As the aircraft was being rotated for take-off, the pilot detected a slight loss of performance from the right engine. He looked towards the engine and saw evidence of fire around the air intake on top of the cowling. The take-off was abandoned, both propellers were feathered and heavy braking was applied. The aircraft overran the strip and entered a very muddy field. The nosegear collapsed and the right engine was torn from its mounts before the aircraft came to rest 110 metres beyond the strip threshold. The pilot rapidly vacated the aircraft and waited for several minutes until rescuers arrived and extinguished the fire. The subsequent investigation did not reveal any evidence of a pre-impact fire, and all fire damage was found to have occurred after the aircraft had come to rest. No positive reason for the reported power loss was established, however tests showed that the spark from the magnetos was weaker than normal. At the point where the take-off attempt was abandoned, insufficient strip length remained in which to stop the aircraft.