ATPL THEORY OF FLIGHT EXAM
QUESTIONS AND ANSWERS
The lift equation - Correct Answers -L = ½×ρ×V²×S×Cι
ρ = air density
V = TAS
S = surface area of wings
Cl = lift coefficient, determined by the shape and AOA of the wing
What are the 3 types of parasitic drag? - Correct Answers -Skin friction
Form drag
Interference drag
The speed of sound equation - Correct Answers -Speed of sound (kts) = 39×√Temp (K)
How to convert temperature in °C to Kelvin? - Correct Answers -Temp in Kelvin = °C +
273
How to calculate Mach number? - Correct Answers -Mach number = TAS / LSS
LSS = local speed of sound
What is subsonic flight? - Correct Answers -Mach below 0.75
What is transonic flight? - Correct Answers -0.75≤Mach≤1.2
What is supersonic flight? - Correct Answers -1.2<Mach
What is a shock wave and where does it form? - Correct Answers -Leading edge: when
an airfoil travels near the speed of sound, it compresses air molecules together thus
increasing pressure, density and temperature resulting in turbulence and separation.
Upper wing surface: air flow over the wing surface will reach the speed of sound first.
The air will be forced to slow down to subsonic speed as it travels towards the trailing
edge. The slowing down of the air flow forces air molecules together thus increasing
pressure, density and temperature resulting turbulence and separation.
QUESTIONS AND ANSWERS
The lift equation - Correct Answers -L = ½×ρ×V²×S×Cι
ρ = air density
V = TAS
S = surface area of wings
Cl = lift coefficient, determined by the shape and AOA of the wing
What are the 3 types of parasitic drag? - Correct Answers -Skin friction
Form drag
Interference drag
The speed of sound equation - Correct Answers -Speed of sound (kts) = 39×√Temp (K)
How to convert temperature in °C to Kelvin? - Correct Answers -Temp in Kelvin = °C +
273
How to calculate Mach number? - Correct Answers -Mach number = TAS / LSS
LSS = local speed of sound
What is subsonic flight? - Correct Answers -Mach below 0.75
What is transonic flight? - Correct Answers -0.75≤Mach≤1.2
What is supersonic flight? - Correct Answers -1.2<Mach
What is a shock wave and where does it form? - Correct Answers -Leading edge: when
an airfoil travels near the speed of sound, it compresses air molecules together thus
increasing pressure, density and temperature resulting in turbulence and separation.
Upper wing surface: air flow over the wing surface will reach the speed of sound first.
The air will be forced to slow down to subsonic speed as it travels towards the trailing
edge. The slowing down of the air flow forces air molecules together thus increasing
pressure, density and temperature resulting turbulence and separation.
