Lavochkin La-5 In Soviet Service. Part two.

 

The Lavochkin La-5F got its name from the ASh-82F engine, where the letter 'F' stands for 'boosted' in Russian. This engine , initially denominated as ASh-82A, was considered as an interim powerplant for the La-5 as it was considered as 'immature' as it suffered from overheating, so attempts to fix that problem, resulted in the ASh-82F. 
The new radial engine yielded better theoretical results than its predecessor, so the first ASh-82F-equipped La-5 rolled out from the factories in December 1942, as some very late production La-5s were fitted with the new ASh-82F engine. 
The La-5F, however, had many more characteristics apart from the new engine. It had an entirely new canopy design which allowed for a 360º view (something that the La-5 lacked) with its subsequent cut in the rear fuselage decking.
The cockpit was equipped with a 66 mm (2.5 inch) thick armoured glass panel to protect pilot's head and shoulders. The windscreen was also redesigned to include a horizontal frame on top. This change was initially made in the La-5 in order to include a 55 mm (2.1 inch) thick armoured glass panel. A rear view mirror was also added, however most of the pilots removed it. 
The La-5F was equipped with a better gun-aiming system, better cockpit ventilation and, although the initial batches were equipped with the same radio system the La-5 had, the radio system was also improved gradually with the new batches, resulting in various antenna mast and aerials configurations throughout the manufacture process. 
The fuel tank arrangement was also revised in order to make the aircraft lighter, to match its performance to that of the German Messerschmitt Bf.109G.
The first La-5F rolled out from State Aircraft Factory 21 at Nizhny-Novgorod in March 1943 and in April one La-5F was tested at the Soviet Air Force's Scientific Research Institute in Sverdlovsk. Those tests showed that La-5F's top speed was only 10 km/h (6.2 mph) better than the one of the La-5 but it had much better climb rate. 
The La-5F served mainly with the Fighter Aviation Regiments (IAP for Russian terminology) of both the Soviet Air Force (VVS) in the Eastern Front, and the Fighter Aviation Regiments of the National Air Defence Forces (PVO). The units of the PVO were assigned to defend the aerial space of major Soviet cities and industrial centres. 
During World War 2, USAAF's 8th and 15th Air Forces carried out various ferry bombing raids against Germany from Soviet territory, the first of which took place on 2nd June 1944 when 128 Boeing B-17 bombers and their escort took off from Italy, bombed the railroad marshalling yards in Debrecen, Hungary and landed at Poltava and Myrhorod, in the Ukrainian SSR. The aerial escort over Soviet air space was provided by the 210th Fighter Aviation Division of the PVO, with most of its IAPs being equipped with the La-5F. 
On 21st June 1944 USAAF's 3rd Air Division bombed the synthetic oil plant at Ruhland, Germany, while enroute to Poltava. In retaliation the Luftwaffe attacked Poltava shortly after midnight with a force of eighty Junkers Ju.88 and Heinkel He.111 destroying fourty-four out of 72 B-17s and damaging the remaining ones. No Soviet fighters engaged the attacking force and this grew some tensions between the Americans and the Soviets about shuttle bombing operations, although they continued until September 1944.

Sources:

1st Signal Squadron - Aircraft In Action 169 - La5-7 Fighters in Action

2nd https://en.wikipedia.org/wiki/Lavochkin_La-5