I often hear stories of flamethrower troops storming the beaches of Iwo Jima and burning bunkers full of troops.

But isn't it more risky to carry a tank of flammable liquid with limited fuel and range when chucking a few grenades into a bunker could suffice? Wouldn't you just become a bigger target for the enemy?

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    I was present at a flamethrower demonstration a few years ago. I was 90 degrees off the axis of attack and probably 50 yards away, and I was uncomfortably warm. If he'd pointed that thing at me I wouldn't have had a chance to run. The only way to understand a flamethrower is to be near one.
    – MCW
    Commented Dec 14, 2015 at 15:40
  • Even still, wouldn't the limited range of the weapon, large weight, accident prone, whilst Making you a bigger target mitigate the psychological advantage?
    – RN_
    Commented Dec 14, 2015 at 16:33
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    Have you ever tried to hit a bunker loophole with a grenade? It's quite difficult.
    – gdir
    Commented Dec 14, 2015 at 17:10
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    And, while standing up and aiming wouldn't it be nice to have some way of making those in the bunker not shoot at you? Something really bright and hot just might do it...
    – Jon Custer
    Commented Dec 14, 2015 at 23:16
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    Grenades only throw shrapnel a relatively short distance, largely in a straight line. Flames on the other hand can travel around corners and will expand to fill a small void: youtube.com/watch?v=vtQucipCzW8
    – Richard
    Commented Dec 14, 2015 at 23:38

5 Answers 5


Flamethrowers can be useful for the assault on field fortifications:

  • Burning fuel can splash through the firing slits of a bunker and reach inside.
  • Smoke and oxygen depletion can kill troops in bunkers even if there is no direct hit on the individual.
  • Flamethrowers can be fired over obstacles like trench sides.

Flamethrowers are less effective as a general-purpose infantry weapon:

  • They are heavy, for relatively few shots.
  • The soldier is at risk if the tank is hit.
  • They have a short range compared to a rifle or LMG.
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    It's not what you said but I must add that contrary to movies, in real life if a bullet hits the tank it doesn't explode.
    – Nikko
    Commented Dec 14, 2015 at 21:20
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    @Nikko, there were two or tanks, fuel and propellant (often pressurized gas). Nitrogen is relatively harmless, but running around drenched in fuel would reduce a soldier's life expectancy on the battlefield.
    – o.m.
    Commented Dec 15, 2015 at 6:42
  • Yes this is why I agree that the soldier is still at risk
    – Nikko
    Commented Dec 15, 2015 at 9:05
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    Might be worth noting that flame thrower range can approach 100 yards - not a bad distance to be destroying a pillbox or bunker from. Commented Jul 22, 2016 at 21:45
  • The USSR deployed flametrowers on tanks in the Winter War, to burn out fortifications. Hiding the fuel tanks behind armor helped.
    – SPavel
    Commented Aug 14, 2017 at 23:29

Basic flame weapons are effective against flammable targets or in very close quarters. Normally they are not used in any situation where the defenders would have a clear view of the attackers. Flame weapons are currently popular among insurgent fighters due to their simple operation and effectiveness in ambush situations.

In World War II, flame throwers were used to clear out no-surrender fortified positions which were primarily found in the Pacific theater of war. Normally when a line or position is overrun the defenders will retreat or surrender. This was not the case for Japanese forces which would often hole up in pillboxes or bunkers and fight to the end. Against such positions a flame thrower is effective if the attacker can approach it from the side or the rear and incinerate it. When the defensive line is intact this is not usually possible, so flame throwers were primarily used in "mop up" operations to destroy fortifications that had already been strategically nullified.

In modern warfare, flame throwers are considered to be largely superseded by thermobaric weapons or incendiary rockets which are more powerful and work at longer ranges. Thermobaric weapons are useful in urban or other close quarters in which it is either (1) difficult to target projectile weapons, or (2) the situation is so close, that the use of projectile weapons could harm friendly forces accidentally.

thermobaric weapon

The US equivalent is the Flash rocket launcher. American forces rarely use the Flash due to the high probability of civilian casualties if the weapon is used in an urban environment. Modern military soldiers also have access to incendiary grenades which can be used to ignite flammable materials. These weapons can be effective against pillboxes or other positions which have a limited field of view. Normally such positions are no longer tactically relevant because modern artillery and rockets are so accurate and powerful that pillboxes can be destroyed from a long range.

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    Flamethrowers were also used in Europe. The USA/UK deployed flamethrower variants for some tanks, IIRC the Germans did that too.
    – SJuan76
    Commented Dec 14, 2015 at 19:18
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    @SJuan76 I didn't say that they weren't. Commented Dec 14, 2015 at 19:20

Everyone has covered all the pertinent points, except one: fear. Not only can a single flamethrower clear out a bunker effectively, the lone flamethrower cause the abandonment of nearby bunkers as well.

