Home : World War II : The Axis :

Anti-aircraft Gun

To fire a projectile into the air to an altitude of 20,000 feet, which a World War I aircraft was capable of reaching, required a gun with a bore of about three and one half inches or 88mm; thus a standard was set that was to continue into World War II.

This was the dreaded "88," the anti-aircraft gun used by the German Luftwaffe that was to play such havoc with the Allied bomber formations, especially the USAAF because of their predominantly daylight operations. During daylight operations predictors (sighting range-finders) could be used to aim flak cannons fairly accurately. The preference, of course, was gun laying radar. As a result, as any World War II bomber crewman of the United States Army Air Forces can testify, losses to flak cannon were severe.

It was not a new weapon, but was developed from a World War I design, entered into service in 1916. As a mobile weapon, it was mounted on a four-wheeled carriage and towed by specially built and equipped trucks. When in action, arms with self- contained screw jacks could be swung out to form a secure firing platform. At that time, when aircraft were slow and flew at low altitudes, the design allowed for quick fire, but lacked refinements that were found necessary in modern warfare leading up to and including World War II. The standard 88mm antiaircraft cannon of World War I was the Geshutze 88 manufactured by Krupps of Essen.

German anti-aircraft fire of the First World War was called "Archie" and was not very effective, as the various mechanical devices used to calculate precise aiming of guns were not very accurate. However, when attacks on enemy observation balloons were made, it was a different story. With the altitude of the balloon known, it was easier to make the calculations required to lay the guns properly.

Commanders of Archie batteries would resort to area defenses employing barrage firings. When one considers that one cubic mile of airspace contains 5,500,000,000 yards and the effectiveness of one anti-aircraft shell is only a few thousand cubic yards and exists for less than 1/50th of a second, the effectiveness of barrage fire was nil. It was estimated that 3000 rounds were required to shoot down one aircraft. The ratio of rounds per aircraft downed was considerably higher during World War II when sight and radar tracking was used to aim the Luftwaffe flak batteries.

The usual practice during World War I was to mount batteries of anti-aircraft guns behind the front in such a manner that when approaching aircraft were detected by sound ranging equipment, gun crews were alerted and then could concentrate their fire on the aircraft. To protect cities or vital military targets, guns were positioned along the lines of approach. As navigational devices were quite crude, WWI pilots often followed roads, rivers, and rail lines leading to the cities and vital targets so gun batteries were sited along these same natural barriers and man-made features.

According to the strict terms of the Versailles Treaty (which Hitler blamed as the cause of World War II), Krupps was forbidden to manufacture the 88 in Germany after World War I. To overcome this restriction, Krupps came to an agreement with Bofors of Sweden, whereby Bofors acquired the foreign rights for all Krupps designs in exchange for granting design and research rights to the Krupps team working at Bofors. In 1928 Bofors developed a new design for a high velocity 88mm gun with a semi-automatic breech which re-cocked the striker on ejection of the cartridge case. A Krupps representative took the design back to Essen in 1931 where manufacture began in 1933, when the Versailles Treaty provisions were being openly violated by the Nazi government which took power when Hitler became chancellor.

The new gun, the 88 Flak 18, was mounted on a cross shaped carriage with dual wheeled bogies that could be turned in pairs for positioning on the ground. The fore and aft legs of the cross were mounted over the wheels with the side legs swiveling up for storage. This was a great improvement over the 1916 model. This design proved rather clumsy from the experience the German Condor Legion gained during the Spanish Civil War, as it was found that the gun platform was somewhat unstable. To over- come this restriction, before firing, the gun had to be lowered from the bogies to the ground. When the gun barrel was elevat- ed to fire at aircraft, the strain on the center of the star-shaped cruciform carriage was greatest after the projectile was fired. Battle experience in Spain dictated a need for a reduction in time to bring the gun into a battle-ready state. It was evident also that provision had to be made to facilitate quick changing of the gun barrel in the field if the weapon was to reach its full potential. This necessitated that the manufacture of the barrel would have to be accomplished in sections so that worn parts could be replaced individually instead of a whole barrel assembly. The butt end of the outer barrel where the rifling began was threaded so a new barrel section could be easily screwed on. This extended the gun's service life and allowed assembly line manufacture without the need for specialized machinery. In 1936-37 the gun platform was improved by the installation of winches to the bogies which allowed the platform to be lowered to the ground, eliminating the bending force on the carriage support. The bogies/ limbers could then be wheeled away and the side arms were lowered. The mounting was then levelled by screw jacks at the end of each arm.

