Weapon Name- HMX Thermobaric Grenade
Round Type- Grenade
Weight- 1 lb, 2 oz
Lethal Range- 5 meter radius
Injury Range- 20 meter radius
Velocity- 9,400 m/s, 3,500 m/s - 500 m/s
Miscellaneous/electronic information- The weapon is essentially intended as an extremely powerful concussive grenade relying more heavily on the overpressure wave of the round and the secondary incendiary effects rather than shrapnel to kill, which makes it more effective at close ranges. The weapon can also be electrically ignited in order to produce less-lethal concussive effects, designed to stun but not kill the target, by utilizing a much lower pressure wave.
Basic Information
The weapon is essentially intended as an extremely powerful concussive grenade relying more heavily on the overpressure wave of the round and the secondary incendiary effects rather than shrapnel to kill. The thermobaric explosives works by utilizing a central explosive core to generate an initial shockwave and disperse incendiary material in the air, which causes it to ignite with oxygen and produce a secondary, much larger explosion. While most concussion grenades have an incredibly short range (such as the MK3A2 concussion grenade with a lethal range of only 2-3 meters, or 6-10 feet), the thermobaric grenades produce substantially more power than normal grenades, both by using incendiary material to incinerate the targets and by the secondary overpressure wave having a much farther range than traditional explosives. Thermobaric grenades utilize the air as a fuel source, which decreases the weight of the individual explosive itself, giving it a very high strength-to-weight ratio. Most thermobaric grenades, pound for pound, are significantly stronger than ordinary explosives alone; RDX for instance only has approximately 6.5 megajoules per kilogram of energy in it, while gasoline has 46, and hydrogen has 142. Mixed with incendiary materials such as Polytetrafluoroethylene (PTFE, or Teflon), hydrogen gas and aluminum powder, the explosive typically has 5-10 times the power of an ordinary bomb within it.
Thermobaric explosives behave differently from traditional fragmentation grenades in a number of ways. While more likely to kill in it's lethal range, it's energy dissipates rapidly without fragmentation to absorb it and thus it's highly effective in close range, but the lethality diminishes rapidly. The thermobraic explosive produces a fireball from burning aluminum, which is sufficient to catch most metals on fire, and thus the incendiary material can melt through certain defenses, such as steel armor or cars. The incendiary material consumes large amounts of oxygen, and thus can suffocate individuals, particularly inside of an enclosed space, and the explosive force itself is more powerful within enclosed spaces. Finally, the grenade produces a secondary shockwave which is far less powerful than traditional explosives, but still able to kill soft targets. The weapon is far more effective in enclosed spaces such as a bunker or sewer, and thus is widely used for bunker busting. These peculiar effects enhance it's power in regards to traditional explosives, but cause it to function much differently than most grenades and cause it's effects to change more dramatically in certain situations (such as enclosed spaces).
As the primary explosive HMX must be ignited with a detonator to detonate, and will not explode when burned or even exploded, the explosive can be deliberately weakened by only igniting the secondary explosive material, or even be used like a thermite, incendiary grenade by utilizing yet a third detonator. The grenade essentially contains three different detonators, one that is high explosive, one that is only weakly explosive, and one that is not explosive at all and is designed to cause the grenade to behave like an incendiary grenade. The grenade in effect can be used in lethal, less-lethal, and incendiary functions, rather than just as an explosive. The first detonator causes the thermobaric explosive to act as usual, creating a powerful, extremely lethal shockwave. The second is only designed to cause only the secondary explosive to ignite, which creates a much smaller, weaker explosion that is unlikely to kill, but can stun or incapacitate the user by producing a very powerful overpressure wave that is still far below lethal detonation velocities (similar to being hit by a strong gust of wind). This is achieved by mixing the aluminum with magnesium and copper oxide, which also creates a secondary flashbang like effect on top of the low velocity concussive force, allowing it to rapidly incapacitate the target without killing them. The secondary detonator bypasses the initial detonator and only causes the material to burn, or deflagerate, which causes the HMX to burn harmlessly and causes the shockwave produced by the grenade to be shorter range and lower velocity, and to be unlikely to cause burns to or kill the target. The third doesn't cause the weapon to explode at all, but rather just to burn, which due to the temperature of the burning aluminum and copper allows it to melt through solid steel, such as with tank armor or the engine of a car. These three different uses allow for greater versatility over normal grenades. The objective with the secondary detonator is to produce a low-velocity shock wave, unlikely to kill the individual but more likely to stun them. It also produces a flashbang like effect which can also temporarily deafen or blind the target. In this way, the weapon can be turned on and off to be lethal or non-lethal, when desired. This can be held in with a screw to make it more securely locked so it is not turned on or off by accident, or designed to be turned on and off when desired.
