Flashcards in Aircraft and Engine Operations Deck (17)
What are the four main control surfaces and what are their functions?
a) Elevators - pitch
b) Ailerons - roll
c) Rudder - yaw
d) Trim tabs - releases pressure on primary control
What are the flaps and what is their function?
Movable panels on the inboard portion of the wing that increase lift and drag. Their purpose is to permit a slower airspeed and steeper angle of descent during a landing approach. May also be used to shorten takeoff distance.
Describe the braking system on the Cherokee
Hydraulically actuated disc-type brakes are utilized on each main gear wheel. A hydraulic line connects each brake to a master cylinder located on each pilot's rudder pedals.
What type of engine does the Cherokee have?
A four-cylinder, direct drive, horizontally opposed engine rated at 150 HP at 2700 RPM. It is equipped w/ a starter, a 60 amp 14 volt alternator, a shielded ignition, dual magnetos, vacuum pump drive, a fuel pump and a wetted polyurethane foam induction air filter.
What four strokes must occur in each cylinder of a typical four stroke engine in order for it to produce full power?
Intake - begins as the piston starts its downward travel causing the intake valve to open and the fuel-air mixture to be drawn into the cylinder.
Compression - beings when the intake valve closes, and the piston starts moving back to the top of the cylinder. This phase of the cycle is used to obtain a much greater power output from the fuel air mixture once its ignited.
Power - this stroke begins when the air-fuel mixture is ignited which causes a tremendous pressure increase in the cylinder and forces the piston downward away from the cylinder head, creating the power that turns the crankshaft.
Exhaust - this stoke purges the cylinder of burned gases and begins when the exhaust valve opens and the piston starts to move toward the cylinder head once again.
Remember: Suck, Squeeze, Bang, Blow
What does the carburetor do?
The carburetor vaporizes liquid fuel into small particles and then mixes it with air to form a combustible mixture. It measures the airflow and meters accordingly.
How does the carb heat system work?
A carb heat value, controlled by the pilot, allows unfiltered, heated air from a shroud located around an exhaust riser or muffler to be directed to the induction air manifold prior to the carburetor. Carb heat should be used anytime icing is suspected.
What change occurs to the air/fuel mixture when applying carburetor heat?
Normally, the introduction of heated air into the carburetor will result in a richer mixture. Warm air is less dense, resulting in less air for the same amount of fuel. Use of carburetor heat can cause a decrease in engine power.
What does the throttle do?
It allows the pilot to control the air/fuel mixture in the cylinders of the aircraft. This is turn regulated the engine speed and power.
What does the mixture control do?
It regulates the fuel-to-air ratio. All airplanes engines incorporate a device called a mixture control, by which the fuel/air ratio can be controlled by the pilot during flight. The purpose of mixture control is to prevent the mixture from becoming too rich at high altitudes, due to a decrease in air density. It can also be used to lean the mixture during cross-country flights to conserve fuel and provide optimum power.
What type of ignition system does the Cherokee have?
Engine ignition is provided by two engine-driven magnetos and two spark plugs per cylinder. The ignition system is completely independent of the aircraft electrical system. The magnetos are engine-driven, self-contained units supplying electrical current w/o using an external source of current.
Before the magnetos can supply current, the magnetos must be actuated, as the engine crankshaft is rotated by some other means. To accomplish this, the aircraft battery furnishes electrical power to operate a starter which, through a series of gears, rotates the engine crankshaft. This in turn, actuates the armature of the magneto to produce the sparks for ignition of the fuel in each cylinder.
After the engine starts, the starter system is disengaged, and the battery no longer contributes to the actual operation of the engine.
What type of fuel system does the Cherokee have?
The fuel system is driven by an engine operated/driven fuel pump that is backed up by an auxiliary electrical fuel pump.
What purpose does the fuel tank vents serve?
As the fuel level in the aircraft decreases, a vacuum would be created within the tank which would eventually result in a decreasing fuel flow and finally engine stoppage. Fuel system venting provides a way of replacing fuel with outside air, preventing formation of a vacuum.
The electrical system provides power for what equipment in an airplane?
Radio equipment, turn coordinator, fuel gauges, pitot heat, landing lights, taxi lights, strobe lights, interior lights, instrument lights, position lights, stall warning, oil temp gauge, electrical fuel pump
What does the ammeter indicate?
The ammeter indicates the flow of current, in amps, from the alternator to the battery of from the battery to the electrical system. With the engine running and master switch on, the ammeter will indicate the charging rate to the battery. If the alternator had gone off-line and is no longer working, or the electrical load exceeds the output of the alternator, the ammeter indicates the discharge rate of the battery.
What does the voltage regulator do?
Its a device which monitors system voltage, detects changes, and makes the required adjustments in the output of the alternator to maintain a constant regulated system voltage.