The hammerhead (Stall Turn) was nicely done in this video. I have to point out that when done properly the wing is never actually stalled. This may help.
The Stall Turn:
1/4 loop (pull or push) to vertical, as momentum/airspeed decreases, rudder is applied and the aircraft rotates around its yaw axis, the nose falls through the horizon and points towards the ground, a momentary pause is made to draw the vertical down line, and 1/4 loop to level flight. This figure is sometimes called a stall turn which is a misnomer because the aircraft never actually stalls. The maneuver is performed when the airplane decelerates through 20 - 30kts (more or less, depending on the airplane flown) of airspeed. The cartwheel portion of the hammerhead is performed with full rudder and full opposite aileron. Gyroscopic forces from the propeller during the rapid rate of yaw will produce a pitching and rolling moment and a degree of forward stick will be required to keep the airplane from coming off-line over the top. The yaw is stopped with opposite rudder while the ailerons and elevator remain in position, and then once the yaw is stopped and the airplane is pointed down vertically, all controls are returned to neutral together. Although they can be flown left or right in any airplane with the proper technique, a hammerhead is best flown to the left with a clockwise rotating prop, and to the right with an anticlockwise rotating prop (as in a Yakovlev type), due to propeller torque/gyroscopic effects.
