THE PLT WAS A PARAPLEGIC. HE HAD PREVIOUSLY PURCHASED A CESSNA 172 & HAD IT MODIFIED FOR HAND CONTROL. HOWEVER, HE HAD DISCONTINUED INSTRUCTION IN THE PLANE WHEN HE WAS DENIED A MEDICAL WAIVER ON THE GROUNDS THAT HE HAD TO TAKE VALIUM AS A MUSCLE RELAXANT. LATER, IN 1982, HE PURCHASED PLANS FOR A WASPAIR TOMCAT, ULTRALIGHT VEHICLE AFTER ASSEMBLING THE ULTRALIGHT, THE PLT DECIDED TO PRACTICE 'CROW-HOPS' ON THE LOCAL ARPT. ACCORDING TO WITNESSES, THE WINDS WERE NORTHERLY AT ABOUT 10 GUSTING UP TO 30 KTS. THE PLT STATED THAT HE HAD CHANGED DIRECTION OF HIGH SPEED RUNS TWICE BEFORE BECOMING AIRBORNE. REPORTEDLY, ON ITS 1ST TAKEOFF, THE VEHICLE ENCOUNTERED A GUSTY X-WIND. AT AN ALTITUDE OF APRX 40 FT AGL, HE LOST CONTROL & THE VEHICLE IMPACTED THE GROUND. THE VEHICLE WAS EQUIPPED WITH A TILTING CANARD THAT PROVIDED BOTH PITCH & YAW CONTROL. THE CANARD WAS THE ONLY MOVABLE CONTROL SURFACE & WAS USED FOR AIRBORNE MANEUVERS. THIS WAS THE 1ST FLT FOR THE VEHICLE. THE PLT'S INSTRUCTOR HAD NOT ENDORSED HIM FOR THIS FLT.