Evidence and Theory Presented by Jim Long
The Zero's radio installations and its weapons systems were the features of the September 1974 installment of Koku-Fan's articles on the A6Ms. In that issue you can see the placement of the transmitter and receiver in the A6M2s. These are views that can be compared to the drawings of the A6M1 cockpit arrangements, as identified in Part Two.
Also included in the September issue are technical drawings of the 20mm wing cannon installation, the bomb-dropping equipment, and the 7.7mm machine guns. The drawings of the cowling-mounted machine guns are of particular interest in that they show the A6M1 layout. One can know that the drawings show the A6M1 by noticing the placement of the machine-gun interrupter gear on the engine and the look of the engine profile.
The three drawings at the top of page 189 illustrate the 7.7mm fixed machine gun mounting of the A6M1. Notice that the interrupter gear fixture is low on the right side of the rear part of the engine. Also notice that the engine is equipped with a downdraft carburetor. Only an outline of the engine's accessory section is shown, but it is enough to tell us that the engine has a downdraft carburetor. It is the item at the top that looks like the profile of a man looking toward the right - a man with a sharp nose, a heavy brow ridge, and a knot on the top of his flat head. Since no A6M2 ever had a downdraft induction system, this must be the back part of the Zuisei 13 of the A6M1s that we are looking at here.
If this isn't enough proof for you, let's have another look at the A6M2 handling manual as reproduced in Model Art Publication No. 323. Diagram No. 150, which spreads across pages 130 and 131, presents two of the three drawings that appeared in the Koku-Fan Monthly, except that these two have been updated to show the A6M2 installation as well as that of the A6M1. What the Mitsubishi company's draftsman did in that long-ago time in 1939 was to superimpose the A6M2 configuration upon the drawing of the A6M1 installation that already existed, thereby saving the time and the effort that would have been expended to create an all-new drawing just to illustrate a minor change. It was an appropriate expedient because the only features that had to be added were the outline of the Sakae 12's interrupter gear fittings and a short length of cabling.
By the way, the labeling on the drawing points out that the lower fitting and cable-run applied to the original installation and that the upper fitting and cabling applied to Airplane No. 3 and all after. This all makes perfect sense, since A6M Nos. 1 and 2 (the originals) were the two A6M1s and A6M No. 3 was the first A6M2, with the Sakae 12 engine.
If you have the Green Arrow book, you can get a direct view of the three A6M1 drawings. They are on page 102, but are inaccurately labeled as applying to the A6M2-A6M5.
If you have FAOW No. 5/1987-7, check page 44 to see a reproduction of a photocopy of the side and front views of the A6M1 and A6M2 cowl-mounted machine guns. These are the same drawings as the ones in the Model Art Publication No. 323, showing both installations on the same diagrams.
(No new references cited in this part.)
to Part IV