Airframes, Engines, and Systems Flashcards
What are the three types of airframe construction?
Truss, monocoque, semimonocoque
Define monocoque
Airframe construction where the structural skin supports tensile and compression loads
Define semimonocoque
Airframe construction where stressed skin supports tensile loads, and longerons and ribs prevent compression
What is a conventional landing gear?
Tail dragger
What are the types of landing gears?
Fixed, retractable, conventional, tricycle
What is the advantage of retractable landing gears?
Reduces parasite drag in high speed aircraft
What is another name for mechanical retractable landing gear?
Mooney
What is another name for hydraulic retractable landing gear?
Seminole
What type of brakes do modern aircraft use?
Hydraulic disk brakes
What type of brakes do larger aircraft use?
Power assisted brakes
What is the benefit of controlling brakes individually?
Can aid in taxiing
Name the different types of flaps
Plain, split, slotted, fowler
What type of flaps does a Cessna 172 have?
Fowler flaps
Describe the advantages and disadvantages of a two stroke engine
Advantages - simplicity, high power, and low weight Disadvantage - not very reliable
What type of engine is most popular and why?
The four stroke engine, because of reliability and efficiency
What is the purpose of mixture?
To select how much fuel gets mixed in with incoming air
What is the purpose of the throttle?
To select how much air/fuel mixture goes into the cylinder
Describe the following engine designation: O-320-E2D
O = Opposed
320 = 320 cubic inches
E = crank case design
2 = crank case model number
D = accessory case design
Describe the following engine designation: R-985
R = radial
985 = 985 cubic inches
Describe the following engine designation: V-1710
V = vee type
1710 = 1710 cubic inches
Describe the following engine designation: TSIO-520
TS = turbo supercharged
I = injected
O = oppossed
520 = 520 cubic inches
Describe the following engine designation: LTO-360
L = left turning
T = turbocharged
O = opposed
360 = 360 cubic inches
Name the four different types of aircraft cooling
Liquid cooling, air cooling, oil cooling, fuel cooling
What cooling system is most popular?
Air cooling
Why isn’t liquid cooling used anymore?
Extra weight and complexity
What types of flaps do air cooling systems use? What are they used for?
Cowl flaps are used to regulate airflow through the engine. They are opened during taxi, takeoff, and climb to maximize cooling. They are closed during descend and cruise to reduce drag and keep the engine warm
When are oil cooling and fuel cooling used?
To supplement air or liquid cooling
Describe how fuel cooling works
Fuel is cooled as it is vaporized in a carburetor. This combined with a rich mixture will cool the engine
What is the purpose of the magneto?
Generates high voltage electricity to power the engine spark plugs
How many magnetos do standard aircraft have?
2 magentos
Describe the principle of electromagnetic induction
When a magnet is passed through a coil of wire it generates electricity. The voltage is increased with the number of coils or the speed of the magnet
How is the magneto shut off?
The primary coil is grounded so no power can reach the secondary coil
Describe how the primary and secondary coils interact to generate power
The primary coil generates its own magnetic field from the electricity in it, while the secondary coil has more coils and picks up on the primary coil’s magnetic field to increase the voltage
What is the purpose of opening the primary coil with a contact breaker?
To increase the voltage to the sparkplug
When will the contact breaker open?
When the magnetic field is the greatest and the engine cylinder is on the compression stroke
Name and describe the four strokes of the engine in correct order
Why are exhuast systems usually made of stainless steel?
Exhaust sytems carry hot, corrisive exhaust gasses away from the aircraft
Will the engine still run if the battery is dead?
Yes
What is the purpose of turbo charging?
To compress air going into the engine so it doesn’t lose power at high altitudes
Describe how a venturi works
Creates low pressure as air is passed through it. The more air passes, the lower the pressure
What is the best ratio of air to fuel?
14.7:1
Define rich mixture and lean mixture. What is an issue associated with these mixtures?
Rich mixture - ratio of air to fuel is less than 14.7:1
Lean mixture - ratio of air to fuel is greater than 14.7:1
If the mixture is too rich or too lean, the engine will not run
How can the amount of air going into the engine be controlled?
