1. 9.01 Four Stroke Cycle and Engine Types References: FTGU pages 51-53
Aero Engines
9.01 Four Stroke Cycle and Engine Types
References:
FTGU pages 51-53

2. 9.01 Four Stroke Cycle and Engine Types
MTPs:
Parts of the Cylinder
4 Stroke Cycle
Types of Combustion Engines

3. Parts of the Cylinder Piston: moves up and down Bore: hole for piston
Spark Plug(s): ignites fuel
Valves: intake and exhaust
Piston Rod: moves crankshaft
Crank Shaft: rotates prop
Sump: contains oil at bottom
Cam: opens / closes valves

4. 4 Stroke Cycle

5. Induction (Suck) Cam pushes down Intake Valve
Piston forced down by moving Crankshaft
Down-moving piston sucks air/fuel mixture through intake valve
Cam
Cam

6. Compression (Squeeze)
Both valves closed
Piston forced upwards by moving crankshaft
Up-moving piston compresses air/fuel mixture

7. Power (Bang) Both valves closed Spark plug ignites fuel air mixture
Piston forced down by expanding gasses
Down-moving piston pushes connecting rod which rotates crankshaft

8. Exhaust (Blow) Cam pushes exhaust valve open
Piston forced upwards by moving crankshaft
Up-moving piston pushes exhaust gasses out

9. Confirmation
Match the parts of a reciprocating engine by matching their names with the letter.
Cylinder ____
Crankshaft ____
Intake valve ____
Piston ____
Sparkplug ____
Connecting rod ____
Exhaust valve ____

10. Confirmation
Match the actions of a four-stroke cycle by matching the action with the engine diagram.
Compression ____
Exhaust ____
Intake ____
Power ____

11. Types of Combustion Engines

12. Horizontally Opposed
Two banks of cylinders on opposite sides of a centrally located crankcase.
Flat design fits inside aircraft nose well.
Common in Cessna aircraft

13. Radial
Odd number of cylinders (5, 7, 9…) surrounding a centrally located crankshaft.
Single or multiple banks of engines may be used (stacked behind one another).
Cylinders fire opposite each other to reduce vibrations.
Poor shape increases parasite drag and reduces forward visibility.

14. Inline
Cylinders lined up behind each other, typically underneath crankshaft (aka inverted inline).
Advantage: small frontal cross section (streamlined aircraft nose)
Disadvantage: poor air cooling and long, heavy crankshaft.

15. Confirmation Match the engines with the correct engine type:
A – Horizontally opposed engine
B – Radial engine
C – In line engine

16. Confirmation

17. Confirmation

18. Confirmation

19. ?