Principles of Flight Flashcards
Why are advanced propeller blades designed broader and swept back at the blade tips
To reduce the adverse effects of high speed tips
How can the solidity of a propeller be increased
By increasing the number of propeller blades to help with power absorption
What is the effect known as where the thrust produced by the down going propeller blade when the aircraft is at a higher angle of attack
Asymmetric blade effect
If air mass is M, intake air low velocity is Vi and exhaust velocity is Ve, what does Mx (Ve - Vi) x TAS express
Gas turbine jet propulsive power
What does M x (Ve - Vi) express
Gas turbine jet thrust
Why is the propeller tip speed a critical factor in turbo prop efficiency
Because of the rotational drag at the tip due to compressibility at high tip speeds.
How can the adverse effects of the loss of an outboard critical engine be minimised on multi engine turbo prop aircraft
The use of counter rotating propellers
How does a turbo fan engine generate high levels of thrust at lower speeds, significantly increasing overall mass flow and thrust
Additional turbine stages absorb more of core gas flow to drive a bypass fan stage
What is the ratio of power output over the power generated by the chemical energy of fuel consumed defined as?
Gas turbine efficiency
What is meant by the term critical engine in propeller powered aircraft
When it fails, the remaining engine produces the most use due to increased asymmetric thrust moment
What is the immediate and secondary effects of asymmetric thrust
Yaw then roll towards the dead engine
With wings level, which way will the slip indicator move following an engine failure
Towards the live engine
What is the preferred method of asymmetric control in flight
Level the wings and then opposing yaw with rudder
What is the preferred method of asymmetric control following an engine failure before V1
Reduce power
What conditions are used to calculate an aircraft’s VMCA
Landing gear up
Flap 1
Critical engine feather (prop only)
Live engine at TOGA
Full rudder
5 degree bank toward live engine
Rearmost C of G
What is the VMCA of the phenom
97 kts
What will happen if no corrective action is taken following an asymmetric engine failure
The aircraft will enter a spiral descent towards the dead engine
Once control has been established was is dead leg dead engine used to identify
Which engine has failed
What will a low thickness/chord ratio and low aspect wing ratio delay the onset of
Compressibility effects
What happens when the airflow over the aircraft surfaces reaches the speed of sound
Shockwave start to form 
What are the features of a super critical wing profile?
Blunt nose
Flat upper surface
Thick trailing edge
Higher thickness to chord ratio
S shaped camber
In aircraft design what insures a smooth change in cross-sectional area from nose to tail?
Area ruling
Below, what speed does air behave like an incompressible fluid
250 to 300 knots
What is the only variable in calculating the local speed of sound?
Temperature
What is the name given to the ratio of TAS to the local speed of sound?
The Mach number
What is Mcrit
The speed at which shockwaves first form on an aircraft
What is Mfs
The mach number of the airflow past an aircraft that is unaffected by its passage
What does Mdet indicate
The end of transonic flight and the beginning of supersonic flight
What effect does the formation of shockwaves have on drag?
The coefficient of drag increases
What causes aerodynamic heating at high Mach numbers?
Compression of airflow
Why did early sweptwing aircraft tend to pitch up at low speeds, leading to a deep stall or sabre dance?
Swept wings tend to stall at the tip, first, moving the lift centre of pressure forwards
How does CLMAX Swepson Street wing compare in relation to AOA
A swept wing has a Lower CLmax at a higher AoA
What is the term for the point in the flight envelope at which the aerodynamics stall speed is the same as shock stall speed
Coffin corner
What are the three functions of spoilers
Speed break
Lift dumping
Roll control
What is a leading edge flap called
Krueger flap
Other than a flap what other leading edge lift augmentation devices are there
Slotted flap
Droop
What kind of training edge flap increases CL, by increasing wind, camber and cord length
Fowler flap
What is lateral stability
The tendency for wing to return level when disturbed in the role axis
What is spiral stability
The tendency for the wing to return level, when the control forces are released in a balance turn
What do slats increase during climb?
Higher AoA
What would happen if slats were attracted before flaps to high angle of attack
Stall
