Aircraft Flight Control Systems

Question 1

What are the flight control surfaces to move the plane in the principle axes of inertia?

Answer 1

Yaw- Rudder
Pitch- Elevators
Roll- Ailerons

Question 2

What are the primary flight controls?

Answer 2

Move around the principal axes of inertia
Reversible commands
-The deflection of the control surfaces (CS) are linked to the position of the joystick
-Force applied to the joystick is linked to that on the CS

Question 3

What are the secondary flight controls?

Answer 3

Flaps, spoilers, air brake, engine control-thrust reversers, LG extraction, retraction
Irreversible commands
-Fixed positions
-No feedback of force

Question 4

What is an Elevon?

Answer 4

For delta wings with no horiz tail

Elevators+Ailerons

Question 5

What is a Flaperon?

Answer 5

TE Flaps+Ailerons

Question 6

What are Tailerons?

Answer 6

Tail+Ailerons

Question 7

What is a Ruddervator?

Answer 7

Rudder+Elevator

Question 8

Name the methods for actuating flying controls

Answer 8

Manual
Electric
Pneumatic
Hydraulic

Question 9

What is the purpose of a balance tab on the control surface?

Answer 9

Provide aerodynamic balance and make it easier to move the controls

Question 10

What is the difference between power assisted and power operated controls?

Answer 10

Assisted- Movement of control column will move both the flying control and the pilot valve. Reversible

Operated- Movement of the control column only moves the pilot valve. Irreversible

Question 11

What are the main characteristics of a fly-by-wire (FbW) system?

Answer 11

• Replaces manual controls with an electronic interface
• Movements are converted to electronic signals and computers determine how to move the actuators at each CS
• Computers also stabilise aircraft and perform other tasks as well as provide flight envelop protection
• Reduce weight and pilot workload

Question 12

+ of FbW?

Answer 12

-Flight envelope protection
-Increase stability and handling. Possibility of flying inherently unstable aircraft
-Decrease turbulence
-Thrust vectoring
-Optimise trim settings to reduce drag
-Easier interface to auto-pilot
Reduce weight and maintenance

Question 13

• of FbW?

Answer 13

-Software is a critical aspect can have bugs in

Risk of aircraft loss is 2x10^-6 per flight hour for military, this is reduced to 10^-9 for civil

Question 14

What types of planes cannot fly without FbW?

Answer 14

Flying Wing- B-2 bomber
Forward swept wing- Grumman X-29
Thrust Vector Control- Sukohoi T-50
Manoeuvring difficulties- Harrier

Question 15

What are the Helicopter Controls?

Answer 15

Cyclic (Lateral)-Left and Right
Cyclic (Longitudinal)-Forwards and Backwards
Collective- Up and Down
Anti-torque pedals- Yaw rate/ heading