Engines

Question 1

Radial Engines

Answer 1

• Circular in Shape
• Odd number (usually 9 max) of cylinders arranged around crank case
• Good cooling, good power, easy to maintain
• Poor forward visibility and excessive drag

Question 2

Inline Engines

Answer 2

• Cylinders arranged side by side in a row
• Usually a max of 6 for vibration
• Engine may be inverted for better visibility
• Greatest weight to horsepower ratio
• Less drag and better visibility

Question 3

Horizontally Opposed Engines

Answer 3

• Most common in small aircraft
• 2 rows of cylinders arranged horizontally
• Even number of cylinders
• Small frontal area
• Less drag

Question 4

Four Stroke Cycle

Answer 4

• Two Rotations of the crank shaft
• Intake
• Compression
• Ignition
• Exhaust

Question 5

Compression Ratio

Answer 5

• Volume of cylinder above piston at bottom of compression stroke compared to top of compression stroke

Question 6

Two Stroke Cycle

Answer 6

• One rotation of the crankshaft
• Intake
• Compression
• Ignition
• Exhaust
• Spark Plug fires every time piston reaches top dead centre on compression stroke

Question 7

Diesel Engines

Answer 7

• Air/Fuel mixture ignited due to air being heated from compression stroke
• No separate ignition
• Fuel injected under pressure into combustion chamber
• No carburetor
• Fewer moving parts
• Greater power per pound of fuel
• Longer time between overhaul
• Heavier, Cost more, harder to balance

Question 8

4 Functions of Oil

Answer 8

• Cooling
• Sealing
• Lubrication
• Flushing

Question 9

Requirements of Oil

Answer 9

• Proper Viscosity
• High Flash Point
• Low Carbon Content
• Low Freezing Point

Question 10

Mineral Oil

Answer 10

• No Additives
• Used to break-in engine
• Granular

Question 11

Ashless Dispersant

Answer 11

• Contains dispersants
• suspends contaminants (carbon or lead)

Question 12

Additives - Detergents

Answer 12

Cleans inside of engine

Question 13

Additives - Oxidation Inhibitors

Answer 13

Improves Oil Stability

Question 14

Additives - Anticorrosion Additives

Answer 14

Deter Corrosion

Question 15

Additives - Pour Point Depressants

Answer 15

Lower the freezing point temperature

Question 16

Methods of Lubrication - Splash Oil

Answer 16

• Oil contained in sump/reservoir
• Cheap, simple, effective, lightweight
• No aerobatics

Question 17

Methods of Lubrication - Force Feed

Answer 17

• Oil is pumped and forced through hollow crankshaft under pressure
• Two types include dry sump and wet sump

Question 18

Dry Sump

Answer 18

• Oil contained in separate tank
• Forced by pump through hollow crankshaft
• Drained from sump through scavenging pump, goes through cooler than back to tank

Question 19

Wet Sump

Answer 19

• Oil contained in a pan (sump) under crankcase
• Pumped to different engine parts
• Can be splash lubricated as well
• Oil drains back to sump