Wind Engineering - Finals

Air

aircrafts move through what

Ground

aircrafts move through air, not on __________

Wind

why is the atmosphere moving

Wind

continuously influences an aircraft's motion from takeoff to landing.

Ground Speed

directly affects flight time and fuel consumption.

Tailwinds

increase ground speed, reducing travel time and fuel burn.

Headwinds

decrease ground speed, increasing flight time and fuel consumption.

Crosswind

are among the most challenging weather conditions during takeoff and landing.

wind

motion of the surrounding air

Flight Vector Analysis

combines these motions (aircraft motion, and the wind) to determine the aircraft's actual movement over the ground, making it a fundamental tool for safe, accurate, and efficient aircraft navigation.

Compass Rose

True North

reference of the compass rose

True Bearing

Angle measured clockwise between the True North and the Target as observed from own vessel

Relative Bearing

Angle measured clockwise between the Ship's heading and the Target as observed from own vessel

True Bearing

is measured clockwise from geographic True North (the Earth's axis of rotation).

Magnetic Bearing

is measured clockwise from Magnetic North (the direction a magnetic compass needle points).

True North

the Earth’s axis of rotation

Magnetic North

direction a magnetic compass needle points

Magnetic North

the magnetic bearing is measured clockwise from _________

Magnetic Declination or Variation

difference between the true bearing and a magnetic bearing

Magnetic Declination or Variation

changes depending on location

True Bearing

• Reference Point: Geographic North Pole.

• Used In: Nautical charts, aviation flight plans, and surveyed property maps.

• How to Find: Usually calculated using a gyrocompass, GPS, or by applying a correction (declination) to a compass reading.

Magnetic Bearing

• Reference Point: Magnetic North Pole.

• Used In: Hiking, standard handheld compass navigation, and basic topographic maps (which often include a declination diagram).

• How to Find: Read directly off an unadjusted magnetic compass.

Whole Circle Bearing System

• Measured clockwise from True North

• Values range from 000° to 360°

Quadrantal Bearing System

• Expressed from North or South toward East or West

• Always less than 90°

Heading

direction in which the aircraft’s nose is pointing

Heading

measured relative to North

Heading

determined by the pilot

Heading

may not be the actual direction of travel

Track (Ground Track)

actual path the aircraft follows over the ground

Track

affected by wind

Track

‘where I actually went’

Course

intended direction of flight over the Earth’s surface

Course

the planned route

Course

‘where I want to go”

Bearing

direction from one point to another, measured from North

Course

The horizontal direction in which a vessel is intended to be steered.

Heading

The direction in which the vessel is actually pointing.

Bearing

The direction of a fixed object from the vessel.

Aircraft Velocity

speed and direction of the aircraft relative to the surrounding air

Wind Velocity

speed and direction of th moving air

Ground Velocity

actual speed and direction of the aircraft relative to the Earth’s surface

Aircraft Velocity

velocity controlled by the pilot

Wind Velocity

velocity determined by atmospheric conditions

Ground Velocity

velocity observed by GPS and navigation systems

Triangle (Head-to-tail) Method

vectors are drawn sequentially. Thebtail of each new vector begins at the head of the previous vector.

Parallelogram Method

two vectors are drawn from the same starting point (tail-to-tail). A parallelogram is completed, and the diagonal represents the resultant vector.

Drift Angle

measure of deviation from the original flight course

Wind direction

is a major factor on active runway selection

Headwind

increases the drag force and eases landing and increases lift force eases take off

150 A.D.

when was the first recorded use of anemometers

1. Anemoscopes

2. Anemometers

2 (1 way each) to measure Direction and Speed

Dracones

dragon-shaped or conical fabric banners used by Roman Cavalry

Dracones

were attached to poles and allowed to inflate.

Dracones

served a dual purpose: they helped soldiers identify unit positions, and their open-ended design showed troops the speed and direction of the wind.

• This was critical for archery tactics such as for adjusting and coordinating the trajectory of their arrows volleys.

Takeoff Performance

focuses on how far an airplane must travel on the ground and in the air before it is safely airborne

Takeoff Performance

It involves acceleration from rest to liftoff, and it's especially critical when considering engine failure or obstacles ahead.

Ground Roll

Distance the airplane travels on the runway before it lifts off.

Ground Roll

Starts at zero speed when brakes are released and engines go full power.

