Vet Souvenir: Bf 109 K-4 Instrument Panel
This rare original main instrument panel of a Messerschmitt Bf 109 K-4 currently for sale by Warpath Militaria. A US soldier brought it back to the US as a souvenir. He most likely found it near a final assembly line. Presumably, this panel had not yet been installed in an aircraft but was waiting to be installed. Below is a photo of such a final assembly line with several instrument panels in crates (see lower left corner) next to Bf 109 K-4s that were almost completely assembled.
The instrument panel of the Messerschmitt Bf 109 K-4 consists out of the Main Instrument Panel (made out of plywood with a thickness of 15 mm, roughly 1 mm per layer), the Blind Flying Panel (made out of plywood with a thickness of 8 mm, 7 layers), the so-called Geraetebretttraeger (mounting bracket for main panel), and (if the Retrofit R1 was used) the Auxiliary Panel for the ZSK244 bomb switch box which was attached to the lower center of the main panel. The panel shown above was sold by Warpath Militaria and consists of the main and blind flying panel.
The Blind Flying Panel Fl 22000-1, which carried delicate instruments like the air speed indicator, altimeter, etc. was attached to the Main Panel with four rubber shock mounts. The Main Instrument Panel was attached with hexagonal screws (M6x58, LgN14180.1) to the Geraetebretttraeger which itself was fixed to the windshield assembly.
he Geraetebrett carried not only the main instrument panel but also control instruments for the armament, a pressure gauge for the MW50 equipment (or the clock, respectively), and the Revi 16B gunsight mounting. Critical values on instruments were distinguished with red markings applied directly onto the front glass of the instrument or by means of adjustable markers inside the instruments.
The following sections describe each instrument of the Me 109 K-4 instrument panel. The Anforderungszeichen Fl (instrument code for flight equipment) and the designations for the electrical system are highlighted.
AIR SPEED INDICATOR Fl 22234: The air speed indicator (Fahrtmesser; 100 to 900 km/h) was mounted on the upper left side of the Blind Flying Panel. It was connected to the static as well as dynamic air pressure flexible tube (see figure below). The pitot tube was installed in the left wing tip (in flight direction). The indicated air speed usually did not exactly match the true air speed since the dynamic pressure was not only dependent on air speed but also on air density. The air speed indicator was designed for low altitudes. Hence the error increased with increasing altitude. Therefore the maximum allowed indicated air speed decreased with increasing altitude. The speed limits for different altitudes were indicated with red markings on the instrument front glass (at 400, 500, 600, 700 and 800 km/h for the maximum allowed air speed in 11, 9, 7, 5, and 3 kilometers altitude).
RATE OF CLIMB INDICATOR 22386: The rate of climb indicator (Variometer) was mounted on the upper right side of the Blind Flying Panel. It had a measurement range of +/- 30 m/s and was connected to the static pressure flexible tube and to the compensation container (see figure below). There existed three major types of dials with a slightly different font type. Early ones had only 10-20-30 m/s on the dial compared to later ones with 5-10-20-30 m/s. Some of the indicators had a bulge on the lower side which usually was used for adjusting the pointer in e.g. altimeters. However, all of the rate of climb indicators with this bulge I have seen so far did not have the possibility for adjusting the pointer.
COMBINED ARTIFICAL HORIZON / TURN & BANK INDICATOR Fl 22410, 22411, 22415: The combined artificial horizon and turn & band indicator (Wendehorizont) 1L104 was used for indicating the position of the aircraft with regard to the horizon. It was mounted in the top center of the Blind Flying Panel. The Wendehorizont was driven by a converter, which was attached to the left fuselage side behind the instrument panel. The original spare parts list mentions a Fl 22410. However, all of the three above mentioned types were used (late war fighters usually had a Fl 22411 or Fl 22415). Note that in this panel, the horizon had not yet been installed.
ALTIMETER Fl 22322 or Fl 22320: The standart altimeter for late war Luftwaffe fighters was the Fein- und Grobhoehenmesser Fl 22322 (maximum altitude 13km) or Fl 22320 (maximum altitude 10km) with one pointer for meters and one for kilometers. Interestingly, in the panel shown in this article, a Grobhoehenmesser Fl 22316-10 (maximum altitude 10km) is installed with only one pointer for kilometers. The altimeter was mounted on the lower left side of the Blind Flying Panel below the air speed indicator. It was connected with the static pressure flexible tube.
REMOTE INDICATING COMPASS Fl 23334: The remote indicating compass (Fuehrertochterkompass FT / f2; Geraete-Nr. 127-113 A-2) 1L101 was mounted on the lower center of the Blind Flying Panel. It received the input signals from the main compass (Mutterkompass) mounted in the rear fuselage. There existed different types of this compass. Some had a grey casing, some black. Early types had riveted data plates whereas later ones just had a white imprint. Some of the panels received the latest version of the compass (FT / f8; 127-659 A) with a much shorter casing made out of some kind of plastic. It had a rectangular front and the airplane symbol had just a white outline and was not filled white (some of the FT / f2 had this feature as well). Note that the compass had not yet been installed in this panel. Most likely that would have happened only after it were installed in an aircraft.
To be continued …
[a]: Ed Hicks, warpathmilitaria.com
[b]: Wartime aircraft manual Bf 109 K-4