Air Engines

CUO Tonya Brown Apr 11

Flying Camp:Basic/Proficiency/Advanced

Aviationnews.eu

Aim• State the basic principles of operation and

identify the basic components of:– A four stroke cycle internal combustion engine– Basic turbo jet engine

• Demonstration of a type of thrust similar to that of engines found in jet aircraft

Airforce.gov.au

Four Stroke Piston Aircraft Engine

• This has a cycle of four operations:1. Induction2. Compression3. Expansion (or Ignition)4. Exhaust

Aussiex.org

Induction

• Inlet valve opens• Down stroke, to allow mixture

of fuel and air into cylinder chamber

Compression

• Compression• Both valves remain closed• Rising piston compresses

mixture

Power/Ignition• Piston reaches end of compression• Inlet and Exhaust valves both

closed• Mixture ignited by an electrical

spark• The heat generated rapidly

expands mixture• Forcing the piston down, thus

turning the crankshaft

Exhaust

• At the beginning of final up stroke

• Exhaust valve opened (Inlet valve remains closed)

• Burnt gases released into atmosphere

• Complete sweeping of cylinder by piston during upward travel cleans for next cycle

The Jet Engine

• Sequence of induction, compression, expansion and exhaust can be applied to turbo jet engine

• All of these processes occur continuously in engine and delivery is uninterrupted (unlike a piston engine)

Airforce.gov.au

• Turbojet engine has no reciprocating parts• Therefore mechanically smoother and parts

are less stressed than a piston engine• Figure shows general make-up of basic gas

turbine engine

• Incoming air is squeezed through the front fan (compressor) into the compression chamber

• Add the fuel and ignited• Gases expand and flow out the rear of the

engine

• To maintain the movement of the compressor another fan (rear turbine) is located at the rear. Connected to the compressor by a shaft

• Fan turned by hot gases passing through at very high velocity

• After passing through turbine, the heated gases, still expanding, leave from exhaust nozzle as a jet

Afterburning (Reheat)

• Used for obtaining additional power • Feeding fuel into hot gases at back of engine• Heats the gases even more• Fuel ignited as soon as it comes in contact w/

hot gases• Increased expansion of air which was

originally drawn from front gives aircraft extra thrust

Airshow-reviews.com

Use of Afterburning

• Uses very large amount of fuel• Usually used to:– Shorten take-off– Increase rate of climb– Give extra speed for a short period of time

Birch.family.tripod.com

Like this...

Newlunches.com

Pixdaus.com

No, obviously like this...

Model Air Engine

• Imagine that...– Straw = Fuselage– Balloon = Aircraft Engine

• Air propelled to create forward motion