That not how they maked, they carried small smoke bombs on the central hardpoint for that.
http://www.gunsofmuschu.com/boomerang.html Featuring in one segment in "The Guns of Muschu" the CAC Boomerang gave valuable service to the Australian campaign in New Guinea.
Opening the throttle, speed built quickly and soon passed three hundred knots. Altimeter unwinding, Martin aimed at the western end of the island. At a thousand feet, he began pulling back on the stick. He felt the G forces coming on as he leveled from the dive one hundred feet above the trees. At over three hundred knots he streaked along the middle of the island, engine howling and supercharger whistling. Flashing over the hills at the eastern end, he hauled back the stick and climbed vertically. He snap rolled the little aircraft, counted one, two, three clockwise rotations, paused, then reversed it. One, two, three.
Passing three thousand feet, he flipped inverted, pulled through, tucked back down into another dive, this time at half throttle. Again he howled low over the trees, then allowing speed to wash off, began a wide circuit out over the southern coast.
Martin was thoroughly enjoying himself. For an aircraft someone once described as being built from spare parts, baling wire and Golden Syrup tins, the Boomerang was a bloody marvel. It might not be the world’s greatest fighter, but it was maneuverable, strong and very, very noisy. By now every Jap on the island would be aware that he was around...
