The pilot said that the aircraft owner had invited him to fly his airplane, which was similar to the biplane he had flown for 400 hours over the past 28 years. This was to be his first time flying this particular airplane. After preflighting and familiarizing himself with the layout of controls and instruments, he started the engine. After completing his pre-takeoff checks and an engine run-up, the pilot taxied to the end of the runway and took off. After climbing to about 500 feet, the pilot “sensed the loss of power.” He lowered the nose and began looking for a place to land. The sink rate was high and it became apparent that he would be unable to clear trees ahead. The pilot aimed for a field below and the airplane “hit the ground hard in a flat attitude and bounced." The landing gear collapsed and the airplane nosed over. Later, the pilot said he checked the fuel valve --- "which was difficult to see due to its position underneath and forward of the instrument panel" --- and found the selector handle to be in the "OFF" position.