The Vault

Vintage Saturday: Wingshooting

Russian DA-2 aircraft dual-mount machine guns

Very good guns. Not so sure about that landing gear.

The guns are aircraft Degtyarevs (DA-2), and appear to not have the drums mounted when the photo was taken. Note the vane-type front sight, and the distinctive muzzle brakes.

22 comments to Vintage Saturday: Wingshooting

  • Paul C.

    The aircraft are TB-3 heavy bombers. Also used for paratroop drops (paratroopers slid off the wings!)

  • Chris Morton

    And those TB-3s were used through the start of Barbarossa, some of them carrying Polikarpov biplanes as parasitic fighter bombers. They were used to dive bomb some high value targets (mostly bridges) at the start of the war.

    • Speedy

      Actually, in final, combat-used TB-3 “aircraft carriers” (called Zveno) they used Polikarpov I-16 monoplanes. More precisely, it was I-16SPB (Skorostnyi Pikiruyushchij Bombardirowshchyk – Fast Dive Bomber) with 2×250 kg bombs. But in previous versions of Zveno, Russians experimented with other planes, including I-5 biplane fighters. http://en.wikipedia.org/wiki/Zveno_project

  • Earl Liew

    There is in existence a quite well-known black-and-white photograph taken of a TB-3 in three-quarters plan view as seen from the starboard side that demonstrates the drop technique Paul C. mentioned. The TB-3 was originally designed by the Antonov Bureau and was also known as the ANT-6. It had very clean aerodynamic lines, and was of basic all-metal construction. The fixed landing gear on the ANT-6/TB-3 may appear primitive at first glance, but it was enormously strong and enabled the bomber to operate reliably from unprepared airfields.

    It was in Russia that the much-heralded 1920′s air war theory of the “aerial battleship” (a giant aircraft with long range and a heavy bomb load, and with negligible performance but which relied on multiple machine gun positions to provide all-round protection against enemy fighters) actually first came to fruition in the form of the ANT-4 (TB-1) and later the ANT-6. The concept had its roots in 1914 at the beginning of World War One when the Imperial Russian Air Service fielded a very effective force (the E.V.K.) of four-engined Ilya Mourometz bombers under the able leadership of Major-General M.V. Shidlovski. The civil predecessor of the Ilya Mourometz, designed and developed by Igor I. Sikorski (yes, THAT Igor Sikorski) was the world’s first four-engined aircraft, and boasted such unheard-of refinements as a fully-enclosed crew cabin when it first flew on May 13th, 1913. The I.M., built by the R.B.V.Z., was basically a re-designed, enlarged and upgraded militarized descendant of this prototype machine, and later marks followed a constant upward trend in size, range, payload, general performance, armor and armament as they were constructed in small production batches.

    It was not long before Germany, Great Britain and Italy followed suit in establishing long-range heavy bomber units, thus furthering a new dimension to the air war.

    It is said that the Soviet Union had about one thousand ANT-4′s and ANT-6′s in service in the 1930′s, the largest — and practically the only — viable strategic bombing force in the world at the time.

  • Leszek Erenfeicht

    On the DA-2 this “2″ meant just a twin mount, not 2nd Model or anything like that. TB in TB-3 stood for Tyazhely Bombardirovshchik, or Heavy Bomber, but this aircraft was also known under the nickname “Tuberculosis” – the disease also used TB for short :-)
    DA was a specialized variant of the DT machine gun, with slightly pumped up ROF, but using the same receiver and drum – a 63 round three-tier spring loaded “compact” (at least compared to a DP single-tier) drum. The main difference between the DA and DT drum was a clever magazine catch release strap fitted to a DA drum. This was a simple scissor-type lever on the side of the drum, and when shooter inserted his open palm underneath the strap, and clenched a fist, the strap was lifted, tugging on the upper end of the scissor, prying with the lower end the magazine release slide back and thus freeing the magazine in one fluid motion without the shooter having to take a glove off (in harsh subzero temperatures high in the air) and pull the magazine release slide with his fingers, as you had to in a much more popular tank DT machine gun.
    The DAs and DA-2s were manufactured for a relatively short period of time, between 1929 and mid-1930s, when a fenomenal belt-fed ShKAS replaced them as an aerial weapon. The ShKAS was almost the same size and weight, but delivered unbelivable ROF – up to 1800 RPM from a single barrel, more than twice the rate of fire of the DA. Some aerial DT/DA drums with their tell-tale release gear and straps can be seen in WW2 photos of the DT in action, but a regular DT drum had neither the release gear nor strap.

  • Denny

    I am glad we are stepping into this area – aircraft weaponry. Here is link you may find interesting: gladhttp://www.ww2aircraft.net/forum/weapons-systems-tech/

    Soviet early air MGs and cannons are fascinating subject. Their designers created them out of nothing and in very short time; they were often without precedent, such as mentioned SKAS. This is not to take credit from others, of course.

