Messerschmitt Bf.109F, German Users - part five

The whole wing was redesigned, being the most notorious change the quasi-elliptical wingtip shape and the reduction of the wing area to 16.05 square meters (172.76 square feets). Other features of the redesigned wings included new leading edge slats, which were shorter but had a slightly increased chord plus a new removable wingtip that changed the planview of the wings and increased the span slightly over that of the E series. Ailerons were also replaced with Frise-type ones. The 2R1 profile with a thickness-to-chord ratio of 14.2% at the root reducing to 11.35% at the last rib. Just like before, dihedral was 6.53º.
Wing radiators were shallower and set farther back on the wing. A new cooling system was also introduced which was automatically regulated by a thermostat with interconnected variable position inlet and outlet flaps that would balance the lowest drag possible with the most efficient cooling. A new radiator shallower but wider than the one of the E-model was developed. A boundary layer duct allowed a continuous airflow to pass through the airfoil above the radiator ducting and exit from the trailing edge of the upper split flap. Lower split flap was mechanically connected to the main flap while both the upper and forward ones were regulated via a thermostatic valve which automatically positioned the flaps for maximum cooling efectiveness. New "cutoff" valves were introduced in 1941 which allowed the pilot to shut down either wing raditor in the case of one was damaged, allowing that way the remaining coolant to be preserved and allow the damaged aircraft to return to its base. However, those valves were delivered to the frontlines as kits, the number of which, for not known reasons, was limited. Anyway, those valves were the standard ones for the next G and K variants.

Sources:
1. https://en.wikipedia.org/wiki/Messerschmitt_Bf_109_variants#Bf_109F
2. Salamander Books - The Complete Book of Fighters
3. Signal Squadron - Aircraft In action 57 - Messerschmitt Bf-109 in Action Pt.2
4. Osprey - Air Vanguard 23 - Messerschmitt Bf 109 E-F series(1)