Flak has returned.

Russian and Ukrainian forces are both discovering that they need a lot of air defenses, including relatively low-tech anti-aircraft guns.

Machine guns and cannons were used to shoot down flying machines during World War I. Half of the Allied bombers shot down over Germany during World War II may have had victims of "flak", a shortened version of a German word.

Cannons and machine guns were less useful than guided missiles because of the advent of high altitude jets.

Russia is bombarding Ukrainian cities and power plants with missiles and Ukraine is sending drones to shoot down Russian tanks.

Ukrainian President Volodymyr Zelenskyy stands next to an Iranian-made Shahed-136 drone.
Ukrainian President Volodymyr Zelenskyy next to an Iranian-made Shahed-136 drone.
Screenshot/President of Ukraine official website

It's like using an elephant gun to stop a flea, because using big, expensive long-range surface-to-air missiles is like that. The increased reliance on missiles and aircraft has made flak essential again.

Nick Reynolds is a land-warfare expert for the Royal United Services Institute, a British think tank.

The new RUSI study analyzed what Ukraine needs to do to counter the mass of Iranian-made Shahed-136 "kamikaze" drones being used by Russia.

The study wants Western countries to send more self-propelled anti-aircraft guns, like the German-made Gepard, and more short-range man-portable air-defense systems.

According to the RUSI report, gun systems are preferred over missiles where possible due to the lower cost per engagement and higher availability of bullets.

Russian 2K22 Tunguska anti-aircraft weapon
A destroyed Russian 2K22 Tunguska self-propelled anti-aircraft weapon in eastern Ukraine on September 15.
SERGEY BOBOK/AFP via Getty Images

The Soviet-made S-60 anti-aircraft guns are being used by both Russia and Ukraine. The Cold War-era ZSU-23-4 Shilka and 2S6 Tunguska are only used against drones.

The Shahed-136 is difficult to shoot down due to its relatively small size, shape, low altitude flight and low speed.

The study rates Germany's Gepard as highly effective.

50 Gepards, some of which have already been delivered, are part of a polyglot array of Western air defense missiles and cannon being sent to Ukraine. The US should send the 1960s-era M163, a 20-mm Vulcan cannon mounted on a M113 armored personnel carrier, because it lacks an onboard radar needed to detect targets.

Old weapons, new dilemmas

German Chancellor Olaf Scholz Gepard anti-aircraft gun
German Chancellor Olaf Scholz inspects a Gepard self-propelled anti-aircraft gun near Oldenburg on August 25.
AXEL HEIMKEN/AFP via Getty Images

Ukranian faces an air-defense dilemma according to a study.

Western-made SAMs are better against Russian jets and cruise missiles than spare anti-aircraft missiles. With Ukraine's 1,000-mile frontline, a lot of numbers are needed to protect troops at the front and infrastructure in the back. The range of anti-aircraft guns is small.

The Shahed-136 is simple and not particularly difficult to intercept, but most of the current means of doing so are too expensive or draw on unacceptable numbers of weapons required for other defense tasks to provide an adequate medium-term solution.

Political advantage is offered by older anti-aircraft guns. For fear of antagonizing Moscow, countries supporting Ukraine have been reluctant to provide jet fighters and long range missiles.

Ukrainian troops anti-aircraft anti-drone machine gun
Ukrainian troops with a civilian-designed anti-aircraft machine gun in Mykolaiv on November 9.
Vladimir Shtanko/Anadolu Agency via Getty Images

According to the RUSI report, neither MANPADS or SPAAGs should be considered politically sensitive as they are fundamentally defensive weapons needed to protect civilian infrastructure that do not require the absolute latest in cutting-edge technology to be effective.

Anti-aircraft guns have remained useful despite the deployment of more sophisticated weaponry. During the October War in 1973, Israeli pilots who dived low to avoid SAMs were chewed up by the Shilka and other anti-aircraft cannons.

Anti-aircraft guns are still lethal against helicopters, attack jets, and drones, as many Russian aircraft are forced to do over Ukranian.

"Medium- and long-rang SAMs are most effective when they are complemented by a robust network of AA guns that can threaten any aircraft trying to avoid higher-altitude threats by flying low." An integrated air defense net consists of layers of different systems.

His work has been published in Forbes, Defense News, Foreign Policy magazine, and other publications. He has a masters degree in political science. You can follow him on social networking sites.