Lavochkin La-7
The Lavochkin La-7 () was a piston-engined single-seat Soviet fighter aircraft developed during World War II by the Lavochkin Design Bureau. It was a development and refinement of the Lavochkin La-5, and the last in a family of aircraft that had begun with the LaGG-1 in 1938. Its first flight was in early 1944 and it entered service with the Soviet Air Forces later in the year. A small batch of La-7s was given to the Czechoslovak Air Force the following year, but it was otherwise not exported. Armed with two or three cannon, it had a  top speed of . The La-7 was felt by its pilots to be at least the equal of any German piston-engined fighter. It was phased out in 1947 by the Soviet Air Force, but served until 1950 with the Czechoslovak Air Force. Design and development. By 1943, the La-5 had become a mainstay of the Soviet Air Forces, yet both its head designer, Semyon Lavochkin, as well as the engineers at the Central Aerohydrodynamics Institute (), felt that it could be improved upon. "TsAGI" refined earlier studies of aerodynamic improvements to the La-5 airframe in mid-1943 and modified La-5FN c/n  39210206 to evaluate the changes. These included complete sealing of the engine cowling, rearrangement of the wing center section to accommodate the oil cooler and the relocation of the engine air intake from the top of the cowling to the bottom to improve the pilot's view. The aircraft was evaluated between December 1943 and February 1944 and proved to have exceptional performance. Using the same engine as the standard La-5FN c/n 39210206 had a top speed of at a height of , some faster than the production La-5FN. It took 5.2 minutes to climb to . It was faster at  low to medium altitudes than the La-5 that used the more powerful prototype Shvetsov M-71 engine. Lavochkin had been monitoring "TsAGI"s improvements and began construction in January 1944 of an improved version of the La-5 that incorporated them as well as lighter, but stronger, metal wing spars to save weight. The La-5, as well as its predecessors, had been built mostly of wood to conserve strategic materials such as aircraft alloys. With Soviet strategists now confident that supplies of these alloys were unlikely to become a problem, Lavochkin was now able to replace some wooden parts with alloy components. In  addition Lavochkin made a number of other changes that differed from c/n 39210206. The engine air intake was moved from the bottom of the engine cowling to the wing roots, the wing/fuselage fillets were streamlined, each engine cylinder was provided with its own exhaust pipe, the engine cowling covers were reduced in number, a rollbar was added to the cockpit, longer shock struts were fitted for the main landing gear while that for the tail wheel was shortened, an improved PB-1B(V) gunsight was installed, and a new VISh-105V-4 propeller was fitted. Three prototype Berezin B-20 autocannon were mounted  in the engine cowling, firing through the propeller, arming the 1944 standard-setter (), as the modified aircraft was designated. The "etalon" only made nine test flights in February and March 1944 before testing had to be suspended after two engine failures, but quickly proved itself to be the near-equal of c/n 39210206. It was lighter than the earlier aircraft, which allowed the "etalon" to outclimb the other aircraft (4.45 minutes against 5.2 minutes climb to 5,000 meters). However it was slower at sea level, but only slower at . The flight tests validated Lavochkin's modifications and it was  ordered into production under the designation of La-7, although the B-20 cannon were not yet ready for production and the production La-7 retained the two 20-mm ShVAK cannon armament of the La-5. Five La-7s were built in March by Factory () Nr. 381 in Moscow and three of these were accepted by the Air Force that same month. The Moscow factory was the fastest to complete transition over to La-7 production and the last La-5FN was built there in May 1944. "Zavod" Nr. 21 in Gorky was considerably slower to make the change as it did not exhaust its stock  of wooden La-5 wings until October. The quality of the early production aircraft was significantly less than the "etalon" due to issues with the engine, incomplete sealing of the cowling and fuselage, and defective propellers. One such aircraft was tested, after these problems had been fixed, by the Flight Research Institute () and proved to be only slower than the "etalon" at altitude. Aircraft from both factories were evaluated in September by the Air Force Scientific Test Institute () and the problems persisted as the aircraft could only reach at a height of and had a time to altitude of 5.1 minutes  to 5,000 meters. Combat trials began in mid-September 1944 and were generally very positive. However four aircraft were lost to engine failures and the engines suffered from numerous lesser problems, despite its satisfactory service in the La-5FN. One cause was the lower position of the engine air intakes in the wing roots of the La-7 which caused the engine to ingest sand and dust. One batch of flawed wings was built and caused six accidents, four of them fatal, in October which caused the fighter to be grounded until the cause was determined to be a defect in the  wing spar. Production of the first