The drop tanks of the 109F through K

Because of the range problems experienced by the E versions during the Battle of Britain, Messerschmitt included the drop tank provision on all 109F-K series.

All planes had 4 belly hardpoints. These hardpoints were naturally perfectly centered and when a bomb rack was installed, it was in the middle.

For the drop tank, things are different. While the rack itself is mounted centered, its 4 stabilizing arms are offset to the left. This was needed to allow the fuel lines from the fuselage to match those of the tank. Seen from below, the fuel lines connections are offset. The fairing covering the drop tank rack is offset on the rack.

Notice how the fairing is centered but the arms offset. The rack release system (a) is in place. Rack locks (c,b) can be accessed from the holes

Picture showing how the retaining strap locks into the rack release system (e). See also fuel line (a) and pressurization line (b)

So, the support is mounted at the center but the arms are offset. The tank is then installed in the center of the arms, therefore it is offset too.

Hardpoints : Centered
Fairing :Offset
Rack : Centered
Support arms : Offset
Drop tank : Offset

You can see below the overall fuel system when the drop tank is in place :

Drop tanks

Currently, 3 types of drop tanks have been identified on the 109 :

Regular 300L with rings (see photo "Abb. 7" above). This tank existed in few variations (With or without pressurization intake, Flat or rounded underside). The pointed tip was made of fabric mixed with glue and it was very often lost in operation
Tear drop 300L made of 2 halves welded. No pressurization apparatus, seen from 1944 onward (Similar to that shown in "Abb. 8")
Cylinder pointed tip tank (200L ?) quite rare