THIS WAS THE INITIAL TEST FLIGHT FOR THE EXPERIMENTAL AMATEUR BUILT AIRCRAFT. TWO GALLONS OF FUEL WAS ADDED TO THE AIRCRAFT WHICH DID NOT COMPLETELY FILL THE TANK. AFTER REFUELING, NUMEROUS HIGH SPEED TAXI RUNS AND LOW ALTITUDE LIFT-OFFS AND LANDINGS WERE MADE ON RUNWAY 23. THE PILOT WAS THEN OBSERVED TO MAKE A NORMAL TAKEOFF AND CLIMB TO ABOUT 100 FT AGL. HE THEN TURNED 90 DEG LEFT AND CONTINUED CLIMBING TO ABOUT 300 FT AGL. ANOTHER 90 DEG TURN WAS MADE TO DOWNWIND AND THE CLIMB WAS CONTINUED UNTIL ABEAM THE MIDPOINT OF THE AIRPORT. AT ABOUT THAT TIME, THE RIGHT WING DROPPED AND THE PLANE ENTERED A SPIN AND CRASHED. THE CONDITION OF THE PROPELLER SUGGESTED THE ENGINE WAS NOT DEVELOPING POWER AT IMPACT. NO INTERNAL MALFUNCTION WAS EVIDENT. THE FUEL TANK HAD RUPTURED BUT THERE WAS NO SIGN OR ODOR OF FUEL. NO FUEL WAS FOUND IN THE FUEL SYSTEM TO THE ENGINE.