TKS reconnaissance tank with 20 mm FK-A wz. 38

Thanks to the newly created replica of the TKS tank with the NKM, today we can admire the most advanced version of the Polish reconnaissance tank during various historical reconstructions.

Attempts to arm the TK-3 and later TKS tanks with weapons of greater caliber than the Hotchkiss wz. 25 were launched in 1931. The initial intended use of the 13,2 mm Nkm Hotchkiss reconnaissance tanks ended in a fiasco, mainly due to too much dispersion and completely unsatisfactory armor penetration.

In addition to the actual technical and ballistic studies, organizational issues were also intensively considered. For example, on February 20, 1932, in the Directorate of Armored Weapons (DowBrPanc.) under the project "Organization of armored weapons at a combat level", where TK-3 tanks were also mentioned, it was indicated that each company should include at least 2 3 vehicles, armed with anti-tank guns that allow you to fight enemy tanks. The question remained open whether this type of vehicle should be given to the unit commander, should it be given to platoons with vehicles with larger caliber weapons, and if so, in what quantity?

Unknown repository of Polish equipment. The TK-3 tanks bear the characteristic, though still unrecognizable, emblem of an armored squadron/battalion.

Solothurn

After leaving Hotchkiss, they turned to the products of the Swiss Solohturn, as a result of which, in June 1935, the only 100-mm Solothurn S.18 (S100-20) was purchased, which at that time was one of the most modern design guns in its class. The gun was placed in the classic spherical traverse, and then in the cardan traverse of the TKS tank. During the first ground tests, it was found that the weapon was overly sensitive to contamination that caused jamming, which, in turn, could not be quickly eliminated due to the cramped reconnaissance tanks.

The gun in question was installed on the TKS tank at the turn of 1935/36, and in February 1936 the first ground tests of the vehicle were organized using a somewhat improvised version of the yoke. Known to history lovers, the characteristic semicircular rocker was developed by Eng. Jerzy Napierkowski won't show up until the end of this year. Equipment tests took place mainly at the Rembert military training ground.

For example, the vertical spread "n.kb. The repeated "Solothurn" was tested by firing at the Infantry Training Center (CWPiech.) in May 1936, but by firing from an infantry base. The result obtained at a distance of 500 m was: 0,63 m (height) and 0,75 m (width). To establish accuracy, a target depicting the silhouette of a TK tank was fired at at a speed of 12 km / h. along an oblique line to the position of the heaviest machine gun. The result was considered good, with an average of 36% of hits when shooting from different distances.

The practical rate of fire against moving targets was only 4 rds / min, which was considered a completely insufficient result. According to the commission's calculations, 4-6 accurate shots should be expected in the case of firing at a target initially 1000 m away and approaching the gun position at a speed of 15-20 km/h. At the same time, it was found that: When firing from n.kb. repetition from the TK (TKS) tank due to the difficulty of observation and the need to shoot sometimes on the move - the effectiveness of the fire will be even lower.

In terms of armor penetration, the Polish military members of the experimental commission noted that with the use of light armor-piercing shells it is possible to penetrate armor of increased resistance, 20 mm thick, from a distance of 200 m with a 0 ° hit. The general comments of our servicemen on the weapons already placed in the car were: N.kb. Solothurn, placed in the TKS tank, due to lack of space, requires considerable effort to manually retract the bolt mechanism; in addition, the breech and the weapon as a whole are susceptible to contamination, causing a number of jams. It is possible that the same ailments may occur in more modern weapons of this type. Compared to more modern guns of this type, the 20 mm n.kb. Solothurn now has a lower rate of fire and muzzle velocity, resulting in a slower

armor penetration.

In the next part of the article about tests with foreign nkm/n.kb. the so-called machine gun n. km Solothurn. We don't know exactly when the automatic version of the weapon came to Poland, although it was undoubtedly purchased by the Polish army and was not the subject of a loan or even a series of demonstrations. It is also known that both copies were tested in parallel since May 1936 at the infantry base intended for them. Vertical dispersion when firing at a distance of 500 m was significantly greater than that of a single-shot weapon. For a single fire, the area is 1,65 x 1,31 m, for continuous fire, only three of them hit a target measuring 15 x 2 m 2 with shells, and these were the first shots of the series. It was decided that the single shot model was better in single fire, while the automatic model was described as "completely inaccurate", and the evaluation did not even improve the rate of fire at the level of 200 rounds / min.

