The pilot reported that just after takeoff and during the initial climb, the airplane's engine suddenly lost power and the propeller stopped. The airplane's altitude when the power loss occurred was about 400 feet above the ground. The pilot attempted to return to the departure runway but realized that he did not have sufficient altitude. The airplane impacted trees and the ground in a wooded area near the runway. All of the biplane's wing surfaces were fragmented during the accident and the fuselage came to rest nose down. The airplane was powered by a converted automobile engine. Examination of the airplane revealed that the ignition high voltage coil wire had separated from the coil. The coil wire was re-inserted into the coil and the engine was able to be started. The engine could not be run to full power due to the fragmented propeller. The coil wire was held in place by a friction fit. No other means of retention was provided.