1. Conestoga Valley High School Aviation Technology Powerplant Engines

2. Aircraft Engines Two common types – Reciprocating (Piston) – Turbine (Turbofan or turboprops) Additional Engine Types – Ramjet – Scrams – Rockets

3. 1903- 1940s: Propeller & Piston Era From 1903 (Wright bros.) until the Early 1940s, all aircraft used the reciprocating engine combined with a propeller as their propulsion system. Reciprocating engine or internal combustion is similar to a car engine. – A propeller is essentially a type of fan which transmits power by converting rotational motion into thrust to propel the aircraft (move forward). Reciprocating engines use the energy produced by burning a mixture of air and fuel to drive the propeller.

4. History of the IC Engine 1820-1900 Advancements First Patent 1826: American Samuel Morey First gas IC on a wheeled vehicle 1862: Frenchmen Alphonse deRochas Four-stroke engine patented 1876: German Nikolaus Otto (Otto Cycle) First “modern” gasoline engine patent 1887: German Gottlieb Daimler Otto Daimler

5. Reciprocating Engine Parts Basic Parts – Cylinder – Pistons – Connecting Rod – Crankshaft – Valves – Spark Plugs – Valve-operating Mechanism (CAM)

6. DEFINITIONS TDC Top Dead Center Piston at top of stroke. BDC Bottom Dead Center Piston at Bottom of stroke. STROKE TDC to BDC BDC to TDC 180 degrees of crankshaft rotation FOUR CYCLE (Stroke) 4 x 180 = 720 degrees to make one complete cycle.

7. Reciprocating Engine Operating Principles Intake – As the piston moves down from the top of the cylinder the intake valve opens & a mixture of air/fuel is drawn into the cylinder. Compression – The intake valve closes when the piston is at the bottom of the cylinder. It moves back up the cylinder & compresses the air/fuel mixture.

8. Reciprocating Engine Operating Principles Ignition & Power – As the compressed air/fuel mixture is compressed the spark plug ignites the mixture which creates an explosion and pushes the piston back down. Exhaust – When the piston reaches BDC & starts back up the cylinder the exhaust and heat of the ignition is released from the exhaust valve.

9. 4 Stroke Reciprocating Engine INTAKE COMPRESSION POWER EXHAUST

10. Engine Cycles

11. Cylinder Arrangements Most Common four cylinder arrangements In-Line “V” In-Line Horizontally Opposed In-Line Radial

12. Measuring Power/Thrust An engines power is measured in horsepower One horsepower equals 33,000 foot-pounds of work per minute Speed is measured in Knots d 1 knot =1.15 mph

13. Review Questions What type of engine was the most common for planes up until the 1940’s? Who invented the 4 stoke engine which is still in use today? What are the 4 basic operating principles of a 4 stroke engine? Reciprocating or Piston Intake, Compression, Power, Exhaust Nikolaus Otto