A helicopter (Bell 206B, N2282T) and an airplane (Pitts S-2A, N31512) collided in mid-air during their initial takeoff climb from an uncontrolled airport. The collision occurred as the airplane was taking off from runway 22 and the helicopter was departing from an adjacent helipad near the midpoint of the 2650' runway. The helicopter pilot said that after lift-off from the helipad, he brought the helicopter to a hover and hover taxied it to the runway. He said he visually cleared the runway, and after about 10 seconds, he began his departure. Subsequently, the helicopter's flight path merged with the flight path of the airplane over the runway. Forward visibility from the tailwheel equipped airplane would have been restricted while its tailwheel was on the runway surface. Aircraft tiedowns were located between the approach end of runway 22 and the helipad; aircraft parked in this tie-down area would have restricted the view between the approach end of the runway and the helipad.