Oral P.O.H Sect 7 Flashcards
(42 cards)
What is the airframe?
It is an all metal, four place, high wing, single engine airplane equipped with a tricycle landing gear.
What is the construction of the Fuselage?
Semimonocoque: the internal structure of the fuselage, layered with stressed skin, stringers and sheet metal
What is the skin of our plan made of?
Corrugated aluminum skin
How are the flight controls powered?
Pulleys and wheels and cables
What are the primary flight controls?
Ailerons
Rudders
Elevator
Stabilator
What are the secondary flight controls?
Flaps
Rudder Trim
Elevator Trim
Anti-Servo Tab
What Kind of Breaks are on the Cessna 172?
Single Disk, Hydraulically Actuated
What kind of flaps does the Cessna 172 have?
Single slotted with Fowler type characteristics
Slotted: One single slot, delays airflow separation
Fowler: Multiple Slots
What type of Trim does the Cessna 172 have?
Manual Trim
Differential Trim: the trim functions opposite
Nose up: Trim Down
Nose Down: Trim Up
What is the attitude indicator?
Shows the airplanes orientation relative to the horizon, based on the planes pitch and bank angles
What Instrument would you lose if the Pitot Static Tube became clogged?
Air Speed Indicator
What are the 4 stages to our engine?
- Intake: brings air and fuel in
- Compression: the valve closes and and the mixture in compressed
- Combustion: the spark plug ignites the mixture (piston) creates mini explosion
- Exhaust: the spring release and exhaust is vented out
How many cylinders does the Cessna 172 have?
4
What are the advantages to a Fuel Injected engine?
Precisely meters fuel to each cylinder ⇒ increased performance/fuel economy
• Eliminates the hazard of icing over
How is our engine air cooled?
It uses cooling fins and baffling to redirect airflow between the cylinders this prevents hot spots from forming
Describe how Air is Induction works.
The air intake is located below the engine cowling
1) Uses air filter to remove contaminants before flowing to the fuel/air control unit.
2) If air intake became clogged
• Alternate air door would automatically open by suction
Engine experiences 10% power loss (Unfiltered)
Explain the Oil System.
It is a wet sump system (gravity fed back to the
sump located at the bottom of the engine)
1)Strainer
• Located inside sump; remove solid particles before pump
2)Pump
• Toothed gears driven by crankshaft, pressurizes oil
3) Bypass
• Cold oil ⇒ straight to filter
• Hot oil ⇒ oil cooler
4) Oil Cooler
• Matrix that spreads out oil allowing it to be cooled
• Cooling dependant on airflow
5) Filter
• Removes small contaminants
• If clogged
6) Spring-loaded relief valve back to sump
o Then lubricates engine components before returning to sump
What is the purpose of oil?
Cools, lubricates, prevents corrosion and carries away contaminants
What does the Nose Wheel have?
a shimmy damper which limits oscillations
What are symptoms for break failure?
What is the solution?
Gradual decrease in braking action
• Noisy or dragging brakes
• Soft or spongy pedals
• Excessive travel and weak braking action
Solution:
• Let up on pedals, then apply heavily (restore hydraulic pressure)
GET SERVICED!
Explain the Magnetos.
Self-contained engine-driven generator producing high voltage for spark to ignite fuel/air
(engine must be running)
o 4 cylinders
• 2 spark plugs/cylinder fed by independent magnetos (redundancy)
• More complete burn ⇒ better performance
o Impulse coupling [engine starting]
• Spring inside magneto winds up when engine rotates at low speeds
• When spring unwinds
Spins rotating magnet at high speed generating a sudden high voltage for
spark plugs (engine start)
• Engine starts: centrifugal force inside magneto disengages impulse coupling
o Turning ignition switch OFF grounds primary circuit (shuts off spark)
• If engine does not shut off
Defective switch, loose ground ⇒ “hot” magneto
Engine could start if propeller turned rapidly
Explain the Starting system.
o Master – ON connected to boost pump
o Ignition – START
• Closes circuit – energizes starter relay
• Current flows to starter motor
o Electro-mechanical solenoid connects bendix gear to the engine flywheel
• Begins rotation of the propeller[impulse coupling helps start]
The flywheel then connects to the crankshaft and that beings to turn the piston starting the 4 cylinder cycle and starting the engine
Explain the fuel system.
The fuel system consists of two vented integral fuel tanks, a three-position fuel selector, auxiliary
fuel pump, fuel shutoff valve, fuel strainer, engine driven pump, fuel/air control unit, fuel
distribution valve, and fuel injection nozzles
Explain the Exhaust System.
Exhaust gas is directed through a muffler on the right side of cowling this Reduces noise and directs exhaust gas away from aircraft.
Air is routed under the engine to the hot muffler shroud then fed to the cabin for heat