One thing that has not been mentioned about the flamethrower in its bunker-clearing ability is that, in close quarters, i.e. a bunker, the liquid fuel has the tendency to turn into an aerosol. When it does this, the fireball expands DRASTICALLY. You may have seen WWII/Korean War/Vietnam War footage of bunkers that will be hit with a flamethrower, and they will virtually explode in every direction, this is the reason.

When you combine this effect with the primal fear of burning alive, you get a devastating psychological weapon. Humans evolved alongside fire for millions of years. It's deeply engrained in our psyche. We have all been burned and know that pain VERY well. Most of us can imagine, to a degree, what it would feel like to burn alive, and unpleasant doesn't begin to describe it. Conversely, bullets and explosions are new. We didn't evolve alongside these threats, so they are not as deeply engrained. Most of us can't even begin to imagine a gunshot wound feel like.

I'm sure if you asked combat soldiers and veterans what's scarier, dying or being wounded by being shot, or dying or being wounded by a flamethrower, a large percent of them would say the flamethrower is scarier, in a different kind of way. And this bears in several videos I have seen over the years of bunkers being cleared by flamethrowers. I can't be sure (terrible memory), but I think a lot, maybe most of the videos I have seen, are the flamethrowing tanks. They will withstand the machine gun from the bunker, and get close, then everyone scatters, they don't even bother trying to defend. So, the single tank will quickly clear out several bunkers out of fear.

It's benefits greatly outweigh the risks, however, it has been judged inhumane, rightly so, I believe. Having it makes you a vulnerable target, but it terrifies the enemy and can cause surrender before confrontation begins. While, I am sure you can find footage of this in almost any WWII documentary on the Pacific Theater, as well as Vietnam, I also remember a book I read when I was a kid by a Marine, I forget which war, and he said something about the psychological effect of the weapon, if I can find which book, I'll link it here.

  • The fuel is not liquefied, it is liquid. Sublimation is the turning of a solid into gaseous form without going through a liqiud (e.g. dry ice or iodine). You are either referring to evaporation (through heating), aerosolization (through dispersal), or a combination of both. Movies tend to exaggerate a lot, but a flamethrower's stream can and does bounce off surfaces, filling the inside of a bunker. And carrying a flamethrower does not make you significantly more vulnerable -- but it makes you a priority target for the enemy.
    – DevSolar
    Commented Aug 5, 2022 at 7:57
  • Yeah, I wasn't confident about the sublimation, that's just the word that he used. But, basically, the liquid is turned into a gas that quickly spreads throughout the structure. And, you're right about it not being liquified, if it were liquified, I don't think it would come out in a stream like it does, it would be just a blast. So, you're right on those points, but a being a priority target makes you more vulnerable, it just means 'susceptible to physical or emotional attack or harm'. Being a higher (among the highest) priority target is kind of the definition of being more vulnerable. Commented Aug 5, 2022 at 16:58

I am fairly fearless facing most weapons, but flamethrowers are a major exception. In truth, I almost never thought about risk in combat, being under the influence of adrenaline and trained to think tactically. But you cannot evade an in range flamethrower if the operator aims it at you. Modern tactical combat is maneuver warfare, although I once used a fixed defensive positions (with the advantage of a major water barrier and only one causeway to defend). That enemy was mainly 13 year old boys who were pressed into service (their whole family would die if they refused) and no significant heavy weapons (RPG's excepted). Aimed fire was so effective I directed shooting at "anyone giving orders" and, indeed, never fired a shot myself (which was consistent with what Marines taught in Landing Party School - the leader should be observing, thinking and giving orders unless things go badly wrong).

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    This doesn't really answer the question of the tactical advantage(s) of deploying a flamethrower.
    – Steve Bird
    Commented Aug 1, 2022 at 15:19
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    This could be valuable background, and thus part of a useful answer, to some other question - but it doesn't even attempt to answer this question. Commented Aug 1, 2022 at 15:26
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    His answer is that the tactical benefit of flamethrowers is that it's impossible to take cover from them.
    – Ne Mo
    Commented Aug 1, 2022 at 16:28
  • This answer would be better if it more clearly answered the question and if it removed all extraneous material.
    – MCW
    Commented Aug 1, 2022 at 16:48
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    The effect of flamethrowers on enemy morale is a tactical benefit, which is hard to quantify and easily unterestimated.
    – Dohn Joe
    Commented Aug 4, 2022 at 7:17

If it's bunker warfare at close range (the only range at which flamethrowers work), you're crawling along or under cover anyway, so it's not like you're that bigger of a target. Throwing a 1-lb / 500g grenade through an aperture sometimes not much bigger than that would be hard from close range even if you weren't pinned down by the bunker's machine gun, adrenalized, and terrified you were shortly going to die horribly. Flamethrowers were used in conjunction with other weapons - probably rifles & BARs trying to suppress the MG to give the flamethrower guy a chance to stand up and use it. Yes, it's dangerous, but that's what close combat was.

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