SPIN AWARENESS AND AVOIDANCE
To teach the student the avoidance and proper recovery from spins.
• Uncoordinated stalls
• Aerodynamics of a spin
• Recovery procedure
Discuss what is a spin (an aggravated stall that results in autorotation). Autorotation results from unequal angles of attack on the wings. The key is aggravated (i.e. uncoordinated). Draw or show the corkscrew/helical flight path of a spin. The difference between a spin and a steep spiral: spin—airspeed low, wings stalled; spiral—airspeed increasing, not stalled.
Discuss the aerodynamics of a spin. Draw a wing in ...view middle of the document...
FAA-S-8081-6CS Flight Instructor for Airplane Single-Engine Land and Sea PTS p. 1-56
A stall is a loss of lift and increase in drag
that occurs when an aircraft is flown at an angle of attack
greater than the angle for maximum lift. If recovery from a
stall is not effected in a timely and appropriate manner by
reducing the angle of attack, a secondary stall and/or spin may
result. All spins are preceded by a stall on at least part of
the wing. The angle of the relative wind is determined primarily
by the aircraft's airspeed. Other factors are considered, such
as aircraft weight, center of gravity, configuration, and the
amount of acceleration used in a turn. The speed at which the
critical angle of the relative wind is exceeded is the stall
speed. Stall speeds are listed in the Airplane Flight Manual
(AFM) or the Pilot Operating handbook (POH) and pertain to
certain conditions or aircraft configurations, e.g., landing
configuration. Other specific operational speeds are calculated
based upon the aircraft's stall speed in the landing
configuration. Airspeed values specified in the AFM or POH may
vary under different circumstances. Factors such as weight,
center of gravity, altitude, temperature, turbulence e.t.c
Angle of Attack.
Angle of attack is the angle at which
the wing meets the relative wind. The angle of attack must be
small enough to allow attached airflow over and under the airfoil to produce lift. A change in angle of attack will affect the amount of lift that is produced. An excessive angle of attack will eventually disrupt the flow of air over the airfoil. If the angle of attack is not reduced, a section of the airfoil willreach its critical angle of attack, lose lift, and stall.
Exceeding the critical angle of attack for a particular airfoilsection will always result in a stall.
Airspeed is controlled primarily by the
elevator or longitudinal control position for a given
configuration and power. If an airplane's speed is too slow, the
angle of attack required for level flight will be so large that
the air can no longer follow the upper curvature of the wing.
The result is a separation of airflow from the wing, loss of
lift, a large increase in drag, and eventually a stall if the
angle of attack is not reduced. The stall is the result of
excessive angle of attack - not airspeed. A stall can occur at
any airspeed, in any attitude, and at any power setting.
Flaps, landing gear, and other
configuring devices can affect an airplane's stall speed.
Extension of flaps and/or landing gear in flight will usually
increase drag. Flap extension will generally increase the
lifting ability of the wings, thus reducing the airplane's stall
speed. The effect of flaps on an airplane's stall speed can be
seen by markings on the airplane's airspeed indicator, where the
lower airspeed limit of the...