Air Cadets Aviation Test

Wings

designed in such a way to generate lift with different designs and materials for different purposes

Lift

force upwards

Engines

Generate thrust with different styles, speeds, and designs

Thrust

force forwards

Spoilers

decrease (spoil) lift, increase drag

Drag

force backwards

Speed brakes, Dive-brakes

increase drag, no effect on lift

Empennage

entire tail section of aircraft (important for directional control/stability)

What does empennage consist of?

consists of the Vertical/Horizontal Stabilizers, Rudder, Elevators

Roll

(think of a barrel roll) helps direct lift in directions and aircraft turning

Pitch

(nose up and nose down) increases/decreases angle of attack (angle between chord and relative airflow)

Yaw

nose of the aircraft left and right

What are the four forces of flight?

lift, thrust, drag, gravity

lift opposes?

gravity

thrust opposes?

drag

Horizontal Stabilizer

control pitch

Vertical Stabilizer

control yaw

Rudder

change yaw

Elevator

change pitch

Flaps

increase lift and drag

Aileron

change roll, create airflow

Spoiler

change lift, drag and roll

Slats

increases lift

Fuselage

main body of the aircraft, holds things together - carry payload

Cockpit

command and control

Turbine Engine

generate thrust

Winglet

decrease drag

Chord Line

An imaginary straight line joining the leading and the trailing edges of the wing

Camber

The curvature of the wing (average curve)

Ribs

built to help support the wing (leading edge to trailing edge)

Spars

ensure the wing remains intact (fuselage and wingtips)

Boundary layer

the very thin layer of air lying over the surface of the wing is called the boundary layer

Laminar layer

The area at the front of the wing where the boundary layer flows smoothly over the surface

Turbulent layer

The layer that becomes thicker and turbulent as the air flows further along the wing and slows down due to skin friction

Laminar Flow Airflows have their thickest point

at 50 percent of the chord

Laminar Flow Airflows

the leading edge that is more pointed and upper and lower surfaces are nearly symmetrical

Conventional Airfoils are thickest

at 25 percent of the chord

How does the design of the laminar flow airfoil reduce drag?

by maintaining the laminar flow of air throughout a greater percentage of the chord

Planform

The shape of the wing as seen from directly above.

Aspect Ratio

The relationship between the length and width of a wing (chord)

comparison between high and low aspect ratios

A wing with a high aspect ratio generates more lift with less induced drag than a wing with the same wing area but a low aspect ratio

Angle of Incidence

the angle at which the wing is permanently inclined to the longitudinal axis of the aircraft

Wash-in wings

increasing the angle of incidence at the wing tip

Wash-out wings

decreasing the angle of incidence at the wing tip

What are the wing modifications that can increase life and reduce drag?

installing wing-tip fuel tanks, using wing-tip plates or winglets, and drooping the wing tips

Flats, slats, and slots increase \_____ and \_____

increase lift and increase drag

Slats

move out in front of to increase lift and decrease drag

Slots

do NOT move, but permanently fixed but achieve the same purpose

The five layers of the atmosphere

exosphere, thermosphere, mesosphere, stratosphere, troposphere

Exosphere

a layer wherein pressure drops a little more than a vacuum

Thermosphere

temperature continues to rise in this section of the atmosphere and continues to rise for an indefinite distance into space

Mesosphere

marked by a decrease in the temperature carried from the stratosphere

Stratosphere

the pressure decreases while the temperature continues to increase to 0 degrees Celsius. in this layer, the thickness varies. it is quite deep over the poles and thinner over the equator. water vapour is almost non-existent and air currents are minimal. a layer of ozone is present

Troposphere

the lowest part of the atmosphere and varies in height in different parts of the world. most of the weather occurs in the troposphere because of the presence of water vapour and strong vertical currents

What are the properties of the atmosphere?

mobility, capacity, and capacity for compression

ICAO Full Form

International Civil Aviation Organization

ICAO Standard Atmosphere

* the air is perfectly dry gas
* mean sea level (MSL) pressure of 29.92 inches of mercury (inHg)
* MSL temperature of 15 degrees Celsius
* Lapse rate of 1.98 degrees Celsius per 1000 feet - every 1000 feet of an increase in altitude, the air will be 1.98 degrees cooler.

classification of clouds

high, middle, low, and vertical development

2 basic clouds

stratus and cumulus clouds

Nimbus clouds

rain clouds (which precipitation falls)

High Clouds

- range from 16,500ft to 45,000ft
- average about 25000 in temp
- composed of ice crystals
- little effect on flying
- moderate turbulence

Cirrus (Ci)

- high, thin, wispy, wavy sprays of white clouds
- feather or ribbon-looking
- delicate-looking

Cirrocumulus (Cc)

- thin
- cotton or flake like
- "mackerel sky"

Cirrostratus (Cs)

- thin high sheet cloud where sun and moon can be seen through
- halo effect
- indication of warm front approaching or occlusion

Middle clouds

- range from 6500ft to 23000ft
- composed of ice crystals or water droplets which may be at temps above freezing or supercooled
- little turbulence unless cumulus clouds are embedded in them or unless altocumulus is developing

