The Spanish Civil War began on July 17th, 1936. By the end of the month, the rebels gained the support of Italy and Germany, who promised, among other things, supplies of military hardware. In mid-August, Italian L3/35 tankettes arrived in Spain. German tanks arrived much later: 32 PzKpfw I Ausf. A tanks and one command vehicle were received in October of 1936. At approximately the same time, the first Soviet T-26es arrived in Spain and became the main opponents of the rebel tanks. As for the "Spanish" PzKpfw I Ausf. A, one of them became a Soviet trophy and was run through a whole spectrum of trials. What did the Soviet testers discover and what conclusions did they make?
Unsuitable for Tank Combat
Unlike the Condor Legion, where German planes were crewed exclusively by German crews, participation of German tankers in Spain was limited. Specialists under the command of Wilhelm Josef Ritter von Thoma mostly acted as instructors. Of course, they participated in combat, but their main task was to train Spanish tank crews and service the tanks. The first time that German tanks saw battle was on October 30th, 1936.
The first report on the combat use of PzKpfw I Ausf. A tanks was prepared by von Thoma by the end of November of 1936. By that moment, the tanks fought only with infantry, who fired on them with small arms. Soviet tanks were mentioned in the report, but briefly. Mostly the report discussed the resistance of the PzKpfw I Ausf. A to small arms, and even here, there was much left to be desired.
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Unsuitable for Tank Combat
Unlike the Condor Legion, where German planes were crewed exclusively by German crews, participation of German tankers in Spain was limited. Specialists under the command of Wilhelm Josef Ritter von Thoma mostly acted as instructors. Of course, they participated in combat, but their main task was to train Spanish tank crews and service the tanks. The first time that German tanks saw battle was on October 30th, 1936.
The first report on the combat use of PzKpfw I Ausf. A tanks was prepared by von Thoma by the end of November of 1936. By that moment, the tanks fought only with infantry, who fired on them with small arms. Soviet tanks were mentioned in the report, but briefly. Mostly the report discussed the resistance of the PzKpfw I Ausf. A to small arms, and even here, there was much left to be desired.
PzKpfw I Ausf. A re-armed with an Italian 20 mm Breda gun. The turret had to be altered in order to fit it.
First of all, problems arose from the multiple observation devices. They provided good visibility, but at the same time became a prime target for Republican bullets. There were cases of bullets or fragments penetrating through the slits and wounding the crews. The bullets were partially blocked by armoured glass, but even it was useless against 6.5 mm bullets, very popular at the time. Republican infantry could fire at the observation devices at point blank range, and the armoured glass, expected to resist only shrapnel, could not hold.
The crews were also wounded from secondary projectiles. Impacts against rivets led to them breaking, with the inner rivet head flying off and wounding the crew. These cases, however, were rather rare.
Spanish PzKpfw I in Madrid on May 19th, 1939. Interestingly, the tank in the background has Soviet DT machineguns in the turret instead of German MG.13s.
The same problems plagued the turret. Enemy fire concentrated on the vision and armament ports. There was a case where a bullet penetrated the slit between the gun mantlet and the turret, wounding the commander in the head. The opening for the sight was also a tempting target for enemy sharpshooters, and there were cases of the sight being destroyed. Fire was also aimed at the base of the turret, which made it jam. During combat, 23 machineguns were disabled by enemy fire. Another drawback, which was also noticed by Soviet tankers, was a lack of gun elevation. In city battles, this is very important.
On some tanks, a flamethrower was installed in place of the right machinegun.
Captured PzKpfw I Ausf. A. The missing observation device on the right side of the turret is noticeable.
In late October of 1936, the first Soviet T-26 tanks began appearing on Spanish soil. On October 29th, they joined the battles for Madrid, upsetting Franco's offensive. The first clashes between T-26 and PzI tanks occurred by the end of November. German tankers omit the results of these clashes in their reports, but Soviet reports mention the destruction of 12 German and Italian tanks. From December 15th to December 20th, another ten tanks are claimed. The main character of this article ended up in Republican hands around this time: PzKpfw I Ausf. A serial number 10184, produced by Henschel as a part of the 3rd series of the La.S.
Same vehicle, left.