In terms of armor penetration, it was found that it is higher for the n.km (machine gun) than for the n.kb (single shot), but only when using solid shells. However, with the use of light armor-piercing ammunition, worse results were achieved than with n.kb. Practical rate of fire 200 rds / min. So the final opinion on the weapons in question was crushing: (...) n.km. Solothurn, due to inaccuracies and ailments (jamming when loading), does not correspond to the tasks of armored weapons.

Following the adaptation of the tank (collar) to the Swiss NKM is the bill 1261/89 of May 18, 1936, concerning the order issued at the very beginning of the year. From this one-page document, we learn that the Experimental Workshops PZInż. F-1, for PLN 185,74, completed the modification of the tank casing for the NKM "Solothurn" at the direction of representatives of the design and engineering department of BBTechBrPanc. On February 7, 1936, a protocol was drawn up at the Bureau of Technical Research of Armored Armaments on the inspection and testing of the 20-mm NKM "Solothurn" mounted on the TKS tank.

The document states that test firing from weapons took place on February 5 at the training ground of the Center for Ballistic Research (CIBAL) in Zelonka in difficult weather conditions (fog, fairly strong wind, the shooting area was overgrown with shrubs). The studies used a short sight, which was adjusted after the first shot to improve shooting results. The maximum deflection angle of the weapon is set - 0° to the right and 12° to the left. It is interesting that the decrease in the firing angle of the gun was affected not by its installation, but by the gunner's tight clothing (sheepskin coat), which

he restricted his movements.

The commission came to the conclusion that the accuracy of the weapons installed on the TKS tanks is very good. The only drawback was the location of the machine gun in such a way that it was impossible to tilt the weapon to the right. Results obtained during testing at CBBal. they were also better than previous CWPiech firing (shooting from an infantry base with less stiffness than a tracked vehicle). From the documents it is known that in February 1937, work was carried out simultaneously to install the Solothurn machine gun on old TK (TK-3) tanks. Equipping old vehicles of the TK NKM family is a rather extensive issue that requires a separate discussion, in addition to the history of the TKS tanks.

Oerlikon

Machine guns of the 20 mm caliber of the French company Oerlikon appeared in Poland as early as 1931, when the NKM of this company was tested at the Rembert training ground along with the 47-mm cannon of the Pochisk company. However, the test results did not satisfy the National Experimental Commission. In 1934 during the July trials at CW Piech. The JLAS model was tested. When firing in short bursts at a distance of 1580 m, the dispersion was 58,5 m (depth) and 1,75 m (width), when firing single shots, the result was more than twice as good. The overall accuracy of the weapon was considered good if fired in single or short bursts, the practical rate of fire was up to 120 rounds / min.

Due to the short period of training in Poland, no information was collected on penetration and ailments, and the weapons were returned to the Oerlikon factory. The JLAS model was described as quite heavy, not meeting the requirements of the Polish army in terms of parameters. At the same time, however, it was noted that this type should be taken into account, subject to the availability of its more modern version.

October 26, 1936 DowBr Panc. and BBTechBrpanc. announced its intention to purchase one Oerlikon 20 mm automatic anti-tank rifle with the necessary ammunition (letter L.dz.3204/Tjn. Studia/36). The reason for the expected deal, indicated in the letter, was the desire to compare the weapon in question with the already well-known Swiss-made MGM. The test sample was to be installed in the TKS tank and tested for “superiority over a similar design bureau. Solothurn. November 7, DepUzbr. reported to the Armored Weapons Command that DowBrPanc indicated. the weapon did not pass all factory tests, so it is not possible to confirm the catalog data. In this situation, while waiting for information about the completion of firearms testing by the manufacturer, its purchase was considered premature.

It should be noted that information about the superiority of the Swiss Oerlikon over Solothurn was given in his memo dated October 24, 1936 by the head of the Independent Research and Testing Department. Shistovsky, who, on a business trip, met the director of the Oerlikon plant in Bern. The gentleman had to declare that the initial speed of the projectile produced by his company was to be 750 m / s and that the finished product would be submitted for testing no later than December 1, 1936. The technique was supposed to gain an advantage over competitors due to the greater penetrating power and accuracy caused by the newer base. Rtm Szystowski also received information on prices, which gave him another field to compare the weapons on offer. Solothurn cost about $13. Swiss francs, and Oerlikon about 20 thousand, although a company representative called the indicated cost approximate. We add that in the period under review, the ratio of the Swiss franc to the zloty was at the level of 1:1,6.

