A PA-12 PILOT REPORTS STRIKING THE PROP ON THE RUNWAY ON TAKEOFF ROLL.

Narrative

THIS EVENT OCCURRED DURING TKOF ON RWY 21. AFTER ADDING FULL PWR; I PUSHED THE STICK FORWARD TO ATTAIN TKOF ATTITUDE; THE ACFT ROTATED AT A GREATER THAN NORMAL RATE. I ATTEMPTED TO COUNTERACT THE RAPID ROTATION; BUT WAS UNABLE. WHEN IT BECAME APPARENT THAT THE PROP MAY STRIKE THE RWY; I PULLED THE THROTTLE TO IDLE AND SHUT DOWN THE ENG. THE NOSE CONTINUED TO ROTATE DOWN AND THE PROP STRUCK THE RWY. CONTRIBUTING FACTORS: 1) ALTHOUGH AWOS WAS RPTING CALM WINDS; I; AFTERWARDS; NOTICED THE WINDSOCK TO BE SHOWING WINDS GUSTY FROM THE R REAR QUARTER OF THE ACFT WHEN IN THE TKOF POS. I ALSO NOTICED SOME DUST DEVILS IN THE AREA. I BELIEVE THAT WINDS WERE A SIGNIFICANT CONTRIBUTING FACTOR IN THIS EVENT. 2) THIS ACFT HAS A LYCOMING 4 CYLINDER ENG RATED AT 160HP. I BELIEVE THIS ACFT WAS ORIGINALLY EQUIPPED WITH A 100HP ENG. I SUSPECT THIS ENG/FLT CTL COMBINATION HAS THE ABILITY TO AFFECT PITCH CTL GREATER THAN ON THE ORIGINAL PA12 100HP VERSION. NOT THAT THIS IS BAD; BUT EXTRA CARE MUST BE TAKEN IN CERTAIN REGIMES. 3) AFTERWARDS; I NOTICED THAT THE TKOF TRIM INDICATOR WAS IN A MORE THAN NORMAL NOSE DOWN POS THAN I WAS USED TO; WHICH MAY HAVE CONTRIBUTED TO THE OVER ROTATION. 4) I WEIGH 180 LBS AND WAS FLYING SOLO (FRONT SEAT); WITH NO OTHER PAX OR BAGGAGE BEHIND ME; WHICH I BELIEVE WOULD RESULT IN A MORE FORWARD CTR OF GRAVITY. CORRECTIVE ACTIONS: 1) DON'T RELY SOLELY ON AWOS FOR WX INFO. USE VISUAL CUES FOR WIND INFO; SUCH AS WINDSOCKS; FLAGS; DUST; DUST DEVILS; ETC. 2) BE AWARE OF HOW LOAD CONFIGNS AFFECT CTR OF GRAVITY AND PITCH RESPONSE. 3) ENSURE PITCH TRIM IS APPROPRIATE FOR CONDITIONS. 4) I'M NOT AN AERODYNAMIC ENGINEER; BUT BE MORE ATTENTIVE TO DIFFERENT AIRFRAME/PWR PLANT CONFIGNS.