Air-burst hand grenades

Rheinmetall appears to be developing a new defensive (1) hand grenade for Sweden and showed it off at an infantry symposium in Germany a few weeks ago (~an industrial fair).

The hand grenade can be thrown as usual, erects itself upright with a mechanism, launches its warhead into a height of 1.5 metres and there it explodes, showering the lower hemisphere with fragments.

The only photo known to me is in the current issue of the SuT journal (German). I didn't ask Rheinmetall for permission to use the photo in light of what I'm going to write about the concept.

My first impressions were of course "mean!" and "technically interesting!".

Next, I recalled the technical predecessors:

* Jumping warheads have been employed with medium mortars, 30mm low-velocity grenades and anti-personnel mines. The principle appears to have satisfied the users (and horrified the enemies) when a clear shot upwards was possible (such as with AP mines). High trajectory grenades of such a kind were apparently rather unreliable.

* The mechanical principle for erecting the device after impact has been widely used for scatter mines and appears to be quite effective as well. Here's a mine which shows the principle:

POM-2S anti-personnel mine
The technology was clearly available at least a generation ago, maybe two. Why wasn't such a high performance hand grenade developed before? There's sometimes a reason for such an omission.

- - - - -

I did recover quickly from the first impression, though. Effectiveness isn't all that you need. The most deadly hand grenade is not necessarily the best one. Well, it may be sometimes, but not necessarily in the whole picture.

A maximization of a hand grenade's lethality like this reveals probably a fundamental misunderstanding of a hand grenade's purpose (this blames the Swedish army material procurement, not the developer).

The German production of hand grenades from 1941 till 1945 was 140 million. Most likely less than one per cent killed a soldier, while most likely the vast majority of the production was spent in combat or training. 

This should come as no surprise, for hand grenades are not primarily about killing and wounding. They are much more often employed for two other purposes:

* Scaring the enemy; deterring the enemy against closing in / chasing the enemy away

* Security; attack on an area (such as a room or tunnel) that might be occupied by the enemy

One example; combat in woods. Forget the daring attacks through woods in peacetime exercises. Infantry combat in woods among well-supplied regular army infantry tends to look differently.
Even as early as 1914 when no machine gun was at company level or below and when there were only handguns and bolt action rifles, infantry got pinned down regularly in wood combat. The deadliness and scariness of the rifle fire simply did not permit much offensive movement. Such combat often degenerated into hand grenade duels. Both sides threw many hand grenades because raising the head for locating enemies and aiming ranged from futile to suicidal. Rommel's "Infanterie greift an!" book mentions several such hand grenade duels, for example.

Now think about it - how much does the increased frag effect really help? Even a 100% increase in lethality (just an example figure) could in practice turn out to help only in 5% of the cases, leading to a net loss of capability because of the increased weight.
It's likely very dependent on the situation,and on the ground condition (flat or waved). It might even be prohibitive if the cover of friendlies is too low and would protect against an air burst frag effect.

I would rather prefer a lightweight hand grenade for most purposes. There are such lightweight hand grenades. Examples:

Austria: Arges Type HG 86 - 180 g, fragmentation
Egypt: Kaha Number 1 - 210 g, concussion
France LU 216HE - 165 g, concussion
France Alsetex SAE 210 - 190 g, concussion
Greece Elviemek EM 02 - 140 g, concussion
Netherlands: NWM V40 - 136 g, concussion

Such hand grenades can be as small as 6 x 4 x 4 cm.
Normal hand grenades range from about 270 to about 570 g, with fragmentation types usually being much heavier than concussion types. The mini hand grenade throwing range can reach out to 40 m, while the heavy examples can be typically thrown to about 30 m. Safe handling with a glove is a concern, though.

- - - - -

Hand grenades can be 'improved' in a technical, engineering sense. Such an improvement would be about better explosives and better fragmentation pattern. The simulation of fragmentation patterns of warheads in computers keeps quite a few engineers in their jobs. It's a typical technical way of looking at hand grenades.

