Lecture 8

Question 1

Heat Engines

Answer 1

Utilize heat energy to produce the power for propulsion

Question 2

2 Types of Heat Engines

Answer 2

Reciprocating
Gas Turbine

Question 3

Engine definition

Answer 3

converts a source of energy into useful work

Question 4

What is the source of energy in an engine?

Answer 4

Fuel

Question 5

What is the work the engine produces?

Answer 5

Heat expands gases creating pressure against a piston in a cylinder. The piston causes the crankshaft to rotate

Question 6

What is energy?

Answer 6

The capacity for doing work

Question 7

Law of Conservation

Answer 7

Energy cannot be created or destroyed- only changed from one form to another

Question 8

Kinetic vs Potential Energy

Answer 8

Energy of motion
Energy of position or stored energy

Question 9

Normal Category G’s

Answer 9

+3.8 G, -1.52 Gs
Non acrobatic operations

Question 10

Utility Category G’s

Answer 10

+4.4 Gs, -1.76 Gs
limited acrobatic operations

Question 11

Normal Category G’s

Answer 11

+3.8 G, -1.52 Gs
non acrobatic operations

Question 12

Positive G Loads

Answer 12

Centrifugal force acts in the same direction as WEIGHT- a downward force on the aircraft = you feel heavier

Question 13

Negative G Loads

Answer 13

Centrifugal force acts in the opposite direction as WEIGHT- an upward force on the aircraft = you feel lighter

Question 14

What is a G load?

Answer 14

(weight caused by aerodynamic load)/ (weight of the aircraft)

Question 15

Static vs dynamic stability

Answer 15

initial response vs long-term response

Question 16

Positive Static

Answer 16

Returns to initial position

Question 17

Neutral Static

Answer 17

Stays in new position

Question 18

Negative Static

Answer 18

Gets worse

Question 19

Yaw stability

Answer 19

Stability about vertical axis

Question 20

What maintains yaw stability?

Answer 20

Vertical stabilizer

Question 21

How do sweptback wings increase yaw stability?

Answer 21

The wing hits the air at an angle, air gets more time to climb up camber, less effective at making lift and thus less induced drag

Question 22

Pitch stability

Answer 22

Stability around the lateral axis

Question 23

How does the tail contribute to pitch stability?

Answer 23

Camber on the bottom of the tail uses Bernoulli Effect on the
bottom of the horizontal stabilizer, and creates negative lift

Question 24

How does negative lift contribute to pitch stability?

Answer 24

Weight / CG wants
to pull the airplane
nose down, but the
nose is being held
up by the force down
on the tail

Question 25

Primary purpose of high lift devices?

Answer 25

Increase the maximum coefficient of lift of an airplane

Question 26

Wing flap definition

Answer 26

a hinged, pivoted, or sliding airfoil usually near the trailing edge

Question 27

What are wing flaps for?

Answer 27

Used for landing. Increases the lift, drag, or both by increasing AOA and camber

Question 28

Split flap

Answer 28

Hinges a lower part of wing open. Not good at producing lift, better for drag

Question 29

Slotted flat

Answer 29

Most effective flap. Lift greatly increased. Drag only slightly. There is a small gap between wing and flap.

Question 30

Fowler flap

Answer 30

Tucks into wing when retracted. Increases wing SA when deployed.

Question 31

Leading edge flap

Answer 31

Moves forward and droops down.

Question 32

Droop leading edge

Answer 32

Lowers AOA and raises camber as the air sees it.

Question 33

Kreueger leading edge

Answer 33

Lower AOA, increase camber, more rounded leading edge

Question 34

Aspect ratio equation

Answer 34

S^2/ A

Question 35

High aspect ratio wings are good because?

Answer 35

produce less induced drag

Question 36

Effective aspect ratio

Answer 36

gives the wings characteristics of a higher aspect ratio

Question 37

Elliptical wing

Answer 37

good lift, drag, stall characteristics

Question 38

Why does elliptical wing have good characteristics?

Answer 38

controls pressure differential and airflow along the span from root to tip

Question 39

Why are elliptical wings expensive?

Answer 39

each wing station is a unique size

Question 40

Winglets and sharklets do what?

Answer 40

reduce induced drag

Question 41

When wing tapers in thickness...

Answer 41

CP moves less when AOA changes Max Cl greater Lift curve is greater since all the wing does not reach max lift at once C(d) is lower (notable at low AOA)

Question 42

When wing tapers in planform (chord)...

Answer 42

CP moves more when AOA changes Max Cl greater C(d) is lower (notable at high AOA)- reduced induced drag

Question 43

When wing tapers in both thickness and chord...

Answer 43

decreased and increased CP offset one another Max Cl greater Cd is low at both high and low AOA