Cerrtain Black Hawk Models kits contain this plywood cowling material.   An opening is pre-cut for the engine cylinder, however this opening may required modification and other opening may be required depending on the type of engine used to power the aircraft.   The cowling material is easily formed by briefly soaking it in a solution of water and ammonia and holding it in the desired shpe until dry.   Small screws, shortened straight pins, and glue will hold the cowling in place.