For quick firing when used on ground targets or as an antitank weapon, the gun could be used from the wheeling position by applying hand brakes and chocking the wheels. With the barrel set almost parallel to the ground, the recoil forces would be to the rear and the need to lower the weapon was not as great. The side arms were then dropped and secured, readying the gun for action. From 1940 onwards the Flak 18 and Flak 36 were mounted on a Sonderonhaenger type trailer. Later improvements included the installation of twin wheeled bogies and protective shielding for the gun crew. The gun was designed to be towed by a half track vehicle, the Sd. Kfz7 tractor built by Krauss-Maffei. It had seating for the gun crew, and ammunition lockers, making the tractor-gun trailer self-contained. When equipped for battle, the gun and trailer weighed seven tons.

The earlier models of the Flak 18 used a data transmission system whereby information on bearing, elevation, and fuse setting was sent from the gun computer (predictor) via electric signals that illuminated three rings of colored lamps. The gunner merely turned his hand controls until all of the lights were put out. This system was replaced by a dual pointer system in the Flak 37 model so that the gunners then just turned the control wheels until both pointers matched up. Later improvement of the basic 88mm design consisted of the use of a turntable instead of the usual pedestal mount, allowing a lower profile. But with the advent of high altitude bombing during World War II, higher muzzle velocities were required to lift the shells to the higher operating altitudes. This was obtained partly by increasing the length of the barrel. This led to the model 41, a new design that led to a host of teething problems that were not completely solved, one being that the spent cartridges could not be cleared quickly from the platform. Further refinements were abandoned in favor of weapons of larger caliber.

Flak The Germans produced an incredible number of Fliegerabwehrkanone or "Flak" guns to protect their troops in the field and eventually to provide a moderately effective system of radar directed Flak and searchlight systems to protect their major industrial cities, in particular those of the Ruhr valley. Light Flak typically consisted of heavy 12.7 mm machine guns and 20 mm towed cannons that could be set up quickly around troop and armoured groups for anti-aricraft protection. These guns were light, fast firing and quite effective against aircraft at low altitudes. They eventually were found all throughout the German held countries to provide protection for railroads, bridges, towns, important cross-roads and anywhere the Germans felt they needed protection. They made it quite dangerous to fly low over certain areas, such as coast lines in a slow bomber, as they would fire at almost anything flying in their area. Medium Flak guns were typically 37 mm towed guns operated by a large crew. They were slower firing than the 20 mm guns, but had a longer range and were more deadly. They were used in conjunction with the smaller guns or at more important military installations. Their longer range allowed them to be used in the defence of German cities. Their streams of shells could be seen rising into the bomber stream as globes of yellow or red. They were contact bursting shells only. Heavy Flak typically consisted of the highly effective and ubiquitous 88 mm cannon set up in anti-aircraft mode. By 1942 over 15,000 88 mm cannons formed the bulwark of Flak defenses for Germany arrayed in Flak belts stretching across Holland and Germany, in places 20 km thick. Many batteries were radar directed and worked cooperatively with searchlight batteries. The image above is of a radar directed battery of 88's night firing. Heavier guns of 130 mm and 150 mm were also used. The heavy Flak shells exploded at pre-set heights. Flak was the nightmare of bomber crews as it wasn't predictable, you couldn't see it coming and if you swerved to avoid the bursts in front, you could just as easily fly into the next set of shells. They exploded in daylight with puffs of black smoke with little red interiors, and made muffled "krumppp" sounds (due to the high levels of noise in the Allied bombers). At night they flashed quickly yellow or red and dissappeared. When one hit close the shards of shrapnel banged through the aircraft and pinged off of more solid members. With a direct hit from an 88 mm or larger shell the aircraft would stagger, sometimes stall, fill with smoke and screaming wounded airmen. Sometimes a wing would fold up and the bomber would go straight down in flames. Other times the entire aircraft would simply vanish in a dirty ball of fire, smoke and bits of plane and man. Many other times the aircraft and men would fly on, riddled with holes but still fighting. Only to have to try to land somewhere without lights, damaged under carriages, missing engines and wounded or dead crew. Often they bombed their targets only to die in a crash landing.

