On October 9, 2004, about 0822 central daylight time, an experimental amateur-built Buss Rotorway Exec helicopter, N82DR, operated by a commercial pilot, sustained substantial damage on impact with terrain during an autorotation following an in-flight loss of engine power while on its base leg to runway 28L at Flying Cloud Airport (FCM), near Eden Prairie, Minnesota. The personal flight was operating under 14 CFR Part 91. Visual meteorological conditions prevailed at the time of the accident. No flight plan was on file. The pilot reported no injuries. The local flight originated from FCM. The pilot stated in his accident report: I launched at 08:15 from General Aviation Services at Flying Cloud Airport, Eden Prairie, MN. I was given clearance to runway 28L. Upon take off clearance I commenced flying left pattern. I was given clearance for the option and on the base leg I reached for, and pulled, the carburetor heat lever. After releasing the lever, I inadvertently bumped and threw the main battery switch. I felt the switch move. (These switches are located on the top of the center console, and they are hidden from view by the pilot's right leg due to cramped quarters). I then tried to find and reengage the switch and I threw the avionics switch. I immediately re-engaged the avionics switch. While searching for the battery switch, the engine stopped. (The switch had shut off the fuel pumps, enabling the engine to continue running for a few seconds) I immediately lowered the collective and went into auto-rotation. I picked my spot to land and auto-rotated to that spot, and then initiated my cyclic flare. Just before touchdown I leveled the machine and pulled in all of the collective. I landed level, fairly softly, but with forward ground speed, in a soybean field diagonal to the rows. Calm winds were not a factor. Due to forward groundspeed, the helicopter slid forward and tipped forward. The rotor blades struck the ground in the front of the ship, which created torque forces, which tipped the machine onto its left side. The tower contacted me and confirmed that I was uninjured. I unbuckled my harness, shut off the fuel and all switches. I climbed out the passenger door. The pilot reported that there were no mechanical malfunctions in reference to the helicopter on the flight. The pilot's safety recommendation was that the "battery switch should be relocated or [guarded]."