In his note, the Polish officer stated: “Due to the fact that our aviation purchased a 20-mm cannon from Oerlikon for placement on gliders and that in about a month these sections were to be assembled in Switzerland, it would be advisable to be interested in this new type of kb. p-panc. Orlikon in terms of placement on the TK-S tank.

and even adopting it as infantry or cavalry equipment. (…) If there was a new CCP. Oerlikon turned out to be better than Solothurn and its price was not excessive for the purchase of this KB. The fact is that the 20 mm Oerlikon cannon was purchased for aviation and the ammunition of 20 mm cannons for the KB. 20mm are the same.

As you can see, the issue of large-caliber weapons for reconnaissance tanks went far beyond the scope of armored weapons proper and to some extent depended on political decisions, and not strictly technical or military ones.

In the context of the use of Polish armored vehicles of the design under discussion, a lot is said in the DowBrPanc magazine. dated November 16, 1936: “20 mm kb. Semiautomatic (automatic) "Oerlikon" (L.dz.3386.Tjn. Studia.36), in which Lieutenant Colonel Dipl. Stanislav Kopansky states that he is only interested in the weapon in question if it turns out to be better than the already known KB armored personnel carriers. Solothurn. A summary of efforts to equip armored weapons with the heaviest Western machine guns is the document "Expansion of armored weapons", prepared for discussion by the Committee on Arms and Equipment (KSVT).

In a document from 1936, the Solothurn model was indicated as the closest to Polish needs, estimated at one third of all available tanks of the TK family. However, this position was taken even before the appearance of the new Oerlikon model, which in the end proved to be no better than the weapon proposed by Solothurn. The conclusions of the tests carried out confirmed that the tank as a platform performs its task much better than the classic tricycle base, guaranteeing stability and accuracy of fire. The initial sight turned out to be insufficient, so almost immediately attempts were made to develop their own design, which will be discussed below.

It was further stated that: Kb. Solothurn is an anti-tank weapon. effective against scout tanks, light tanks and armored cars, and even against medium tanks. Piercing tests carried out at CWPIech. in Rembertov showed permeability at the level of catalog data and even higher. We are talking about breaking through a 25-mm plate from 500 m, which was characterized as typical armor for medium tanks.

The estimates given in the article determined the cost of re-equipping one third of the KT vehicles with weapons of this type at PLN 4-4,5 million. This number should have included 125 nmi, ammunition for 2 years of training, ammunition for 100 days of hostilities, as well as significant parts and accessories. As the coming years will show, the calculations prepared for the KSUS will be very optimistic.

Used

On November 6, 1936, the Institute of Weapons Technology (ITU) called on all parties concerned to agree on the requirements that the heaviest Polish machine gun must meet. Although work on the domestic model was already being carried out by the Warsaw Rifle Plant, the possibility of purchasing abroad was still considered. Of course, in both cases, the most important thing was to reconcile two entities that clearly differed in expectations, i.e. armored vehicles and aviation.

The requirements for armament, which is designed to arm reconnaissance tanks TK-3/TKS, include:

• • food from the magazine for 8-10 rounds,
  • single and continuous fire,
  • the total length of the weapon is not more than 1800 mm, the length from the axis of rotation to the hand of the shooter is 880-900 mm,
  • pistol grip and method of gripping weapons like Solothurn NKM,
  • the possibility of replacing the barrel in the field,
  • removal of the store to the butt of the weapon,

In February 1937, head of BBTechBrPanc. Patrick O'Brien de Lacey and DowBrPanc. Colonel Józef Kočvara stated in a joint report for KSUS that none of the respondents so far n.kb. and n.km. did not fully meet the requirements of the Polish Army. It was considered necessary to get acquainted with newer designs, indicating, in addition to the already well-known Swiss Oerlikon, also such giants as the French Hispano-Suiza (20-23 mm) or Hotchkiss (25 mm) and the Danish Madsen (20 mm). plants.

Interestingly, the 25 mm Bofors gun tested on the Vistula River was not mentioned here, considering the gun probably too large to fit in the small TK/TKS hull. The aforementioned officers called for companies of officer commissions to be sent to the aforementioned to familiarize themselves with new models of weapons, participate in firing and prepare detailed reports upon their return.

