Aerodynamics

Question 1

What are the 3 Principles of Lift

Answer 1

Bernouli’s Principle
Newton’s 3rd Law
Magnus Effect

Question 2

What is Bernouli’s Principle?

Answer 2

A descriptor of how a wing develops lift when the wind is deflected over it.

Question 3

Newton’s Third Law

Answer 3

For every action there is an equal and opposite reaction

Example: as the wing moves through the air the leading edge deflects the air downwards a reverse reaction to this downward force is an upward force

Question 4

Magnus Effect

Answer 4

A spinning object generates lift

Airflow separation as the air meets the surface of the spinning object and is pulled over the top of the spinning surface due to the rotation increasing airflow over the surface and “recreating” Bernouli’s principle.

Question 5

What are the 4 forces acting on a Plane in Flight?
What forces balance in equal unaccelerated flight?

Answer 5

Lift
Weight
Drag
Thrust

Lift = Weight
Thrust = Drag

Question 6

Lift

Answer 6

A force that is produced by the dynamic effect of the air acting on the airfoil and acts perpendicular to the flight path through the CL

Question 7

Weight

Answer 7

The combined load of the aircraft and all of its combined items acting in the downwards force because of gravity 9.8m/s^2

Question 8

Thrust

Answer 8

The forward force generated by the powerplant/propeller or rotor

Excess Thrust: usually seen in a climb or in takeoff where excess thrust fights excess drag to get you airborne (because you are too slow) Determined by Angle of Climb

Total Thrust - Total Drag = Excess Thrust

Question 9

Engine/ Power Souce in Relation to Lift

Answer 9

The ability for the engine to generate movement of the propeller, powerplant, or rotor

Question 10

Drag

Answer 10

A rearward, retarding force caused by a disruption of airflow

Question 11

What are the Two Types of Drag?

Answer 11

Induced Drag
Parasite Drag

Question 12

Explain Induced Drag

Answer 12

The rearward component of Lift/ Downwash (Wake Turbulence)

The drag that is created through the development of lift

Most prominent when the aircraft is slow

Question 13

Talk about Parasite Drag

Answer 13

Is created when an object creates friction by flying through the air

Seen when the aircraft develops speed

3 types!!

Form Drag: the drag developed by the structure of the aircraft moving through the air
Ex: wing struts, pitot tube, landing gear, etc…

Skin Friction Drag: the microscopic friction causes the air to stick to the surface creating drag (nothing is totally smooth)
Ex: rivets

Interference Drag: small thin spaces that creates airflow separating causing turbulent airflow and drag
Ex: hard angles, connections to the plane, wing strut connections

Question 14

Total Drag

Answer 14

Sum of Both Parasite Drag and Induced Drag

Question 15

How Well Does the Wing Work?

Answer 15

L/D max the ratio of total lift / total drag = the ratio of lift

The greater the ratio = the better or more efficient the wing is

L/D max is the Best Performance and Best Fuel Economy
For our Plane it is 68 kts

Why not Fly All the Time?
Closer to Stall Speed
Save Time, Less Controllable

Question 16

Left Turning Tendencies

Answer 16

Toruqe
Spiraling Slipstream
Gyroscopic Precession
P-Factor

Question 17

Torque

Answer 17

Based off of the clockwise motion of the propeller (in relation to Newtons 3rd Law) the Propeller experiences a counterclockwise opposite motion that causes a roll to the left

Question 18

Spiraling Slipstream

Answer 18

The clockwise rotation of the propeller spirals down the plane in a corkscrew fashion striking the top of the vertical stabilizer pushing the aircraft to the left

Question 19

Gyroscopic Precession

Answer 19

A rule applied to a spinning gyroscope in that any action acted upon a spinning gyro will be acted on at 90 after in the direction of the turn (Only a Left Turning Tendency in a Descent)

Question 20

P-Factor

Answer 20

Also known as “Asymmetrical Loading” experienced because of a Higher A.O.A on the descending blade than the ascending blade (the descending blade displaces more air than the upper blade) causing a yawing motion to the left)

Question 21

When are most left turning tendencies most prominent on the aircraft?

Answer 21

At higher A.O.A’s and slower airspeeds
I.e. takeoff and landing