Chapter 1 Flashcards
What height is the tropopause and troposphere?
Between 7.5km and 16.5km
Usually 11km
Whats ISA?
International Standard Atmosphere
A standard atmosphere defined in the troposphere and stratosphere for comparison of aircraft performance, calibration of altimeters, and other.
Whats the ISA for pressure at sea level?
1013.2 mb
Whats the ISA for density at sea level?
1.226 kg/m ^3
Whats the ISA for temperature at sea level?
15 degrees celcius
Whats maximum camber
Maximum distance between the mean camber line and the chord line
Whats an aerofoil?
Any surface which when inclined to an airflow will provide a lifting surface
Whats chord ratio?
The ratio of the maximum thickness to the chord length
Whats the Angle of Attack?
The Angle between chord line and relative airflow
Whats angle of incidence? (AOI)
The angle between the chord line and the fixed aircraft datum line?
Whats the span?
The distance from wing tip to wing tip
Whats the aspect ratio? (AR)
Ratio of wing span to chord
What are the temperature changes for an increase in altitude? M & ft
6.5 degrees Celsius per km
2 degrees Celsius per 1000ft
Whats Static stability?
An objects immediate response to a disturbance
Whats dynamic stability?
Response over time following a disturbance
Whats unstable (negative stability)?
Object that never returns to original place after disturbance
Whats stable (positive stability)?
Returns back to original position
Whats Neutrally stable?
Neither returns to or continues away from original position
What axis is a rolling motion?
Longitudinal
What axis is pitch?
Lateral
What axis is yawing?
Normal axis
Effects of ice forming on an aircraft?
Drag
Weight (overnight)
CoG displaced
Vibration
Stiff controls
Vision impaired
Undercarriage locked
Engine & intake components damaged by ice
At what temp can snow form on aircraft?
When isotherm is below 0 degree C
Where does ice form the quickest?
Objects with a thin cross section
- pitot
- rotor blades
- leading edges
Whats hoar frost?
Light deposits that form on aircraft skin at 0 degrees C or lower when on a rapid descent or after being parked outside on a clear winter night. Restricts visibility.
Whats the tropopause?
Pause section where temperature stabilises in between the troposphere & stratosphere
Whats the stratosphere?
Temperature increases section due to ozone layer
Whats viscosity?
Fluids (liquid or gas) resistance to internal friction
Whats the formula for pressure and density?
P = ma
D = m/v
Whats the boundary layer?
Airflow slowed due to viscosity and friction close to the aerofoil surface 0.1-0.2mm thick
5mm - no lift
Whats laminar flow?
Neat orderly flow over an object
What are the 3 types of aerofoil shape?
High lift - curved shape (more drag)
High speed - sharp leading and trailing edge
General purpose
Whats the stalling angle?
15-16 degrees
Whats the stalling speed?
Slowest speed it can be flown before not enough lift is produced
Whats the total reaction?
Resultant force of lift and drag
What factors affect lift?
Density
Velocity
Shape
Surface area
AoA
Surface finish
Dynamic pressure
What are the 4 leading edge augmentation devices?
Slot - permanent fit allows airflow from lower to upper camber makes turbulent flow laminar
Slat - pitot or automatically operated (not permanent)
Kreuger flap (leading edge)
Droop nose
What are the 3 trailing edge devices?
Flaps
- plain
- split
- fowler (best)
What two groups make up total drag?
Lift dependant
Zero lift (drag)/ parasite drag
What component parts make up lift dependant drag?
Form drag
Skin friction drag
Induced/ vortex drag
Zero lift drag
Parasite drag
Form drag
Skin friction drag
Interference drag
Whats TP & SP in regards to boundary layer?
TP - transition point where the layer goes from laminar to turbulent
SP - when the air becomes too turbulent to continue following the profile of the aerofoil
After separation there is no lift