It was expected that the final completion of the work would take place by January 1, 1938, after which the most suitable weapons for the Polish Army would be selected and purchased. On the basis of already existing experience, the requirements for the future Polish NKM were detailed. The “machine” nature of the weapon should be specially emphasized, since options characterized only by a single fire did not enjoy special approval at that time. The following requirements are imposed on the NKM tanker:

• maximum weapon weight 45 kg (initially 40-60 kg);
• air-cooled guns with an easily dismantled/replaced barrel;
• three types of ammunition (conventional armor-piercing, tracer armor-piercing and light armor-piercing ammunition), with the proviso that the shells after breaking through the sheets must be fragmentation (explosion and spatter on the inside of the plate);
• practical rate of fire up to 200-300 rounds per minute, mainly due to the small amount of ammunition carried in the tank;
• the possibility of single fire, series of 3-5 shots and automatic, it is necessary to use a double trigger;
• the desired initial speed is greater than 850 m/s;
• the ability to penetrate 25 mm armor plates at an angle of 30 ° (subsequently modified to 20 mm armor plates at an angle of 30 ° from 200 m); the ability to conduct effective fire on armored vehicles

  from a distance of 800 m;

• overall length, as short as possible due to the tightness of the tank. The distance from the axis of rotation of the fork to the end of the stock should not exceed 900 mm;
• weapon loading: suitable for a place in a TK and TKS tank, not desirable in advance;
• reliability in operation, the ability to protect the shutter from contamination and reload weapons without effort;

exterior design that provides easy assembly of the sight and convenient installation of the weapon in the bracket.

As a result of the work of the commission, one NKM "Madsen" was purchased, and work on its own design was continued by the Polish Rifle Plant. At the same time, due to the high rate of fire, the Air Force purchased the Hispano-Suiza NKM. Unfortunately, due to the fact that purchases were made with the erroneous assumption that one model of weapons could satisfy the needs of infantry, armored weapons and aviation, things began to get complicated very quickly, and the previously agreed deadlines were postponed. Paradoxically, the delays became an additional accelerator of the work carried out in the country since the first half of 1937, and an opportunity for the development of the NKM FK-A in the country.

Despite the innovative nature of the task undertaken by Eng. Bolesław Jurek, his nkm, unexpectedly quickly gained favor with pancerniaków from DowBrPanc. The weapon, although underdeveloped and in need of improvement, had a number of major advantages, one of which was the penetration of armor plates of a certain thickness at distances 200 m longer than similar foreign models. The prototype of the Polish NKM was completed in November 1937 and sent for testing. The history of the Polish 20-mm MGM is inextricably linked with the fate of reconnaissance tanks, but this article is not about the fate of the gun itself.

Therefore, it should be briefly pointed out that the intensive testing of the Polish NCM, which lasted from March to May 1938, was summed up in the ITU report of June 21, which was supposed to finally decide the fate of the FCM in version A. NKM for testing. The first actual order for 14 copies of the new weapon was placed by the Arms Supply Department (KZU; No. 100 / i.e. / Armor 84-38) in July 39, with delivery dates for the 1938th batch for May next year. . The second hundred, ordered in July 1939, were to be delivered to the army no later than the last days of May 1940.

As for the use of weapons in TK tanks, it was again found that the Polish model is better suited for this purpose than foreign models, as it meets a number of WP requirements for mounting optics, trigger and yoke shape. The undoubted advantage of the weapon was the ability to replace the barrel without disassembling the entire NKM in front. The breech block worked much easier than in foreign analogues, and the disassembly and cleaning of the weapon (even when it was completely removed from the tank) did not constitute big problems for the service. In terms of fire efficiency, the results of range shooting showed that, on average, every third shot from a tank gun is accurate, even when firing at a moving object (short bursts/single fire).

Another partially identified TKS tank with the heaviest machine gun, photographed several times in one of the farms where the German armored unit is deployed.

We add that for each of the heaviest machine guns manufactured by FK in July 1938, a set of five 5-round magazines was initially ordered, while 4- and 15-round (cartridge) versions were also allowed for testing. Contrary to the information of even some modern authors, the new version of the TKS with NKM was equipped with 16, and not 15, stores for five rounds. In total, therefore, the tank carried 80 shots, half of the approved ammunition load. The monthly ammunition subsidy was to be 5000 rounds for the FK-A tanker. For comparison, we recall that the 4TR tank, conceived as the successor to the TKS, was supposed to contain a stock of 200-250 shots. The price of the cartridge was high and amounted to 15 zł. For comparison: 37 mm Bofors wz. 36 costs about 30 PLN. Due to the large dimensions of the weapon, the ammo rack located behind the driver's seat was removed, which was moved back.

The placement of ammunition inside the modernized two-man tank was completely dictated by the prevailing tightness and, according to the author's conclusions, was as follows: 2 stores in four slots on the right side of the fender inside the tank, 9 stores at the rear on the right side on an inclined superstructure plate, 1 store on the left side on sloping superstructure deck and 1 stores in three slots between the engine and gearbox and gunner's seat.