WHILE PREPARING FOR A FLIGHT TO FILM A SEGMENT FOR A TV PROGRAM ABOUT ULTRALIGHTS,THE PILOT COMPLETED A SERIES OF TAXI TESTS & CLIMBS TO ABOUT 50FT AGL FOLLOWED BY AN IMMEDIATE LANDING. HE HAD BEEN PREVIOUSLY INSTRUCTED TO USE NO MORE THAN3/4 POWER & NEVER FLY BEYOND VNE OF 55MPH. HE THEN COMMENCED A TAKEOFF & STEEP CLIMB AT FULL POWER & PROCEEDED TO MAKE SOME TURNS,CLIMBS & DESCENTS FROM ABOUT 500-1000FT. THE ULTRALIGHT THEN ENTERED A FULL POWER DESCENT & BEGAN A PITCH OSCILLATION FOLLOWED IMMEDIATELY BY THE FAILURE OF THE LEFT WING. IN REVIEWING A VIDEO TAPE,IT APPEARED THAT THE PILOT LOST HIS FOOTING ON THE NOSE WHEEL STEERING BAR & WAS TOSSED FORWARD DURING THE PITCH OSCILLATION. THE PILOT WAS LIFTED UP OUT OF HIS SEAT DURING THE OSCILLATION. BOTH WINGS FOLDED & THE PILOT FELL CLEAR OF THE ULTRALIGHT. THE PILOT DID NOTHAVE HIS SEAT HARNESS FASTENED. NO PILOT CERTIFICATE HAD EVER BEEN ISSUED TO THE PILOT. FEDERAL REGULATIONS DO NOT REQUIRE A PILOT OF AN ULTRALIGHT TO RECEIVE TRAINING OR POSSESS AN AERONAUTICAL RATING IN THIS CATEGORY OF AIRCRAFT.