Lecture 9

Question 1

High wing benefits

Answer 1

Better lift/drag ratio
Better lateral (roll) stability
Shorter ldg distances

Question 2

Low wing benefits

Answer 2

Easier to build strong landing gear support
Better roll maneuverability
Shorter takeoff distance

Question 3

Which wing configuration is the most susceptible to ground effect?

Answer 3

The one with the wings closest to the ground.

Question 4

Tee Tail Horizontal Stabilizer

Answer 4

TEE tail allows flow over the rudder at high AOA. Typically the horizontal stabilizer blocks the air flow= no rudder= no yaw control. This keeps the horizontal stabilizer and rudder out of the main wing downwash

Question 5

Disadvantages of tee tail horizontal stabilizer

Answer 5

vertical stabilizer must be larger and heavier

Question 6

What does the Tee Tail decrease?

Answer 6

Interference drag by eliminating number of acute angles
Pressure drag and skin friction drag by eliminating one of the horizontal flight controls

Question 7

What happens when you press the left pedal on a tee tail?

Answer 7

deflects the left-hand ruddervator down and left and the right-
hand ruddervator up and left

Question 8

How to produce up pitch with tee tail?

Answer 8

moving the control column or stick back which deflects the left-hand ruddervator up and right and the right-hand ruddervator up and left

Question 9

Why do fighters have 2 tails?

Answer 9

to be able to stabilize in the event of damage and reduce the height needed for full control

Question 10

Biplanes have short wings and short wing spans because…

Answer 10

Short wings= fast rolls
Short span wings = thinner than monoplane wings and still strong

Question 11

Flying wires

Answer 11

Transmit the lift back to the fuselage

Question 12

Landing wires

Answer 12

Transmit the downward impact of landing, or negative G loads, on the wings back to the fuselage

Question 13

Interplane struts

Answer 13

Transmit the lift loads and landing loads between the top and bottom wings

Question 14

Cabane struts

Answer 14

Support the top section of wing above the fuselage and transmits the lift loads

Question 15

Center Section

Answer 15

an airfoil shaped section above the fuselage to which the upper wings attach

Question 16

Interplane Interference

Answer 16

Airfoils flying in proximity reduce the pressure differential differential

Question 17

What is the “gap”

Answer 17

the distance between the chord of the top wing and the chord of the bottom wing (interference becomes a problem when the gap is less than one chord length apart)

Question 18

What is Decalage

Answer 18

the angle of difference between the upper wing and lower wings of a biplane
one of the wings is set to a higher angle of incidence than the other wing

Question 19

Main advantages of ruddervators

Answer 19

Lighter, less wetted surface, less drag
Increase stealth- canted surfaces reflect the radar away from source
Reduce infrared signature
Improve safety and reduce cabin noise

Question 20

Main disadvantages of ruddervators

Answer 20

Require a more complex rudder system
Required to be more structurally robust
Control forces required for operating the ruddervators are higher

Question 21

Tandem wing

Answer 21

Both wings lift up and no horizontal stabilizer pulls down- limited CG range

Question 22

Who made and what is a canard wing?

Answer 22

Wright brothers, special type of tandem wing

Question 23

Negative of canard wing and solution

Answer 23

Less pitch stability. The canard wing stalls before the main wing

Question 24

Do most airplanes worry about CG movements left and right?

Answer 24

No

Question 25

If we took away the tail, how would the airplane fly?

Answer 25

Use split control at wingtips- split rudders
Move ailerons inboard and combine with elevators- Elevons