The question of how effective helmets were and which were most effective initially arose in World War I. This was one of the first wars to feature airplanes, heavy use of artillery, tanks, and massive trench warfare.
The helmet became particularly important as huge artillery pieces were used to soften positions in rolling barrages before soldiers stormed the trenches.
Artillery could use various types of shells like anti-personnel and fragmentation shells that could rain metal on the heads and shoulders of soldiers in the trenches.
The Germans started the war largely using their Pickelhaube or spiked helmets. These were visually impressive, but they were hard boiled leather and did little to stop bullets and shrapnel. The spikes actually made the soldiers easier to identify and target.
The German scientist Dr. Friedrich Schwerd designed the Stahlhelm, a helmet made of heated steel that covered the head and neck much better. It was loosely based on the sallet from the medieval period.
After the Stahlhelm’s adoption by stormtrooper units and the general army at the Battle of Verdun, casualties due to shrapnel dramatically decreased, some historians estimating by as much as 70%.
Through 1940 and World War II, minor modifications were made to increase the durability and efficiency of the helmet while lowering the cost. The helmet became the distinctive feature of the German army through the war.
Variations of the helmet are still in use today. It was a simple but effective tool for dealing with the shrapnel of modern warfare and set a high bar for other models.
The French and British both saw the need for a helmet and fielded their own models in 1915. The British inventor John Leopold Brodie produced the most effective helmet.
It was constructed in one piece by pressing one thick sheet of steel. This made it more durable and cheaper to build than both the French and German models. It was loosely based on the medieval kettle hat and has a distinctive wide brim.
This was also used in the interwar period and part of World War II. Improvements included adding a better liner for the helmet and a stretchy chin strap until it was replaced by the M1 during World War II.
The M1 consisted of a hard outer shell that removed the wide brim of the Brodie, which soldiers complained was too sharp and light-reflective. It also had inner netting that could be adjusted to fit the helmet. It included two hooks for chin straps.
There are no direct studies of which helmet was “best” and it often comes down to a matter of taste. The wide-brimmed Brodie tends to lose out to the Stahlhelm’s sleek look. A more definitive factor is how long they were in use.
The British Brodie was phased out in favor of the M1 and models based on it.
The Stahlhelm is still in use today which suggests it still has substantial value. The Stahlhelm has a harder shell as its production used a different process to make it tougher (but also more difficult to produce).
The M1 made a trade-off in that it has a slightly less hard shell than the Stahlhelm but has much better lining and padding inside the helmet. This helped paratroopers or anybody else receiving a concussion from bumping their head or having debris from artillery land on them.
Not only did it reduce head trauma, it also helped to save the soldier from shrapnel wounds.
Given the start of the helmet as a way to avoid shrapnel wounds in World War I, and the tendency of wars after World War II to be more low-intensity counterinsurgencies, the helmet that provides a good balance of protection from artillery as well as bumps seems the more useful.
In the final analysis, the Stahlhelm gets the advantage in World War II due to its harder shell, but ultimately loses out to the M1 which has a more useful balance of features relating to the different needs arising after World War II.