  • Earl Liew

    Leszek brought up the subject of the ShKAS aircraft machine gun in a previous post — what a fascinating and incredibly functional and effective yet grossly under-rated weapon that was! The Soviet Air Force had realized very quickly that, owing to the almost-quantum leaps in aircraft development, performance, armor and armament that the Degtyarev aircraft guns would soon be left wanting, and F.V. Tokarev (also of Tokarev TT-33 pistol fame, among numerous other innovations) was asked to produce a suitable up-to-date replacement within a year. In a letter to the Director of Tula Arsenal, Tokarev pointed out, quite rightly, that with few exceptions, most cases of gun development could be advanced to the penultimate stage with reasonable speed and success but that it was the last stage of development that often negated or at least rendered very difficult the final resolution of the design. It took him three years to come up with his version of a rifle-caliber aircraft gun, and it proved a failure on almost every count when subjected to field testing.

    The Aviation Commission realized then that it would not be wise to expect designers of ground-based machine guns to produce a viable aircraft machine gun because they were too steeped in design principles that worked very well for the former, but not necessarily for the latter, which had very different requirements. The Commission began to search for fresh, unfettered ideas as the best approach and were astute enough to appoint Boris Shpitalny and Irinarkh Komaritsky to come up with a new gun. Shpitalny was a young and very innovative designer who had nevertheless served a fruitful apprenticeship that had taught him well, and Komaritsky had a solid mechanical and manufacturing technology background. In other words, they were the perfectly-balanced “dream team” for the task at hand.

    The end result was the ShKAS gas-operated aircraft machine gun, approved for service in July 1932. It was chambered in 7.62mm x 54R and was capable of reliably producing a cyclic rate of fire of 1800-2000 rds./min. from a single barrel. All this was due in no small part to the very smooth rotary feed system (revolving drum) on the gun, which alleviated the usual abrupt withdrawal of a cartridge in the feed belt by the claw as well as the stop-start shocks of the belt as it was indexed forward. In the end, the withdrawal of the cartridge was spread over ten operating cycles and this helped ensure minimal stress. Other than that, the ShKAS was a very conventional and relatively simple machine gun that was easily field-stripped and had no special maintenance requirements. It is a tribute to the genius of Shpitalny and Komaritsky that it worked so well yet needed no additional care in spite of its outstanding performance. “Elegant utilitarian simplicity” would be the phrase to most aptly describe the ShKAS. The only downsides to the design were accelerated barrel wear resulting in a barrel life of only 2000 rounds, later improved to 5000 rounds, and increased recoil forces that necessitated a re-design of existing observer’s and turret mountings.

    Incredibly, Shpitalny and Komaritsky came up in May 1937 with an even faster-firing Ultra-ShKAS with a cyclic rate of fire of 2800 rds./min. by adopting the forward-recoiling barrel design of the rival 7.62mm SN (Savin-Norov) machine gun, which itself generated 3000 rds./min. from its single barrel. Both weapons were used in the Russo-Finnish Winter War of 1939-1940 with a good degree of success, but the advances in stressed-skin all-metal airframe construction, self-sealing fuel tanks and armor were making it apparent that the future belonged to heavier-caliber weapons.

    There are so many interesting and successful Soviet aircraft machine gun and automatic cannon such as the previously-mentioned 7.62mm SN, 12.7mm Berezin, 20mm Shpitalny-Vladimirov (ShVAK), 23mm and 37mm Volkov-Yartsev (VYa), 23mm and 30mm Nudelman-Rikhter (NR), and 23mm, 37mm and 45mm Nudelman-Suranov (NS), to name a few. I think they would provide a fascinating array of topics that would go on for a very long time for Forgotten Weapons if we get a chance to pursue them.

    • Denny

      I am on same tune: the ShKAS was apparently a phenomenal design and 20mm ShVAK was its sound continuation. From what I read in source I mentioned previously, the 12.7mm Berezin was arguably the best aircraft gun of the war. It edged out even German MG-151. I am not sure what is availability of these guns on NA continent to see. When and if I travel in future to Europe I will try to visit museums which display actual samples. In meantime I search in every available literature. The WWII period was a peak of aircraft gun development, no doubt.

      • Earl Liew

        Thanks, Denny — It seems to me that if any of these weapons were actually present in North America, they would more than likely be housed at various Air Force or military bases as captured exhibits, which may or may not make them available for viewing. Also, I’m wondering if Leszek would know of some museums and armories in Eastern Europe that have these weapons available for public inspection, since he is intimately familiar with the region. If Ian and the gang are planning on traveling that way this year, it might be a good opportunity for everyone to share a unique experience together.

        In the meantime, I’ll keep an eye out for any leads on this topic.

        • Well, the one of these sorts of guns that I have actually seen in person is a ShKAS. I took some external photos of it, but didn’t have a chance to take it apart (or fire it). I’ve been doing some reading, though, and will be posting an article on it next week. I would love to find out more about all of the Russian aircraft guns, but I’m afraid that will have to wait until I can get over to Russia or elsewhere in Europe, as I don’t think there are many of then in the US.

