Ch 3B - Stability Flashcards
Most training aircraft are designed with
Positive static and positive dynamic stability
All aircraft movement takes place around the
Longitudinal, lateral, and vertical axes; which pass through the CG
Longitudinal stability
Lateral axis; affected by center of pressure, CG, power changes, and design of the horizontal stabiltizer
Lateral stability
Longitudinal axis; affected by wing dihedral, sweepback, keel effect, weight distribution
Directional stability
Vertical axis; maintained by the vertical tail
Dutch roll
Most likely to occur with weak directional stability and strong lateral stability
Spiral instability
Aircraft with directional stability and weak lateral stability are susceptible to
A stall will always occur
When the critical angle of attack (Clmax) is exceeded and can occur at any airspeed, in any configuration or attitude
A spin will not develop unless
Both wings are stalled
A normal erect spin
Results in the airplane entering a nose-low autorotative descent with one wing stalled more than the other, but both are stalled
An airplane is said to be inherently stable
Will require less effort to control
An airplane loaded to its CG limit will
Be less stable at all speeds
As the CG moves aft
The airplane becomes more difficult to control; if CG beyond the aft limit, it could be impossible to lower the nose to recover from a stall or spin
A power reduction will
Decrease the downwash on the horizontal stabilizer causing the nose to pitch down
