The Renault R35 was a French light tank development of the pre-World War 2 period and followed general French tank design measures of the time. It proved a serviceable combat tank though not without limitations and was wholly undone by German tactics and French planning during the Battle of France. Many were captured in the onslaught which meant that the tank served the Germans in a greater role than they served their original owners. The R35 was notable as being the most numerous of all the French tanks in service at the time of the German invasion of May 1940. Total production eventually netted 1,685 vehicles including the R40 offshoot.
Naturally, the R35's design influence stemmed from the French battlefield experience of World War 1 (1914-1918) in which tanks spearheaded infantry offensives by providing fire support and breaking through defensive strongpoints along a given front. As such, armor protection and a short-range gun were the qualities of the day over speed and direct long-range engagement of enemy armor. By this time, French Army authorities sought a successor for their once-revolutionary Renault FT-17 Light Tank of World War 1 which introduced the concept of a turreted main gun.
Under no threat of war, the French approach evolved throughout the 1920s and into the 1930s by which point several limited-use products emerged. In 1933 a competition was opened to all interested French tank-makers including Renault which delivered its "ZM" prototype. With a few alterations made into 1935, French authorities raised their interest in the vehicle amidst worsening tensions with long-time neighbor Germany who promised to make new waves as its military might grew. The modified ZM was hurried along with thicker armor and a revised turret which led to an initial batch order for 300 of the type even before testing had even completed - such was the drive to modernize the French Army. Initial production vehicles followed in 1936.
The Renault vehicle - christened "R35" - featured a three-part cast hull design and was, by qualities of the time, a wholly modern tank. Its short-barreled 37mm L/21 SA18 gun was fitted to a traversing turret sat atop a shallow hull superstructure. The engine was encased at the rear with the glacis plate at front being near-horizontal. The driver sat at front-center in the hull superstructure with the commander/gunner in the turret - the R35 was a lightweight two-man tank as the FT-17 before it. The track-and-wheel running gear included five small road wheels to a hull side with the drive sprocket at front and the track idler at rear. Three track return rollers were used while the track link section was slim. The hull was suspended atop a horizontal rubber cylinder spring arrangement.
As completed, the R35 was in the 12-ton range with a 13 foot length, 6 foot width, and 7 foot height. Armor protection peaked at 43mm thickness which was a drastic increase from the 30mm design form originally offered by Renault in 1934. Beyond the 37mm main gun was a 7.5mm MAC31 Reibel series machine gun for anti-infantry work and this fitted as a coaxial weapon in the turret. Drive power to the vehicle was supplied through a Renault V-4 gasoline-fueled engine of 82 horsepower output. This provided the vehicle with a maximum speed of 12.5 miles per hour with an operational range out to 80 miles.
Formal serial production of the R35 spanned from 1936 into 1940 with manufacture terminating at the time of the Fall of France in the summer of 1940. 1,540 of the original R35 design would be built along with about 145 of the related R40 models to follow. R40 tanks differed primarily in their use of a new suspended wheel arrangement featuring twelve road wheels and vertical spring suspension systems. The tanks also standardized on a longer 37mm L/35 SA38 main gun mounted within a new cast turret. The long gun aided in longer-range engagement of enemy armor which was sorely lacking in the original R35 short-barreled forms and some of the earlier R35 tanks were quickly upgraded to the R40 standard when possible.
Before the German invasion of 1940, the R35 was already being shipped overseas to stock French colonial inventories as well as to fulfill foreign orders from customers like Poland and Yugoslavia. Operational use of the R35 during the German invasion of France proved a mixed bag for properly trained R35 tankers were few and far between - the French Army was simply not ready for total war of the magnitude enacted by the Germans in their famous "blitzkrieg" campaigns - yet there stood a collection of nearly 945 combat-ready R35/R40 tanks. What tanks were in active service were typically contained units coupled with obsolete French Army tanks still in play and tied to infantry formations. At least nine French Army battalions fielded some R35 tanks along with their infantry components and lacked the support structure common to all armies of World War 2 by the end of the conflict.
Sadly, the R35s could do little to contend with the German advance and French political bickering coupled with inept war planning. The swiftness of the German assaults often meant that scores of the new French tanks were simply overtaken if not destroyed. As such, stocks of R35s fell to the enemy who saw obvious value in reconstituting the captured vehicles for their own use. German-managed R35s were then reissued for local security and to shore up garrisons where needed after the conquest of France and the Low Countries. Others were in some cases rearmed with more potent main guns and still others were modified as tank destroyers and artillery carriers or relegated for driver/crew training purposes. Leftover turrets were set as defensive-minded static guns overlooking key strategic positions - as was the case along the Atlantic Wall overlooking the English Channel towards Britain. Some of the German stock was also passed on to allies in Hungary, Italy, and elsewhere.
The German Army designation for captured R35s was "Panzerkampfwagen 35R 731(f)" - the small "f" to indicate their French origins.
For its time, the French R35 proved serviceable-enough combat platform for the light tank role. Its protection was actually quite good against German light anti-tank guns of the day. However, it was not a perfected battlefield product and relied on a two-man crew. The commander, in particular, was given a great deal of responsibility in a rather cramped operating space. He stood in as his own gunner and loader while also having to observe the battle and direct the driver under combat conditions all the while attempting to see the action through a poor vision arrangement. The 37mm main gun in play eventually proved largely ineffective against even the early Panzer forms. Additionally, the French practice of committing small teams of French tanks along with infantry and no supporting fire limited what French tank battalions could realistically due against a better-prepared and better-trained enemy.
Beyond World War 2 actions, the R35 survived long enough to see combat service in the immediate post-war years where Syrian R35s were fielded during the 1948 Arab-Israeli War against the newly-founded nation of Israel. The French Army managed to reclaim some of its captured tanks after the war and reused these systems until more surplus American armor became available by the late 1940s.