          • R. Aballe

            Several Spanish military museums have in their collections all the Degtyarev variations (infantry, tank and aircraft versions, i.e. DP, DT and DA) and many ShKAS. Several of the later can be seen (and handled, I guess, with the due authorisations) at the main air force museum near Madrid, in Cuatro Vientos (Museo de Aeronáutica y Astronáutica , in its full name).
            The many military museus also house lots of rare weapons from the XX century, including many prototypes virtually unknown outside Spain, rare or seldom seen machine guns, submachine guns acquired by both sides during the Civil War and many other items that I am sure the readers of this blog would find fascinating.

        • Leszek Erenfeicht

          Sure, we got ShKAS here, in various stages of decay, unfortunately, but I think I can find a complete one to strip and photograph. Just let me return from the yearly hajj to the SHOT Show, OK? :-)

      • Earl Liew

        I was just thinking — Max Popenker would also probably know of various institutions that would house examples of these aircraft guns.

        • Denny

          Super idea Earl!
          Lets get activated Max (I hope he reads this) so he can join discussion and tell us more. There are museums in former SU where items of this kind are on display. Tony Williams also has good book on WWII aircraft armaments. I always wish to learn more. Thanks to Ian for starting the string!

    • Ian Hutchison

      Fascinating, do you know if any were ever used by ground forces? Perhaps in static defenses?

  • Earl Liew

    That’s a really good question, Ian — I haven’t yet come across any specific information indicating the adoption of these aircraft guns for ground-based use, although it is conceivable that the Soviets may have done so in the dark days of 1941-1943 when there were acute intermittent shortages of weapons and ammunition.

    However, there are several factors that would have mitigated against this, especially in the case of the ShKAS and SN. They were specifically designed for the air combat role, and using them in the ground role would have given rise to a host of real issues, namely :

    1. Lack of sufficient cooling (no airstream).

    2. Reduced reliability (ingestion of sand, dust and debris not present in aerial combat); the guns were designed and built to precise tolerances to make them accurate at very high rates of fire, ideal for air warfare but anathematic for a reliable battlefield weapon.

    3. Excessively high rate of fire unsuited to ground warfare, where a practical balance between ammunition consumption and effective weight of fire is more desirable.

    4. Special ammunition requirements. To function properly, these weapons used tighter-toleranced 7.62mm x 54R ammunition, which would have created yet another logistical headache.

    5. Insufficient durability. The weapons were designed to generate a very high volume of fire in relatively short engagements on the assumption that adeqaute maintenance intervals would be available, and not for prolonged exposure to the rigors of the battlefield where they would have been subject to every conceivable abuse and lack of regular maintenance. As noted before, the short barrel life would also have been a part of this problem.

    It is therefore unlikely that many aircraft guns would have seen any amount of ground service, although we should remember that the exigencies of war may occasionally have dictated otherwise.

    An intriguing side note on the topic of ShKAS ammunition is that Soviet snipers sometimes used “seconds”, rejected by quality control inspectors on the basis of tiny imperfections, in their Mosin-Nagant M91/30 PU rifles. The precise mechanical requirements of the ShKAS machine gun demanded that only the best high-end special ammunition be used, and anything that fell even minutely short of that standard was culled. Rather than waste otherwise perfectly good match-grade rounds that would work well in infantry weapons, the rejected ammunition was issued to the sniper units where the inherent accuracy could be used to advantage. Due to the different ballistic trajectory of the aircraft rounds, the end users would have had to make appropriate adjustments to sights and scopes when time permitted, or aimed off-center when it didn’t.

    For a start, there are some interesting articles and discussions on this subject at http://www.mosinnagant.net and forums.gunboards.com. From what I have read, there seems to be some debate as to whether or not the ShKAS cartridges are loaded to a higher pressure than standard ones, and whether it is safe to fire them from a rifle. Given that the Soviet Army regarded trained snipers as a high-value asset, it is doubtful that they would have risked issuing incompatible ammunition to the latter. Again, however, it is at least possible that the exigencies of war may sometimes have superceded safety.

    Among the many available articles on aircraft armament and equipment, an excellent one detailing the various combinations of 7.62mm ShKAS, 12.7mm UBS and UBK, and 20mm ShVAK installations in a typical Soviet Air Force fighter of the period, the MiG-3, can be viewed at mig3.sovietwarplanes.com. Some rare photographs and very good line drawings are included for viewing.

    If I come across any information on the use of Soviet aircraft guns in the ground role, I will post them on this site.

  • Paul

    Reading the posts above made me think about how much of this knowledge may have been distributed or at least inspired by Oleg Maddox’ great IL-2 Sturmovik flight simulator on the eastern front air war. I remember being very surprised by the effectiveness of the Soviet rifle caliber guns there and then reading more and more about them.

    IIRC there is a ShKAS at the Wehrtechnische Studiensammlung in Koblenz here in Germany (http://www.fahrzeuge-der-wehrmacht.de/Artikel/Koblenz_2010.html). The small arms are all behind glass though (a large collection of unsual items), unlike the large pieces. The place describes itself as a ‘research collection’ that is open to the public and not as a museum. I can really recommend it.

  • Brian

    What is the purpose of the “vane type” front sight? Does it move in the airstream to compensate for the lateral force of the airstream on the bullet?

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