Lecture 4 Flashcards
what is longitude static stability?
The tendency of the aircraft to return to equilibrium after a disturbance in pitch
What is stick fixed stability
The aircraft is able to be stable with the pilot holding the elevator at a fixed position
stick free stability what
the trim tab stabilising the aircraft with the elevator being free to move
What is static margin
the distance from the current location of CoG to the neutral point
What is the fwd limit of the CoG?
the point in which the aircraft CoG cant go past for balancing
What happens when the Cog gets near the fwd CoG?
nose heavy, higher stalling speed, more induced drag, reduced effectiveness of elevator
What do you want the gradient to be for Cm alpha for aircraft to be longitudinally stable
negative
Apart from negative gradient of cm alpha what is other condition of longitudinal static stability
Cm,0 >0
why does cm,0 >0 for longitudinal static stability
so that fwd of the neutral point there will be a nose up tendency
what is the zero lift line of an aerofoil
Line through the aerofoil that is parallel to velocity when aircraft is at zero lift angle of attach
At the neutral point what does dCm/da =
0
What is trim?
Adjustment of an aircrafts control surfaces to remain flying at a desired altitude
