While revisiting older postings of this blog on Facebook, we noticed something puzzling on the cowlings of Model 52 Hei or A6M5c Zeros.
From the Model 52 Ko (A6M5a) onwards it became standard practice to paint white stripes of 500mm length, 120~140mm on the port side of each machine gun trough to help with the synchronization of the guns.
In the Model 52 Otsu (A6M5b) a 13mm machine gun was installed on the starboard side of the cowling, and the synchronization white lines became as shown below.
But in the Model 52 Hei or A6M5c....here's what Wikipedia says about the type:
"A6M5c, Model 52δΈ™ (Hei, 52c) – Armament change: One 13.2 mm (.51 in) Type 3 machine gun was added in each wing outboard of the cannon, and the 7.7 mm gun on the left side of the cowl was deleted."
Francillon also mentions only "One 13.2 mm Type 3 machine-gun in the upper fuselage decking, two wing-mounted...".
ALL Japanese publications, without exception, agree with the above. The 7.7mm machine gun in the cowling was removed.
Nevertheless, in all the A6M5c photos in all Japanese publications, machine gun troughs can be seen on the starboard AND the port or "left" side of the cowling and, as we can see in the attached photos, they had rather long synchronization lines painted as well.
I could maybe understand using A6M5b cowlings but without having the machine gun trough faired over? And if there isn't a 7.7mm machine gun under the A6M5c cowling, why are there synchronization lines?
Did the A6M5c actually have two guns in the nose or one? Leave a comment if you know what's happening.
My guess...is that the synchronization mechanism was designed to synchronize TWO guns and therefore it's timing method still operated as if two guns were being fired??
ReplyDeleteQuestion: For earlier versions with two 7.7mm's did both guns stop firing when each prop blade was passing the section of the cowl between the two white lines/troughs?? (Stopping the guns just before left-side white line and letting them fire again just after the right-side line)
IIRC, synchronization reduced the rate of fire of the 7.7mm by over 40%, which is extremely bad for an already light caliber...
Any further info on the type of synchronizer used?? Thx!
Love this blog!
I agree with Dan.G, the standard A6M gun synchronizer calibration process may require timing off the two marks, even if only 1 gun is fitted.
ReplyDeleteCockpit photos of A6M5c/7 show no 7.7mm port gun. Note a 13.2mm port gun would have made it extremely hard for the pilot to get into his seat as the 13.2mm gun breech extends into the cockpit (as seen in the starboard 13.2mm fitment!).