Thijs Postma - Poster - Northrop P-61 Black Widow With SunsetAdmire this mysterious plane. The Northrop P 61 Black Widow looks frightening when you encounter it at night. The Black Widow was the first US warplane that was designed as a night fighter. The P 61 was also the first aircraft designed to use radar. It had four 20mm cannons and four . 50 calibre machine guns. It was operated by a pilot, a gunner and a radar operator.