9 WWII-era weapons that are still needed on today's urban battlefield

The Soviets and Germans fielded large numbers of "turretless" armored self-propelled guns during World War II, with the SU-76 and StuG III becoming the respective infantry-support workhorses of their armies.

Their 3-inch-equivalent high-velocity guns were effective against armored vehicles and could penetrate double-brick walls. Both armies would use them to move closely behind advancing troops to provide fire support as soon as resistance was encountered. The effects of their impact-fused, high-explosive shells would suppress defenders, but to eliminate or drive out determined defenders from a substantial building by fire was a slow process, often requiring its systematic destruction from the top down.

Defenders often chose substantial concrete and stone buildings as strongpoints, so to breach their walls and neutralize those within a bigger explosive round proved necessary. The Germans developed the Sturmpanzer IV with a potent 150-millimeter short-barreled gun, but the 43-ton Soviet ISU-152 assault gun was probably the best of its class. It had thick frontal protection and was reliable and relatively agile. The 152-millimeter high-velocity gun could punch shells through substantial concrete walls to detonate its 12-pound explosive payload within. It proved a devastatingly effective close-support weapon in the urban battles up to and including Berlin.

At the bottom end of the scale we find an interesting, "asymmetric" German armored vehicle that, while remembered as a utilitarian anti-armor platform, proved remarkably useful in urban combat.

The Hetzer (JgPz38) light tank destroyer was small — weighing a mere 15 tons — and reliable, and had a potent 75-millimeter gun that would defeat virtually any Allied tank at urban ranges.

While its side armor was thin and it needed infantry protection because of poor crew visibility, it was an ideal ambush weapon that could be readily hidden in urban cover or even within buildings. In offensive operations such as the suppression of the Polish uprising in Warsaw it proved a surprisingly effective platform for working closely on the street with German infantry sections.

Infantry troops could advance using the vehicle hull for protection while the remote-controlled overhead machine gun provided fire support on contact. A combination of the low height and a commander's hatch that opened angled to the rear made it possible for an infantryman to climb on the vehicle to communicate with the crew while remaining protected. The Hetzer remains an archetype for a simple infantry close-support platform.

The British Churchill tank was slow and initially mechanically unreliable, yet later models were as well armored as a German Tiger. A low center of gravity and good hull clearance meant it could climb steep slopes and cross rubble that few other vehicles could attempt. It performed well in its intended role as an infantry support tank, and outstandingly as the basis for a family of specialist vehicles, often referred to as "funnies."

A particular advantage was that it had forward access hatches between the tracks on both sides, allowing soldiers to dismount in relative safety. This feature was exploited in the turretless "Kangaroo" infantry carrying version as well as in engineer vehicles where dedicated demolition crewmen were carried to place explosives or smoke pots by hand.

Variants included bridge-layers, mine-clearing flails, and explosive hose launchers, but two other versions working together proved devastatingly effective in urban fighting in northern Europe after D-Day.

The Churchill Armoured Vehicle Royal Engineers (AVRE) was equipped with a 290-millimeter spigot mortar that fired a 40-pound bomb containing 26 pounds of high explosive. While the maximum range was only 100 yards, the weapon reliably knocked out reinforced concrete bunkers and collapsed buildings.

The Churchill Crocodile had a hull-mounted flamethrower supplied with gas-pressurized fuel from a trailer, with a flame range of 120 yards. In street battles in France, the Netherlands, and Germany, strongpoints would be abandoned when an approaching Crocodile fired a demonstration burst. If the defenders did not yield, the Crocodile and AVRE would close up in the resulting smoke, the AVRE would fire a bomb to "crack" the position, and the Crocodile would flow flame into the breach or onto the rubble.

While the effects of flame weapons are undoubtedly horrific, the British and Canadian use of specialized armored vehicles to evict defenders rather than systematically clear buildings in detail not only reduced their own and enemy casualties, but avoided the previous reliance on heavy bombardment, which invariably caused many civilian deaths. Consequently, the use of specialist engineer vehicles, including flamethrowers, can counterintuitively be argued to represent a restrained approach that better satisfies the humanitarian-law requirements of proportionality.

