ACR LGT TAIL STRIKE ON TKOF FROM DTW.

Narrative

WHEN CLRED FOR TKOF ON RWY 21C AT DTW OUR TKOF ROLL WAS BEGUN AS AN MLG ROTATED ON THE SAME RWY AND AT DERATE 1 PWR WE MADE A NORMAL TKOF ROLL IN LITTLE OR NO WIND CONDITIONS WITH A ROTATION AT PROPER ROTATION SPD AT A NORMAL RATE OF ROTATION TO THE CHART PITCH ATTITUDE. ROTATION OCCURRED AT THE INTXN OF RWY 9/27 AND UPON ROTATION AN AUDIBLE BUMP WAS HEARD AND FELT. UPON EVALUATION OF THE PROCS USED WE DISCOUNTED THE POSSIBILITY OF A TAIL STRIKE AND ASSUMED THAT EITHER AS A RESULT OF OUR LOCATION AT THE INTXN OUR STRUTS STRUCK THE CREST OF RWY 9/27; OR THAT THERE WAS DISTURBED AIRFLOW OR SOMETHING CAUSING A SLIGHT SETTLING RIGHT AT ROTATION CAUSING MAIN STRUTS TO BE JARRED. IN MY EXPERIENCE FLYING THE LGT I HAVE ALWAYS BEEN CONSISTENT WITH MY PROCS AND TECHNIQUE WITH ROTATING THE ACFT ALWAYS AWARE OF THE DANGERS OF TOO HIGH A RATE OF ROTATION. THIS TKOF WAS NO DIFFERENT YET WE STRUCK THE TAIL. I CAN ONLY SURMISE THAT SOME EXTERNAL FORCES BEYOND OUR CTL OR ABILITY TO INFLUENCE THEM CONSPIRED TO CREATE THIS INCIDENT. BELIEVING THERE WAS NO REASON TO TAKE FURTHER ACTION WE CONTINUED ON TO OUR DEST.