Systems Flashcards
What does the carburetor do?
The carburetor vaporizes liquid fuel into small particles and then mixes it with air. It measures the airflow and meters fuel accordingly.
What are 4 strokes that must occur in each cylinder of a typical 4 stroke engine in order for it to produce full power?
Intake - Fuel mixture is drawn into cylinder by downward stroke
Compression - Mixture is compressed by the upward stroke
Power - Spark ignites mixture forcing piston downward and producing power
Exhaust - Burned gases are pushed out of the cylinder by an upward stroke
How does Carb Heat work?
A Carb Heat valve 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.
What does the throttle do?
The throttle controls the amount of fuel/air charge entering the cylinders .
What does the mixture control do?
The mixture regulates the fuel-to-air ratio.
What is the purpose of a fuel tank vent?
Allows air to enter the fuel tank as fuel is consumed, preventing the formation of a vacuum inside the fuel tank
What color of dye does 80, 100, 100LL, and JetA have?
80 - Red
100 - Green
100LL - Blue
JetA - colorless
What is the purpose of a primer?
Engine Start. The primer draws fuel from the fuel strainer and injects it directly into the cylinder intake ports.
What are two kinds of oil?
Mineral - (non detergent oil) contains no additives. Usually used after an engine overhaul or when an aircraft engine is new… for engine break in purposes
Ashless dispersant - Mineral Oil with additives. Contains anti-wear properties along with multi-viscosity. Picks up contamination and carbon particles and keeps them suspended so that buildups and sludge do not form in the engine
What causes Carb Icing and what are the first indications?
Carb icing occurs when the vaporization of fuel, combined with the expansion of air as it passes through the carburetor, causes a sudden cooling of the mixture. The temperature of the air passing through the carburetor may drop as much as 60degrees F within a second. Water vapor is squeezed out by this cooling, and if the temperature is 32deg F or less, you will build up ice. The first indication is a loss of RPMs
How do you know when carburetor icing is gone?
After applying carb heat, you will see a loss in engine RPM, followed by a rise with engine roughness possible. When you turn carb ht off, your rpm should rise to the normal levels
What conditions are favorable for carburetor icing?
When temperatures are below 70 degrees (21C) and the relative humidity is above 80%.
What is detonation?
An uncontrolled, explosive ignition of the fuel/air mixture within the cylinder’s combustion chamber. Usually characterized by high CHTs and most likely to occur at high power settings
What are some common causes of detonation?
Using a fuel grade lower than specified by the aircraft manufacturer
Operating at high power settings with an excessively lean mixture
Operating with extremely high manifold pressure in conjunction with low RPM
Extended ground operations or steep climbs where cylinder cooling is reduced
What should you do if detonation is suspected?
reduce temperature and pressure of the fuel air charge
Reduce power, reduce climb rate, enrich the fuel/air mixture, open cowl flaps