Von Thoma's report prepared on December 6th, 1936, contains no information on losses at all, creating the impression that German tankers, unlike their Soviet colleagues, preferred to evade this sensitive topic. Nevertheless, a document with the descriptive title "Experience in combat between German machinegun tanks and Soviet gun tanks" perfectly summarizes the crux of the issue that German tankers faced in Spain.
Even the introduction of the report pulls no punches: tanks with cannons have an obvious advantage over tanks with machineguns. Knowing that the Republicans were using T-26 tanks, the Germans supplied armour piercing bullets for their PzIs. This didn't help much: while the T-26 could be penetrated at a range of 120-150 meters, the bullets were completely useless at a range of over 200 meters, while the 45 mm gun of the T-26 could destroy a PzI from a range of a kilometer or more. Italian 20 mm Breda 35 autocannons were installed in a few tanks, but this was not a widespread phenomenon.
Despite the fact that machinegun tanks are unquestionably inferior to gun tanks, the PzKpfw I remained the main type of German vehicle that fought in Spain. In total, 102 regular tanks were shipped, half of which were Ausf. A variants, plus four command tanks. The report was definitely noticed at the top, and production of the PzKpfw I ceased in May of 1937. Around this time, the PzKpfw II, with a 20 mm gun, entered production.
From Spain to Moscow
German tanks were first studied by Soviet specialists in Spain. They noticed that a large amount of armoured plates on the PzI were positioned at an angle, improving protection against rifle bullets. According to trials performed against knocked out tanks, an armour piercing bullet could penetrate the PzI at a range of 250 meters or less. The engine, powerful for such a small tank, was also of interest, as was the machinegun trigger mechanism.
The tank was painted in the standard three-colour camouflage used by the Wehrmacht until 1938.
Overall, the evaluation was not favourable for the German tank. This was mostly because the "tankette", as the PzI was often called, had only machineguns for armament. The weak armament drastically reduced the tank's value on the battlefield. It's worth noting that the purpose of the tank was comparable to the T-26, and production of that tank with only machineguns stopped in 1933. By the end of 1936, the only Soviet tanks being produced with only machineguns were the T-38 amphibious scout tanks.
The overall conclusions of the Soviet specialists are similar to that of von Thoma. The PzI had no chances when it went up against the T-26. Attempts to close in to effective range resulted in unpleasant consequences for the German crews. Even the higher speed compared to the T-26 could not save them.
From the rear, it can be seen that the turret also lacks one observation device.
A tank with the serial number 10184 was sent to the USSR for further study. By March of 1937, the captured vehicle ended up at the Scientific-Experimental Auto-Armoured Proving Grounds at Kubinka. According to the tank's instruments, the tank traveled 3426 km before reaching the proving grounds. No repairs were made, the tank was only oiled and tuned.
According to correspondence, the tank's missing track was replaced by a track from a "Carden-Loyd tank". The PzI's track links were similar to those used on this tractor, purchased by the USSR in the 1930s, which is not surprising. It is most likely that the captured tank's tracks came from this tractor. The tracks weren't 100% compatible and didn't fit well into the drive sprocket. As a result, the tank veered to the right.
In addition, two observation devices from the turret, the machineguns, and ammunition racks were missing.
Diagram of the tank with dimensions.
The tank, titled "Tank #1", was thoroughly inspected by the proving grounds staff. All properties of the tank were tested, including ease of access to its components. The specialists remarked on the tank's armour and large amount of observation devices, which gave good visibility.
The tank's positive sides included ease of crew entry. The commander's station, doubling as the gunner and loader, was deemed comfortable. The seat could be adjusted vertically and had seatbelts, which reduced the risk of falling off on uneven terrain. The turret traverse flywheel handles were also placed well. The specialists also noticed the bulletproof glass which protected the vision slits.
This hatch was used by the crew to enter the tank.
There were also a number of significant drawbacks. Access to the transmission was convenient, but the same could not be said for the engine. However, this was only a drawback when it was time for maintenance, there were more pressing issues in battle. The tank's hatches were not watertight and did not prevent liquids from seeping through, which made the tank vulnerable to Molotov cocktails. This was confirmed during trials.
This weakness was also seen in the engine compartment. The upper rear plate had two openings for ventilation, covered with a mesh. They turned out to be very vulnerable, as they were placed right next to the oil and fuel tanks. These meshes did nothing to stop enemy bullets. Modernized PzI tanks had their meshes replaced with armoured covers as a result of the experience in Spain.
