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Updated on June 4, 2023
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The most of MiG-3s were armed with three syncronized guns over the
nose:
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UBS 12.7
The Universal'ny Berezina Synkhronny (Universal
Berezin Syncronized) was developed since 1940 into four versions:
UB - multipurpose by Berezin, Universal'ny Berezina;
UBS - synchronized, Synkhronny;
UBK - wing mounted, Kryl'evoj;
UBT - or turret, Turel'nij;
The UBS fired the 12.7x108 mm round at a rate of 1000 rpm, at
a muzzle speed of 860 m/s; it weights 21.5 kg
It was an highly effective weapon.
ShKAS 7.62
The ShKAS, Shpitalny-Komaritski Aviatsionny Skorostrelnij
(Shpitalny-Komaritski rapid fire machine gun for aircraft)
was the standard 7,62 mm gun since 1935.
It fired the 7,62x54R round at a rate of 1800 rounds for minute, at
a muzzle speed of 825 m/s; the weapon weights 10 kg, and existed
both for fixed fighter installation and with handle for defensive installation.
This weapon was not too effective against bombers, fighters and armoured
vehicles because its lack of penetration into armoured plates.
Another shot of both weapons ( here the ShKAS has the handle for some defensive installation; by Lee Jong Tae).
Here are the gun firing slots on the nose of three-guns-armed MiG-3s. Note again the obliquely shaped protruding thermal sleeves. |
Here is a cutaway of the fuselage, giving a good idea of the armament and ammo
boxes mount.
There is one UBS machine gun on central position, and two ShKAS on its sides.
The UBS ammo box is in front of the front fuel tank; the cartridge case discharge
is on the left side.
The ShKAS ammo boxes are in oblique position, one for each side of the
aircraft. All the guns receive the ammunitions from the right side; for this
reason, the left ShKAS ammo box appears in a more internal position than the
right one, and the guns position is asymmetrical.
Metal wires pass from each gun to a handle on the instrument panel, to move
the gun breechblocks; these wires pass throught a curved firewall separing the
instrument panel from the guns bay.
Some thin levers between the engine and the guns should be for the syncronization
mechanism.
A shell expulsion slot was on the left side of the water cooler fairing.
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This good image shows some details of the gun bay:
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The image shows the nose of an early MiG-3; we recognize:
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The panel hold by the German soldier is from an early MiG-3; it goes
over the engine, not on the gun bay as it could seem from the photo above.
The same image shows:
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Here is a photo showing the inner face details of a side panel. The color looks slightly darker than the external face; it could be the same green of the exterior face (but not faded by sunlight), or dark grey A-14. The shape of internal structure of panels can be extrapolated, when not visible on photos, from the rivets lines visible on some good drawings. Photo copyright Jan Koennig
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From February 20, 1941, a new version with two further 12,7 mm
BK guns on under-wing pods with 145 rounds each
The new standard revealed itself unsatisfactory, as the weight increased
of about 150 kg, deteriorating the flight characteristics of the aircraft;
besides, the firing at high g manoeuvres was imprecise due to torsion flexing
of the wings, so the most of the gun pods were removed when the aircrafts
arrived at the units.
821 examples with 5 guns were produced through July 27, 1941, when the under-wing guns were deleted from production, and the armament returned to the original standard. The predisposition for under-wing guns pods (i.e., reptangular panels for ammo visible under the wings) seems to have remained on following aircrafts too, and it looks to have been suppressed only towards the end of MiG-3 production. |
Left:
this image shows an underwing pod, without the gun barrel protruding from it. We see the opened ammunition door too, and a distorted landing light panel. Some undercarriage structures appear distorted too. The aircraft is an early one, without slats. Note that the pods are painted separately from the wing. (image from Ian Konning) Below:
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315 late production examples were armed with 2 UBS with 700 rounds each,
instead of the usual armament. Here is an image of the internal arrangement. The ammo boxes were probably disposed on the lateral positions previously occupied by ShKAS, but moved rearwards as the original UBS and extended downwards into the space left free by remotion of the ShKAS ammo boxes.; both UBS should receive their rounds from the right side, and expell wasted cartridges on the left. What we see on the photo are probably wasted cartridges ducts. It is not clear if MiG-3s armed with two UBS were externally distinguishable from usual ones armed with three weapons; probably they weren't. |
About 50 late production MiG-3s were armed with a couple of ShVAK 20
mm guns; their general layout can be supposed as for the 2 UBS armed aircrafts.
The ShVAK gun was designed and first built in 1936, and utilized an
operating system similar to that of earlier ShKAS.
Rate of fire: about 800 rounds for minute
Weight: 42 kg
Overall lenght: 1,76 m
Barrel lenght: 1,25 m