Midterm

Question 1

How much brake horsepower is converted to thrust horsepower?

Answer 1

85%

Question 2

How much can propeller efficiency vary by?

Answer 2

50-87%

Question 3

What factors does the amount of thrust depend on?

Answer 3

• angle of attack
• speed
• shape of airfoil
• propeller efficiency

Question 4

How are propellers classified?

Answer 4

-according to position on aircraft and pitch

Question 5

What is mach 0.87?

Answer 5

565 knots

Question 6

What is mach 0.85?

Answer 6

prop efficiency begins to decrease dramatically when tip velocity approaches or exceeds this

Question 7

Explain thrust bending force

Answer 7

• caused by thrust loads
• compression and tension acting upon blades
• bends blades forward in line of flight

Question 8

Where do blades try and stay in the centrifugal twisting moment?

Answer 8

-try to stay in parallel rotation to the propeller plane of rotation

Question 9

What 3 forces cause the propeller to vibrate when a propeller is connected to an engine

Answer 9

• thrust
• aerodynamic
• mechanical

Question 10

What is the resonant frequency?

Answer 10

The frequency of which the system will vibrate if it is excited by a single pulse

Question 11

What are the hardwoods used to manufacture aircraft propellers?

Answer 11

• birch
• ash
• maple
• cherry
• oak
• black walnut

Question 12

In wooden propellers, all types and laminations must be free of

Answer 12

• grain irregularities
• knots
• air pockets
• Insect damage

Question 13

How many layers are wooden propellers fabricated from?

Answer 13

5-10

Question 14

What do laminated layers glued together form?

Answer 14

blank

the rough cut and allowed to season

Question 15

Dimensions, pitch and shape are milled from the laminated wood using

Answer 15

airfoil jigs and blade station measurements

Question 16

In some cases the last —- inches of the blade has a fabric covering to reinforce the thinner section of the propeller tip

Answer 16

12-15

Question 17

What is applied to wooden propellers to prevent moisture ingress?

Answer 17

Clear water proof varnish

Question 18

What colour paint is used on the tip of wooden propellers?

Answer 18

Red or white

Question 19

In model number 70D42, what is 42?

Answer 19

Geometric pitch as 75% radius station

Question 20

Which direction are wooden propellers stored?

Answer 20

horizontally

for even moisture distribution - prevents warping

Question 21

Aluminum round tip

Answer 21

• large arc

- no advantage for tip disturbances

Question 22

aluminum Square/klip tip

Answer 22

• shorter than round

- lower rpm, quieter

Question 23

aluminum Scimitar sweptback

Answer 23

• reduces tip vortices

- higher speed

Question 24

aluminum q tip

Answer 24

• 90 degree bend at tip towards face
• quieter
• reduces tip vortices

Question 25

What are the three mount types of aluminum propellers

Answer 25

- splined shaft - tapered - flange

Question 26

Aluminum propellers Field Repair of Aircraft Propellers Part _ Standard _ Appendix _

Answer 26

Part 5 Standard 571 Appendix D

Question 27

How are aluminum propellers balanced?

Answer 27

Vertically and horizontally

Question 28

When you paint an aluminum propeller, what does the paint further protect it from?

Answer 28

corrosion and FOD

Question 29

What materials can be used in composite?

Answer 29

- core of wood, honeycomb or rigid foam and reinforcing shank - fiberglass or carbon fibre and aramid fibre

Question 30

In composite propellers, wear occurs from what?

Answer 30

- high rpm in rain or sandy areas - fod on taxis and runways - delamination when damage is left unrepaired which allows moisture to enter

Question 31

How are composite propellers balanced (direction)?

Answer 31

Statically in the horizontal plane

Question 32

How (method) are composite propellers balanced?

Answer 32

-by adding lead wool to centrally located balance tube in metal blade shank

Question 33

On a composite propeller, what does a finish covering of polyurethane paint protect the blade against?

Answer 33

erosion and uv damage

Question 34

What is the constant speed range of a constant speed propeller determined by?

Answer 34

the high and low pitch stops

Question 35

For constant speed propellers, the throttle can be placed anywhere between the min and max setting based on the required -------

Answer 35

manifold pressure

Question 36

What are the 3 main functions of the governor?

Answer 36

- boosts engine oil pressure - senses rotational speed of engine - controls the amount of oil to the propeller hub

Question 37

Engine oil is boosted in the governor by an _____ which is geared to the engine

Answer 37

integral gear type pump

Question 38

What is the normal engine oil pressure and what does it increase to?

Answer 38

normal 60, increase to 180 to 300

Question 39

What is the name of the thing that senses engine speed in constant speed propeller>

Answer 39

propeller governor

Question 40

The propeller governor oil is controlled by the _____

Answer 40

pilot valve

Question 41

The governor is operated by the pilot with the ______ in the flight deck

Answer 41

propeller lever

Question 42

A combination of ___ and ____ in the hub allowed the propeller to maintain a constant speed for constant speed propeller

Answer 42

speeder spring and oil pressure

Question 43

THe ____ regulates the flow of oil based on the position of the flyweights

Answer 43

governor

Question 44

There is a failsafe incorporated into the governor in the form of a

Answer 44

return spring

Question 45

What is the RPM time for initial climb

Answer 45

the time to bring the rpm back from peak to around max continuous rpm