CEA Fundamentals Block 3

What is aerodynamics?

The study if properties of moving air and the interaction between the air and solid bodies moving through it

Basic understanding of aerodynamics is essential for us to

Achieve heavier than air flight

What are the 5 fixed wing major components

Fuselage-Structural Unit

Empennage-Vertical/ horizontal stabilizers, Tail of aircraft

Wings-Force to lift Rapidly

Landing gear-Absorbs shock/ Supports aircraft on ground

Powerplant-Supplies thrust

Four forces of flight

Lift-Acts vertically counteracts effect of weight

Weight-force of gravity acting downward

Thrust-Jet engine or propeller engine to overcome drag

Drag-backward force , distribution of airflow over sings, fuselage, and protruding objects

Lift (5)

Key aerodynamic force

Airfoil-Any surface that produces lift when passing through air

Bernoulli's Principle-As fluid velocity increases, pressure decreases

Angle of Incidence-Angle formed by longitudinal axis of the aircraft and chord of the wing

Relative wind-Direction of airflow with respect to the wing

Angle of Attack (AOA)-Angle between chord line and flight path/relative wind

What is airfoil

Any surface that produces lift when passing through air

Bernoulli's Principle

As fluid velocity increases, pressure decreases

Explain Bernoulli's Principle

An airfoil is designed so oncoming air travels faster over the top of it.

The low pressure area over the wing pulls the wing up while the high pressure under the wing pushes the wing up, resulting in lift.

Angle of Incidence

Angle formed by the longitudinal axis of the aircraft and the chord of the wing

Relative wind

Direction of airflow with respect to the wing

Angle of Attack

Angle between chord line and flight path/relative wind

As AOA increases, drag, and pressure on the lower surface of the wing will

Increase

Too high AOA can result in ________, which could result in a _____

Burbling

Stall

Explain the C-5 Garcia Stall Incident

During a night flight with low visibility, the crew became confused about the INSs and extended full flaps. They became fixated on the malfunctions, leading to channelized attention and task saturation, which caused them to lose situational awareness. The pilot kept climbing, so the airspeed decreased until the aircraft became too slow, the AoA increased, and the jet stalled. The pilot held the stall, but after regaining visual reference, lowered the nose to build airspeed and recover.

Weight is & is never

Force of gravity acting downwards

Constant

Thrust is produced by & overcomes

Jet engine/propeller engine

Drag

Drag is caused by

Disruption of airflow over the wings, fuselage, and protruding objects

Two types of drag

Parasitic -Disruption in the airflow around the aircraft's surface

Induced -Main by-product of lift. Higher the airflow, higher the drag

Three kinds of parasitic drag

Form: and protruding structure

Interference: varied currents of air meet

Skin friction: roughness of aircraft's surface

Thrust and drag are equal when you are at

Straight, level, and constant airspeed

If thrust is less than drag, the aircraft will

Decelerate until two forces are equal again

Thrust is increased, it momentarily exceeds drag and ________ will increase

Airspeed

If airspeed is increased, drag will

Increase

Drag increases _x that of increased airspeed

Two times

Lift always acts _____________ to the direction of the relative wind

Perpendicular

5 factors that affect lift/drag

Wing area

Airfoil shape

Flaps/Slats

Airspeed

Air density

Airfoil shapes

Zero camber

Negative camber

Positive camber

Flaps and slats cause _________ lift

increased

Elevators change curvature of this surface

Horizontal tail

Rudder changes curvature of this

Vertical stabalizer

Increase of velocity increases

Lift and drag

Increased air density cause

Increased lift and drag

The longitudinal axis of an aircraft runs

From nose to tail

An aircraft rolls by manipulating

Ailerons

The lateral axis of an aircraft runs

Wing tip to wing tip

An aircraft pitches by

Manipulating elevators

The vertical axis of an aircraft runs

Top to bottom

An aircraft yaws by

Manipulating the rudder (on vertical stabilizer)

Secondary flight controls

Control tabs

Trim tabs

Where are ailerons located

On each wing, move simultaneously

Where are elevators located

The trailing edge of the horizontal stabalizer

Where are rudders located

The trailing edge of the vertical stabilizer

Control tabs move

The aileron, elevator, and rudder by aerodynamic pressure

The horizontal stabilizer system is used on

Larger and passenger aircraft

Auxiliary flight control surfaces

Flaps

Slats

Spoilers

C-130J Jammed Elevator Incident

Pilot was requested to hold elevators up for cargo loading, wedged NVG case in front of yoke and forgot to remove it.

Aircraft lifted prior to takeoff speed, and pitched to a high AoA.

The problem was misidentified to be a trim malfunction.

Aircraft stalled and crashed.

No use of 'techniques' in lieu of procedure.

