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FLIGHT POWER

FLIGHT POWER. Know basic engine principles. 1. Define a list of terms related to basic engine principles. 2. Define Boyle’s Law and Charles’ and Gay-Lussac’s Law. 3. Describe how engines evolved from the earliest version to present day. FLIGHT POWER. Know basic engine principles.

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FLIGHT POWER

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  1. FLIGHT POWER • Know basic engine principles. • 1. Define a list of terms related to basic engine principles. • 2. Define Boyle’s Law and Charles’ and Gay-Lussac’s Law. • 3. Describe how engines evolved from the earliest version to present day.

  2. FLIGHT POWER • Know basic engine principles. • 4. Describe the mechanical, cooling, and ignition systems of the reciprocating engines. • 5. Describe the role of reversers and suppressors used in jet aircraft. • 6. Given real causes of pollution, state the method to eliminate the stated cause.

  3. Overview Basic Engines Scientific Terms Reciprocating Engines Laws of Physics Jet Engines How Jet Engines Operate Types of Jet Engines Reversers and Suppressors Pollutants

  4. Basic Engines • History of Flight Power • Ancient pictures show evidence of the dream of flying on the walls of caves. • Through the use of engines, the dream of flight has been partially fulfilled. • Basic engines developed in three major stages. • External combustion engines • Internal combustion engines • Gas turbine engines

  5. Basic Engines • External Combustion • The development of the steam engine was the first successful harnessing of mechanical power for useful work. • A steam engine uses steam to change into motion the heat that is released by burning.

  6. External Combustion Thomas Savery • Developed the first steam engine in 1698 • Used hand-operated valves to let steam enter a sealed vessel or container

  7. External Combustion Thomas Newcomen • Built steam engine with piston inside cylinder • Cold water was sprayed into the cylinder and condensed the steam

  8. External Combustion James Watt

  9. External Combustion James Watt • Invented steam engine with two separate parts • Cylinder remained hot and condenser cool all the time

  10. External Combustion Henri Giffard

  11. External Combustion Steam Engines • Used today primarily in power plants

  12. Internal Combustion

  13. Gas Turbine Engines

  14. Scientific Terms Energy Work Horsepower Thrust

  15. Energy • Capacity for doing work and overcoming resistance • Force behind the movement of all things • Humans and animals use food as energy source

  16. Energy • Potential Energy (stored) • Kinetic Energy (active)

  17. Work • Exertion of a force over a given distance • Measured in foot-pounds • W = F x D • W = work • F = force • D = distance

  18. Horsepower • Measures the output of engines • James Watt attached an apparatus to a horse and developed a formula to measure it James Watt

  19. number of foot-pounds of work seconds/minutes 550/33,000 Horsepower

  20. Thrust • Power of a jet engine is expressed in pounds of thrust Thrust = Weight of air x acceleration

  21. Reciprocating Engines

  22. Mechanical System • Cylinder • Piston • Crankshaft • Connecting Rod • Valves

  23. Mechanical System • Cylinder • Known as the engine’s combustion chamber • Where the power is developed

  24. Mechanical System • Piston • Fits snugly in the hollow cylinder allowing up-and-down linear (straight) motion • Fit will not allow air or fluid in the cylinder

  25. Mechanical System • Crankshaft • The crankshaft and connecting rod allow for the movement of the propeller.

  26. Mechanical System • Connecting Rod • Attached to the throws • With the crankshaft, they change the direction of the pistons into a circular motion

  27. Mechanical System • Valves • A rocker arm regulates the opening and closing of each valve. • Lobes or rings on a camshaft push the rocker arm

  28. Four-Stroke Cycle Stroke one is also called the intake stroke. The second step is the compression process. Near the end of the compression stroke, the air and fuel mixture is ignited by an electric spark from the spark plug. The fourth stroke is also called the exhaust stroke.

  29. Four-Stroke Cycle - Stroke 1 • Called intake stroke • Piston moves down the cylinder creating vacuum • Cam arrangement opens the intake valve • Fuel and air drawn into the cylinder

  30. Four-Stroke Cycle - Stroke 2 • Piston moves up the cylinder • Both valves closed • Air and fuel compressed and pressure rises

  31. Four-Stroke Cycle - Stroke 3 • Air and fuel ignited by electrical spark • Rise in temperature forces piston down

  32. Four-Stroke Cycle - Stroke 4 • Piston moves up forcing burned gas out of cylinder • Burned gas transmitted to exhaust system

  33. Four-Stroke Cycle • Occurs at the same time in all cylinders, but not on the same step • Ignition sequence of the cylinders called the firing order

  34. Cooling System • Engine produces vast amount of heat • Modern aircraft engines use an air cooling system

  35. Cooling System • The liquid cooling system on an aircraft works the same as does the cooling system on most automobiles. • The coolant flows through the engine block and around cylinders. • The liquid circulates through a system of pipes to a radiator.

  36. Ignition System • Must receive an electrical spark originating in the magneto

  37. Ignition System Pistons move up and down Fuel and air mix in cylinder and compression begins Starter keeps rotating crankshaft Compression Stroke Rotor spins Electricity delivered from the magneto

  38. Types of Reciprocating Engines • How to get more horsepower from an engine? • (1) Increase the number of cylinders or (2) Increase the size of each cylinder • Attention focused on designs

  39. Types of Reciprocating Engines • In-line Engines • Cylinders are located in a row, one • behind the other • Two classifications: • Upright • Inverted

  40. Types of Reciprocating Engines • Opposed Engines • Two rows or banks of cylinders on each side of the crankshaft • Rows directly opposite each other called horizontal opposed

  41. Types of Reciprocating Engines • V and X Engine • “V” engine features two rows of cylinders set • at an angle of about 45° • The “X” engine is essentially an opposed “V” • engine

  42. Types of Reciprocating Engines • Radial Engine • Crankshaft with only • one throw • Odd number of • cylinders in each bank • or row • Maximum number of • cylinders in each bank • is nine

  43. Construction of Reciprocating Engines

  44. Fuels Used in Reciprocating Engines • Most common form of • fuels is hydrocarbons • derived from petroleum • Gasoline and kerosene • offer several advantages

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