Weaver Systems 1 test 1 kent

George Cayley (early 1800s)

Developed Cambered airfoil

Principles of flight (lift, drag, thrust, weight)

Stacked wings

CG and early form of a rudder

Otto (late 1800s)

Built and flew gliders

Gliders were made of willow and cloth

Proved man can fly

Octave

“Progress in Flying Machines”

WW1 stronger engines allowed designers to develop

Thicker wings with stronger spars

Stacked wing

1930s

All metal aircraft

Lighter more powerful engines

Larger seminonocoque fuselages

“Egg shell” designs

Reduction in fabric skin aircraft

WW2

All metal technology

Technological advances

Post WW2

Development of turbine engine

Pressurized aircraft

Increased speed, lighter, better structurally

1960s

Larger aircraft

Jumbo jet built

Honeycomb structures

Aluminum/ fiberglass skin

1970s

Advanced composites

Very light jet - almost entirely composite

Categories of aircraft consist of

Airplane

Rotorcraft

Glider

Lighter than air vehicles

Fixed wing aircraft

Most common type of aircraft consist

Wings are attached to fuselage and don’t move

Five principle units of airframe

Fuselage

Stabilizers

Flight control surfaces

Landing hear

Aircraft structural components are designed to take what?

Carry a load

Resist stress

Stress v strain

Stress - a materials internal resistance, or counterforce that opposes deformation (psi)

Strain - the degree of deformation (change in length)

The major structural stresses consist of

Tension

Compression

Torsion

Shear

Bending

Tension

Stress that resists force that tends to pull something apart

Measured in psi

Load (in pounds) / square inches

Compression

Stress that resists a crushing force

Measured in psi

Squeezing aircraft parts

Torsion

Stress that produces twisting

Shear

Stress that resists force tending to cause one layer of material to slide over an adjacent layer

Bending

Combination of compression and tension

Compressed on the inside of the bend

Stretched on the outside of the bend

Fuselage

Main structure or body of aircraft

Truss

Rigid framework made up of members

Beams, struts, and bars

Mostly covered in fabric

Monocoque type

Single shell

Relies on skin covering to carry most loads

Semimonoque type

Uses longerons and stringers for support/ strength

Mostly alloys of aluminum and magnesium

2 advances it has is it is rigid and strong and spreads the loads along various parts

Pressurization

Higher altitude flights are pressurized

Air gets pumped into cabin air for pax and crew

Causes metal fatigue

Airfoils

Create lift on the wing

Full cantilever (most widely used)

Supported internally (spars and stringers) and supported skin

Aluminum most common, wood, carbon fiber/composite

Internal wing structure

Support distributed loads, fuselage, landing gear, and engine

Skin transfers stress to wing ribs, then from ribs to wing spars

Wings - monospar (not common)

Open main span wise or longitudinal member

ribs/bulkheads shape/contour the airfoil

Wings - multispar

More than one main longitudinal member

Ribs/bulkheads support shape/contour

Wings - box beam

Uses two main longitudinal members with connecting bulkheads for additional strength

Wing spars

Structural member of wing; metal, wood, composite

Runs parallel to lateral axis of aircraft (fuselage to tip of wing)

Attached to fuselage by fittings, beams, or truss

Wing ribs

Spars and stringers make up the framework of the wing

Wing leading edge to trailing edge

Transmit load form skin and stringers to spar

Used in ailerons, elevators, rudders, and stabilators

Wing skin

Designed to take flight and landing loads

Fabric, wood, or aluminum

Honeycomb skin

Mostly aluminum

Core

In between wing and fuselage

Fairings

Nacelles (Pods)

Streamlined enclosures used primarily to hold engine

Round or elliptical profile

Wings - Cowlings

Protect engine

Empennage

Tail section of aircraft

Tail cone, stabilizers, and aerodynamic surfaces

Flight control surfaces

Control aircraft around lateral, longitudinal and vertical

Hinged or movable surfaces

Primary Control Surfaces

Critical to be balanced, so there is no vibration/flutter

Ailerons - attached to trailing edge of both wings (longitudinal)

Elevators - attacked to trialing edge of horizontal stabilizer (lateral)

Rudder - attached to trailing edge of vertical stabilizer (vertical)

Ailerons

Makes aircraft roll, controlled by the yoke or stick

Outboard trailing edge of each wing

Light aircraft use cables, pulleys, turnbuckles, etc.

Large aircraft use hydraulics, electric, etc.

Elevator

Makes aircraft pitch

Controlled by yoke or stick

Trailing edge of horizontal stabilizer

Rudder

Allows aircraft to yaw

Trailing edge of vertical stabilizer

Controlled by pedals

Light aircraft use cables, pulleys, etc.

