LOW TIME PVT PLT PORPOISES DURING LNDG CAUSING PROP DAMAGE.

Narrative

PROP STRIKE OCCURRED AFTER 2 OR 3 OSCILLATIONS UP AND DOWN ON LNDG. ENG DID NOT STOP; BUT LAST 4 INCHES OR SO OF THE PROP BLADES WERE FOLDED OVER. I BELIEVE THAT I TOUCHED DOWN AND THEN BECAME AIRBORNE AGAIN AFTER A SHORT DISTANCE FROM A SMALL WIND GUST. WINDS WERE ABOUT 10 KTS AT THE TIME; PRETTY MUCH STRAIGHT DOWN THE RWY. AT THE TIME; I DID NOT REALIZE I HAD BECOME AIRBORNE AFTER THE INITIAL TOUCHDOWN SO WHEN I BEGAN TO LOWER THE NOSE AND APPLY THE BRAKES I WAS ACTUALLY 4-5 FT ABOVE THE RWY. THIS MISJUDGEMENT OF HEIGHT LED TO THE OSCILLATION (PORPOISING) THAT ENDED IN PROP BLADES CHEWING ASPHALT. WITH THE NOSE DOWN I FLEW INTO THE RWY; BOUNCED ON THE NOSE GEAR; POPPED UP AGAIN AND THE CYCLE REPEATED IN A VERY RAPID FASHION. THERE WERE 4 PAX ONBOARD; SO THE ELEVATOR WAS TRIMMED FAIRLY NOSE LOW TO COUNTERACT THE WT IN BACK. I BELIEVE THIS NOSE LOW TRIM HELPED INDUCE THE OSCILLATION. AFTER THE FIRST BOUNCE I WENT TO FULL PWR FOR A GAR; BUT I DID NOT DO IT FAST ENOUGH OR MAYBE I DID NOT GIVE ENOUGH BACK PRESSURE TO FIGHT THE NOSE DOWN TRIM SO THE PLANE BOUNCED EVEN HARDER. IT WAS THIS SECOND STRIKE THAT BANGED THE PROP (I THINK). AFTER THE SECOND BOUNCE I REDUCED PWR TO IDLE; YANKED BACK ON THE YOKE AND THE PLANE SETTLED ON THE RWY. WE TAXIED BACK UNDER PWR; I SHUT DOWN AND THEN DISCOVERED THE BANGED UP PROP. NO ONE WAS HURT IN THE INCIDENT.