# Why don't napalm canisters have fins? **URL:** \ **Category:** Factual Questions\ **Created:** [August 26, 2015, 2:56am UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911 "2015-08-26T02:56:35Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![chacoguy](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Post date:** [August 26, 2015, 2:56am UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/1 "2015-08-26T02:56:35Z")
Is there a reason, or benefit, to have them tumble like that? ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [August 26, 2015, 2:59am UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/2 "2015-08-26T02:59:36Z")
Perhaps to slow down the decent? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [August 26, 2015, 3:06am UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/3 "2015-08-26T03:06:21Z")
They’re just going _splat_ anyway, why not let them tumble? ---
**Author:** ![chacoguy](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Post date:** [August 26, 2015, 3:12am UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/4 "2015-08-26T03:12:58Z")
Even in WWI, there was need to drop them into the mouth of a cave, additionally, you can slow them with fins or parachutes. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [August 26, 2015, 3:15am UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/5 "2015-08-26T03:15:31Z")
Does it help them spread out? ---
**Author:** ![spifflog](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@spifflog](https://boards.straightdope.com/u/spifflog)\ **Post date:** [August 26, 2015, 12:43pm UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/6 "2015-08-26T12:43:23Z")
Unlike many iron bombs, you want napalm to be dispersed. You want as large a pattern as possible. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 26, 2015, 2:19pm UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/7 "2015-08-26T14:19:09Z")
Napalm was traditionally deployed from very low altitude. Low enough that when it hit the ground the delivering airplane was just above the target. In that case it’s desirable to have the ordnance be retarded somehow so it impacts somewhere behind the delivery aircraft. This protects the aircraft from not only the ordnance detonation/deflagration, but whatever else of the target catches fire or explodes as a result. A very simple way to make a retarder is to leave the fins off and have the ordnance tumble. A more complex way is to build in movable fins [wiki pic](https://en.wikipedia.org/wiki/File:North_American_F-100D-75-NA_(SN_56-3184)_in_flight_dropping_a_Snake-Eye_bomb_060922-F-1234S-005.jpg) or, more complex yet, some kind of ballistic parachute [wiki pic](https://en.wikipedia.org/wiki/Ballute#/media/File:F-111F_dropping_high-drag_bombs.jpg). Simple is good and cheap. Complex is bad and expensive. Finally, the very original napalm tanks were simply ordinary jettisonable external fuel tanks (“drop tanks”) that some clever guy rigged with an incendiary fuze. Those tanks never had fins since they were designed for minimum weight, complexity, and drag in cruise with no thought at all to how they fell after they were jettisoned. The field expedient experiment with dropping drop tanks full of fuel worked. Switching from ordinary gasoline to gelled gasoline to later flammable mixtures were just minor refinements in the basic idea. Napalm is obsolete today. ---
**Author:** ![MichaelEmouse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/michaelemouse/32/101_2.png) [@MichaelEmouse](https://boards.straightdope.com/u/MichaelEmouse)\ **Post date:** [August 26, 2015, 3:04pm UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/8 "2015-08-26T15:04:41Z")
> [@LSLGuy](#): > > Napalm is obsolete today. Superseded by thermobaric, white phosphorus and cluster bombs? Anything else? Why deliver it from quite low altitude? ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 26, 2015, 5:27pm UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/9 "2015-08-26T17:27:04Z")
This [Mark 77 bomb - Wikipedia](https://en.wikipedia.org/wiki/Mark_77_bomb) is the last sorta-napalm I’m aware of. USAF had already phased out all this kind of stuff when I was in the biz in the 80s. It appears USN/USMC was using this as recently as a decade ago. I don’t know whether it’s still in the inventory. WP has been used as a smoke charge since forever. AFAIK it’s still used a bit as an incendiary, but more as an artillery or mortar-delivered item than air-delivered. IMO there’s a bunch of propaganda hype against this stuff that’s bogus, but given that the hype has traction in the civilian world, the political headaches aren’t seen as worth the incremental weaponeering effects. At least not by US and NATO in most scenarios. As such, WP is also being phased out from practical use even though it may well remain in the stockpile for a couple more decades. Why close … Since WWII the step-change in aerial bombardment has been in actual as-delivered-in-combat accuracy. Now we can deliver a single small hunk of