopilot control?
The aircraft about the longitudinal axis using ailerons.
p.2
Mechanical Flight Control Systems
What are the primary components of a helicopter flight control system?
Anti-torque pedals, cyclic stick, and collective lever.
p.7
Stabilators and Canard Designs
What are the two types of canard designs?
One with a horizontal surface of about the same size as a normal aft-tail design, and the other with a surface of the same size and airfoil as the aft-mounted wing (tandem wing configuration).
p.3
Primary Flight Controls: Ailerons, Elevator, and Rudder
What is the effect of aileron deflection on the aircraft's roll?
The upward deflection of one aileron decreases lift on that wing, while the downward deflection of the opposite aileron increases lift, causing the aircraft to roll.
p.2
Primary Flight Controls: Ailerons, Elevator, and Rudder
How do helicopters control yaw?
Using anti-torque pedals.
p.2
Mechanical Flight Control Systems
What is the function of the collective lever in a helicopter?
To manipulate rotor pitch.
p.8
Primary Flight Controls: Ailerons, Elevator, and Rudder
What is the effect of speed on rudder effectiveness?
Rudder effectiveness increases with speed; larger deflections are needed at low speeds.
p.6
Stabilators and Canard Designs
What systems do many aircraft have to compensate for the dangers of high AOA and aft CG?
Control stops, elevator down springs, and stick pushers.
p.1
Introduction to Flight Control Systems
How do flight control systems vary?
They can vary greatly depending on the type of aircraft flown.
p.12
Autopilot Systems and Their Integration
How can an autopilot be directed?
By the pilot or coupled to a radio navigation signal.
p.10
Trim Systems and Their Functions
What are common types of trim systems?
Trim tabs, balance tabs, antiservo tabs, ground adjustable tabs, and adjustable stabilizers.
p.7
Stabilators and Canard Designs
What is the function of antiservo tabs on a stabilator?
To decrease sensitivity and make the stabilator less prone to pilot-induced overcontrolling.
p.9
Secondary Flight Controls: Flaps and Spoilers
What effect does flap extension have on aircraft pitch?
Flap extension may cause a nose-up or down pitching moment, requiring trim adjustment.
p.10
Secondary Flight Controls: Flaps and Spoilers
How do spoilers assist in roll control?
By destroying lift and creating more drag on one wing, causing the aircraft to bank and yaw.
p.7
Stabilators and Canard Designs
Why is the canard design considered more efficient?
Because it helps lift the weight of the aircraft, resulting in less drag for a given amount of lift.
p.3
Adverse Yaw and Control Coordination
What is the relationship between adverse yaw and bank direction?
Adverse yaw causes the aircraft to yaw opposite the direction of the bank.
p.1
Mechanical Flight Control Systems
What type of aircraft still commonly uses mechanical flight control systems?
Small general and sport category aircraft.
p.7
Stabilators and Canard Designs
What is a stabilator?
A one-piece horizontal tail surface that pivots up and down about a central hinge point.
p.7
Stabilators and Canard Designs
How does a stabilator affect the aircraft's nose when the control column is pulled back?
It raises the stabilator’s trailing edge, pulling the nose of the aircraft up.
p.3
Primary Flight Controls: Ailerons, Elevator, and Rudder
How do ailerons affect lift and drag?
Ailerons change airflow and pressure distribution, affecting lift and drag on the airfoil/control surface combination.
p.12
Primary Flight Controls: Ailerons, Elevator, and Rudder
What is the role of a jackscrew in an adjustable stabilizer?
To pivot the horizontal stabilizer about its rear spar.
p.12
Autopilot Systems and Their Integration
What safety feature is incorporated in autopilot systems?
A disconnect safety feature to disengage the system automatically or manually.
p.4
Adverse Yaw and Control Coordination
How do differential ailerons work?
One aileron is raised a greater distance than the other, increasing drag on the descending wing.
p.4
Adverse Yaw and Control Coordination
What is the purpose of coupled ailerons and rudder?
To automatically deflect the rudder at the same time the ailerons are deflected, correcting for aileron drag.
p.8
Primary Flight Controls: Ailerons, Elevator, and Rudder
How is the rudder controlled?
By the left and right rudder pedals.
p.12
Autopilot Systems and Their Integration
What is the function of an autopilot system?
To keep an aircraft in level flight or on a set course.
p.11
Trim Systems and Their Functions
How do antiservo tabs differ from trim tabs?
Antiservo tabs move in the same direction as the stabilator, while trim tabs move in the opposite direction.
p.5
Secondary Flight Controls: Flaps and Spoilers
What are flaperons?
Control surfaces that combine the functions of flaps and ailerons.
p.3
Adverse Yaw and Control Coordination
What happens to control feel at low airspeeds?
