Nationalist Armor

Its debut (combat test) was during Spanish Civil War (1936-38). Approximately 100 ( Ausf A, Ausf B and Kleiner Panzer Befehlswagen I) saw service with "Condor Legion" (Major Ritter von Thoma's Panzer Abteilung 88 also known as Abteilung Drohne) and General Franco's forces. Pz.Abt.88 with its 3 companies was based at Cubas near Toledo, where German instructors trained future Spanish crews, while the unit was used for training duties and combat (e.g. assault on Madrid). Panzer I tanks proved to be outclassed by Soviet T-26 and BT-5 provided to the Republicans.

Some Panzerkampfwagen Is were captured by the Republicans and rearmed with French Hotchkiss 25mm Model 1934 or 1937 anti-tank guns mounted in a modified turret . During the Spanish Civil War, PzKpfw I Ausf B was experimentally armed with Italian 20mm Breda Modello (model) 1935 light anti-aircraft gun mounted in a modified turret, in order to increase its combat potential.

PzKpfw Is equipped two Nationalist tank battalions (Agrupacion de Carros) - 1st and 2nd Tank Battalion. German High Command used the opportunity of the Spanish Civil War to test their new weapons and tactics of Blitzkrieg. Its very thin armor offered only protection against small firearms and its twin MGs were no match for anything other than infantry units and proved completly useless in combat.

Panzerkampfwagen I was produced in two main very similar variants Ausf A (1934) and Ausf B (1935), which had different suspensions and engines. Ausf A was produced from July of 1934 to June of 1936 , while Ausf B was produced from August of 1935 to June of 1937. Both were produced by Henschel, MAN, Krupp-Gruson and Daimler-Benz. Ausf A proved to be underpowered and its very loud 57hp Krupp engine overheated and Ausf B with its 100hp Maybach engine was an improved version of Ausf A. Both models had identical turret and superstructure but Ausf B was longer (additional roadwheel) and had new modified engine deck (new engine). Both variants were operated by two men crew - a driver and a commander/gunner. In 1935/36, Panzer I Ausf A was experimentally mounted with Krupp M601 diesel engine, but it could only produce 45hp of power, and the idea of diesel powered vehicle was rejected.
Both Ausf A and Ausf B were also produced as turretless tanks used for training purposes (PzKpfw I Ausf A ohne Aufbau) and as maintenance vehicles (PzKpfw I Ausf B ohne Aufbau). Eventually both vehicles were used as training vehicles.

The L.3 tanks saw action during the Ethiopian War (1935) and the Spanish Civil War (1936-39).

While the Abyssian campaign benchmark, in spite of a severe handicap given the machine guns' narrow traverse capability, had demonstrated the L.3 sufficient reliability as infantry support tanks, even on impervious and mountainous terrain, the Guadalajara event, during the Spanish War, represented a real "fiasco" for the Italian tank units (the "Corpo Truppe Volontarie" or "CTV", supporting General Franco's Nationalists).
The failure can be, however, attributed mainly to the following reasons :

* The Italian armored force were inadequate, being limited to only four tank companies and one armored car company.

* Heavy rains precluded the possibility of providing adequate air protection to the tanks.

* The L.3's narrow tracks were totally unreliable on soft and muddy soil.

* The Russian T-26 tanks, supporting the Republican troops' counterattack, were superior to the Italian tanks in terms of both gunnery (45 mm gun + 2 MG 7.62 mm) and armor (25mm).