Messerschmitt Bf 109 G-6/U4

CONTROL STICK:

The Bf 109 G-6/U4 used a KG 13A (Knüppelgriff 13A) control stick. It had the Fl-number Fl 47915 (Gerät-Nr. 102-288A). 

Wiring diagram August '43

ARMAMENT:

The Bf 109 G-6/U4 was equipped with two fuselage mounted MG 131 13mm machine guns and one engine mounted MK 108 30mm cannon. Rüstsatz R6 offered the possibility to add one MG 151 20mm cannon underneath each wing.

ELECTRICAL WIRING DIAGRAM:

The electrical wiring diagram code for the control stick was the same as for the standard Bf 109 G-6 (click here to go to the Bf 109 G-6 article): ‘V23’.

Image from the Bf 109 G-6/U4 manual (August '43)

While the MG 131s were automatically charged when the safety switch in the round counter control box SZKK3 (Schuss-, Zähl- und Kontrol-Kasten 3) was toggled, the MK 108 cannon had to be manually charged. However, after take off the MK 108 was already charged and manually charging was only necessary in case of a gun jams. According to the wartime manual (dated August 1943) the MK 108 was charged via a small switch (see 'e' in image on the left and 'P301' in the image above) that was attached to the instrument panel. At the time the manual was prepared, it was envisaged to replace the switch by a button. The manual did not state where this button was to be located, but it was most likely attached directly to the control stick like seen on later Bf 109 G-10s.

BUTTONS:

A factory delivered KG 13A had three buttons used for weapons and one radio button. The top trigger was called A-Knopf (Knopf = button), the top center button was called B-Knopf (or also B1-Knopf) and the top left button was called B2-Knopf. Depending on the equipment the aircraft carried, additional buttons could be attached to the KG 13A control stick or the wiring was adjusted. The buttons in the Bf 109 G-6/U4 were used as follows:

Bf 109 G-6/U4 without Rüstsatz R6 (two wing-mounted MG 151 cannons):

A-Knopf: 2x MG 131 (fuselage mounted)

B1-Knopf: 1x MK 108 (engine mounted)
B2-Knopf: drop ordnance

When the Rüstsatz R6 was installed, it was originally planned to fire the MK 108 and MG 131s via the A-button and the wing mounted MG 151 cannons via the B1-button. However, a later added note in the manual stated that based on combat experience, the MK 108 should be fired via the B1-button and the wing mounted MG 151s together with the fuselage mounted MG 131s via the A-button:

Original scheme: Bf 109 G-6 with Rüstsatz R6 (two wing-mounted MG 151 cannons):

A-Knopf: 2x MG 131 (fuselage mounted) and 1x MK 108 (engine mounted)

B1-Knopf: 2x MG 151 (in wing pods)
B2-Knopf: drop ordnance

Revised scheme: Bf 109 G-6 with Rüstsatz R6 (two wing-mounted MG 151 cannons):

A-Knopf: 2x MG 131 (fuselage mounted) and 2x MG 151 (in wing pods)

B1-Knopf: 1x MK 108 (engine mounted)

B2-Knopf: drop ordnance

SOURCES:
L. Dv. T. 2109 G-6/U4/Wa. "Bf 109 G-6/U4. Schusswaffenanlage. Bedienungsvorschrift/Wa. (Stand Juli 1943) Ausgabe August 1943."