The Panzerfaust was a simple, handheld recoilless infantry anti-tank weapon first fielded by the Germans in 1943. It was aimed with a simple peep sight while holding the launching tube under the arm. On firing, there was a backblast of several meters as the projectile launched, stabilizing fins popped out, and the fuse was armed.

When the projectile impacted, the detonation of the hollow-charge warhead collapsed the conical metal liner and blasted it through the target. Early models had a range of 30 meters and would penetrate about 140 millimeters of steel armor, and in later models this increased to 220 millimeters. More modern hollow-charge warhead designs yielded almost three times this penetration for a similar amount of explosive, mainly by distributing the explosive further back and increasing the distance from the target at which detonation occurs.

However, the penetration hole of Panzerfaust warheads was larger, while shockwave within the target material, frontal spalling, and blast were greater. This meant that when a Panzerfaust projectile struck a wall, especially interior brick walls, it would often create a man-passable breach—unlike, say, a contemporary RPG-7 or M72 HEAT round, which make neat, small holes. Furthermore, the Panzerfaust could be readily fired from cover, one-handed, around a doorway or window against an interior far wall.

This capability was not only exploited by the Germans. In the urban battles as the Soviets fought toward Berlin, they distributed captured stocks to their storm detachments in order to conduct explosive mouse-holing during assaults.

The German Sturmgewehr 44 was the innovative forerunner of modern selective-fire assault rifles. With a 30-round magazine and firing a new "intermediate" 7.92-millimeter short round to an effective range of 300 meters, it revolutionized infantry tactics — and inspired Kalashnikov's design.

Concurrently, the Germans developed a curved barrel attachment, the Krummlauf. This allowed the Sturmgewehr 44 to be fired from inside an armored vehicle at enemy infantry attempting to hand-place explosive charges — a constant danger in dense terrain. The infantry version of the attachment had a mirror sight that allowed a soldier to fire around a corner or from inside a trench while remaining behind cover.

Even after initial technical problems were addressed, the attachment only had a life of a couple of hundred rounds, bullets often broke up in the device, and it was unlikely to achieve a hit on a target beyond 100 meters. These were great disadvantages in open terrain, but less so in urban, close-quarters fighting, when the bullet disintegration increased hit probability and lethality.

There are reports of a few weapons being used in the battle for Berlin and the Soviets were sufficiently impressed to trial a curved barrel version of the PPshK submachine gun (and later the RPK LMG). However, the great potential of the Sturmgewehr 44 with Krummlauf was to address a problem that barely existed at the end of World War II — to reduce risk to attackers during building clearing under restricted rules of engagement.

During World War II the Germans progressively fielded a family of light rocket artillery of increasing size and range: the Nebelwerfer series. Rocket propulsion allowed a thin-walled projectile with a relatively large smoke composition or high-explosive payload, the latter giving blast effects equivalent to larger artillery rounds.

The most-produced 1941 model was a six-barrelled, two-wheeled towed launcher that ripple-fired 150-millimeter high-explosive or smoke projectiles up to 6,900 meters. A battery of six launchers could deliver its 36 rounds within 12 seconds, either inflicting a devastating barrage or rapidly smoking off a substantial area of the battlefield. The latter is an often-forgotten but crucial capability for urban operations — not only for the break-in urban battle, but to blind snipers who could otherwise often bring an attack to a halt.

The Nebelwerfer was not intended for direct fire, but soldiers developed crude but effective aiming techniques and, on occasion, were able to hit and destroy tanks. In the 1941 model, the rocket motor was at the front of the spin-stabilized projectile, ensuring that a high-explosive warhead would normally be above ground on detonation, thus giving maximum fragmentation spread. If delay-fuzed ammunition was fired against buildings, the initial impact of the motor assembly assisted the warhead in penetrating walls to burst beyond.

The larger, longer-range, later-model systems were less portable and therefore less valuable in urban combat; however, some projectiles could be fired from the frames or cases in which they were delivered. This meant that it was possible to manhandle these rocket projectiles within buildings to reach firing positions, such as the upper stories of buildings, where it was not possible to take conventional guns or tanks.

