THE PLTS OF 2 HIGH WING, PTERODACTYL ASCENDER, ULTRALIGHT VEHICLES TOOK OFF & WERE OPERATING IN A DESIGNATED AREA FOR ULTRALIGHTS. ONE PLT (PLT-A) WAS MAKING TOUCH & GO LANDINGS WHILE THE OTHER PLT (PLT-B) WAS MANEUVERING IN THE VECINITY. AFTER PLT-A MADE A TOUCH & GO, PLT-B TURNED TO PARALLEL HIS COURSE. REPORTEDLY, THIS PUT PLT-B HIGH, BEHIND & TO THE RIGHT OF PLT-A, WHO WAS CLIMBING ON A SOUTHBOUND HEADING. PLT-B SAID THAT HE THOUGHT PLT-A HAD SEEN HIM AS THEY CONTINUED ON A SOUTHERLY COURSE. REPORTEDLY, PLT-A DID NOT SEE THE OTHER VEHICLE, BECAUSE IT WAS HIGH/BEHIND HIM. PLT-A REPORTED THAT AFTER CLIMBING TO APRX 100 TO 150 FT, HE TURNED WESTBOUND IN THE PATTERN & THE OTHER ULTRALIHGT WAS STILL IN THE BLIND SPOT OF THE HIGH WING VEHICLE UNTIL JUST BEFORE IMPACT. DURING IMPACT, THE FLYING WIRE FOR THE LEFT WING OF PLT-A'S VEHICLE HIT THE RIGHT MAIN GEAR OF PLT-B'S VEHICLE. PLT-A'S ULTRALIGHT ENTERED AN UNCONTROLLED SPIN & CRASHED. PLT-B LANDED WITH A BROKEN RIGHT MAIN WHEEL & A BROKEN STRENGTHENING WIRE.