Lighter-Than-Air Craft

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PowerplantEngines
Conestoga Valley High School Aviation Technology
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Aircraft Engines

• Two common types
• Reciprocating (Piston)
• Turbine (Turbofan or turboprops)
• Additional Engine Types
• Ramjet
• Scrams
• Rockets

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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.
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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
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Reciprocating Engine Parts

• Basic Parts
• Cylinder
• Pistons
• Connecting Rod
• Crankshaft
• Valves
• Spark Plugs
• Valve-operating Mechanism (CAM)

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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.
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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.

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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.

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4 Stroke Reciprocating Engine
INTAKE COMPRESSION POWER EXHAUST
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Engine Cycles
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Cylinder Arrangements

• Most Common four cylinder arrangements
• In-Line
• V In-Line
• Horizontally Opposed In-Line
• Radial

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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

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Review Questions

• What type of engine was the most common for
  planes up until the 1940s?
• 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
Nikolaus Otto
Intake, Compression, Power, Exhaust