HISTORY OF FLIGHTOn September 11, 2021, about 0745 eastern daylight time, a Quad City Ultralight Challenger II experimental airplane, N778H, was substantially damaged when it was involved in an accident near Rogers City, Michigan. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The noncertificated pilot reported that about 100 ft into the takeoff roll on runway 27 the airplane began to swerve right, but before he could abort the takeoff, he heard a bang and the airplane pitched up and rolled. A witness reported that the airplane abruptly pitched up, rolled right, and impacted the ground in a left-wing-down attitude. The witness stated that the airplane completed about 270° of right roll when the left wing impacted the ground. PERSONNEL INFORMATIONA search of FAA airman certification records found no record of a pilot certificate ever being issued to the pilot. The pilot reported that he had previous flying experience in 14 CFR Part 103 ultralights. AIRCRAFT INFORMATIONThe pilot did not maintain maintenance records for the airplane, nor had the airplane undergone a condition inspection since the FAA issued the experimental airworthiness certificate on December 14, 2007. AIRPORT INFORMATIONThe pilot did not maintain maintenance records for the airplane, nor had the airplane undergone a condition inspection since the FAA issued the experimental airworthiness certificate on December 14, 2007. WRECKAGE AND IMPACT INFORMATIONPostaccident examination revealed substantial damage to the airplane’s left wing, fuselage, tailboom, and left horizontal stabilizer. Flight control continuity was confirmed from the cockpit controls to each flight control surface. Further examination of the right wing revealed that the forward lift strut separated from the fuselage longeron, as shown in figure 1. The channel bracket remained attached to the lift strut, but the AN4-24A bolt pulled out of the fuselage longeron. The 0.25-inch AN365-248 nylon-insert lock nut, depicted in figure 2, that normally secured the AN4-24A bolt was not located during the investigation. Figure 1. Lower attachment point of the right wing forward lift strut (FAA photos). Figure 2. Wing lift strut assembly, lower attachment.