explosive with enough accuracy to pop almost anything we can identify and locate while having statistically bearable collateral damage effects. Whereas achieving the same effect in WWII required moon-cratering an area the size of a mid-sized town, and by Viet Nam that had improved all the way to moon-cratering an area equal to a village-sized town. Now we crater parts of individual houses. Napalm was originally a close support anti-personnel anti-truck weapon. You could drop it from WWII or Korea-era fighter bombers close enough to friendlies to affect the battle without undue risk to them. IOW, the effects pattern was (relatively) small and controlled, provided you could control the impact point both accurately \*and \*precisely. In aircraft of that era, the way to get accuracy was to get down close enough to really see what you were doing; you could tell the trucks or troops were theirs and not ours by seeing the shape, the paint, the uniforms, etc. with your own eyes. For any unguided air-dropped (or artillery-fired) weapon, precision is a worse-than-linear function of slant range to the target. IOW, if you’re 2x as far away, your dispersion of actual impact goes up more than 2x, maybe 2.5 or 3x. The inverse consequence of that is that if you really need to gnat’s ass the point of impact, you need to get close to your work. Napalm the weapon system was never an area weapon. Various incendiaries, such as the WWII [https://en.wikipedia.org/wiki/M-69\_incendiary](https://en.wikipedia.org/wiki/M-69_incendiary) may have used similar or even identical chemistry, but they were never the same weapon for the same military purpose. Nor were they properly called “napalm”, at least as those of us in the tactical forces used the term. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [August 26, 2015, 6:40pm UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/10 "2015-08-26T18:40:32Z")
> [@MichaelEmouse](#): > > Superseded by thermobaric, white phosphorus and cluster bombs? Anything else? Yeah, something very similar to napalm, but made from JP-8/JP-5/kerosene instead of gasoline, and with less benzene. My suspicion is because JP-8/JP-5 are pretty commonly available, with JP-8 being what the Army runs on- diesels and turbines, and JP-5 being the Navy’s jet fuel. > **[Mark 77 bomb](https://en.wikipedia.org/wiki/Mark_77_bomb)** > > The Mark 77 bomb (MK-77) is a United States 750-pound (340 kg) air-dropped incendiary bomb carrying 110 U.S. gallons (416 L; 92 imp gal) of a fuel gel mix which is the direct successor to napalm. > The MK-77 is the primary incendiary weapon currently in use by the United States military. Instead of the gasoline, polystyrene, and benzene mixture used in napalm bombs, the MK-77 uses kerosene-based fuel with a lower concentration of benzene. The Pentagon has claimed that the MK-77 has less impact o... My guess as to why it’s dropped from such low altitudes is because it’s typically used in a close air support role against dug-in enemies or troop concentrations, and airplanes typically have to fly pretty low to perform that job, regardless of what they’re dropping or shooting. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [August 26, 2015, 7:40pm UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/11 "2015-08-26T19:40:53Z")
Does the new stuff stick to kids? ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [August 26, 2015, 8:31pm UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/12 "2015-08-26T20:31:28Z")
Care to say why you asked? War is dangerous for children and other living things. That was the darnedest cutest poster. ETA: “poster” as in you put it up on the wall. ETA: while listening to Donovan. I knew it. [Another Mother for Peace - Wikipedia](https://en.m.wikipedia.org/wiki/Another_Mother_for_Peace) ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [August 27, 2015, 12:07am UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/13 "2015-08-27T00:07:18Z")
> [@Leo\_Bloom](#): > > > [@TriPolar](#): > > > > Does the new stuff stick to kids? > > Care to say why you asked? Oh, everybody knows that one! But seriously–do our currently-used incendiaries have similar (or better!) viscosity, all the better to minimize rapid removal from particularly flammable surfaces? ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [August 27, 2015, 1:17am UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/14 "2015-08-27T01:17:03Z")
♬ _I am stuck on napalm 'Cause napalm sticks to me!_ ♬ ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 27, 2015, 1:45am UTC](https://boards.straightdope.com/t/why-dont-napalm-canisters-have-fins/728911/15 "2015-08-27T01:45:30Z")
> [@The Great Sun Jester](#): > > Oh, everybody knows that one! But seriously–do our currently-used incendiaries have similar (or better!) viscosity, all the better to minimize rapid removal from particularly flammable surfaces? It’s on fire when it hits whatever it hits. AFAI can tell from the ingredient list it’s sticky. Removal really isn’t an option in the time available.