Prior to starting the engine, the pilot had tied down the airplane's tail on the ramp with a rope because no wheel chocks were available. After the pilot started the engine via hand turning the propeller, the rope that retained the airplane broke. The pilot attempted to hang onto the airplane in order to regain control, however, he was unsuccessful. The unoccupied airplane then struck a parked aircraft, a fence, and came to rest on its nose against the fence. The pilot was not injured.