CEN15LA402

The private pilot was conducting a personal flight in the experimental airplane. The pilot reported that, during the takeoff roll, he observed a "puff" of smoke emanate from the engine's left side and noted that the airplane did not accelerate as quickly as it normally did. The pilot leaned the mixture control, which was at 3/4 rich, and the engine subsequently started to develop normal power. The airplane lifted off about midfield and 80 mph. When the airplane reached about 150 to 200 ft above the ground, the pilot noticed that it was not climbing as he would have expected. The manifold pressure was 47 inches, and he was concerned about "overboosting" the engine, so he reduced the manifold pressure to 40 inches, and the airplane then started to descend. The pilot increased the manifold pressure to 45 inches, but the airplane continued to descend. The pilot chose to perform a forced landing to a field, during which the airplane struck a wire fence and then the ground. During postaccident examination, the engine started without hesitation and ran up to 40 inches of manifold pressure for several minutes. Examination of the engine revealed a 1/2-inch square crack in the exhaust pipe. No other anomalies were noted with the engine or its systems. An examination of the airframe, flight controls, and remaining systems revealed no anomalies. The takeoff weight of the airplane at the time of the accident was estimated to be 1,310 lbs, which was 110 lbs over the airplane's maximum gross weight. It is likely that the combined effects of the hole in the exhaust pipe and the airplane being over its maximum gross weight negatively affected the airplane's climb performance during takeoff.

On September 8, 2015, about 0825 central daylight time, a Viking (Clarke) Dragonfly MK II experimental airplane, N24TL, was substantially damaged when it hit a barbed wire fence during a forced landing near the Albertus Airport (KFEP), Freeport, Illinois. The pilot sustained serious injuries. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted under the provisions of 14 Code of Federal Regulations Part 91 without a flight plan. The flight was originating at the time of the accident and was en route to Poplar Grove Airport (C77), Poplar Grove, Illinois. According to the written statement provided by the pilot, the preflight walk around and engine run up were uneventful. During the takeoff roll the pilot observed a "puff" of smoke from the left side of the engine and the airplane did not accelerate as quickly as it normally did. The pilot leaned the mixture control, as it was at 3/4 rich, and the engine started to develop normal power. The airplane lifted off about midfield and 80 miles per hour. Between 150 and 200 feet the pilot noticed that the airplane was not climbing as he would have expected. The manifold pressure was at 47 inches and he was concerned about "overboosting" the engine. He reduced the manifold pressure to 40 inches, at which time the airplane started to descend. The pilot increased the manifold pressure to 45 inches and the airplane continued to descend. The pilot elected to perform a forced landing to the field during which the airplane struck a wire fence and then the ground. According to the Federal Aviation Administration inspector who responded to the accident, both main landing gear legs, the left canard, and two of the three propeller blades separated from the airplane. The fuselage was split apart at the instrument panel and cabin. The left side of the instrument panel was pushed forward about 6 to 8 inches and the pilot's rudder pedals were pushed forward into the firewall. Fuel was not visible in the fuel tank; however, during the recovery of the airplane fuel spilled out and it was apparent that the fuel tank was compromised. The inspector was able to start the engine without hesitation and run it up to 40 inches of manifold pressure. He ran it for several minutes. Examination of the engine revealed a ½ inch square crack in the exhaust pipe. No other anomalies were noted with the engine or its systems. An examination of the airframe, flight controls, and remaining systems revealed no anomalies. The inspector provided weight and balance information for the airplane, luggage, and pilot. The gross weight of the airplane was 1,200 pounds. The pilot reported that there was 21 gallons of fuel on board. The weight of the airplane at the time of the accident was estimated at 1,310 pounds.