The controls feel soft and sluggish, and the aircraft responds slowly.
p.4
Adverse Yaw and Control Coordination
What is necessary to maintain altitude during a turn?
Elevator back pressure must be applied.
p.5
Secondary Flight Controls: Flaps and Spoilers
Why are flaperons often mounted away from the wing?
To provide undisturbed airflow at high angles of attack and/or low airspeeds.
p.2
Primary Flight Controls: Ailerons, Elevator, and Rudder
What are the primary flight control surfaces of an aircraft?
Ailerons, elevator (or stabilator), and rudder.
p.6
Stabilators and Canard Designs
Why are T-tails popular on aircraft with aft fuselage-mounted engines?
They remove the tail from the exhaust blast of the engines.
p.8
Secondary Flight Controls: Flaps and Spoilers
What is the primary function of flaps on an aircraft?
To increase lift and induced drag for any given angle of attack (AOA).
p.8
Secondary Flight Controls: Flaps and Spoilers
What is a characteristic of slotted flaps?
They significantly increase the lift coefficient more than plain or split flaps.
p.1
Introduction to Flight Control Systems
What is the primary focus of flight control systems?
To control the forces of flight and the aircraft’s direction and attitude.
p.10
Secondary Flight Controls: Flaps and Spoilers
What is the primary function of spoilers on an aircraft?
To reduce lift and increase drag during descent and landing.
p.10
Trim Systems and Their Functions
What do trim systems help relieve pilots from?
The need to maintain constant pressure on the flight controls.
p.5
Adverse Yaw and Control Coordination
How do rudder and ailerons interconnect during a left roll?
The interconnect cable and spring pull forward on the left rudder pedal to prevent yawing to the right.
p.9
Secondary Flight Controls: Flaps and Spoilers
What is unique about Fowler flaps compared to other flap designs?
Fowler flaps slide backwards on tracks and increase both wing area and camber.
p.5
Primary Flight Controls: Ailerons, Elevator, and Rudder
What effect does moving the control column forward have on the elevator?
It increases elevator camber, creating more lift and pitching the nose down.
p.5
Stabilators and Canard Designs
What factors determine the strength of the pitching moment in an aircraft?
The distance between the center of gravity (CG) and the horizontal tail surface, and the aerodynamic effectiveness of the horizontal tail surface.
p.9
Secondary Flight Controls: Flaps and Spoilers
How do fixed slots benefit the wing at higher angles of attack?
They direct airflow to the upper wing surface and delay airflow separation.
p.2
Autopilot Systems and Their Integration
What is the goal of Intelligent Flight Control Systems (IFCS) being researched by NASA?
To develop an adaptive neural network-based flight control system that improves aircraft performance and safety.
p.6
Stabilators and Canard Designs
What is a potential issue during the landing flare for T-tail aircraft?
A forward CG may cause problems in holding the nose up.
p.11
Trim Systems and Their Functions
How does the movement of the elevator relate to the elevator trim tab?
The movement of the elevator is opposite to the direction of movement of the elevator trim tab.
p.11
Secondary Flight Controls: Flaps and Spoilers
What is the function of a servo tab?
To help move the entire flight control surface in the desired direction, decreasing the pilot's workload.
p.3
Adverse Yaw and Control Coordination
What is adverse yaw caused by?
Higher drag on the outside wing that is producing more lift.
p.4
Adverse Yaw and Control Coordination
When is the amount of rudder control required greatest?
At low airspeeds, high angles of attack, and with large aileron deflections.
p.7
Stabilators and Canard Designs
How does the canard design differ from a conventional aft-tail design?
The canard creates lift to hold the nose up, while the aft-tail design exerts downward force to prevent the nose from rotating downward.
p.4
Adverse Yaw and Control Coordination
What are the four systems engineered to reduce adverse yaw?
Differential ailerons, frise-type ailerons, coupled ailerons and rudder, and flaperons.
p.9
Secondary Flight Controls: Flaps and Spoilers
What is the advantage of slotted flaps over plain or split flaps?
Slotted flaps produce much greater increases in maximum coefficient of lift (C L-MAX).
p.6
Stabilators and Canard Designs
What is a key advantage of the T-tail design in aircraft?
The elevator is above most effects of downwash, allowing consistent control movements.
p.6
Stabilators and Canard Designs
What additional design consideration is needed for T-tail aircraft?
Increased design stiffness of the vertical stabilizer to counter flutter.
p.8
Secondary Flight Controls: Flaps and Spoilers
How do plain flaps affect the airfoil?
They increase the airfoil camber, significantly increasing the coefficient of lift at a given AOA.
p.3
Primary Flight Controls: Ailerons, Elevator, and Rudder
What are the three primary flight control surfaces?