The gun was capable of firing 25 rounds per minute. Normal rates of fire for the 88mm gun were reduced to 15-20 rounds per minute. The longer barrel tended to vibrate under high rates of fire, reducing the accuracy of the weapon, so that the gun would have to lay silent for short periods to allow the barrel to cool.

There were two methods of fire control in the AA role: (1) Radar, (2) Predictor through a data transmission system. The gun crew consisted of eleven artillery men, a gun layer, a trainer, a breech-worker, a fuse setter, five ammunition workers, a detachment commander, and the tractor driver. Each round weighed about 22 pounds. Muzzle velocity was 2690 feet per second.

Much of the fame of the 88mm gun rests not on its performance as a flak gun but as an anti-tank weapon. During its baptism of fire in Spain it was called upon for use as a defense weapon when tanks broke through front line positions and were threatening the anti-aircraft batteries. In the battle for France and in later campaigns it became common practice to attach motorized Luftwaffe flak companies to army field units when German air superiority was uncontested. Again in North Africa, when a German commander was faced with an attack of heavy British tanks at Halfaya, Libya during the Battle of Solum in June 1941, he used his 88s very effectively, destroying 123 tanks of the total force of 238 tanks. Badly mauled, the British tanks withdrew. The Germans claimed one British tank for every twenty rounds. When the Germans first confronted the new Russian T-34 and KV tanks, their standard 5 cm anti-tank guns had little or no effect, so once again the trusty 88 was called upon to stop the Russian heavies. There is an account during the Russian fighting where one 88 gun destroyed six T-34 tanks at a range of two miles. The 88 had earned its reputation.

Because the gun could be mounted on a mobile carriage, it was often towed from place to place, creating problems for the Allied intelligence officer whose duties were to estimate the number of guns defending targets that were likely to be attacked by his bomb group. Bomber crews often cursed the pre-mission briefing on the expected defenses of their target because the information was often old and inaccurate. Generally the number of guns were underestimated or not placed accurately. Bomber crews often had to interpolate the intelligence estimates using a sixth sense that developed over the experience of many missions. As the war progressed, the formations began to loosen up as enemy fighter activity lessened, but mainly to allow the bombers more elbow room to take evasive action. When enemy fighters would appear suddenly the loose formations often suffered greatly as the defensive firepower was spread over a large area, making it less effective.

The defense of the Reich was given to the Luftwaffe, the German air force. It employed in excess of a million men and auxiliaries to defend the country. The flak arm had two responsibilities: one was to protect military targets, cities, factories, and rail lines, and the other was to offer support to ground objectives of the field armies. As casualties in the field armies increased with the advancement of the war, able-bodied men were drawn from the flak defenses to serve in the army. They were replaced by Home Guard personnel (Luftwaffehelfer), as young as 12 but usually 15- and 16-year-old schoolboys who were called away from their classes or out of their beds at night, and youths from the labor service (Reichs Arbeit Dienst), which all young men were taken into after leaving high school. Excepted were boys who went directly into the armed forces, female auxiliaries (Kampfhelferinnen) used in non-combatant roles at the gun sites, Russian prisoners who volunteered for the labor battalions, and Italians and Hungarians who acquiesced to work in the flak arm. The flak division responsible for defense of the synthetic oil refinery at Leuna in southern Germany employed a total of about 62,000. Of this total the greater portion were of the auxiliaries.

Larger caliber flak guns such as the 105mm cannon and 128mm cannon were used to obtain greater hitting power. The larger weapons were often mounted on top of the huge flak towers that were springing up in the larger cities during the latter half of the war. These larger caliber guns shot mostly time fused rounds, eliminating the manually set fusing where a ring had to be rotated at the base of the projectile.

