Underrated armament that changed warfare
The most efficient cost effective weapons of WWII where used and developed during WWI. Warfare doctrines used in WWII including the Blitzkrieg, strategic air-bombing, Mechanized warfare, U-boat attack methodologies and integrated battle-plans were also developed during WWI as a result of the trial and error of the static front-line experience. At the same time weapons that were introduced in WWII where the backbone of the Cold War warfare including Aircraft Carriers, L2L Missiles, Guided bombs, Infrared optics, Electronic warfare, A-bombs and so on.
Flak 88
The Flak 88 was the artillery piece most effective in Anti tank warfare in many turning points battles including the English counterattack in France, Lybia, Kasserine Path and so on. It could destroy any ally tank even from 1500 meters although it was developed for Anti-Aircraft defensive purposes.
The WWI 88 mm 1916 AA double purpose gun was the predecessor of the WWII 88 mm gun, that was also used and installed on tanks and tank destroyers. Many of them were transferred from France in 1944 do defend the German industry against ally air-raids with many bombers gunned down, but the Germany Military industry was outgunned by numbers.
Flamethrowers
Flamethrowers were developed and used by the Allies and Germans in both wars as part of a storming group doctrine. During WWII quantities and mobility solutions enabled a vast use for close combat support against entrenched enemy, urban fighting and bunker suppression.
Bombers
Bombing civilians from the Air was carried out mainly over Britain by Gotha airplanes and airships in the midst of WWI where the goal was to terrorize population and force their governments to abdicate or make concessions in the peace treaty table. The same idea was turned out to be Strategic bombing in WWII where the major aim was to deplete the industrial and transportation means of the enemy. Submission aimed bombing was effective on Tokyo Hiroshima and Nagasaki. Other bombings that were oriented on terrorizing population got the reversed effect by strengthening the fighting spirit. revenge and will of the attacked peoples.
Submarines
Britain in both wars was blocking the ocean supply routes of Germany. The Germans tried to do the same by attacking and blocking the shipping lanes to Britain. by use of U-Boats. The evolving technologies that enabled anti submarine warfare where radars, destroyers, nets, longer-range spotting and attacking airplanes. Airplane extended range and improved armamantt (like airborne torpedoes and radars) is what made spotting and attacking viable and enabled the turning point in favor of the allies by the end of 1942. The U-boats managed to sink about 1500 valuable cargo ships of raw material, food and armament desperately needed in the UK and USSR in the battle of the Atlantic by then. The Allies managed to sink about 730 U-boat submarines.
Carrier Airplanes
The Swordfish airplane which was a WWI era biplane mostly was launched from ships and used to hunt battleships and later on submarines. It did it effectively in important turning point sea battles of the Mediterranean including Taranto, the hunt of the Bismark and second Battle of Narvik in Norway. where U-boat and nine German destroyers were sunk after Swordfish action. By the and of the war the doctrine of Navy warfare it is based battleships was obsolete. Because they were vulnerable with submarines and air attacks, be it a Kamikaze or carrier planes. The battle of Taranto, Leite Gulf and Midway proved that the maximum range of an airplane that takes off from a carrier nullifies the long ranges of huge guns and thick armor of battleships like the Bismark, Yamato and HMS Hood. From then on through the cold war it was understood that domination of the seas is decided by the quantities and qualities of air carriers, electronic technologies and submarines.
Mortars
One of the most underrated weapon increase in use and manufacturing were the mortars. The were introduced as means to overcome the limitation of direct gunfire which is not effective against trench warfare in WWI. They were cheap to produce, easy to carry, easy to operate and suitable for infantry. As mechanized movement evolved tanks were vulnerable to cheaper AT weapons and guns. The doctrine was changed that tank units shouldn’t advance without infantry and if possible iwth air support. It was relatively easy to stop a tank with couple of guns that are 20 times cheaper to produce. The infantry mortars or the carried mortars where the most price/effective tools to defend, smokescreen and to attack AT guns teams and rocket launchers so advancing tanks would have suppressing fire and smokescreens against Gun ambushes. Axis powers manufactured 725,000 mortars (which is 7 times more then artillery pieces) and the Allies manufacured about 544,000 mortars during WWII.
Related Sources & Links
Swordfish Attack on the Bismark
http://www.kbismarck.com/article2.html
Infantry Mortars
https://ospreypublishing.com/infantry-mortars-of-world-war-ii-pb