Large aircraft use hydraulics, electric, etc

Dual purpose flight controls

Control surfaces that serve two purposes

Elevons - combined ailerons and elevator

Stabilator - combines horizontal stabilizer and elevator

Flaperons - combine ailerons and flaps

Ruddervator - combine rudder and elevator

All secondary (auxiliary) flight control surfaces

Flaps, trim tabs, balance tabs, anti-balance tabs, servo tabs, spoilers, slats, slots, leading edge flap

Flaps

Inboard trailing edge of wings

Extends camber of wing for greater lift and slower flight

Slow speeds for short takeoffs and landings

Trim tabs

Trailing edge of primary flight control surfaces

Reduces the force needed to move a primary control surface

Balance tabs

Trailing edge of primary flight control surfaces Reduces

Reduces the force needed to move a primary control surface

Anti-balance tabs

Trailing edge of primary flight control surfaces

Increases feel and effectiveness of primary control surface

Servo tabs

Trailing edge of primary flight control surfaces

Assists or provides the force for moving a primary flight control

Spoilers

Upper and/or trailing edge of wing

Decreases (spoils) lift and create drag

Slats

Mid to outboard leading edge of wing

Extends the camber of the wing for greater lift and slower flight. Allows controls at low speeds for short takeoffs and landings

Slots

Outer leading edge of wing forwards of ailerons

Directs air over upper surface of wing during high AOA. Lowers stall speed and provides control during slow flight

Leading edge flap

Inboard leading edge of wing

Extends the camber of the wing for greater lift and slower flight. Allows control at low speeds for short takeoffs and landings

Winglets

Vertical upturn of wing’s tip resembling a vertical stabilizer

Vortex generators

Small airfoil sections usually attached to upper surface of a wing aft of leading edge

Stall fences

Chord wise (leading edge to trailing edge) barriers on upper surfaces of wing

Gap seals

Promote smooth airflow in gap areas between wing or stabilizer and control surfaces

Landing gears

Fixed/ retractable gear

Tricycle and tail wheel (conventional)

Not wheels; skids, skiis, or floats

Aerodynamics and atmosphere

Laws proven physically to make a plane fly

Properties of the air dictate performance of plane

Air is considered a because it is considered a substance that can flow or take shape of an object. Air pressure is __ at sea level.

Fluid

Highest (heaviest)

Atmospheric pressure / (P=F/A)

Force exerted against earth’s surface by weight of the air above surface

14.7 psi standard

Barometer

Device that uses mercury in a tube to record atmospheric pressure / average (29.92”Hg)

Density

Weight per unit of volume and governed by proportion with pressure and temperature

Air is a mixture of gases that get compressed = compressed air is more dense

Relative wind

Flow of air around an object caused by movement of air or the object, or both

Pressure in motion

Speed, Velocity, and Accleration

-the rate of motion in relation to time

-the rate if motion in a particular direction in relation to time

-the rate if change in velocity

Newton’s 1st law

A body at rest does not move unless force us applied to it (inertia)

Newton’s 2nd law

If a body moving with uniform speed is acted upon by an external force, the change of motion is proportional to the amount of the force, and direction it is heading in (F=ma)

Newton’s 3rd law

Every action (force) there is an equal and opposite reaction (force)

Newton’s 3rd law

Every action (force) there is an equal and opposite reaction (force)

Camber

Curvature of an airfoil above and below chord line surface

Chord line

An imaginary straight line that passes through section from the leading edge to trailing edge

Relative airstream

Relative wind with reference to the flow around the wing

Resultant force

Sum if all small forces of lift acting on every part of the wing, has magnitude, direction, and location, and can be seen as a vector

Center pressure (CP)

Point of intersection of the resultant force line with the chord line of the airfoil

Angle of incidence

The acute angle the wing chord makes with the longitudial axis of aircraft

AOA

Angle between chord line of the wing and its direction to relative wind

Changes with altitude

AOA is increased to eventually stall

Boundary layer

Part of airflow closest to surface of aircraft

Critical AOA

Angle at which the aircrafts wing produces maximum lift coefficient before it starts to stall (typical 15* to 18* for airfoils)

Wing efficiency

Measured in lift to drag ratio (L/D)

The shape of the airfoil determines AOA at which the wing is most efficient

Wing efficiency

Measured in lift to drag ratio (L/D)

The shape of the airfoil determines AOA at which the wing is most efficient

Lift

Force pushes aircraft upwards

Thrust

Force that moves aircraft forwards

Thrust is needed to overcome drag in flight

Drag

Resistance of the air to objects moving through it

Increases with increase in AOA

Parasite drag

Exposed and protruding objects on an aircraft (includes skin and rivets) offer some resistance to the air

Profile (form) drag

The aerodynamic resistance that occurs due to shape of the aircraft moving through the air

Induced drag

A byproduct of lift, air beneath moves spanwise from high pressure to low pressure around wing tips

Static stability

An aircraft at equilibrium when the sum of all forces exerting on aircraft equals zero

Positive goes back to equal and negative continues in the direction of disturbance

Dynamic stability

Resulting motion with time after a disturbance

Longitudinal stability

Tendency to keep a constant AOA with reference to relative wind. Horizontal stabilizer primary surface control longitudinal stability

Direction stability

Stability dealing with vertical axis

Straight-and-level flight without constant pilot intervention

Vertical stabilizer is primary surface to control directional stability

Lateral stability

Wings remain level during flight and tend to return to original level alt after being disturbed by rolling motion

Vertical stabilizer is primary surface that controls lateral

Dutch roll

An unstable condition due to an out-of phase combination of yaw and roll

Yaw dampener can assist in stabilizing aircraft