PossiblyInsane said:
What exactly is the point of flamethrowers? A machine gun will kill ordinary people much faster for less weight, and its not much good against zombies because the avereage human body will burn for at least an hour.
Several reasons flame-throwers were quite common in the early 20th century yet now virtually non-existent:
-cheap: they are quite simple in design, just a load of plumbing, any country could make one and the flammable fuel for it was usually cheaper than the expense of ammunition (precision casting each brass case, each lead bullet and each carefully measured gunpowder load).
-Range: not the biggest concern as back then weapons with poor sights and archaic marksmanship training practices (emphasis on prone shooting, useless in a stand-up fight) meant most soldiers would be lucky to hit a target beyond a flame-thrower's maximum range.
-Technological niche: before sub-machine gun and assault rifle technology matured in price and reliability, flame-throwers were ideal close range weapons, like storming a trench or tunnel system. It was also more versatile as you just have to shoot it down a hole and everyone in the hole dies, shoot at the entrance of a machine-gun nest and everyone dies.
-FEAR: this was a weapon that had great psychological threat, very effective against conscript forces that were more common in the EARLY 20th century, often with poor training they had no idea the range or how to counteract flame-throwers so they panic and suffer worse losses.
-intention: in the early 20th century, property destruction was almost as important as killing the enemy. People holed up in buildings it was considered acceptable to burn the entire building down and the up-side was the enemy couldn't occupy it again.
Why flame-throwers died:
-too visible: This was noticed by the US marines in Iwo Jima, the second a flame-trooper lights up everyone within 2000 meters knows EXACTLY where a flame-trooper is. That draws sniper fire, machine gun fire but most deadly was mortar fire. That's why flame-troopers suffered the highest casualties, everyone was shooting at them! And everyone hated flame-troopers.
-New Weapons: the invention of compact and lightweight rocket launchers negated the flame-thrower's last niche, as they could launch a bomb right onto or into a foxhole or bunker from a much safe distance rather than in the past where a flame-trooper would have to implausibly sneak extremely close to channel the flame through the opening. Also, personal weapons now had huge capacities, fast fire rates and sights+training to be very accurate at long range, and flame-throwers could not be improved to match that.
-Weight: there is no getting around the fact that flame-throwers are very heavy as the fuel itself cannot be lightened. But as trooper are burdened with more and more equipment from body armour to personal radios to specialist weapons as well as their personal weapon... flame-thrower became impossible
-too much collateral damage: both against the enemy and if the tank ever gets hit incinerating anyone around or near it. It was a big, heavy liability. In the latter half of the 20th century when it became expected that conquering armies pay to clean up their mess, weapons that create that much destruction were discouraged.
-loss of edge: flame-thrower has lost it's psychological edge, it is no longer new and there are scarier things on the battlefield. Most armies now are volunteer (yes, even the Taliban are volunteer, though motivated by insanity, lies and extremism) which are harder to scare as they are not fighting against their own will.
-Propaganda: I think the biggest reason most flame weapons have gone is propaganda, it serves invading armies to not seem too brutal, and death by incineration can't seem like anything other than the worst possible way to die. Not like being shot. So it goes and other sides do the same as even the enemy are fighting a propaganda war. In this connected and democratised world it doesn't matter so much what you do, but what your are perceived to do.