Airborne Distance

After liftoff, the airplane continues to fly low over the ground until it clears a specific obstacle (usually 35 ft for commercial aircraft, 50 ft for military).

Vstall (Stall Speed)

The minimum speed where the wings can start generating enough lift.

• Below this, flight is impossible.

Vmcg (Minimum Control Speed on Ground)

For multiengine planes, this is the lowest speed where the pilot can still control the airplane on the ground if one engine fails.

Vmca (Minimum Control Speed in Air)

Similar to Vmcg but applies when the airplane is off the ground.

V1 (Decision Speed)

Critical speed where the pilot must decide:

• If engine fails before V1, abort the takeoff

• and if engine fails after V1, continue the takeoff—it’s still safe.

VR (Rotation Speed)

Speed where the pilot pulls the nose up (rotates the aircraft) to begin liftoff.

Vmu (Minimum Unstick Speed)

The lowest speed the airplane can actually lift off, assuming maximum safe rotation.

VLO (Liftoff Speed)

The actual speed at which the airplane leaves the ground.

• Slightly higher than Vmu for safety and comfort.

Landing Performance

is the study of how much distance an aircraft requires to safely land, from the moment it clears an obstacle (typically 50 feet above the ground) to the point where it comes to a complete stop on the runway.

Total Landing Distance

is the entire distance needed to land safely starting from a point 50 feet above the runway down to a full stop on the ground.

Approach Distance

is the segment where the aircraft descends from a 50-foot obstacle height toward the runway on a shallow glide path.

Flare Distance

is the part of the landing where the aircraft transitions from a steady descent to a level attitude just before touchdown.

Ground Roll

is the distance an aircraft travels on the ground after touchdown until it comes to a complete stop.

Range

refers to the maximum distance an airplane can travel on a single trip without needing to refuel.

Range

refers to the maximum distance it can travel on a single trip without needing to refuel.

Propeller

type of aircraft that excel in short-range, regional flights with better fuel economy at lower speeds

Jet

type of aircraft that are built for high-speed, long-distance travel

Endurance

maximum time an aircraft can remain in steady flight using a given amount of fuel.

Cruise

during __________, endurance depends on how efficiently the aircraft uses fuel over time and not how far it travels.

Endurance

during cruise, __________ depends on how efficiently the aircraft uses fuel over time and not how far it travels.

Max Endurance

happens at minimum fuel flow, usually at low speeds and high L/D ratio.

Propeller Aircraft

are typically optimized for endurance over jets.

Jet Endurance Formula

is designed for aircraft flying at higher speeds and altitudes, where thrust is the dominant factor in fuel burn.

Wind Engineering

a vital field in aerospace that studies the relationship between atmospheric winds and aircraft performance.

Wind

defined as the movement of air relative to the Earth's surface, significantly influences aircraft operations during all phases of flight; takeoff, landing, and cruise.

Wind

is characterized by its speed and direction, which can be steady (constant) or turbulent (gusty).

Headwind

Wind blowing opposite to the aircraft's direction of travel, increasing lift and reducing ground speed during takeoff and landing.

Tailwind

Wind blowing in the same direction as the aircraft, decreasing lift and increasing ground speed, which can extend runway requirements.

Crosswind

Wind perpendicular to the aircraft's path, requiring precise control inputs to maintain directional stability, particularly during landing.

Wind Shear

A sudden change in wind speed or direction over a short distance, posing significant hazards during critical flight phases.

Headwinds

help airplanes take off and land in a shorter distance.

Tailwinds

make takeoff and landing longer and riskier.

Crosswinds

require pilots to adjust controls to stay straight on the runway.

Wind Shear

can cause sudden speed changes, making flying harder.

Headwinds

slow the plane down, increasing fuel use.

Tailwinds

speed the plane up, saving fuel.

Headwind

improves takeoff and landing by increasing airflow over the wings, allowing lift at lower ground speeds.

• This shortens takeoff and landing distances and enhances control, making headwinds beneficial for safe and efficient aircraft operations.

Headwind

increases airflow over the wings, allowing lift-off at a reduced ground speed

Headwind

reduces horizontal distance covered during climb, enhancing obstacle clearance.

Headwind

lowers groundspeed, significantly reducing kinetic energy and braking distance.

Tailwinds

during takeoff and landing increase the aircraft’s groundspeed, leading to longer runway distances and reduced safety margins.