Using a throttle
Describe how a venturi is used to control the fuel flow so that it matches airflow
To add fuel to the air, put a nozzle in the venturi and let the low pressure suck the air out. When the throttle is opened to increase airflow through the venturi, the pressure will decrease and allow for more fuel flow
Describe how the main metering jet works
As fuel enters the float chamber, the float rises and closes the valve. As fuel levels drop, the float opens the valve to let more fuel in
As an aircraft climbs, the fuel mixture becomes too rich. What is a solution to this problem?
Add mixture control. The mixture transfers the low pressure from the venturi to the float chamber to reduce fuel flow. When the mixture control is pulled all the way out, it stops fuel flow with a valve
Name and describe the three types of carburetor icing
Impact ice - forms on air filter
Fuel vaporization ice - caused by evaporating fuel
Throttle ice - forms on throttle valve at low power settings due to the large pressure change
Describe the purpose of carburetor heat. How does it work?
Carburetor heat prevents ice formation. Hot air will remove ice and bypass the air filter
What type of mixture can carburetor heat result in?
Slightly rich mixture
What is the purpose of batteries?
Provide starting and emergency power for aircraft
What kind of batteries are used in aircrafts?
12V or 24V DC lead-acid
What is the purpose of the master switch?
To connect the batteries to the aircraft
What is the name of the device used charge the battery and provide power when the engine is running?
Generator
What type of power does the generator produce?
14V or 28V DC
What power do aircraft lights run off?
12V or 24V DC power
Name the different lighting systems on an aircraft
Landing/taxi lights, navigation lights, anti collision lights, instrument/interior lights
What device shows the charge/discharge from the battery?
Ammeter/load meter
What is the purpose of circuit breakers/fuses?
To protect the circuit
Describe the two different types of lubricant viscosity
100 weight is used in the summer
80 weight is used in the winter
What oil is used for engine break in?
Mineral oil
Why must mineral and ashless dispersant oil never be mixed?
It will turn the oil into foam
Name the four purposes of oil in an aircraft engine
Lubrication, cooling, cleaning, protecting
Describe the wet sump system
Used in light aircraft, a wet sump system pumps oil through the engine and then drips oil down to the oil pan
Describe the dry sump system
Large engines use a dry sump system which uses scavenge pumps to take the oil to an oil tank after it has passed through the engine
What is the purpose of the crankcase breather line?
To vent the aircraft and prevent oil and air pressure from building up inside of it
How often should engine filter be checked for contamination?
At every 50 hour inspection
What does fuel numbering indicate?
The octane rating at lean and rich mixtures
Describe colour and lead content of the four different types of aviation fuel. Which is the standard avgas?
80/87 - red colour, high in lead
100/130 HL - green, high in lead
100 LL - blue, low in lead (standrad)
Jet fuel - straw coloured
What is the average weight of fuel?
6lbs per US gallon
Why must fuel tanks have valves?
Water collects at the bottom of fuel tanks and must be drained
Where can exact weights and densities of different fuels be found?
In the air section of the IM or the CFS
What 3 things must all fuel tanks have?
A vent to allow air to enter the tank
A valve to drain water and check fuel type
An airframe fuel filter with a drain to filter all fuel entering the engine
Define detonation. Why is detonation dangerous?
When fuel explodes in an uncontrolled manner. It can cause damage to engine components
What can cause detonation?
Fuel grade that is too low, mixture that is too lean, or engine loaded
Describe the function of the priming system
The priming system takes fuel from the fuel system and sprays it into the intake manifold of several cylinders to ensure there is fuel in the engine prior to starting
What type of priming system do carbureted engines use? What about fuel injected engines?
Most carbureted engines use a manual system while fuel injected engines use the injectors themselves
Name three things that should be remembered when handling fuel
Fuel is very toxic and should not come in contact with skin
No smoking around fuel
Avgas creates static electricity when being transferred, can cause explosion
What should you do when filling the fuel tank?
Bond the aircraft the the fuel tank
What fuel type does our Cessna 172 use?
100LL
Does our Cessna 172 have fuel pumps?
No because it’s a gravity feed from the overhead wing tanks
