Aircraft Systems Pt. 1 Flashcards
Up until Carburetor Heat
This is made up of supporting structural members that resists deformation by applied loads
Truss Type
These are lengths of tubing that are wielded in place to form the framework
Longerons
This uses stressed skin to support all imposed loads
Monocoque Type
This uses a substructure to which the airplane’s skin is attached
Semi-Monocoque Type
What does the bulkheads and stringers do for the semi-monocoque type structure?
It reinforces the stressed skin by taking some of the bending stress from fuselage
This is a combination of materials that are mixed to achieve specific structural properties
Composite Type
What are the materials used for composite type?
Fiberglass, carbon fiber cloth, kevlar cloth, and mixtures of all
What is the “glue” that holds the fibers together and when curved gives the part its shape
Matrix
What are the two control surfaces found on the wing?
Ailerons and flaps
This controls the roll about the longitudinal axis
Ailerons
This increases both lift and induced drag for any given AOA
Flaps
This has an antiservo tab extending across their trailing edge
Stabilator
These accepts and transmit shocks to the airplane at an acceptable rate
Spring Steel and Bungee Cord struts
This absorbs pressure rapidly and then slowly releases it
Oleo Strut
What does Oleo Strut houses in its enclosed cylinder?
Piston, Oil and Air
This pertains to the ability of where we can apply varying degrees of pressure on each brake independent of each other
Differential Breaking
What is differential breaking used for?
Used for steering during ground operations
Other terms for a reciprocating engine?
Four-Stroke Engines or Internal Combustion Engine
What principle does the reciprocating engine operate on?
Converting chemical energy to mechanical energy
Converts the back and forth motion of the pistons to the rotary motion of the crankshaft which in turn rotates the propeller
Reciprocating Engine
What are the 2 primary reciprocating engine designs?
Spark ignition and Compression ignition
This has a small frontal area to minimize drag and has a low power-to-weight ratio
In-Line Engine
The cylinders “radiate” outward from a central crankcase like the spokes of a wheel
Radial Engine
The cylinders in this engine are arranged in two in-line banks
V-Type Engines
This engine always have an even number of cylinders and has a reduced frontal area and better cooling
Opposed Engine
State the parts of a cylinder
- Intake valve
- Crankshaft
- Exhaust valve
- Connecting Rod
Who was the german inventor of the first internal-combustion engine to efficiently burn fuel directly in a piston chamber
Nikolaus August Otto
State the four strokes or otto’s cycle
- Intake stroke
- Compression stroke
- Power stroke
- Exhaust stroke
This piston is moving toward the crankshaft and the intake valve is open, exhaust valve is closed.
Intake Stroke
What happens to the fuel and air mixture during intake stroke?
Allows the fuel and air mixture to flow into the cylinder
As the piston starts moving away from the crankshaft both valves are closed. The fuel and air is compressed in the cylinder
Compression stroke
As the piston nears the end of its outward travel, the fuel and air mixture is ignited (explosion). The rapid burning and expansion of the fuel and air mixture pushes the piston toward the crankshaft
Power stroke
The piston moves away from the crankshaft and the exhaust valve is open, intake valve is closed
Exhaust stroke
What happens to the burnt gasses during exhaust stroke?
Burnt gases are forced out the cylinder
Explain what happens during valve lead
Inlet open before piston reach top dead center (at the end of exhaust stroke) and exhaust open before piston reach bottom dead center (at the end of power stroke)
Explain what happens during valve lag
Inlet valve close after piston passed the bottom dead center (at the beginning of compression stroke), the exhaust close after piston passed top dead center (at the beginning of suction stroke)
This is a short period of time when both inlet and exhaust valve open
Valve Overlap
When does valve overlap happen?
During the end of the exhaust stroke and beginning of intake
It is a secondary means of cooling the exhaust valve by fresh air intake during the overlap
Valve Overlap
What is the duration of the valve overlap?
10-20 degrees of crankshaft rotation
State the Cessna 152’s FCHANDLER acronym
Four Cylinder
Carburetor Type
Horizontally Opposed
Air Cooled
Naturally Aspirated
Direct Driven
Lycoming (Avco Lycoming)
Engine : 0-235-L2C
Rated at 2550 rpm @ 110BHP
This brings in air from outside, mixed it with fuel and delivers the fuel and air mixture to the cylinder where combustion occurs
Induction system
What are the two types of induction system?
