L8 - Static Directional and Lateral Stability Flashcards
Define Static Directional Stability?
The ability of an aircraft to resist slipping.
What component mainly determines directional stability?
Vertical Tail
What direction is positive slideslip angle?
From a top down view, anticlockwise
Wind in right ear
What is the condition for aircraft static directional stability?
dCn/d(Beta) > 0
How does dihedral increase lateral stability?
Once disturbed, a velocity component caused by sideslip is introduced. Dihedral wings means that the lower wing has a higher angle of attack, producing more lift, creating a moment and stabalising the aircraft.
What is the condition for aircraft static lateral stability?
dCl/d(Beta) < 0
Define manoeuvre?
A change of one state of flight to another state of
flight, with a change in the acceleration.
What are the 4 main longitudinal manoeuvres?
Pull up
Push over
Rollercoaster
Loop
What is the opposition of manoeuverability?
Static stability.
What is Manoeuvre stability?
the force that needs to be
applied on the stick to change the g-load
What is manoeuverability usually measured in?
Stick force per g.
What is the condition for longitudinal manoeuvre stability?
dC’m/dC’l < 0
Desh signifies inclusion of pitch rate term.
What is usually more aft? Stick free of Stick fixed points?
Stick fixed.
What factors affect lateral stability?
– Wing dihedral angle
– Wing sweepback angle
– Fuselage – wing position, e.g. high wing
– High vertical tail
What has a higher centre of gravity? High or low wing?
Low wing has higher centre of gravity.
