The pilot receiving instruction and flight instructor were on an instructional flight. While on the downwind leg of the traffic pattern at a small private airport, the flight instructor reduced the engine power to simulate a loss of engine power. The pilot described that the wind was “howling” and that there were tall trees along the approach path to the runway. The flight instructor offered to demonstrate the simulated approach to landing and go-around. The flight instructor reported that during the approach there was some turbulence, and he was monitoring the airplane’s airspeed closely. After clearing the trees, while about 30 to 50ft above the runway, the airplane’s nose suddenly pitched down and the sink rate increased. He applied full power to go around but could not arrest the descent before drifting to the right of the runway and contacting the ground hard. The nose landing gear collapsed and the airplane’s engine mounts were substantially damaged. Both pilots reported that there were no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation.