In 1943, TsAGI continued intensive experimental research to further improve the aerodynamics of the La-5FN. At the same time, the designers also improved their aircraft. As a result, already at the beginning of 1944, a new La-7 fighter was launched for testing. It was distinguished by a lightweight design (finally, metal spars appeared on La planes), enhanced armament and better aerodynamic properties. There are two ways to improve the flight data of an aircraft: by reducing the weight of the airframe and improving aerodynamics. Lavochkin also managed to reduce the mass of the last series of La-5FN by about 100 kg by replacing the wooden power wing set with a metal one, while the structural strength remained at the same level. Due to supplies under Lend-Lease and the establishment of production in the depths of the USSR, the situation with aluminum was facilitated. Replacing wooden structures with metal ones is a big reserve for saving weight. One replacement of wooden wing spars with duralumin ones with steel shelves reduced the weight by 100 kg. It must be said that by this time there was no longer delta-wood in the airframe design - due to the lack of resin, ordinary pine and birch gradually replaced it from the structure. Drawings of the metal wing spars and the center section were developed in the summer of 1943 in Nizhniy Tagil at the plant No. 381 under the leadership of the chief designer P.D. Grushin - later an outstanding designer of anti-aircraft missiles.Considering a number of disasters that occurred with the La-5, on the "standard of 1944" in the rear of the canopy, an anti-hood frame was installed. The frame could save a pilot's life if the plane turned over during takeoff or landing (unfortunately, the frames did not appear on production machines, which led to the death of more than one pilot, including the famous ace A.F.Klubov from the 9th GIAP).The characteristics of speed and rate of climb can be assessed as "standard", somewhat superior to those