One method used by the Luftwaffe to increase the hitting power of the larger caliber flak ammunition projectiles was to groove the inside of the shells that exploded into larger pieces of about 3 1/2 inches long by 3/4 of an inch long. Towards the end of the war, incendiary shells (Brandschrapnel) that burst into 51 small incendiary pellets (88mm shell) and 99 pellets in the 128mm round. When the shell reached its set altitude, a charge exploded sending the pellets up and away, igniting either in the air or when they hit the bomber. After testing, the Luftwaffe judged the controlled bursting shell more effective than its predecessor of small fragmentation, and the incendiary shell the most effective of all.

The standard fire control predictor was the Kommondogeret 36, a long tube range-finder of about four meters in length. As long as the operator of the predictor could keep his sight on the target, a continual stream of information was sent to the gun crews consisting of gun bearing, elevation, and time fuse setting. The instrument was effective on the slow-moving bomber formations that maintained straight and level flight. The later model Kommondogeret 40 could cope with a formation in a steady turn and also receive information sent from nearby radars. From the foregoing it can be seen that evasive action on the part of the bomber pilots could reduce the chances of being shot down.

Flak towers were often constructed in pairs in the large cities such as Vienna, Berlin, and Hamburg, one serving as an elevated gun platform, the other as mounting for the radar and range-finding equipment. Generally the gun tower supported four large caliber guns either in single or dual mounts. 2mm light flak weapons were mounted in half round abutments situated at the corners of the tower for defense of low-flying aircraft. These towers served also as bomb shelters, for ammunition storage, and for use by civil defense authorities. Flak guns of light and heavy caliber mounted on railway flat cars (Eisenbahnfkak) were used to move guns to defend expected targets. They carried their own fire control predictors and could be fired directly from the flat cars where they were placed at sidings or marshalling yards. Because the bombers of the 8th and 15th Air Forces timed attacks around the noon hour or earlier, depending on weather, it was easy to hide the railway guns inside tunnels to avoid detection by recognizance aircraft during the hours when air attacks were not anticipated.

As enemy aircraft could approach the target from any compass point, the flak batteries were laid out so that engagement could take place just as the formation reached the bomb release point. Assuming the maximum speed of the bomber formation would be about 265 miles per hour at a height of 20,000 feet, the bombs would carry forward from the release point for two and a half miles. Flak positions were laid out so that the bombers could be attacked for most or all of the time until the aircraft reached the bomb release line. In less than a minute a bomber flying at a ground speed of 265 miles per hour can cover a distance of about 3 3/4 miles. Within this circle of 3 3/4 miles from the center of the target, was the most effective zone for anti-aircraft engagement. Beyond this circle was the tracking area where the predictors and connecting radars prepared the data that was sent by wire to the gun locations ideally placed within this defending circle. The predictors would sight on the leading aircraft of the bomber stream unless another battery was already sighting this same formation. In this case a second aircraft in the lead group would be sighted on. As the bombers crossed the bomb release line, the battery commander could order sighting on the following aircraft as they approached the flak engagement circle. The fire control command center consisted of a command post, twin predictors, twin radars, and supporting equipment. This allowed orders for two separate engagements to be issued. It allowed smooth transition when more than one bomb group was in the attack force. All of the guns controlled by the battery commander were fired in salvo for the first round. Additional rounds were fired as fast as they could be loaded.

The Luftwaffe employed other flak defenses using smaller caliber guns against bombers and fighters flying at low altitudes. The Allied bombing attacks on the Axis powers during WWII, in addition to its primary role of reducing the enemy's ability to wage war, tied down by the end of the war over 1,250,000 flak troops that were sorely needed on both the eastern and western fronts. The war was shortened considerably by the loss of these troops. The 88mm flak cannon was a formidable weapon which inflicted heavy losses on the Allied bomber formations. But as good as the weapon was, it could not prevent the bombers from coming through.

Bud Markel (484th BG). Reprinted With Permission From The Torretta Flyer (484th BG Assn). The Welcome Wagon It Was Not! The Journal 2nd Air Division. Volume 47 Number 2, Summer 2008.

88 mm FlaK 18/36/37/41 & PaK 43 1936-45 By far the most famous and versatile artillery weapon of World War II, the German 88mm was used primarily as an anti-aircraft and anti-tank weapon, but also saw late-war service on German tanks, as a self-propelled gun, and even as an aerial weapon. This book covers all these variants, explaining their design, development and operational use.

---

top of page

back a page