80 years ago, the Spitfire Mk Vb flew for the first time. It had the "B type" wing which replaced two of the four .303 machine guns seen on the A type wing with a 20 mm cannon. The Mk Vb was the most produced variant of the Spitfire Mk V with 3,911 total built. http://pbs.twimg.com/media/E4-6ImnX0AMhGuM.jpg
The Ki-45 otsu took to the skies 80 years ago. The aircraft was equipped with a deadly 37 mm cannon to counter enemy B-17 bombers. While the armament remained deadly, the Ki-45 struggled to intercept B-29 bombers at high altitudes in the later stages of WWII. http://pbs.twimg.com/media/FztitgPWIAEugW9.jpg