Ailerons, Elevator (or Stabilator), and Rudder.
p.4
Adverse Yaw and Control Coordination
What is the effect of aileron deflection on adverse yaw?
Increased aileron deflection causes an increase in adverse yaw.
p.5
Primary Flight Controls: Ailerons, Elevator, and Rudder
What happens when the control column is moved aft?
The elevator deflects up, creating a downward aerodynamic force and pitching the nose up.
p.7
Stabilators and Canard Designs
What is the role of a canard in aircraft design?
It functions as a horizontal stabilizer located in front of the main wings, creating lift and holding the nose up.
p.9
Secondary Flight Controls: Flaps and Spoilers
What happens during the last portion of Fowler flap extension?
The flap increases drag with little additional increase in lift.
p.2
Hydromechanical and Fly-by-Wire Systems
What is the purpose of hydromechanical designs in flight control systems?
To reduce complexity, weight, and limitations of mechanical flight control systems.
p.12
Autopilot Systems and Their Integration
What is the importance of the Airplane Flight Manual (AFM) or Pilot’s Operating Handbook (POH)?
They provide essential information about the primary and secondary flight control systems of the aircraft.
p.9
Secondary Flight Controls: Flaps and Spoilers
What do double- and triple-slotted flaps achieve in large aircraft?
They allow maximum increase in drag without airflow separation over the flaps.
p.8
Primary Flight Controls: Ailerons, Elevator, and Rudder
What happens when the left rudder pedal is pushed?
The rudder moves left, causing the tail to move right and the nose to yaw left.
p.8
Secondary Flight Controls: Flaps and Spoilers
What are secondary flight controls?
Systems that may consist of wing flaps, leading edge devices, spoilers, and trim systems.
p.8
Secondary Flight Controls: Flaps and Spoilers
What are the four common types of flaps?
Plain, split, slotted, and Fowler flaps.
p.9
Secondary Flight Controls: Flaps and Spoilers
What are the five common types of flaps?
Plain flap, Split flap, Slotted flap, Fowler flap, Slotted Fowler flap.
p.12
Autopilot Systems and Their Integration
What does a three-axis autopilot control?
The aircraft about the longitudinal, lateral, and vertical axes using ailerons, elevator, and rudder.
p.10
Secondary Flight Controls: Flaps and Spoilers
What is the purpose of movable slats on an aircraft?
To delay airflow separation and increase lift at higher angles of attack.
p.9
Secondary Flight Controls: Flaps and Spoilers
What are the common types of leading edge high-lift devices?
Fixed slots, movable slats, leading edge flaps, and cuffs.
p.2
Hydromechanical and Fly-by-Wire Systems
What does 'fly-by-wire' refer to in flight control systems?
A system that replaces physical connections between pilot controls and flight control surfaces with an electrical interface.
p.4
Adverse Yaw and Control Coordination
What is the function of frise-type ailerons?
They pivot on an offset hinge to create drag and equalize the drag created by the lowered aileron on the opposite wing.
p.2
Hydromechanical and Fly-by-Wire Systems
What is the significance of control feedback in fly-by-wire systems?
It simulates the feel of control reaction for the pilot.
p.6
Stabilators and Canard Designs
What is a disadvantage of T-tail aircraft compared to conventional-tail aircraft at slow speeds?
The elevator must be moved a greater distance to raise the nose.
p.6
Stabilators and Canard Designs
What can make T-tail aircraft more susceptible to deep stalls?
High angle of attack (AOA) with low airspeed and aft center of gravity (CG).
p.10
Secondary Flight Controls: Flaps and Spoilers
What is the role of leading edge cuffs?
To improve airflow attachment at higher angles of attack, thus lowering stall speed.
p.2
Secondary Flight Controls: Flaps and Spoilers
What do secondary flight control systems include?
Wing flaps, leading edge devices, spoilers, and trim systems.
p.8
Rudder and V-Tail Configurations
What are ruddervators?
Movable surfaces in a V-tail design that act as both rudder and elevator.
p.6
Stabilators and Canard Designs
What happens to the elevator position during turbulence if the aircraft is properly trimmed?
The elevator may streamline, causing the nose to pitch upward and potentially resulting in a stall.
p.10
Secondary Flight Controls: Flaps and Spoilers
How do spoilers improve braking effectiveness after landing?
By destroying lift, they transfer weight to the wheels.
p.8
Rudder and V-Tail Configurations
What is a V-tail design?
A design utilizing two slanted tail surfaces that perform the functions of both elevator and rudder.
p.6
Stabilators and Canard Designs
How does an elevator down spring help prevent stalls in T-tail aircraft?
It mechanically moves the elevator toward a nose-down position, increasing speed and preventing a stall.