Trial by Snow
Study of the tank's design was only a portion of the trial schedule. The German tank was also scheduled to run a 150 km long course, 40 of which were on a highway, 90 on a dirt road, and the rest off-road, over snow. The function of the suspension compared to the T-38 was studied closely. Presumably, if trials were successful, the same system would be used on that tank. A similar layout was already in use on the T-33 experimental tank and briefly mass produced T-41 tank, after which it was rejected. Shock absorbers on the PzI improved the suspension, but it was still deemed obsolete for 1937.
Commander's station.
The overall volume of trials was greater than scheduled, growing to 210 km. Instead of 40 km on a snowy highway, the tank drove for 100. A maximum speed of 39.96 kph was achieved, a little higher than expected. The average speed of the tank was 25 kph, and the fuel consumption was 31.2 kg for 100 km. The tank was easy to drive and did not require great effort to be applied to the levers or pedals. The engine proved itself reliable and easy to start.
There were also some problems. The brake drums overheated, and the ventilator that was supposed to cool them could not manage its job on long treks.
One of the trials included a measurement of towing capacity, which reached 2 tons in 1st gear.
PzKpfwI Ausf. A during mobility trials, March of 1937.
Trials continued on dirt roads, on which the tank traveled 70 km. These events took place in early March, and the roads were covered in 20-30 cm of snow. The average speed of the tank was 9-10 kph, with fuel consumption of 53.3 kg for 100 km.
Climbing a grade during trials.
The final step was driving off the road, which lasted for 40 km. The depth of the snow was 30-40 cm, and the tank could not achieve a speed of over 6-7 kph here. Serious problems also arose. First, a track pin broke on the left track due to wear. The right track, the one that was not replaced, slipped off twice. The test crew blamed the idler and track design. These conclusions were correct: the same problems would be found on the American Light Tank M3 where the tracks also often slipped off the idler.
Off-road trials included passage over a 0.8 and 0.7 meter tall obstacle. In the first case, the tank could not cross it, in the second, it was possible to cross if the tank was traveling at a speed of over 9 kph.
Attempts to climb a 0.8 m tall wall proved fruitless.
The tank could successfully drive over a felled tree, even though this was not initially included in the trials program. The tank wasn't out of the woods just yet: it was used to fell trees. 200-300 mm trunks were no problem, but a 380 mm diameter pine tree proved an impassable obstacle. This exercise in forestry did not affect the tank's technical condition.
Trials on grades were next. The first one, a 14 degree slope, was passed with no problems. A second one at 24 degrees, could only be passed while moving diagonally. Driving straight up was not possible due to insufficient traction. Trials of driving through snowed over bushes and young trees followed. The tank passed the first stage where the snow was 40 cm deep, but the engine stalled while trying to cross the second stage, where the snow was 50-60 cm deep. This was an excessive test, and almost any tank would get stuck here.
The test crew concluded that the suspension of the PzKpfw I Ausf. A had a series of drawbacks. The design of the idler and track was cause for complaints. The German use of a front drive sprocket did not solve the problem of tracks slipping off. The track tension mechanism was also poor: its travel was short and the design was weak. There were also some complaints about the front road wheel, which weathered heavy shocks that led to the shock absorber mount breaking. The military's interest in the tank's suspension waned.
The right track slipped off twice during driving in the snow. This was caused by the design of the idler.
Five years prior to these events, trials of the Rheinmetall and Krupp Leichttraktors were performed at the TEKO proving grounds at Kazan. Despite the fact that the tanks suffered from a series of technical defects, they were a source of various technical solutions later used on Soviet tanks. The situation with the PzKpfw I was the opposite. Nothing interested Soviet specialists, aside from the thickness and angle of the armour. Compared to this newcomer from Spain, even the Leichttraktor was more interesting. The only benefit of this exercise was familiarization with a foreign tank. The German tank was added to Soviet tank reference books under the index "T-1".
After trials, the tank remained at the proving grounds. According to the list of proving grounds possessions as of April 1st, 1941, the "T-1 German" tank with serial number 10184 and engine #9057 was not running, but externally functional. It placed into the proving grounds museum. After the start of the war, Balkenkreuz insignia were added to the tank, and it was included in a reference book on German tanks prepared on September 11th, 1941. After that, the trail of the captured tank disappears.