The eighty-eight was used in two main roles: as a mobile heavy anti-aircraft and anti-tank gun, in support of the troops at the front; and as a more static anti-aircraft gun for home defence.
Anti-aircraft defense of the Reich
After 1935, the anti-aircraft defense of Nazi Germany was controlled by the Luftwaffe. By the beginning of World War II the Luftwaffe's anti-aircraft artillery employed 6,700 light (2 cm and 3,7 cm) and 2,628 heavy flak guns. Of the latter, a small number were 10.5 cm Flak 38s or 39s, the majority were 8.8 cm Flak 18s, 36s or 37s. This was twice as many heavy AA guns as the Air Defence of Great Britain (ADGB) had at the time, with France and the United States having even less.
Throughout the entire war, the majority of 88 mm guns were used in their original anti-aircraft role.
The financial costs associated with anti-aircraft cannon were substantial, especially when compared to fighter aircraft. For example, in January 1943 – at a time Germany was desperately fighting to regain the strategic initiative in the East and was also facing a heavy bombing campaign in the West – expenditures on anti-aircraft defenses were 39 million reichsmarks, whereas all the remaining weapons and munitions production amounted to 93 million (including 20 million of the navy budget and only nine million of the aircraft-related budget).
By August 1944, there were 10,704 Flak 18, 36 and 37 guns in service, now complemented also by the formidable 12.8 cm Flak 40, owing to the increase in US and British bombing raids during 1943 and 1944. There were complaints that, due to the apparent ineffectiveness of anti-aircraft defenses as a whole, the guns should be transferred from air defense units to anti-tank duties, but this politically unpopular move was never made.
Support of ground troops
The 8.8 cm Flaks performed well in its original role of an anti-aircraft gun, and it proved to be a superb anti-tank gun as well. Its success was due to its versatility: the standard anti-aircraft platform allowed gunners to depress the muzzle below the horizontal, unlike most of its contemporaries. As WW2 progressed, it was becoming increasingly clear that existing anti-tank weapons were unable to pierce the armor of heavier enemy tanks. Ground commanders began increasingly to utilize the 8.8 cm Flak against enemy tanks.
Similarly to the anti-aircraft role, as an anti-tank weapon the 8.8 cm Flak was tactically arranged into batteries, usually four guns to each. The higher-level tactical unit was, most commonly, a mixed anti-aircraft battalion (Flak-Abteilung, gemischte).[N 4] It totaled 12 such guns on average, supplanted by light cannons.
The German Condor Legion made extensive use of the 8.8 cm Flak 18 in the Spanish Civil War, where its usefulness as an anti-tank weapon and a general artillery piece exceeded its role as an anti-aircraft gun.
For the 1940 Battle of France, the army was supported by eighty-eights deployed in twenty-four mixed flak battalions. The 8.8 cm Flak was used against heavily armored tanks such as the Char B1 bis and Matilda II, whose frontal armour could not be penetrated by the light 3.7 cm anti-tank guns then available. The 8.8 cm Flak was powerful enough to penetrate over 84 mm of armor at a range of 2 km, making it an unparalleled anti-tank weapon during the early days of the war, and still formidable against all but the heaviest tanks at the end. Erwin Rommel's timely use of the gun to blunt the British counterattack at Arras ended any hope of a breakout from the blitzkrieg encirclement of May 1940. In the entire Battle of France, the weapon destroyed 152 tanks and 151 bunkers. The Battle of France also saw the introduction of vehicle mounted 8.8 cm Flak 18s, the so-called "Bunkerknacker" on the SdKfz 8 heavy tractor.
During the North African campaign, Rommel made the most effective use of the weapon, as he lured tanks of the British 8th Army into traps by baiting them with apparently retreating German panzers. A mere two flak battalions destroyed 264 British tanks throughout 1941. One example of this tactic later in that theater was the battle of Faid in Tunisia, where Rommel hid and camouflaged many 8.8 cm Flaks (with additional 7.5 cm Pak 40s and 5 cm Pak 38s) in cactus-filled areas. Inexperienced U.S tankers and commanders rushed into a valley at Faid only to be completely obliterated. When the U.S. Army's M3 Stuart and M4 Sherman tanks pursued, concealed German guns picked them off at ranges far beyond those of their 37mm and 75 mm guns respectively.
For the invasion of the Soviet Union, Germany deployed the 8.8 cm Flak in 51 mixed AA battalions. They were mostly Luftwaffe-subordinated units attached to the Heer at corps or army level, with approximately one battalion per corps. The weapon saw continuous use on the eastern front. The appearance of the outstanding T-34 and KV tanks shocked the German panzer crews and anti-tank teams, who could only penetrate the Soviet tanks' armor at extremely close range when using the standard 37 mm and 50 mm guns.
