Aero

Question 1

What are the four left turning tendencies inherent to clockwise-turning props?

Answer 1

Torque Reaction
Corkscrew Effect
Gyroscopic Action
Asymmetric Loading (P-Factor)

Question 2

What is torque reaction?

Answer 2

The torque from the clockwise spinning propeller generates a left-rolling moment on the airframe.

Question 3

Corkscrew Effect

Answer 3

This force creates a left yawing moment and a less prominent right rolling moment.

(Prop Slipstream Corkscrew on T-Tail)

Question 4

Gyroscopic Action

Answer 4

This force can generate a yawing moment or a pitching moment, depending on where the initiating force is applies (e.g., a pitch translates to a left or right yaw)

Resultant force of gyroscopic action is 90 deg ahead and in the direction of the application.

Question 5

Asymmetric Loading (P-Factor)

Answer 5

During positive AOA, downward blade, on right, creates more lift than upward blade. This lift imbalance generates a left yawing moment.

Question 6

T-Tail Design Advantage

Answer 6

Moves elevators upwards into air undisturbed by propwash or wing surfaces, under normal conditions.

Question 7

What is the most dangerous flight regime for a T-Tail A/C.

Answer 7

High AOA, low speed, aft CG.

Airflow across the T-Tail is less clean at High AOA

Low speeds and aft CG both increase the control deflection required to achieve the same effect.

U-28 pusher system designed to mitigate danger

Question 8

Purpose of Winglets

Answer 8

Winglets reduce the induced drag effect of wingtip vortices by blocking some of this airflow.

Question 9

Ventral Strakes and Dorsal Fins

Answer 9

Both surfaces reduce adverse yaw.

Question 10

Primary advantage of fowler flaps

Answer 10

Significant increase in wing area they create in addition to the typical increases in camber.

Question 11

Stalls in the U-28

Answer 11

Bad enough that it requires stick-shaker/stick pusher.

Computer bases responses on a ‘defined AOA’

5-10 knots prior to pusher: stick shaker and aural warning

Question 12

Three factors that effect power-off stall speeds?

Answer 12

Aircraft Weight

Angle of Bank

Flap Setting

Question 13

How is stall speed impacted by weight and angle of bank increases

Answer 13

Stall speed increases linearly with increased weight
Stall speed increases exponentially with increased AOB

0 to 15 flaps results in a significant decrease in stall speed.

Lowering flaps further results in progressively smaller stall speed decreases

This trend is because fowler flaps significantly increase wing area between 0 and 15 deg.

Question 14

Why shouldnt you raise flaps during Stall Recovery

Answer 14

Raising Flaps:

Lowers the wing’s lift coefficient and increases its stall speed, thus increasing the potential sink rate

Question 15

Vs

Answer 15

Stall Speed: Minimum steady-state controllable speed

Question 16

Vr

Answer 16

Rotation Speed: Vs1 for for single engine aircraft

Question 17

Vref

Answer 17

Landing reference speed: 1.3 Vs

Question 18

Vmo

Answer 18

Max operating limit speed (maneuvering): 216 KIAS (0.46 M) U-28
236 KIAS (0.48 M) PC-12

Question 19

List the 3 types of structural loading

Answer 19

Bending Moment
Shearing Force
Torsion Moment

Question 20

Bending Moment

Answer 20

The moment created by a transverse deflection of a body through and perpendicular to its longitudinal axis

Question 21

Shearing Force

Answer 21

A force tending to cause deformation of a material by slippage along a plane or planes parallel to the imposed stress.

Question 22

Torsion Moment

Answer 22

The twisting of a body by the exertion of forces tending to turn one end about the longitudinal axis while the other is held fast or turning in the opposite direction.

Question 23

Turn-Radius Relationship

Answer 23

As speed increases more bank is required to maintain a given turn radius.

Question 24

What are the U-28 general design features?

Answer 24

Single Engine TurboProp
T-Tail
Winglets
Dorsal Fin and Ventral Strakes 
Fowler Flaps

Question 25

What are the U-28 g limits?

Answer 25

No asymmetric limits are published

Flaps Up:
PC-12: +3.3 to -1.32
U-28: +2.5 to -1.0

Flaps Extended:
+2.0 to 0.0

Question 26

Load Factor vs Bank Angle

Answer 26

Load factor is (geometrically) proportional to bank angle.

Question 27

What category aircraft is the U-28?

Answer 27

Normal category