module 8 target summaries

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Passive is the natural features, active is the purposeful inputs.

Static vs dynamic stability -

static is how the aircraft initially reacts after disturbance, positive means that it will return to original attitude, neutral means it will stay in new attitude, and negative means it will drift further away from original.

Dynamic means how the aircraft the. Acts over time after disturbance, positive meaning oscillations dampen, neutral meaning they stay the same, and negative means the worsen

Longditunal stability - lateral axis, pitch, controlled by elevators

Lateral stability - long axis, roll, aileron control

Directional stability - vertical axis, yaw, rudder control

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Boundary layer - thin layer of stagnant air on a surface formed due to friction.

Upwash is air being pulled upward and over the low pressure side of wing

Downwash is air being pulled downward after the trailing edge

Laminar and turbulent flow - laminar is orderly and uniform, but easily disturbed and can separate easily, turbulent is chaotic flow with higher drag, however better stickiness and can help against stalling

Stagnation point is a point where airflow goes to 0 in speed, and static pressure = total pressure, can happen on leading edges, pitot tubes

Vortices form on the wingtips, due to interaction between low and high pressure air

What is chord line?

The straight line between the leading and trailing edge.

What is chord ?

The length of the chord line

What is camber?

The curvature of the wing, the difference between the chord and camber line.

What is the fineness ratio ?

The ratio of chord line, to the max thickness of the wing.

What is the aspect ratio ?

Aspect ratio is the ratio between mean chord and the wingspan, high aspect ratio means good lift with little drag, but low manoeuvres, where as low aspect ratio leads to higher drag but great manoeuvres

What is wash in wings?

Where the wing tips curve

What is wash out?

Wash out is where the roots of the wings are more curved.

What is AOA vs AOI ?

Angle of attack is the angle between the relative airflow and chord line, whereas the angle of incidence is the angle between the chord line and the relative airflow.

What is CP?

Centre of pressure, where all the lift or drag is said to act from on a wing

What are the 4 main type of wing shape ?

Elyptical - stall is consistent throughout wing i think

Rectangular - roots stall first

Swept - tips stall first

Tapered - tips stall first

What is dihedral vs anhedral ?

Dihedral - common in aviation - wingtip higher than root for rotational stability

Anhedral - common in military - wingtip lower than rot gives better agility

What is induced drag?

Induced drag is just an unavoidable big product of producing lift, it occurs due to things like vortices, downwash etc that create forces that are going to act against the direction of flight.

What are the 3 types of parasite drag?

Form

Interference

Friction

What is form drag?

Form drag is solved by streamlining, it occurs due to pressure differences but can be solved by streamlining, blunter = more form drag

What is interference drag?

Interference drag occurs due to multiple components correcting, and is solved by fairings, more pointy edges and corner will lead to more interference drag, but smoother transitions between components solves

What is friction drag?

Friction drag is created by skin friction ie air rubbing on surfaces.

What is compression drag?

Compression drag is created by supersonic shockwaves causing flow sepation

What is total drag ?

Total drag is parasite + induced

factors include - range, payload, rate of climb, cruise alt and speed, fuel economy, take of and landing requirements, manoeuvrability

steady state flight is where all forces are balanced.

glide ratio = how far forward/alt lost

glide ratio isnt affected by weight, the time will change with wieght only,

the forces acting in a turn are

vertical component of lift, which is opposing weight, and providing lift

horizontal component of lift - the force causing directional change i.e Turing the aircraft

centrifugal force - the apparent force, opposing the turn acting away from the centre of the turning circle