During arrival for landing, the pilot was leading a flight of five dissimilar aircraft. After pitching out in a 360 degree, overhead approach, the pilot flew a fairly tight pattern. On base, when he would normally have felt the gear lock in place, his attention was diverted as another aircraft passed beneath his nose. The landing gear indicator was an early model that was difficult to read. Also, it was located at the bottom of a panel where it was hard to see. The pilot stated that he checked the position of the gear handle several times as well as the hydraulic pressure. As he flared for landing, he started to go-around when the aircraft settled lower than normal. The propeller hit the surface as he settled with the gear retracted. He closed the throttle and mixture and slid to a stop. The fuel sump drain for the main tank was located at the lowest part of the fuselage. While sliding to a stop, the drain ground off and a fire started. No fire equipment was readily available.