aircraft fitted with three B-20 cannon began in January 1945 when 74 were delivered. These aircraft were heavier than those aircraft with the two ShVAK guns, but the level speed was slightly improved over the original aircraft. However, the time to climb to 5000 meters increased by two-tenths of a second over the older model. More than 2000 aircraft were delivered before the war's end, most by Zavod Nr. 21. A total of 5,753 aircraft had been built by "Zavod" Nr. 21, Nr. 381, and Nr. 99 in Ulan-Ude, when production  ended in early 1946. Operational history. The 63rd Guard Fighter Aviation Corps began combat trials of the La-7 in mid-September 1944 in support of the 1st Baltic Front. Thirty aircraft were provided for the trials, which lasted one month. During this time the new fighters made 462 individual sorties and claimed 55 aerial victories while losing four aircraft in combat. Four other La-7s were lost to non-combat causes, mostly related to engine problems. A total of three pilots were killed during the trials to all causes. One regimental commander, Colonel Ye. Gorbatyuk, a Hero of the Soviet Union , commented: "The La-7 exhibited unquestionable advantages over German aircraft in multiple air combats. In addition to fighter tasks, photo reconnaissance and bombing were undertaken with success. The aircraft surpasses the La-5FN in speed, manoeuvrability, and, especially, in the landing characteristics. It requires changes in its armament, and urgent fixing of its engine." The twin ShVAK armament inherited from the La-5 was no longer powerful enough to bring down later, more heavily armored German fighters, especially the Focke-Wulf Fw 190, in a single burst, even when Soviet pilots opened fire at ranges of only . The 156th Fighter Air Corps of  the 4th Air Army was the next unit to receive the La-7 in October 1944. At one point during the month, they had fourteen aircraft simultaneously unserviceable with engine failures. By 1 January 1945 there were 398 La-7s in front-line service of which 107 were unserviceable. By 9 May 1945 this had increased to 967 aircraft, of which only 169 were unserviceable. For the invasion of Japanese Manchuria, 313 La-7s were assigned and only 28 of these were unserviceable on 9 August 1945. The La-7 was flown by the top Soviet ace of the war, Ivan Nikitovich Kozhedub. Kozhedub , nicknamed "Ivan the Terrible", a three-time Hero of Soviet Union, scored his last 17 air victories in 1945 in the La-7 numbered 27, which is now preserved in the Central Air Force Museum at Monino on the outskirts of Moscow. One fighter regiment of the 1st Czechoslovak Composite Aviation Division was later equipped with the La-7 after participating in the Slovak National Uprising of August–October 1944 with La-5FN. A total of 56 aircraft were delivered and equipped the 1st and 2nd Fighter Regiments. The bulk of the aircraft, however, were delivered in 1945 and saw no combat during  the war. It remained in service with the Czechoslovaks until 1950 and was designated postwar by them as the S-97. One of these aircraft survives in the Prague Aviation Museum, Kbely. Despite reports to the contrary, no La-7s were ever sold or transferred to the People's Republic of China or North Korea. Such reports arose from misidentification by Western pilots of the La-9s or La-11s that were given to those countries. The British test pilot, Eric Brown, was given the chance to fly an La-7 at the former "Erprobungsstelle Tarnewitz" Luftwaffe aircraft test station on the Baltic coast, shortly  after the German surrender in May 1945. He described the handling and performance as "quite superb", but the armament and sights were "below par", the "wooden construction would have withstood little combat punishment" and the instrumentation was "appallingly basic". Production of the La-7 amounted to 5,753 aircraft, plus 584 La-7UTI trainers. Those aircraft still in service after the end of the war were given the NATO reporting name Fin. The follow-up model, the La-9, despite its outward similarity, was a completely new design. Tactical significance. The La-7 ended the superiority in vertical maneuverability that the Messerschmitt Bf 109G  had previously enjoyed over other Soviet fighters. Furthermore, it was fast enough at low altitudes to catch, albeit with some difficulties, Focke-Wulf Fw 190 fighter-bombers that attacked Soviet units on the frontlines and immediately returned to German-controlled airspace at full speed. The Yakovlev Yak-3 and the Yakovlev Yak-9U with the Klimov VK-107 engine lacked a large enough margin of speed to overtake the German raiders. 115 La-7s were lost in air combat, only half the number of Yak-3s. According to VVS-KA records, only 3 La-7s were actually shot down in air combat in all of 1944  and a mere 10 fell victim to anti-aircraft fire with a further 23 due to non-combat cause. Losses to air combat in 1945 stand at 79 in total, with 115 overall. However, aircraft that went missing (not returning) or lost to wear are not included, e.g. 24 additional La-7s went missing in 1944. However, the total VVS-KA record loss may not give a true picture of combat losses, as combat losses were often claimed as non-combat losses either to conceal losses or for propaganda purposes. Surviving aircraft. Czech Republic Russia