On June 06, 2019, about 1602 eastern daylight time, an experimental amateur-built Avid Magnum, N3062B, was substantially damaged when it was involved in an accident near Frederick, Maryland. The pilot and flight instructor sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The pilot reported that he had recently purchased the airplane. He arranged to fly the airplane with the seller for 2 hours on the day before the accident, and with a flight instructor for 5 hours on the day of the accident to meet his insurance company’s requirements of 5 total hours of dual instruction. During the time he flew with the seller, he did not perform any takeoffs or landings. On the day of the accident, the pilot met the instructor, who did not have any previous experience in the airplane make/model. They “went over” the airplane, practiced maneuvers, takeoffs, and landings, then stopped for lunch and to refuel the airplane. While departing on the subsequent flight, the pilot began the takeoff roll on runway 30 using full power. The airplane made a “small swerve to the left,” which he initially corrected to the right; however, the airplane continued to turn right uncontrollably. He said that he could move the rudder pedal, but it had no apparent effect. He advised that his training had emphasized that he should respond to directional control problems on takeoff roll (in tailwheel airplanes) by “getting the airplane into the air, if possible.” As the airplane veered right, he pushed on the throttle and pulled back to lift off; however, the airplane would not climb and continued to veer to the right, then impacted construction equipment and a small hill. According to the instructor, the takeoff roll was normal until just after the tailwheel lifted off, when the airplane “swerved left and then hard back to the right.” He then “grabbed the stick” and yelled, “power power power” because it seemed to him that the engine was not developing full power based on its sound and the airplane’s performance. As the airplane crossed over the right edge of the runway, it was “barely airborne” until the ground sloped downward about 6 to 8 ft beneath the airplane. He struggled to keep the wings level and believed the airplane was at or near its stall speed. He attempted to avoid the construction equipment; however, the controls were “mushy” and the airplane “would not respond properly to control inputs.” He did not have time to look at the instruments. The instructor believed that the engine should have “had plenty of power to fly us out of the pre-accident situation if it had been developing full power.” In a subsequent statement, the pilot reported that he likely had not advanced the throttle to full power at the start of the takeoff, or when he attempted to lift off as the airplane departed the runway, due to his lack of familiarity with the style of throttle control. The throttle control was a vernier-style and was equipped with a button on the end of the knob. To push the throttle forward, the button needed to be depressed. Like a typical mixture control, the throttle position could be finetuned by rotating the knob. Neither the pilot nor the instructor reported observing the engine tachometer or airspeed indicator at the start of the takeoff roll or at the time of liftoff. According to a witness located at the nearby construction project, the airplane “took off in a steep climb, making small corrections in bank, getting bigger as they went.” An examination of the wreckage by a Federal Aviation Administration inspector revealed that the airplane came to rest inverted against a hill of construction dirt located about 1,400 ft from the departure end of runway 30, and about 400 ft right of the runway centerline. The wings, fuselage, rudder, and vertical stabilizer were substantially damaged. A follow-up examination of the airplane confirmed flight control continuity from all flight control surfaces to the cockpit and revealed no pre-accident anomalies with the engine that would have precluded normal operation. The engine tachometer was marked with a blue range between 2,200 and 2,700 rpm, and a red range above 2,700 rpm. At the time of the accident, the pilot had accrued a total of 715 hours of flight experience, 5 hours of which were in the accident airplane make/model (3 hours were accumulated on the day of the accident). The instructor had accrued a total of 6,030 hours of flight experience, 3 hours of which were in the accident airplane make/model. At 1547, the weather conditions at the accident airport included temperature 31°C, dewpoint 18°C, wind from 330° at 4 knots, altimeter setting 29.82 inches of mercury. The calculated density altitude was 2,384 ft.