WITNESSES STATED THAT THE P.I.C. HAD ABORTED SEVERAL TAKEOFF ATTEMPTS WHILE TRYING TO DEPART TO THE NORTH--THE WINDS WERE ORIGINATING FROM THE SOUTHWEST AT APPROXIMATELY 5 MPH. THE AIRCRAFT EVENTUALLY DEPARTED FROM, AND ALMOST USED THE FULL LENGTH OF, RUNWAY 36. IT THEN BROKE GROUND AND CLIMBED STEEPLY TO AVOID THE TREES--BUT TO NO AVAIL--ACCORDING TO WITNESSES. THE RIGHT WING SHEARED OFF AS THE AIRCRAFT CAREENED THROUGH THE WOODS BEFORE EXPLODING AND BURNING AS IT CAME TO REST. THE PILOT AND HIS PASSENGER WERE FOUND SERIOUSLY INJURED OUTSIDE THE WRECKAGE, BUT THE ALMOST IMMEDIATE EXPLOSION/CONFLAGRATION PRECLUDED THEIR TIMELY RESCUE BY CFR PERSONNEL. SAMPLES OF AUTO GAS WERE FOUND IN THE POWERPLANT; NO RECORD OF AN FAA-APPROVED STC FOR THE USE OF AUTOMOTIVE FUEL COULD BE PRODUCED. ACCORDING TO EVIDENCE GATHERED AT THE SCENE, THE ENGINE WAS PRODUCING POWER AT THE MOMENT OF INITIAL IMPACT.