On October 21, 2000, at 1515 central daylight time, a Bollinger BD-4, N108BC, piloted by a private pilot, sustained substantial damage on contact with a fence and subsequent nose over, during a go-around from runway 27 at a private airstrip near Hedrick, Iowa. 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 minor injuries. The flight departed from Fairfield Municipal Airport, Fairfield, Iowa, at 1450. The pilot stated, "I approached the 2500 foot grass runway #27 and discovered that I would have to clear 50' trees that were indented on the runway about 50' thus shortening the usable r/y to about 1800'. At this point I made a go-around to approach again. Upon my 2nd approach I did my landing check list and reviewed short field landing procedure. Final approach was done at a steeper angle and at 65 kts to clear the trees. I had full flaps on this approach but power was completely off as I made my round out to flair. I had determined previously that I should touch down no less than 800 feet before the end of the runway to allow enough distance for rollout. Everything seemed perfect until the flair. At about 1 ft off the ground the flair seemed to be going on too long so at the moment I decided to add throttle [and] go around the aircraft touched the r/y in a full stall and was slowed by the 4" to 6" grass but the engine was now at full power. At this point, it seemed the best thing to do was to try to take off again because I no longer had enough room to stop before hitting the fence at the end of the runway. This decision was based on the fact that my BD-4 is configured as a short takeoff and landing aircraft relative to other BD-4s and because I was at full throttle now with maybe 500 ft left to stop. My hope was to clear the fence with in ground effect if necessary, maybe even jump the fence. The highest wire of the fence was about 4 1/2 feet high and I caught the top wire on the midpoint of my landing gear. The plane slowed down to almost a stop on the other side of the fence and then slowly turned over on to the right wing tip and prop and then continued slowly to an upside down position. The plane ended up about 75 ft beyond the other side of the fence. The question is why did my flair continue too long and I feel the answer is because my vernier throttle control clicked up a detent or so increasing the RPM just as I was on my flair. This had happened to me before but I thought I had fixed it. I can always tell when this happens because I can hear the increase in RPM but this time I didn't hear it because I was wearing ear plugs in addition to my head set because of the very noisey cabin during flight." The pilot also stated, "I aquired permission by telephone from the owner to land at this runway and I also asked him about the condition of the runway. He did not tell me about the trees or the fence." The pilot's safety recommendation was that "more information about the runway conditions and approach would have made the difference." In a telephone interview, the airstrip owner confirmed that the pilot called to get permission. He stated that the runway direction is about 270 degrees true. He said that its length is about 2,500 feet and there is a tree on the runway's north edge near its northeast corner. He confirmed the pilot's approximation of 1,800 feet of useful runway length. The airstrip owner stated that he would advise pilots that call for landing permission of the current field condition and approach information.