Real-time RM was not used.

Rotary wing components

Air frame

Tail boom

Landing gear

Power plant

Rotor group

Rotary wing forces of flight

Lift

Weight

Thrust

Drag

Flight characteristics of rotary wing aircraft

Hovering

Autorotation

Tiltrotor modes of flight

VTOL: vertical takeoff/landing

CONV: conversion mode

APLN: airplane mode

Engines develop thrust by

burning a combustible fuel-air mixture and changing the gas energy into a mechanical force

Basic continuous process of jet engine operation

Intake, compression, combustion, exhaust

7 Jet engine sections

Inlet

Compressor

Diffuser

Combustion

Turbine

Exhaust

Accessory

The compressor is made up of

Rotors and stators

Where is bleed air tapped off

In the diffuser

Bleed air is used to operate

Anti-ice systems

AC

Pressurization

Where is gas energy transformed into mechanical energy to drive the compressor and accessories

Turbine

The turbine absorbs __% of total pressure energy

60-80%

Fixed wing aircraft ratings are measured in

Pounds of thrust

Who sets the rating for engines

The manufacturer

Conditions that influence the power output of the engine

Temperature

Pressure

Bleed Air

Types of jet engines

Turbojet

Turbofan

Turboprop

Engine indicators/gauges

RPM (rotations per minute, %)

Temperature (TIT, EGT)

Fuel flow

Oil systems

KC-10 Mishap

Crew heard a loud boom, and instruments showed fuel flow trending toward zero, and EGT over-temped.

Crew communicated and coordinated duties.

Pilot continued to fly, engineer dumped fuel and calculated landing, boom inspected aircraft.

Crew applied RM and landed overweight rather than delaying.

Advantages of Turbojet

Best at high speeds

Disadvantages of Turbojet

Cannot produce high thrust at low altitudes and airspeeds.

Climb out capabilities are poor.

The secondary engine rotor assembly in a turbofan engine is known as the

Low-speed / N1 section

The large fan in a turbofan engine splits into

Primary and secondary airflow

Secondary airflow in a turbofan engine goes

bypasses the core and travels directly to the exhaust for additional thrust

Power is set by

Monitoring N1 % RPM

Advantages of a turbofan engine

Better at low speeds and altitudes

Fuel efficient

Weigh less

More ground clearance

Less noise at high thrust settings

Disadvantages of a turbofan engine

Slow throttle response

Turboprop engines are designed to take

max gas energy

The drive shaft

transmits power from engine to rotor system

Reduction gear assembly

reduces turbine RPM to safe propeller RPM

Turboprop engine is rated by

Shaft horsepower (w a torque meter)

Almost all thrust in a turboprop engine comes from

the propeller

Geometric pitch

theoretical rotation through a solid

Effective pitch

actual rotation through the air

Turboprops aircraft are efficient at

lower airspeeds (<450 mph)

Propeller thrust is the result of

The shape & angle of the prop blade

4 prop blade angles

Zero

Positive

Negative

Feathered

Advantages of a turboprop engine

High thrust at low altitudes

Ideal of lifting heavy loads

Near instant throttle response

Disadvantages of turboprop engine

Efficiency drops as airspeed and altitude increase

WC-130H Mishap

Aircraft was on it's way to the boneyard

Poor maintenance performed ("good enough")

Engine RPM decayed and caused aircraft to swerve off of the runway during liftoff

Pilot made the mistake of turning left into the shutdown engine and applying the left rudder.

This resulted in left wing stalling & losing control, then crashing.

Lack of discipline and attitude

Lack of assertiveness; rank intimidation

Fixation/channelized attention

the main rotor provides

Lift to fly, move laterally, and change altitude

The main rotor is adjusted by the

swashplate

The tail rotor provides

Anti-torque and directional control

Main rotor components

Rotor hub

Pitch control rods

Swashplate

Tail rotor components

Rotor head

Rotor blades

The speed reduction devices in a rotary aircraft are

transmission gearboxes

How do transmission gearboxes work

Drive shafts/transmission carry engine torque through gearboxes to main and tail rotors to lower RPM

The intermediate gearbox

Reduces RPM

Changes the angle of drive to tail gearbox

The tail gearbox

reduces RPM

Changes angle of drive to tail rotor

A free-wheeling unit is incorporated to disengage from transmission in the event of

Engine failure

Autorotation

If engine RPM drops below main rotor RPM

Accessory gearboxes are driven by

the main gearbox

A free-wheeling unit allows

the motor system to continue operations even if the engine's RPM drops

Driveshaft sections connect the engines to the

transmission systems

Connect and drive all gearboxes

APUs (Auxiliary Power Units) provide

ground operation to aircraft without ground support equipment

APUs supply air for

AC system

engine starting

shaft power