Airplane Design

Question 1

An airplanes’ location of it’s CG (center of gravity-in front of wings) and CL (center of lift- at wings), determines its’ ________________ stability.

Answer 1

Longitudinal

Question 2

As an airplanes’ CG moves aft, the plane becomes….

Answer 2

Less stable

Question 3

To minimize side loads played on an airplane’s tricycle landing gear during touchdown, the pilot should

Answer 3

Keep the longitudinal body of the plane parallel with its direction of movement

Question 4

Primary flight controls become (more/less) stable as airspeed (increases/decreases).

Answer 4

More as increases
-this is because there is more air moving over the control surfaces

Question 5

Flaps allow pilots to…

Answer 5

Make steeper approaches without increasing airspeed

Question 6

An airplane has been loaded in such a manner that the CG is located aft of the CG limit. One undesirable flight characteristic a pilot might experience would be…

Answer 6

Difficulty recovering from a stall

Question 7

Longitudinal stability refers to an aircraft’s stability about which axis?

Answer 7

Lateral

Question 8

An airplane that is more stable will….

Answer 8

Require less effort to control

Question 9

Center of pressure is the same as….

Answer 9

Center of lift (at wings)

Question 10

Changes in the center of pressure of a wing affect the aircraft’s…

Answer 10

aerodynamic balance and controllability

Question 11

Purpose of rudder is to….

Answer 11

Control yaw

Question 12

Loading an airplane the most aft CG will cause….

Answer 12

The plane to be unstable at all airspeeds

Question 13

3 Types of Single Engine Aircraft that require a special endorsement to fly

Answer 13

High performance
-201+ hp

Complex
-retractable landing gear, controllable propeller, flaps

Tailwheel
-Conventional landing gear with wheel on tail

Question 14

When does lift equal weight and thrust equal drag?

Answer 14

In unaccelerated flight

Question 15

Bernouilli’s Principle states that when the speed of a fluid _________ it’s pressure _________. This also refers to an airplanes’ ___________.

Answer 15

Increases
Decreases

Wing
This causes air molecules to create a low pressure above the wing because they are hitting the leading edge of the wing, thus speeding up. Below the wing is still moving the same speed so it is a higher pressure. Air molecules want to move from high to low so lift is produced.

Question 16

Angle of attack is defined as:

Answer 16

Angle between the chord line of the airfoil (wing) and the relative wind.

Question 17

Ailerons control movement about which axis?

Answer 17

Longitudinal
(Roll)

Question 18

Rudder control movement about which axis?

Answer 18

Vertical
(Yaw)

Question 19

Elevator controls movement about which axis?

Answer 19

Lateral
(Angle of Attack)

Question 20

Newton’s third law states in relationship to an airplane….

Answer 20

For every motion there is an opposite and equal reaction.

An additional upward force is created on the bottom of a wing as air hits and is deflected downward.

Question 21

When do we have left turning tendencies in the airplane?

Answer 21

When climbing out. Need right rudder to correct.

Question 22

When do we have right turning tendencies?

Answer 22

In a climb, need right rudder.

Question 23

4 Left Turning Tendency Factors

Answer 23

Gyroscopic Procession- prop spins right causing a shift to the left
P-Factor- prop spins right, blade is scooping harder on the down spin than on up spin causing more thrust on the right, pushing plane left due to asymmetrical thrust
Torque- prop spins right, causes tail and fuselage to torque left
Spiraling Slipstream- air spins behind prop around the fuselage, striking left side of the tail causing it to turn the plane left

Question 24

Why do we have canted wings (sloped upward towards the tips)?

Answer 24

Dihedral lines
-When we dip for a turn, more lift is produced on uplifted wing
-dihedral line becomes more horizontal as we turn, resulting in more lift on that wing

Question 25

Explain Keel Effect

Answer 25

If wings are the water, a high winged aircraft has most of the plane below the “water”.
-plane acts as a keel to steady and keep plane from overly slipping and skidding

Low wing planes do not have this present and must input stronger rudder control

Question 26

Purpose of horizontal stabilizers

Answer 26

Sloped down in the front
Catch air eddying from wings
Creates pressure differential causing downward force to offset weight of front engine