Straight & Level Flight Flashcards
What is range?
The distance the aircraft travels over the ground
What is endurance?
The time the aircraft stays in the air
What is specific air range (SAR)?
The air nautical miles travelled for every litre of fuel burnt
What is the specific ground range (SGR)?
The ground nautical miles travelled for every litre of fuel burnt
What is specific fuel consumption?
FF/Power (lb / hr / h.p)
What is full throttle height?
A power setting at a height at which the butterfly valve is wide open
What is volumetric efficiency?
The ratio of air entering the cylinder vs actual cylinder capacity
When is VE at its maximum?
At full throttle height
When is an aircraft in equlibirum?
L=W and T=D
What is couple?
A couple is caused by the interaction of two moments separated by a horizontal distance
What are the couples and what do they create?
Lift and weight - create a nose down moment
Thrust and drag - create a nose up moment
Which is the stronger couple?
Lift and weight, so the aircraft tends to pitch down
How is the nose down pitching moment compensated for?
Most horizontal stabilisers provide slight down force to restore equilibrium
What is trim drag?
As the horizontal stabiliser provides a down force, the wing must produce extra lift. The extra lift creates extra drag known as trim drag
What are the factors affecting the coefficient of lift?
Wing shape
AoA
What are the factors impacting the density of air?
Pressure Height
Temperature
Humidity
When does maximum range occur?
At the best lift/drag ratio, which is at minimum drag
When does maximum endurance occur?
At the minimum power (lowest fuel flow)
What impact does a headwind have on range?
Reduces range
What impact does a tailwind have on range?
Increases range
What impact does wind have on endurance?
None
What impact does weight have on endurance?
Increased weight reduces the endurance
What impact does weigh have on the range?
Increased weight reduces the range
What impact will flying higher or lower than minimum drag speed (i.e. best range)?
Reduced range
What impact will flying higher or lower than minimum power speed?
Reduced endurance
What impact does a higher altitude have on endurance?
Reduces endurance
What impact does a higher altitude have on range?
Increases range
What does a variable pitch propeller allow?
It allows efficiency to be maintained over a wide range of airspeeds
When is engine efficiency maximised?
When the ratio of fuel flow to power generated is least
What do plain flaps do?
Increases the effective camber
Useful for lift increases
Generates high drag when fully extended
What do split flaps do?
Produces high drag
Useful for airspeed control during approach and landing
What do fowler flaps do?
Very good at producing lift
Designed to move rearwards as well as down when extending
Results in a small increase of surface area
Delays the breakdown of laminar flow and separation of the boundary layer
What do double slotted fowler flaps do?
Very good at producing lift
Similar to fowler flaps but extend further
