PLT OF A BIPLANE DURING AEROBATIC PRACTICE LOST CTL OF THE ACFT WHILE DOING A RUDDER EXERCISE STALL MANEUVER RESULTING IN THE ACFT FALLING INTO AN INVERTED FLAT SPIN. THE RPTR REGAINED CTL INVERTED AT APPROX 100 FT ABOVE THE GND.

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I WAS FLYING AEROBATICS OVER A PVT RWY AND PASTURE. I WAS USING A BASE OF 1500 FT AGL WHILE I PERFORMED ADVANCED AEROBATIC MANEUVERS. I HAD WORKED ALL NIGHT THE NIGHT BEFORE AND WAS SOMEWHAT TIRED. I HAD MISJUDGED A COUPLE OF MANEUVERS AND WENT BELOW 1500 FT AND REALIZING THIS; ADDED 200 FT TO MY BASE. I WAS ALSO DOING SOME PRACTICE APCHS TO THE NEWLY MOWED GRASS STRIP. IT WILL BE BARELY ADEQUATE TO LAND AND WILL PROBABLY REQUIRE A HEADWIND. I ENTERED A HOVERING MANEUVER AT 1700 FT AGL. I PULLED THE NOSE UP TO A 60 DEG OR SO ANGLE WITH FULL PWR AND USE THE RUDDER TO KEEP IT STRAIGHT. THE AIRSPD READS ZERO AFTER IT STABILIZES. A POPULAR AIR SHOW PERFORMER PERFORMS THIS MANEUVER AND THEN RUDDERS THE ACFT IN A SMALL TURNING CIRCLE TO THE R. I HAVE DONE THIS MANEUVER MANY TIMES. THIS TIME; I DECIDED TO DO A L HAND TURN. THERE IS A REASON THE POPULAR AIR SHOW PERFORMER TURNS R. THE ACFT SUDDENLY BROKE INTO A L HAND FLAT SPIN. I PULLED THE PWR; PUT IN FULL R RUDDER AND RELEASED THE STICK. I REALIZE NOW; DUE TO NO AIRSPD; THE RUDDER HAD NO EFFECTIVENESS. I PUSHED THE STICK ALL THE WAY FORWARD WHICH ONLY RESULTED IN A CROSS-OVER SPIN TO INVERTED. BY THIS TIME; I WAS GETTING VERY LOW. IT FINALLY CAME OUT OF THE SPIN AT ABOUT A 45 DEG INVERTED NOSE DOWN ANGLE. DUE TO MY LACK OF ALT; I CONTINUED A DELICATE; BUFFETING 45 DEG PUSH TO LEVEL INVERTED. I ONLY HAD 100-200 FT BEFORE I BECAME A STATISTIC. I FIGURE THAT I LOST 1500 FT IN ONLY 4 ROTATIONS. SOME BOTCHED MANEUVERS REQUIRE MORE THAN THE 1500 FT MINIMUM MANDATED BY THE FAA. THAT ALT IS THE BOTTOM AND I NEED AT LEAST DOUBLE THAT FOR ANY NEW MANEUVERS. I AM SURE MY LACK OF SLEEP AFFECTED MY JUDGEMENT AND I FEEL THAT I AM LUCKY TO HAVE SURVIVED THIS LACK OF JUDGEMENT.