The 8.8 cm Flak in the anti-tank role was arguably most effective in the flat and open terrain of Libya, Egypt and the eastern front. The less open terrain in Italy and Northern France was less suitable for long-range AT guns.
The success of the German anti-tank weapons caused the Allies to take steps to defend against it in new tank designs. On July 18 and 19 1944 a Luftwaffe 8.8 cm anti-aircraft battery was re-purposed by then Major Hans von Luck to attack British tanks near Cagny taking part in Operation Goodwood. 20 tanks were killed by these guns within the first few seconds and at least 40 tanks were knocked out by 8.8 cm Flaks during the engagement.
By February 1945, there were 327 heavy anti-aircraft batteries delegated against the Soviet land armies, which was 21% of those dedicated solely to the anti-aircraft defense of the country.
On 14 September 1942, Flak-Abt. I./43 (Major Wegener) employed these guns against a commando landing raid called Operation Agreement by the British Royal Navy near Tobruk, damaging the destroyer HMS Sikh so severely that she sank while being towed by HMS Zulu.
Use by other armed forces
In 1937, the Chinese Nationalist Government imported 20 Flak 18 guns and used them to defend the Castles along the Yangtze River. They were captured by the Japanese Imperial Army during the Sino-Japanese War.
In 1943 - 1944 Finland bought 90 8,8 cm FlaK 37 cannons from Germany and they were used for air defence of largest cities in Finland. These cannons played an important role against Soviet air raids in Helsinki in February 1944. After the war these cannons remained in Finnish use as AA-guns until 1977 and after that as coastal guns until the early 2000s.
Four batteries ( 16 guns) of 88mm guns (Flak. 18) initially reached Spain as AA with the Condor Legion in 1936, but it was soon used as anti-tank, anti-bunker and even as anti-battery. More guns were sent later, and some more 88-mm guns were supplied to Spanish army units. At the end of the war the Spanish Army was using all of the Flak 18 guns sent, some 52 units.
Initially, the Flak 18 batteries were deployed to protect the airfields and logistics bases used by German Condor legion. The scarcity of artillery among the Nationalist forces and the general low proficiency of the Spanish gun crews forced the usage of the Flak 18 gun in a variety of roles, including as an artillery piece and as an anti-tank gun. Given appropriate ammunition it proved quite capable in both roles. The war in Spain, with its wildly fluctuating front lines and the presence of Russian tanks, forced the Germans to employ the Flak 18 guns in a direct fire mode against ground targets. By the end of the war the 88-mm guns had performed far more missions as an anti-tank and direct-fire Field Artillery gun than as an anti-aircraft gun. During the war German 88-mm guns were involved in 377 combat engagements, only 31 were against enemy aircraft. The use of the 88-mm direct support of the infantry brought the gun crews in close proximity to the enemy and made the crews susceptible to infantry fire. Casualties among the legion's 88-mm gun batteries in the Spanish Civil War were second only to those among the bomber pilots.
In early 1937 in the fighting around Malaga, a battery of 88-mm guns was assigned to support an infantry brigade. Bad weather grounded the main bomber force, but the assault succeeded, mainly because of the concentrated and accurate fire of the supporting 88-mm guns. Flak 18 batteries were by the nationalist army at the Battle of Ebro, used for direct fire against pillboxes and for indirect fire in the advance towards Barcelona.
Following the Spanish Civil war, more Flak. 36 models arrived in 1943 (88 guns 88/56 mm Flak-36) and since 1943 they were manufactured under license in Trubia under the denomination FT 44 (about 200 guns).
The Flak 36 guns were briefly issued in late 1944 to the American Seventh Army as captured weapons. The 79th Field Artillery Battalion (Provisional) was formed from personnel of the 79th and 179th Field Artillery Groups to fire captured German artillery pieces at the height of an ammunition shortage. Similarly, the 244th Field Artillery Battalion was temporarily equipped with a miscellany of captured German 88mm guns and 105mm and 150mm howitzers. As of December 31, 1944, the 244th Field Artillery Battalion had fired a total of 10,706 rounds through captured German weapons.
During the Yugoslav wars in the 1990s, various Flak guns were used, mainly by the naval artillery of the Yugoslav People's Army (JNA). The Serbian Army (VJ) also used Flak carriages mounted with double 262 mm rocket launch tubes from the M-87 Orkan MLRS, instead of the 88mm gun. It was capable of deploying cluster bombs, as well as anti-personnel and anti-tank mines, at up to 50 km. Only a few were built in mid-1993, the entire project was generally regarded as unsuccessful.