Altocumulus (Ac)

- patches of rounded masses that may lie in groups or lines
- sometimes indicates the approach of a front but isn't a significant indication for future weather development

Altocumulus Castellanus (Acc)

- altocumulus with a turreted appearance
- instability, turbulence, and shower activity
- possibility to turn into cumulonimbus

Altostratus (As)

- thick veil of gray clouds that cover the whole sky
- sun and moon may be visible at the start but disappear when clouds get thicker
- indicates approach of warm front
- light icing or snow may fall from thick Altostratus

Low Clouds

- surface height to 6500ft
- composed of water droplets that are supercooled and ice crystals
- little turbulence
- low cloud base and poor visibility make VFR operations difficult

Stratus (St)

- uniform layer resembling fog but not resting on ground
- drizzles often fall
- St cloud broken up by wind is called "Stratus fractus (Sf)"
- form in horizontal layers and usually form as a layer of moist air that is cooled below its saturation point

Stratocummulus (Ns)

- series of rounded masses or rolls of clouds
- often thin with blue sky showing through
- common in high pressure areas in winter
- gives off a little precipitation

Nimbostratus (Ns)

- low layer of uniform, dark grey cloud
- when giving off precipitation, it is continuous rain or snow
- may be more than 15000ft thick
- generally associated with warm fronts

Clouds of vertical development

- form as low as 1500ft
- composed of water droplets when temp is above freezing

Cumulus (Cu)

- dense clouds of vertical development
- thick, rounded, and lumpy
- resemble cotton balls
- flat bases with rounded tops
- appear in great abundance
- appears in warm part of the day and dissipates during the night
- flights underneath the cumulus are usually bumpy
- form in rising air currents, unstable air

Towering Cumulus (Tcu)

- cumulus clouds that build up
- most likely to develop into cumulonimbus clouds
- rough air will be encountered underneath, and heavy icing may occur

Cumulonimbus (Cb)

- heavy masses of cumulus clouds that extend well above the freezing level
- spreads out to form an anvil shaped top
- turbulent, have heavy icing, and electrical activity
- hail is present, and may fall from it
- indicates cold front

Thunderstorm indication

- strong, gusty winds and turbulence
- heavy rain and hail
- lightning

Gusts

rapid and irregular change of wind speed, which lasts seconds

Squall

rapid and irregular change of wind speed, which lasts minutes

Surface Friction

between ground level and 3000 feet, the surface of the Earth will cause wind speeds to be lower than expected from the pressure gradient

Relative humidity

ratio of the actual amount of water present in the air compared to the amount the same volume of air could hold, also expresses as a percentage

Dewpoint

temperature to which air must be cooled to become saturated with water vapour, and will increase with the addition

Isobars

lines that join, on a weather map, areas of equal pressure, and isobars that are close to each other have a steep pressure gradient and strong winds

Buy Ballot's Law

If you stand with you back to the wind, the low pressure area will be on your left side. In the southern hemisphere, the low pressure area will be on your right side.

Warm Front

mass of warm air advances on a retreating mass of cold air, since the warm air is lighter, it ascends over the cold air in a long gentle slope
Characteristics:
- stability
- smooth air
- poor visibility
- stratiform cloud
- steady precipitation
Warm air is less dense than cool air therefore tends to rise

Cold Front

leading edge of a cooler mass of air that replaces a warmer mass of air
Characteristics:
- instability
- turbulence
- good visibility
- cumuliform clouds
- precipitation in the form of showers, hails, and thunderstorms
Winds blow counterclockwise and inward around a low pressure

Sublimation

process n which water vapour turns directly into ice crystals (gas to solid)

Katabatic Winds

downslope winds flowing from high elevations down the slopes to valleys below

Anabatic Winds

upslope winds flowing from valleys up the slopes to high elevations above

Meridians of Longitude

Semi circles joining the true/geographical poles of the Earth. Longitude is measured from 0-180 degrees east and west of the prime meridian (60 minutes in a degree)

Prime Meridian

the meridian which passes through Greenwich, England and is numbered zero degrees

Parallels of latitude

circles on the Earth's surface that lie parallel to the equator

Equator

imaginary line on the surface of the Earth equidistant from the poles

Great circle

A circle on the surface of a sphere that passes through the centre of the sphere, cutting it into two equal parts. A straight line drawn on a Lambert Conformal Conic Projection map

Rhumb Line

A curved line on the surface of the Earth, cutting all the meridians it meets at the same angle. A straight line drawn between any two points on the Mercator Projection map

How is Direction measured?

measured in degrees clockwise from north, which is 0 degrees (or 360 degrees), east is 90 degrees, south is 180 degrees, and west is 270 degrees

Bearing

angle between the meridian of longitude passing through the observer and the great circle that joins the observer to the object, measured clockwise from the meridian

Heading

angle between the meridian of longitude over which an airplane is flying and the line representing the direction the airplane's nose is pointing, measured clockwise from the meridian

How to calculate compass deviation

One adds when deviation is west, and subtracts when deviation is east

Variation

the angle between true north and magnetic north, also known as magnetic declination, taken into consideration during flight planning