janneh,
La-7 is basically a cleaned up version of the La-5FN. Top of nose is smooth, moving oil cooler to one of the wing roots. Wing spars made of duraluminum to save weight. Engine is same, but aerodynamic refinement and reduced weight make for a much better power loading and reduced frictional drag. La-7 was about 10mph(16kph) faster than La-5FN, but had noticably better energy retention, as well as better acceleration (could catch up with a Fw 190A in a dive). I'm assuming (hoping) that AH La-7 will have optional loadout of three B-20 20mm cannons in nose with 450 rounds total. However, normal armament was same as La-5FN. B-20 had same performance as ShVAK, but was lighter and more compact.
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leonid, aka grisha
129 IAP VVS RKKA