A rather 'military-historical' perspective emphasizes that infantrymen like to expend them for many purposes, not just for actually hitting the enemy with high probability. A large quantity becomes most important.

A practical perspective would emphasize the fact that hand grenades are scarce in part because they weigh a lot. A great weight efficiency becomes important.

A more military-theoretical perspective suggests an emphasis on the psychological effect: Hand grenades define areas in which nobody wants to be. You can use this to keep the enemy out of the area (such as the area immediately in front of your position) or to chase him away.

This psychological value of a hand grenade is certainly improved by a well-deserved reputation for deadliness, but I have little doubt that thirty lightweight hand grenades are scarier than ten high fragmentation hand grenades.

The procurement of lightweight hand grenades with high quality explosives is likely one path of improvement, but there's more: Flash and smoke effects could be added. I don't mean large smoke effects, but rather a small marker cloud as it was used for heavy anti-air gun grenades in both world wars. This would add a potentially effective visual effect to the package.

An enhanced flash effect could help a lot, especially at night. It would require only about five gram of additional filler, preferably on the outside of the explosive. The effective dazzling radius against night sights and unprotected eyes could be enlarged considerably beyond the concussion radius.

There are numerous complaints about the weight carried by the infantry. It's probably not a preferable development path to create a heavier and more complicated hand grenade for increased lethality in the few per cent hand grenade uses where this really counts. 

That approach may be right, but I suspect it's not. I do rather suggest to look more at weight reduction and flash effect.

(1): "Defensive" because of the fragmentation effect. Fragmentation hand grenades are regularly preferred when friendlies are behind cover, while "offensive" blast/concussion grenades are preferred if the casualty radius has to be low or for demolition. The jumping warhead approach is only reasonable for the defensive type.


edit 2016: A video appeared in the meantime:

It's now called "SHGR07".


  1. I think it needs to go one way or the other, heavy or light.

    In the event of sustained harresment with grenades, its likely that noise and light (and smoke) are going to be bigger debilitators than fragments. Ruining sight, hearing and forcing people out of cover.

    In a shock usage, a few bigger ones are more likely to actualy injure someone.

  2. "How low weight can you sensibly go?" would certainly be an interesting experiment in hand grenade design.

    Clearly with a conventional design at some point the non-warhead part can hardly be reduced in weight without endangering the thrower. Maybe a completely new approach could enable much weight loss there?

    Adding more flash could make a sense in quite a few cases.


    1. Flash bangs and thermobaric hand grenades with electronic fuzes could be very lightweight (under 100 gram), but one would first need to turn away from gold plating towards minimised burden or maximised quantity.

    2. For clarification; something like
      'create electric charge with piezoelectricity, store it in capacitor, throw, electronic timer runs, electronic timer releases charge to booster explosive charge, boom'.

      Such a fuse could be much smaller and lighter than one that's still based on the 100 years old Mills bomb fuse design.

    3. Indeed. There is still to be gained a lot from a ligthened classic approach. Yet more from good, smart and disciplined leadership which always has to fight hard against the institutional imperative.

      From Airmobility in Vietnam:

      "By changing our perspective from that of the division commander to the individual soldier, we can perceive one of the often forgotten advantages of airmobility.

      It is ironic to me, after the millions spent to reduce a few pounds from the infantryman's rifle, that many soldiers would end up carrying as much (or more) total weight as the doughboy of World War I. A soldier when he exits a helicopter becomes the Army's most important extension of the airmobile concept; and his individual load should consist of the bare essentials needed for the next few hours - basically ammunition and water. To avoid the classic soldier's syndrome of holding on to everything he owns, the 1st Cavalry Division developed a technique for keeping all the personal equipment of the individual in squad bundles that were consistently delivered when needed.

      This was a tremendous boost to morale as well as a very real increase in effectiveness. However, this seemingly simple technique has to be relearned several times in every campaign."