Stability in Aircraft Design
This type of stability is defined as an aircraft's initial tendency to return to its original attitude when displaced.
What is Positive Static Stability?
When a pilot raises or lowers this control, the pitch angle of the main rotor blades increases or decreases as a whole unit.
What is the Collective?
This primary flight control surface is attached to the vertical stabilizer and is used to yaw the airplane left or right.
What is the Rudder?
These systems are designed to relieve the pilot of the need to maintain constant pressure on the flight controls.
What are Trim Systems?
A person weighing 180 pounds and experiencing 4 Gs of force would feel as though they weighed this much.
What is 720 pounds?
Pitch stability refers to the movement of an aircraft’s nose up and down around this axis.
What is the Lateral Axis?
To compensate for this aerodynamic challenge, where the advancing blade produces more lift than the retreating blade, rotor blades are allowed to flap.
What is Dissymmetry of Lift?
These are the three primary axes of flight that intersect at the aircraft's center of gravity.
What are the Longitudinal, Lateral, and Vertical axes?
Extending these moveable surfaces on the trailing edge of a wing increases both lift and drag.
What are Flaps?
This is the speed at which a pilot can fully deflect a control surface in smooth air without risking structural damage.
What is Maneuvering Speed (or VA)?
This wing structure, featuring an upward tilt of both wings, is used by many aircraft to achieve positive roll stability.
What is Dihedral?
According to Newton’s Third Law, if the engine drives the rotors counter-clockwise, the fuselage will want to turn in this direction.
What is Clockwise?
Pilot inputs can be transmitted to control surfaces via cable and pulley, hydraulic pressure, or these electronic signals.
What is Fly-By-Wire?
When this type of device is lowered on the front of a wing, it increases the wing’s camber.
What is a Leading Edge Device?
According to the Vg diagram, structural failure is catastrophic and involves this happening to the aircraft.
What is the wings or stabilizers separating from the fuselage?
As the Center of Gravity (CG) moves in this direction, the aircraft becomes progressively more difficult to control.
What is aft?
This control, located between the pilot's legs, tilts the arc of the main rotor to allow flight in any direction.
What is the Cyclic?
This undesirable yawing tendency in the opposite direction of a roll is corrected by the pilot using the rudder.
What is Adverse Yaw?
This specific type of flap moves backwards to increase both the wing's surface area and its camber.
What is a Fowler flap?
The relationship between gross weight and maneuvering speed can be describe as this.
What is as gross weight decreases, maneuvering speed decreases.
Unlike static stability, this type of stability refers to the tendency of the aircraft over time following a displacement.
What is Dynamic Stability?
In this flight condition, helicopters are classified as statically stable but dynamically unstable.
What is a Hover?
Pilots use this phrase to describe the act of using the rudder to center the inclinometer ball and achieve a coordinated turn.
What is "Stepping on the ball"?
Most common on large, heavy aircraft, these are used to increase drag for rapid descents and "stick" the aircraft to the ground after landing.
What are Spoilers?
The amount of load that can be safely imposed on an airplane wing depends on the speed of the airplane and this factor of application.
What is the abruptness with which the load is applied?