Revision Flashcards
Convert feet into NM
1 ft = 6080nm
Convert Knots into M/s
X 0.5144 (approx half)
Define power
Power is the work actually being done by the airframe physically
Power = force x TAS
Define all 3 of Newtons Laws
1st - An object will remain at rest unless an external force is applied
2nd - An object will
3rd - every action has an equal and opposite reaction
Properties of air density
Increase in alt = reducing density
Increasig Temp = reducing density
Increasing pressure = increasing density
Increasing humidity = less density
Lift equation
L = IAS2 x S x Cl
What is TAS
True airspeed is the speed at which the aircraft is flying through the air
What is IAS
Indicated airspeed is the dynamic pressure of the air against the plane
The airflow the aircraft is experiencing
Explain the different speeds
Remember Ice tea Pretty Cool Drink
IAS > correct for position error causing changes in dynamic pressure in pitot tube = CAS > correct for compressability = EAS > Correct for density = TAS
In 2D flow for therom what do we assume?
Ideal fluid
No viscosity
No compressability
What is bernoulli’s theroum
Total pressure = Static + Dynamic pressure
Total pressure must remain constant
Difference between chord and chord line
Chord = actual length of the distance from LE to TE
Chord line = physical line keeping the middle of the wing shape
Thickness chord ratio?
Thickness chord ratio = max thickness / chord
Where can we find centre of pressure on a symetrical aerofoil?
25% between LE and TE
What affects coefficient of lift?
Camber
AOA
Thickness
Centre of pressure is affected by what?
AOA - angle of attack
What happens to CP on a cambered wing
CP will move with AOA
What is the best angle for lift and drag?
4 degree
What is profile drag?
Skin friction + Form drag
Skin friction is the particles slowing as they hit the fu
What are streamlines and stream tubes
StreAmlines show the path of a partical of air. In a steady air they can never cross.
Stream tubes are imaginary tubes made of streamlines there is no flow into or out of a tube wall only along
Difference between chord and chord line
Chord line is just a line. Linking LE-TE
Chord = actual distance
What is thickness to chord (or fineness ratio)
This is the ratio of the aerofoils maximum thickness compared to chord length expressed as a %
Thickness chord ratio = max thickness / chord
What is the taper ratio
Tip chord/root chord
What is aspect ratio
Span2/area
Or span/mean aero chord
What is the angle of incidence
The angle between wing root chord and longitudde axis
Think the intermediate stage to EAF
Where to find CL/CD Max on drag polar
At tangent intercept
Where to find CL/CD Max on drag polar
At tangent intercept
What thickness is laminar flow in boundary layer
1-2mm
What thickness is turb flow on boundary layer
1-2cm
Before which point will laminar transistion to turb
A point before max thickness
What type of flight is defined as 1g flight
Straight and level
3 phases of a spin?
Incipient spin, fully developed spin, recovery
What CG position will lead to a flatter spin?
A more AFT cg
CS 23 /25 requirements
CS23 class B
Vs1 - 20% at 50ft
Vs0 - 30% at 50 ft
CS25 class A
Vsref- 23% at 50ft
Vr0 - 13% at 35 ft
How to get VS regulated limited
94% of Vs1g = VS
At what limits will stick pusher activate?
2% or 2knotd
What will TE flap ext do to CP
Move it aft
Why pitch down in ground effect?
Increased EAF on tailplane from main wing = less down force
What happens in ground effect
Downwash surpressee to EAF as a shallower angle. EAOA decreases induced increases = greater lift
At a LF of 1 and aeroplanes minimum drag speed what is ratio of induced and parasite drag?
Di/Dp = 1 … this is where they both cross over to create Vmd
CL prop to Cdi2
CL prop to Cdi2
Calculate AOB?
AOB= TAS/10 + 7 degrees
Radius of a turn
R = V2/Tan0 x Gravity
Time to complete a turn?
2 x Pi x R = Distance
Then do speed = distance / time
Speed in M/S
What is a rate 1 turn?
3 degrees per second
So 180 degrees in 1 minute
Calculate rate of turn
TAS/Radius x 60
What is VMP
Velocity maximum power
Best endurance speed
VMP is 0.76 of Vmd
What is the best speed for glide range?
VMD
