How does a Cessna's engine work?

Answer 1

Cessna currently makes both piston-engined and turbine-powered aircraft.

Assuming you mean a piston engined cessna, the engine works basically the same way as the engine in your car. Most small piston-engined aircraft use an air-cooled opposing 4 or 6 cylinder engine very similar to the engine in an old air-cooled Volkswagen.

Aside from that the other major differences are that aircraft engines usually use a solid-state magneto instead of an ignition coil, and that aircraft engines allow the operator to adjust fuel mixture levels en-route. The magneto is used so that the ignition system can be made independent of the aircraft's electrical system. Even if the electrical system fails entirely, the engine will keep running. The mixture control allows the pilot to adjust fuel mixture in-flight in order to compensate for the lower air pressures at high altitudes. If the aircraft were run at the same mixture all the time, as an auto generally does, the spark plugs would quickly become fouled by carbon and ash deposits.

Answer 2

1. The Intake Stroke

The cycle begins with the piston at top center; as the crankshaft pulls the piston downward, a partial vacuum is created in the cylinder chamber. The cam arrangement has opened the intake valve, and the vacuum causes a mixture of fuel and air to be drawn into the cylinder.

2. & 3. Compression and Ignition Stroke

As the crankshaft drives the piston upward in the cylinder, the fuel and air mixture is compressed. The intake valve has closed, of course, as this upward stroke begins. As the compression stroke is completed and just before the piston reaches its top position, the compressed mixture is ignited by the spark plug.

4. Power Stroke

The very hot gases expand with tremendous force, driving the piston down and turning the crankshaft. The valves are closed during this stroke also.

5. Exhaust Stroke

On the second upward (or outward, according to the direction the unit is pointed) stroke, the exhaust valve is opened and the burned gases are forced out by the piston.

At the moment the piston completes the exhaust stroke, the cycle is started again by the intake stroke. Each piston within the engine must make four strokes to complete one cycle, and this complete cycle occurs hundreds of times per minute as the engine runs.

The overall principles of reciprocating-engine operation are easy to understand if you remember what happens with each stroke that the piston makes. For this reason, you may find the chart in Table 6-3 helpful.

Table 6-3

Direction of Movement

Event (what happens)

1.

Inward (Down)

Intake

2.

Outward (Up)

Compression and Ignition

3.

Inward (Down)

Power

4.

Outward (Up)

Exhaust

Reciprocating-Engine Horsepower.

Most persons are acquainted with the term horsepower as applied to automobile and aircraft reciprocating engines. The term was coined by James Watt, the inventor of the steam engine, who wished to evaluate the power output of his steam engine. Watt hitched a horse to an apparatus and determined that the horse could lift 550 pounds one foot in one second. Thus, one horsepower became the power to lift 550 pounds one foot per second, or 33,000 foot-pounds per minute (550 x 60).

If an aircraft reciprocating engine is rated at 150 horsepower, it means the engine is capable of producing this much power. However, the engine has to be running at a certain speed before that much power is produced. The same is true for all other types of reciprocating engines.

Answer 3

just like any internal combustion engine, except the spark comes from magnetos and the engines are typcially air cooled