Acft crashed immediately after takeoff on a flt to discharge jumpers over a drop zone located on the arpt. Witnesses stated that shortly after liftoff the acft entered a steep left bank estimated between 45 and 70 degs. After about 120 degs of turn the acft stalled and impacted the ground in about an 80 deg nose down attitude, with the left wing leading. Alt at the time the maneuver was attempted was aprx 125′ agl. Winds at the time of the accident were down the departure rwy at 10 kts gusting to 18 kts. One witness estimated the winds at 20 kts gusting to 25 kts. Research indicated that the acfts stall speed would have increased btw 40 and 100 percent during the turn depending on bank angle. The plt had a total of 3 hrs in this make and model of acft. Read the NTSB...