Engines

Question 1

Basic engine design requirements

Answer 1

Lightweight
Small
Powerful
Reliable
Repairable

Question 2

2 engine classes

Answer 2

Piston type
Reciprocating
Intermittent internal combustion

Gas turbine
Rotating
Continuous internal combustion

Question 3

4 cylinder Piston configurations

Answer 3

Radial
Loud, unreliable, heavy
In line
Compact (cooling issues) low horsepower
Inverted in line
Prop = higher
Horizontally opposed
Most common/best combination

Question 4

DA40 engine

Answer 4

Textron lycoming IO-360 M1A
(IO=injected/opposed)
(360 = displacement cubic inches)
(M1A = serial number)

Question 5

Operating principles for piston engine (diesel)

Answer 5

Compression ignition (no spark plug required) (highly compressed air)
Future/current GA contender

Question 6

Operating principles for piston engine (2 stroke)

Answer 6

Spark ignition
Pros:
Very simple
Light/high power to weight ratio

Cons:
Requires maintenance often
Unreliable
Inefficient
Burns oil with fuel

Question 7

Operating principles for piston engine (4stroke)

Answer 7

Spark ignition
More efficient than 2 stroke
Most common GA

Question 8

4 stroke Components

Answer 8

Cylinder
Cylinder head
Piston
Inlet/exhaust valves
Spark plug
Crankshaft
Conrod/crankcase
Camshaft

Question 9

Cylinder

Answer 9

Steel (or iron)
House piston
Smooth inner surface
Air cooled by cooling fins

Question 10

Cylinder head

Answer 10

Air cooled
Fitted at the top of the cylinder
(Spark plug and valves)
Creates enclosed combustion space
Detach from cylinder block (maintenance)

Question 11

Piston

Answer 11

Aluminium alloy
Housed in cylinder
3ring seal (minimised loss of gases to crank case, improves heat transfer between piston and cylinder wall, scrapes oil on wall back to sump

Question 12

Inlet and exhaust valves

Answer 12

Allow fuel air mixture into combustion space
Exhaust expels burnt gases
Operated by camshaft

Question 13

Spark plug

Answer 13

Ignites fuel air mixture
2 per cylinder for redundancy
20000v per
Subjected to 2000 psi pressure

Question 14

Crankshaft

Answer 14

Connected to piston via conrod
Weights to reduce vibration
Translates linear to rotational
Housed within crankcase

Question 15

Conrod and crankcase

Answer 15

Conrod connect piston to crankshaft
Crankcase houses crankshaft

Question 16

Camshaft

Answer 16

Geared to crankshaft
Operated at half the speed
Opens and closes valves at correct time (using rocker arm)
Works in conjunction with spring compress on top of valves

Question 17

TDC & BDC

Answer 17

Top dead centre and bottom dead centre

Question 18

Otto cycles (4 strokes)

Answer 18

1 suck: induction stroke
Air fuel mixture in
Piston tdc to bdc
(Reduction in pressure)

2 squeeze: compression stroke
Inlet valve is closed first
Piston BDC to TDC
Compresses fuel air mixture (higher pressure

3 bang: power stroke
End of compression stroke spark plug ignites FA mixture
Controlled combustion, gases expand, piston forced down

4 blow: exhaust stroke
Exhaust valve opens
Piston BDC to TDC
Burnt gases expelled