The pilot of the experimental amateur-built airplane reported that, he was unfamiliar with the airplane, and that during a pre-purchase flight, he was accompanied by an aircraft mechanic/pilot familiar with the airplane. The mechanic, seated in the right seat, instructed him to anticipate adding right rudder when increasing power during takeoff. During takeoff, the pilot applied right rudder; however, he reported that once full power was applied the airplane continued to veer to the left. The pilot added that, there was a verbal communication shared between the two pilots that they "both were applying right rudder and simultaneous aileron." The pilot then pulled the mixture control to shutoff the engine, however, the airplane continued off the left side of the runway, he heard a loud "pop," the airplane then veered to the right, the landing gear collapsed, and the airplane came to rest off the right side of the runway. The airplane sustained substantial damage to the fuselage and rudder. The pilot reported that he believed there was a "mechanical" failure, causing the airplane to not respond to inputs from the right rudder, right brake, and right aileron; and that the left brake or bearing seized causing enough friction to overcome the control inputs. According to the mechanic, the airplane was not equipped with rudder/brake pedals on the right side, and that prior to the flight the pilot had used the brakes effectively to taxi for takeoff. He further stated, "all brakes were in good shape, and everything was in good operational condition." The mechanic added that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The automated weather observation system on the accident airport reported, that about the time of the accident, the wind was 190° at 7 knots. The pilot was departing on runway 17L.