The explosive works by utilizing an HMX core, which is a high explosive slightly more powerful than RDX, with an explosive force of approximately 9,400 m/s, compared to 8,750 m/s or 8,000 m/s for C-4. It is one of the highest brissance explosives available, with a very high energy-to-weight ratio, and is produced as a by product during RDX production. This is an ideal explosive to disperse the flammable materials, which includes a mix of hydrogen gas, polystyrene, and teflon, combined with a small amount of magnesium, aluminum powder, and isopropyl nitrate. The Aluminum, Hydrogen and polystyrene are the primary fuels for the explosive, containing much of the energy of the blast (with approximately 31 mj/kg with the aluminum, 41.4 mj/kg with polystyrene, and 142 mj/kg with hydrogen), while the other materials in the incendiary increase the burn temperature, low the ignition temperature required to ignite the materials (particularly the aluminum), and ensure a more consistent, even burn to ensure all of the fuel is being consumed. Particularly the magnesium and isopropyl nitrate help in this endeavor. The bomb and explosive must be very precisely calculated to ensure the full burning of the material, which will be significantly less powerful if not properly designed (with some thermobaric explosives being only 30-60% stronger instead of 5-10 times stronger). The Grenade is intended for use in incredibly close ranges, particularly in room or building clearing, and when civilian causalities from fragmentation are a primary fear. Despite it's incredible power the controlled explosion is very short range, and thus does not do much damage to surrounding areas outside of it's initial lethal blast radius. While the grenade can be mediated to produce a smaller explosion, this is not widely done due to the difficulty of controlling the effects in this way and the lower predictability of it. Approximately 10% hydrogen, 20% polystyrene and 70% aluminum powder are used, with aluminum powder being the primary incendiary material. This produces a much more energetic and higher temperature burning fuel, and ensures a clean burn of the material to produce higher energy outputs. The resulting secondary shockwave has a detonation velocity of 3,500 m/s, which combines with the HMX to produce quite lethal effects. The grenade itself utilizes approximately 200 grams of HMX, and 250 grams of flammable materials, with an additional 50 grams of detonation and incendiary materials (as well as safety features) and another 90 grams for the carbon fiber shell. The detonator, which a chemical explosive, is ignited via an electric detonator, which gives some flexibility in it's operation.
The grenades components are housed in a thin, frangible carbon fiber shell, which produces largely non-lethal shrapnel that burns up at long ranges, and increases the transfer of energy to the target at close ranges. The shell is designed to fragment in designed fail-points that are deliberately weakened to produce more consistent results, as to prevent the fragmentation from forming in to large chunks that, at appropriate velocities may become lethal. After the initial fragmentation, in a few meters the carbon fiber largely disintegrates under the continued pressure and heat, thus reducing it's impact slightly. In this way the explosive force is partially transferred by the carbon fiber to the target, making it not a pure concussive grenade. This not only helps to contain the material and keep it from contamination by water or oxygen, but also helps store the material at high pressure and temporarily absorbs some of the shock wave for a short time, allowing the pressure to build up an create a more powerful shockwave, and just as importantly allowing the hydrogen gas to be stored at higher pressures and thus have a greater overall energy density in regards to volume. The added pressure also creates faster dispersion during detonation, creating a slightly more even burn and particularly enhancing the effect of the lower velocity detonation (such as when used in the less-lethal setting). This also produces a much louder noise during detonation, which allows the weapon to have secondary flashbang like effects. Storing the chemicals at higher pressures can lead to some degree of danger however, as if the grenade is ruptured by other means, such as by being penetrated by a bullet, it will vent out gases at high velocities, but is unlikely to explode. This also helps to reduce the external weight of the device considerably, being much stronger than the fiberglass container used in the MK3A2 hand grenade, for instance. All combined this shell takes approximately .2 pounds, or roughly 90 grams of the weight of the grenade, which is far less than the MK3A2 grenade, allowing for most explosive force and fuel.
