On December 4, 2016, about 1525 Pacific standard time, an experimental Velocity XL/RG airplane, N84KJ, was substantially damaged after it contacted the runway with the landing gear retracted at Petaluma Municipal Airport (O69), Petaluma, California. The private pilot sustained minor injuries. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed. The local flight originated from O69 at 1455. The pilot reported that the purpose of the flight was to practice maneuvers required to obtain a commercial pilot certificate. Upon his return to O69, the pilot entered the downwind leg for runway 29, extended the landing gear, and prior to base leg, reduced the power to idle. He also observed a Cessna airplane on final. To keep an adequate separation between the two airplanes, the pilot announced that he would perform S turns. After he had executed two S turns, the pilot realized he was low and slow, so he retracted the landing gear to improve the glide distance. He initially intended to do a go-around, but decided to land after the Cessna exited the runway. As he attempted to extend his landing gear, he observed that the landing gear down position-indicator light did not illuminate. The pilot pushed the gear reset button and subsequently pulled back on the control stick, which resulted in an inadvertent stall 10 to 20 ft above the runway. Postaccident examination of the airplane by a Federal Aviation Administration inspector revealed that the landing gear handle was in the UP position. A witness observed the accident airplane on final approach, about one-third of the way down the runway with the landing gear retracted and at a low airspeed. He immediately started flashing lights in his vehicle to get the pilot's attention. The airplane touched down, bounced back into the air, settled on its belly and slid about 100 ft to a stop. A mechanic who recovered the airplane reported that the landing gear handle was in the UP position, and that he overheard the pilot say that he was distracted on final approach. Maintenance personnel on scene noticed the gear was partially out of the well before they started to lift the aircraft during the recovery process. In the section titled "RECOMMENDATION" in the NTSB Pilot/Operator Report, form 6120.1, the pilot stated that the decision to proceed with the landing proved to be inadequate and that he should have performed a go around instead. The pilot completed necessary repairs on the airplane that included fiberglass repair to the belly and the landing gear system. The nose gear actuator and strut were replaced. The landing gear was then functionally tested and there were no malfunctions.