Spiral Dives
Spiral dives are steep, descending turns with increasing speed and g forces. They are best demonstrated by entering a steep turn and allowing the nose to drop a bit. Once the speed builds up, increased back pressure on the stick generally will not raise the nose and thus the spiral dive has begun. The key to the recovery is to:
1. Ease back pressure and centralize the controls.
2. Level the wings with co-ordinated use of the controls.
3. Ease out of the subsequent dive by raising the nose to the normal gliding attitude.
Spins
Spinning is promoted when one wing stalls before the other. Two effects are
present. The stalled wing drops causing a rolling motion and as well its drag is
greater than the other wing so a yawing motion occurs. The rolling motion is
counteracted by the airplane sideslipping in that direction and any lift
generated in this way counteracts the lift produced on the upper wing due to its
rotation. A state of relative equilibrium is achieved so that the aircraft stops
rolling but continues to rotate. It may take several turns until the spin
appears to stabilize. Spinning includes simultaneous rolling, yawing, and
pitching. The pitch may change from flat to steep but the horizontal and
vertical speeds remain relatively low. As
well aircraft that have significant weight located at their extremities (wings,
nose, tail) tend to resist tilting motions out of the plane of the rotation.
These forces produced during a spin can resist the tilting forces developed by
the elevator. Therefore it is necessary to yaw the glider away from the
direction of the rotation to counteract these effects. The elevator should
initially be held in a centralized position to reduce any blanketing of the
rudder. Proper spin recovery for most aircraft then is as follows:
1. Apply full-opposite rudder to the direction of the spin.
2. Centralize the controls.
3. Pause briefly.
4. Lower the nose to unstall the wings, until the rotation stops.
5. When the dive starts level the wings and centralize the rudder.
6. Start recovery from the dive. Do not pull-up such that visual contact is
lost with the horizon.
7. When the airspeed approaches the normal gliding attitude airspeed lower
the nose to the normal gliding attitude.
All full spin manoeuvres should be completed above 2000 feet above the
ground. This leaves a good margin for error.