Stability

Question 1

Couple

Answer 1

A pair of equal parellel forces acting in opposite directions. Tends to cause totation because forces are acting along different axes (the CP and CG i.e.)

Question 2

If CP is behind the CG

Answer 2

The aircraft will nose down

Question 3

If CP is infront of CG

Answer 3

The aircraft will nose up

Question 4

If thrust is in a higher position than drag

Answer 4

Aircraft will nose down

Question 5

When airplane said to being stable, being disturbed by a sudden gust of wind for example, it will

Answer 5

return to its original attitude

Question 6

Stability def.

Answer 6

The natural ability of the aeroplane to return ot its original condition after being distrubed

Question 7

3 Axis

Answer 7

Normal axis, longitudunal axis, lateral axis

Question 8

Stability around the longitudinal axis is known as

Answer 8

lateral satbility

Question 9

Stability around the lateral axis is known as

Answer 9

longitudinal stability

Question 10

Movement around the normal axis is called

Answer 10

yawing

Question 11

Stability around the normal axis is called

Answer 11

Direcitonal stability

Question 12

Rotation around a point or axis is called

Answer 12

Angular motion

Question 13

Number of degrees of angular motion is called

Answer 13

angular displacement

Question 14

Speed of angular motion is called

Answer 14

angular velocity

Question 15

For lateral stability (longitdunal axis), which is better, forward or aft CG

Answer 15

forward

Question 16

Too forward CG will make the lateral stability much stable, but

Answer 16

Controlling the axis will become harder, much more control force need to be applied

Question 17

When the airplane is banked, the lift vecotr is

Answer 17

inclined, and produces a sideslip into the turn

Question 18

Wing dihedral

Answer 18

Increases lateral stability, found on low-wing planes. The wing is inclined upwards from the fuselage to the wingtips.

Question 19

Wing sweepback

Answer 19

Increases lateral satbility. The lower wing presents more of its span to the relative airflow therefore producing more lift to stabilize the aircraft ????

Question 20

The greater direciton stability,

Answer 20

the greater the tendencay of the aircraft to yaw into the turn, and nose down

Question 21

Spiral dive

Answer 21

A steep turn with nose down and increased IAS

Question 22

If the directional stability is stronger than lateral stability,

Answer 22

the aircraft will tend to bank futher into the sideslip, with nose continuing to drop. Its called sprial instability and it’s okay.

Question 23

If the lateral stability is stronger than directional stability,

Answer 23

Dutch roll. Wallawoing dangerous effect

Question 24

Roll causes

Answer 24

Yaw

Question 25

Yaw causes

Answer 25

Roll

Question 26

Direcitonal stability is acheived through

Answer 26

The fin

Question 27

Static stability

Answer 27

Aircrafts tendency to return its original position