AFCT Flashcards
Hvad er camber-linjen?
En kurve midt i vingen, som påvirker løftet og luftstrømmen
Hvad sker der med luftstrømmen, når angrebsvinklen bliver for høj?
Luftstrømmen kan ikke følge vingen, hvilket fører til stalling.
Hvad er vinkel af angreb (Angle of Attack)?
Vinklen mellem vingens kordelinje og den relative luftstrøm.
Hvordan kan en tynd vingeprofil påvirke flyets ydeevne?
Den kan skabe højere hastigheder, men har mindre plads til brændstof.
Hvad sker der under et stall?
Flyet mister sin evne til at generere løft, og luftstrømmen over vingen bliver turbulent.
Hvad er løftekoefficient (CL)?
En faktor, der beskriver, hvor effektiv vingen er til at generere løft under forskellige forhold.
Hvad er laminar flow?
En glat og uforstyrret strøm af luft over vingeoverfladen, som reducerer modstand.
Hvad er kampelinjen på en vinge?
En linje, der definerer vingens aerodynamiske form og bestemmer, hvordan vingen interagerer med luftstrømmen.
What is the main purpose of a propeller?
To accelerate a large volume of air at a slow rate, generating thrust.
What are the four stages of the four-stroke cycle?
Intake, Compression, Power, Exhaust.
How does a carburetor work in an aircraft engine?
It mixes fuel and air by creating a pressure drop in the Venturi, which draws fuel into the airflow.
What is carburetor icing, and how can it be prevented?
Carburetor icing occurs when adiabatic cooling causes ice to form. It can be prevented using carburetor heat.
What are the advantages of dual ignition systems in aircraft?
Dual ignition ensures that if one system fails, the engine continues running, improving safety.
What is the difference between air cooling and fluid cooling in aircraft engines?
Air cooling is lighter and simpler but less effective at maintaining a constant temperature compared to fluid cooling.
What is the primary function of a propeller?
To generate thrust by spinning through the air and moving a volume of air backward.
How does a jet engine produce thrust compared to a propeller?
A jet engine accelerates a small amount of air at a very high rate, while a propeller moves a larger volume of air at a slower rate.
What is the difference between fixed and variable pitch propellers?
Fixed pitch propellers have a set blade angle, while variable pitch propellers can adjust the blade angle for different flight conditions.
What is a constant speed propeller?
A propeller that automatically adjusts its pitch to maintain optimal engine speed (RPM) during various power settings.
What does feathering a propeller mean?
Feathering is when the blades are rotated to reduce drag, aligning them with the airflow when an engine fails.
What is the advantage of using reverse pitch on landing?
Reverse pitch allows the propeller to push air backward, helping to slow the aircraft down during landing.
Why are propeller blades twisted?
The twist ensures that the angle of attack is optimal along the length of the blade because the outer parts of the blade move faster through the air than the inner parts.
What are the four stages of the jet engine cycle?
Intake, Compression, Combustion, Exhaust.
What is the critical engine in a twin-engine aircraft?
The critical engine is the one that provides more thrust, and if it fails, it makes the aircraft more difficult to control.
Why are turboprops more efficient at lower speeds?
They accelerate a large volume of air at slower speeds, making them efficient below 250 knots.
What is the difference between a turbojet and a turbofan?
A turbojet uses all of the air for combustion, while a turbofan has a large fan, and most air bypasses the combustion chamber for efficiency.
What is the purpose of afterburners in jet engines?
Afterburners inject extra fuel into the exhaust to increase thrust, mainly used in military aircraft.
How is thrust calculated in jet engines?
Thrust is calculated as force = mass × acceleration.