Carburetor system and Fuel Injection System
This mixes the fuel and air before this mixture enters the intake manifold for combustion
Carburetor system
Explain the process for a float-type carburetor system
The outside air first flows through an air filter which flows into the carburetor and through a venturi, a narrow throat in the carburetor.
As the air flows through the venturi, a low-pressure area is created which forces the fuel to flow through a main fuel jet located at the throat.
The fuel and air mixture is then drawn though the intake manifold and into the combustion chambers where it is ignited.
This controls the engine power on single-engine airplanes
Throttle Knob
The throttle knob has a _______________ at the base of the throttle to increase/decrease friction
Friction lock
This is a needle which controls the amount of fuel to the discharge nozzle.
Mixture Knob
As altitude increases, the air becomes _______________
less dense
This refers to when the fuel is injected directly into the cylinders, or just ahead of the intake valve
Fuel Injection System
What are the six components of a fuel injection system?
- Engine-driven fuel pump
- Fuel-air control unit
- Fuel manifold (fuel distributor)
- Discharge nozzles
- Auxiliary fuel pump
- Fuel pressure/ flow indicators
(FUEL INJECTION SYSTEM)
This essentially replaces the carburetor, meters fuel based on the mixture control setting and sends it to the fuel manifold valve at a rate controlled by the throttle
Fuel-air control unit
Give the advantages of using fuel injection
- Reduction in evaporative icing
- Better fuel flow
- Faster throttle response
- Precise control of mixture
- Better fuel distribution
- Easier cold weather starts
Give disadvantages of using fuel injection
- Difficulty in starting a hot engine
- Vapor locks during ground operations on hot days
- Problems associated with restarting an engine that quits because of fuel starvation
This is the energy source for the combustion process
Fuel
This occurs when fuel comes into contact with oxygen (air) and the temp of the mixture is raised to its kindling point
Combustion
Give the Fuel and Air ratio for Stoichiometric ratio
1:14
Give the ratio of fuel to air by weight
Rich - 1:13 , Lean - 1:15
Give the reasons to why we “lean” our aircraft
- Proper leaning at cruise altitude produces optimal engine performance
- When you adjust the fuel and air mixture, you are decreasing fuel flow to the engine to compensate for decreased air density at higher altitudes
- Less fuel is needed for proper engine operation as altitude is gained
- During cruise, leaning is normally required when above 3,000 ft. MSL.
Explain the leaning process
- At altitude, set cruise power
- Lean by reducing the mixture gradually until the engine runs a little rough, and a reduction in RPM will happen
- Slowly enrich the mixture until the engine smooths out
If you need the climb, enrich the mixture before adding power, then lean again at your new attitude
State the advantages of proper leaning
- Good engine performance
- Good fuel economy
State the disadvantages of improper leaning if the mixture is too lean
- high cylinder temperatures
- possible detonation
- possible pre-ignition
- less engine power
- engine roughness
State the disadvantages of improper leaning if the mixture is too rich
- possible fouling of spark plugs
- less engine power at altitude
- excessive fuel consumption
(Carburetor Heat and Icing)
- It occurs due to the effect of a)__________________ and the b)___________________________ in the venturi, which causes a sharp temp drop in the carburetor.
- It usually forms when the relative humidity is c)________ or with temperatures d)_______________.
a. fuel vaporization
b. decrease in air pressure
c. above 80%
d. below 21 degrees celsius
Ice generally forms in the vicinity of the a) ______________ and in the b) ______________
a. Throttle valve
b. Venturi throat
State the process of application of carburetor heat
- Carb Heat : PULL - “ON”
a. This will introduce heated air
b. Fuel and air mixture will become rich - Reduction in the engine RPM
- Engine Roughness
a. Carburetor ice melts - The engine RPM will increase gradually after ice is melted. If ice is not present, the RPM will decrease and then remain constant
This pertains to a decrease in engine RPM, which may be followed by engine roughness
Fixed-pitch Propeller
This pertains to a decrease in manifold pressure, but no reduction in RPM
Constant-speed Propeller
This is an anti-icing system that preheats the air before it reaches the carburetor and is intended to keep the fuel-air mixture above freezing to prevent the formation of carburetor ice
Carburetor heat
The use of carburetor heat causes a a.)______________________ sometimes up to b.)_____, because the heated air is less dense than the outside air that had been entering the engine.
a. decrease in engine power
b. 15%
