In April 1943, Alexander Yakovlev reported to the State Defense Committee that his bureau had built a fighter 300 kilograms lighter than the Yak-1, with a speed increase of 70 km/h on the same engine. Stalin was astonished: "How did you do it?" The secret was obsessive weight reduction—duralumin spars replacing wooden ones, smaller wing area, and refined aerodynamics. The Yak-3 was the lightest fighter of the war, and frontline pilots adored it. In one engagement, eight Yaks fought thirty Fw 190s and came out on top. The Normandie-Niemen Regiment, flying Yak-3s, declared it the best fighter they had ever flown. With the VK-107 engine, it exceeded 700 km/h. German pilots were warned: avoid combat with Yaks below 5,000 meters.