Having been aimed at the target, the rocket would then be fired electrically from a distance, avoiding the risk of return fire to the now-obvious firing point. The Soviets used individual Katyusha rockets in a similar manner, firing them from rails propped between furniture and windowsills.

Reflecting the experience of street fighting in Stalingrad, the German high command generated a requirement for an armored vehicle to clear obstacles and physically breach urban objectives by ramming. (The potential for tanks to assault buildings in this way had long been known, and occasionally practiced with the early-model Panzers, which were smaller, with barrels that did not protrude beyond the front of the hull. However, as vehicles became taller, the risk of either jamming against ceiling beams or dislodging them and collapsing the building on top of the vehicle inhibited commanders. Furthermore, they could no longer slew their turrets within buildings.)

The concept was to mount a turtle-like, heavily armored shell on a turretless version of a Tiger tank. This had a breaching prow at the front and a sloped roof to disperse falling rubble to the sides. Significantly, the overhead armor was 50 millimeters thick while the frontal and side armor was 30 millimeters. The Rammpanzer had thicker top armor than that of the tank on whose frame it was built. This reflects the strength needed to survive falling rubble, but also recognizes the threat from infantry anti-armor weapons fired or thrown from above in urban combat. It appears that this double layer of substantial armor with an air gap would have given unprecedented protection against shaped-charge grenades and satchel charges, which were the main threat at very close quarters.

While there would certainly have been room within the vehicle for a number of assault infantryman, the hatch layouts do not suggest this was intended. The records show that Hitler personally ordered the development of three prototypes and suggest that they were built, although there is some dispute and no genuine photographs have been found. Certainly they did not see action.

Nevertheless, the concept itself may have some merit, although both Allied experience with armored bulldozers and the Germans successful use of turretless "Raumpanzer" tanks with angled dozing blades to clear streets in their bombed cities suggest that the addition of a similar movable blade would avoid the tank drivers' problem of becoming "piered" — jammed on sections of wall or large rubble beneath the hull.

During the early "phoney war" stages of World War II the prospect of conducting deliberate attacks against extensive fortifications akin to the trench warfare of World War I loomed large.

Possibly inspired by Austrian rail-mounted trench-digging machines from that war, Winston Churchill directed the development of machines that would advance just below ground level, excavating its own trench. Infantry and armored vehicles would follow in the trench and use the machine as a ramp to emerge unscathed on the enemy objective.

While large numbers were initially planned, eventually only a few of the narrower infantry version were built by the Royal Navy and none were ever used in action. The machine, codenamed Cultivator No. 6, was massive — 77 feet long (in two sections), 10 feet high, and 7 feet wide — and excavated the lower part of the trench with a large cylindrical cutting blade and displaced the soil above this with a plow arrangement. Even above ground it could only move at 3 miles an hour, and its turning radius of a mile proved problematic.

Nevertheless the "Cultivator" did demonstrate the technical feasibility of a military vehicle capable of moving just below ground level. This, reinforced by developments in small-tunnel boring technology, strongly suggests that it would be possible to build more compact unmanned machines that could operate in a broadly comparable fashion in urban terrain.

It is sobering to reflect that there were technologies and capabilities available in 1944 that are now abandoned and forgotten, yet might today give decisive advantage in an urban fight. A large-caliber "mortar" capable of indirect and direct fire — something like the 380-millimeter launch on the Sturmtiger — would offer the ground commander an assured form of destructive effect that is currently delivered by guided aircraft bombs.

Furthermore, inert projectiles would offer reliable breaching of substantial walls without the blast hazard of other breaching munitions. Effects can be delivered within seconds of the target being identified, largely avoiding the approval processes for airstrikes. Certainly, such a capability avoids the commitment of a squadron of strike aircraft and refuelling support that is required to keep an armed plane permanently on station.

