Slow Roll:

Also called the military-style aileron roll as opposed to the snap roll or flick roll (British) which is a sudden rotating stall done with the elevator and rudder, or the barrel roll which is also a rotation with rudder and elevator but without stalling.

Warbird-style slow rolls are not axial.  Instead, they are slightly arched and slightly cork-screwed.  Rudder finesse is not typically needed.

Starting from level flight and full throttle, pull the nose up slightly and hold a fixed amount of aileron.  As the plane rolls, kill any turning tendency by gradually feeding in down-elevator.  As the plane rolls inverted, begin removing down-elevator.  As the wing returns to level, quickly return the ailerons back to neutral. The entire maneuver should take at least 5 seconds.  The slow roll in the video lasts ten(10) seconds.

If the use of down-elevator is late, the flight path will turn in the direction of the roll.  If it is early, the flight path will turn opposite the roll.  One can use this property to correct heading errors or compensate for a crosswind during the roll.

In the video, notice how the roll rate speeds up during the last quarter of the roll.  This is caused by side-slipping.  Here, the wing is vertical and the nose is pointing slightly down.  The plane is descending.  There is nothing to support the plane except the lift of the side of the fuselage which isn’t very much in this type of bird, so the plane slides vertically—an extreme slide slip.  Because of the dihedral in the wing, the right wing has more lift than the left wing so the roll rate is increased.  The pilot could have compensated for this by reducing the amount of aileron.  But he didn’t.  He needs more practice.

Another common mistake is centering.  The middle of the slow roll should be positioned exactly in front of the observer.  In the video, the pilot started the roll too late, so the center of the maneuver is shifted to the observer’s right.

Stall Turn:

The stall turn is an evasive maneuver going back to WW1.  In Eddie Rickenbacker’s book, Fighting The Flying Circus, he called it a “renversement” (reversing).  Air show announcers call it a “hammerhead” because of the figure it draws in the sky with smoke.  Japanese Zero pilots used it a lot and were very good at it.

A seldom seen variant is the retournement (turn-around), also mentioned in Rickenbacker’s book.  The airplane does a quick half-roll on the way down to exit in the same direction as the entry.  It was a method to get behind or escape a pursuer.  Enter the stall turn at full throttle from level flight or a long shallow dive.  Gently pull straight up as if starting a loop.  Climb straight up until flying speed is almost lost, then throttle back and yaw with the rudder.  Try to rotate 180 degrees in one wingspan.  Drop straight down, returning to the original altitude.

With so little airspeed at the top of the stall turn, the rudder is not very effective.  To reduce the amount of work the rudder must do, use it on the way up to yaw slightly in the direction of the turn.  Sometimes no rudder is needed at all, the plane will just naturally rotate around its center of gravity.  Sometimes a burst of throttle is required to blow air over the rudder at the crucial moment.  The turn looks best if the turn is done in place slowly.

A common mistake is to not lose flying speed at the top, but to fly a 180-degree U-turn instead of rotating in place.  This is not a stall turn.  It is called a bad wingover.

In the video, there is a crosswind from the left.  The pilot yaws the plane with rudder on the way up in order to prevent drifting with the wind.  As airspeed slows, the pilot increases the yaw.  The pilot coaxes the plane into a partial yaw with rudder well before the turn so that very little rudder is needed in the turn.  This causes a slow and graceful rotation in one or two wingspans.  But the plane still has some flying speed so that the turn could have caused an unwanted roll.  The pilot anticipated this and prevented the roll by using full right aileron before and during the turn.  This is one of the few maneuvers that is easier to do in a crosswind.

Wind speed increases with altitude, so extra height can be gained by exploiting a headwind.  Come in low and pull up thru the windshear.  Airspeed actually increases as the plane moves into stronger wind.  This increases lift and kicks the airplane even higher.  For this reason, stall turns are most fun on windy days.