Background
A noninstrument-rated pilot reported receiving a weather briefing before a night flight. Visual flight rules (VFR) conditions were forecast at the destination, located 31 miles to the southeast. At the departure airport, conditions were dark and moonless, but stars were visible and haze was present to the west. Lights were visible 10 miles to the south.
Flight
The pilot departed on runway 29 and executed a right, downwind departure. During the departure turn, at approximately 900 feet, the aircraft entered instrument meteorological conditions (IMC). While in clouds, the pilot had difficulty leveling the wings and noted "some altitude fluctuation." Shortly after, a "pop" sound was heard, and the aircraft became difficult to control. The pilot subsequently broke out on top of the clouds at 2,700 feet and proceeded to the original destination for landing.
Post-Flight
Control of the aircraft required the pilot to input full right rudder control, 90 percent of available right aileron control, and to reduce power on the right engine. Inspection of the left wing revealed damage to the outboard 5 feet of the wing leading edge, along with embedded tree debris.