Self-propelled assault guns such as the Sturmtiger and the ISU-152 were also designed for the close fight, with very heavy armor, and were resistant to the kinetic projectiles of the lighter anti-tank guns they might encounter in an urban area. While shaped and hand-placed explosive charges remained a threat, the vehicles were tough enough to be able to reduce this vulnerability by advancing into their own side's bombardment — or in the case of the Sturmtiger, by using its own mine discharger to suppress infantry nearby.

These vehicles were also extraordinarily robust compared to modern self-propelled guns, which are generally only armored against small-arms fire and shell splinters. This meant that provided the commander was alert for under-floors or cellars and took care to avoid striking main supports, such vehicles could be driven straight through buildings. This toughness was well illustrated during the Chernobyl disaster, when a number of old ISU-152s were used both to ram entries for specialists and as bulldozers to bring down irradiated buildings, literally collapsing walls and roofs on themselves with impunity.

The capability provided by small self-propelled guns, as well as tanks equipped with flamethrowers or demolition guns, would be extraordinarily valuable today — with the clear acknowledgement that while flame weapons are not explicitly prohibited (except against civilians), domestic and international perceptions make their use problematic.

It would also seem that the lessons learned using these manned vehicles during World War II might usefully inform requirements for future platforms. For example, the utility of the forward hatches on the Churchill tank was that it allowed sappers or infantryman to dismount while protected, and this is incidentally the exact capability that Israel has developed on some of its specialist engineering vehicles derived from Centurion tanks, where there is a forward dismounting in the glacis plate.

Importantly, all three of these capabilities — a large-caliber mortar, self-propelled assault guns, and unique tank capabilities — could now be provided by unmanned armored platforms. In particular, spigot mortars offer a way to provide a small tele-operated platform with a very substantial warhead for close-range use.

While Israel has developed and licensed a family of door- and wall-breaching munitions, there has been a curious failure by contemporary armies to adopt these — or their equivalents. Without experience and confidence in their use, it is risky to assert that they would offer radical advantage in building clearing.

Nevertheless, the occasional surviving account of how Russian "storm groups" freely used stocks of captured Panzerfausts to conduct simultaneous multi-entry, through-wall assaults concurrently in cellars and upper stories suggests such potential. The Krummlauf concept — allowing the soldier to engage around cover while remaining hidden — has now been delivered by devices such as the "corner shot," as well as sighting systems where an image from a rifle held around cover is projected to a head-mounted display.

In contrast, there do not appear to be any available equivalents of Nebelwerfer launchers and projectiles. While enhanced blast munitions from shoulder-fired launchers arguably offer dramatically improved terminal effects, these require firers to expose themselves to engage. A direct-fire system that is fired remotely (or even electronically) after setting up, from cover, has great utility in the urban fight.

Possibly the most thought-provoking of the 1944 technologies worth considering are not lethal. A very tough armored vehicle that can move through buildings and obstacles would mitigate some of the tactical challenges presented by the urban fabric. The British Cultivator No. 6 demonstrated that a mole-like trench excavator that advances through an urban area just below the surface is technically possible. A tunneling machine used by ISIS showed that this can be done with modest engineering capability.

Adding the capacity to lay supports on which to spread excavated soil and rubble to form a tunnel appears straightforward. Yet the real significance of these examples is to show that it is possible to build cutting machines for both manned or unmanned armored vehicles to enable them to move through structures by cutting their way rather than ramming.

All of the capabilities described and discussed above had limitations in 1944, and many would be more vulnerable on today's battlefield. Nevertheless, on the streets of Europe commanders had tactical options that we do not have today — options that saved their soldiers' lives — and would still have been valuable in Marawi or Mosul.

It is an indictment that, with few exceptions, we have not exploited contemporary technologies to deliver the special types of effect that offer decision on the urban battlefield. We need to fix that.

Dr. Charles Knight has served with British Army, RAF and several overseas forces and is a lecturer in Terrorism, Asymmetric Conflict & Urban Operations at Charles Sturt University. He developed UK training in Soviet urban doctrine, subterranean recce capability & urban anti-tank guided weapon procedures. He spent a decade in Special Operations development, commanded 2/17 Royal New South Wales Regiment, served in 1 Commando Regiment and developed Australian Army urban doctrine.

The views expressed are those of the author and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.