2021 General Knowledge Flashcards
What is the chord line?
The straights line joining leading edge to the trailing edge.
What is the camber line?
Line which runs midway between the upper and lower surfaces of the wing and curves with the wing.
What is angle of attack?
Angle between the chord and the relative airflow.
What is aspect ratio?
It is the ratio of the wingspan to the wing chord. i.e. a glider would have a large aspect ratio.
What is the angle of incidence?
Angle between the longitudinal axis and the chord line.
Angle of INDUSTRY.
What is the lift formula?
Lift = ½ ✕ ρ ✕ V² ✕ S ✕ Cₗ
ρ = air density V = true airspeed S = surface area of wing Cₗ = coefficient of lift
What is form drag?
Result of air moving over a particular shape like an aircraft’s fixed landing gear.
What is skin friction?
The friction felt by the air when it moves over all surfaces of an aircraft.
What is interference drag?
Drag that results from two or more objects that are joined together; such as the fuselage and the wing.
What is induced drag?
A by product of producing lift; Newton’s 3rd Law.
Does induced drag increase or decrease with speed?
Induced drag is highest at low speeds and lowest at high speeds.
Does induced drag increase or decrease with weight?
Induced drag increases with weight for a given speed.
Does induced drag increase or decrease with altitude?
Induced drag increases with altitude.
What are the three components that make up parasite drag?
Skin friction, form drag & interference drag.
Does parasite drag increase or decrease with speed?
Parasite drag is lowest at low speeds and highest at high speeds.
Does parasite drag increase or decrease with weight?
Remains unchanged.
Does parasite drag increase or decrease with altitude?
Parasite drag decreases with altitude because of reduced air density.
What does weight act through, centre of gravity or centre or pressure?
Centre of gravity.
What does lift act through, centre of gravity or centre or pressure?
Centre of pressure.
In regards to stability of an aircraft, how should the centre of pressure and centre of gravity be aligned with each other?
The centre of gravity must always be ahead of the centre of pressure.
What is flight for maximum range?
Maximizing the distance flown per unit of fuel burnt.
Maximum speed for power (fuel).
What is flight for maximum endurance?
Maximizing the time airborne per unit of fuel burnt.
Lowest power setting for fuel flow
Define the service ceiling:
When an airplane reaches a height where a maximum rate of climb reduces to 100 feet per minute.
Define absolute ceiling:
When an airplane reaches a height where the rate of climb reduces to zero.
What happens to your aircraft during a stall?
Centre of pressure
As the angle of attack of a wing is increased, the centre of pressure of the wing will move forward. When the wing stalls, the centre of pressure rapidly moves backwards.
In conventional aircraft, where are the stalling speeds on the airspeed indicator?
Beginning of the white arc (flaps fully extended) and beginning of the green arc (flaps fully retracted).
What attributes to change in angle of attack in straight-and-level flight and in turn can change the stall speed?
- Weight
- Centre of Gravity
- Load factor (over 1)
- Configuration changes
What is load factor?
The ratio of lift to weight. It is measured in G’s.
Lift/weight = load factor
What is the load factor in straight-and-level flight?
1.
How do you calculate load factor in a bank?
1 / cos(θ) = lift
lift / weight = load factor in G’s
How do you calculate stalling speed in a bank?
stalling speed = √(1 / cos(θ))
How do you calculate the required angle of bank for a rate 1 turn:
True airspeed / 10 + 7
What is aircraft stability?
Refers to the ability of an aircraft to recover from a disturbance about a particular axis.
What is static stability?
The initial response to a disturbance.
What is dynamic stability?
The behavior of the airplane following the static response.
Three basic types: neutral, stable, unstable.
What is stability about the lateral axis?
Longitudinal or pitch stability.
What is stability about the longitudinal axis?
Lateral or roll stability.
What is stability about the vertical axis?
Directional or yaw stability.
Do servo tabs operate in the same or opposite direction of the main control surface?
Deflects in opposite direction.
Does an anti-servo tab deflect in the same or opposite direction to the main control surface?
Deflects in same direction.
Do balance tabs deflect in the same or opposite direction to the main control surface?
Deflects in the opposite direction.
What are the 4 principles of the four-stroke engine?
Intake, compression, power, exhaust
Suck, squeeze, bang, blow
What is valve overlap?
The portion of the four-stroke cycle which both valves are open (intake and exhaust).
What can cause detonation:
- Using fuel with too low an octane
- Running the engine too hot
- Running the engine with too high a manifold pressure for the rpm
What colour is AVGAS 80/87?
Red.
What colour is AVGAS 100/130?
Green.
What colour is AVGAS 100LL?
Blue.
What colour is aviation turbine fuels?
Straw/clear.
What colour is MOGAS 87-90?
Green.
What colour is MOGAS 84-87?
Undyed/no colour.
What are the 4 uses of oil?
Lubrication, cooling, flushing, sealing.
What is normally aspirated?
The air taken into the inlet manifold at atmospheric pressure and is not compressed before being routed to the engine.