Author: Zoe Tolman, Assistant Archivist

We have largely looked at modifications made to AFVs in previous special devices articles. Today we’re taking a slight diversion to include another fascinating approach to mine clearance – the Giant Viper. While flail tanks clear a path behind them as they go, the Giant Viper is designed to clear a large path in advance and all in one go. It relies on the principle of sympathetic detonation, where the shockwave from one explosion triggers the detonation of other explosives nearby. It’s similar to if you’ve ever seen a video of multiple mouse traps in an area or even dominos, where just one impact can trigger many. Mines typically are laid out in a manner to avoid this, it would be far too easy to clear a minefield if you could just blow up one on the edge and let the chain reaction do the rest of the work. The Giant Viper’s explosion is intended to set off many mines itself.

A Giant Viper being towed by a Chieftain MBT (Main Battle Tank).

The explosives of the Giant Viper are carried in a hose made of woven terylene and nylon, 228m long, which is launched from a box on a trailer by means of eight 5-inch rockets fitted in a steel-framed basket. Once fired, it travels through the air with an average speed of 70mph. On the tail of the explosive hose are also fitted three parachutes which act as arrester gear, straightening the hose in flight and keeping it from over-launching. Once the hose has landed, the explosives are detonated and a lane approximately 7.3m wide and up to 183m long is cleared through the field – either through the sympathetic detonation or simply by the mines being blown clear of the area. 

An illustration of the arrester gear in flight.

The effectiveness of the Giant Viper is dependent on several factors such as wind, temperature, depth of mine, type of soil, and type of mine. In general ‘at least 90%’ of blast susceptible mines will be cleared. Against blast proof mines and those with long impulse fuses, the technique is less effective, but these still tend to be disrupted or cast from the area. Those remaining in the area should be exposed enough to be avoided/disposed during daylight. The user manual for the Giant Viper does however state that ‘complete clearance of any gap cannot be affirmed and several gaps should be attempted’ and then the best cleared gap used.

A diagram of the operation sequence of the Giant Viper.

When launching anything through the sky, wind is obviously a large factor; ideal conditions assume light to moderate breezes of up to 20mph. The Giant Viper can be launched in headwinds of up to 25mph but anything beyond that is dangerous as the tail of the explosive may not actually clear the firing vehicle! Tail winds affect the parachutes which can extend the range – although this sounds positive at first, it actually means the hose may not sufficiently cover the beginning of the gap, especially as it can sometimes concertina up at the rear instead of remaining straight. Cross winds similarly affect the rear of the hose the most and, in both cases, winds of over 20mph are inadvisable.

The Giant Viper kit includes a wind gauge but wind is not the easiest thing to measure. It is rarely steady (coming instead in gusts and lulls), it changes regularly, it tends to be stronger higher up than near the ground, the target area is often exposed and open whereas launch areas usually seek shelter, and of course geographical features such as nearby hills and valleys can direct it in unusual ways. With practice and experience of these different factors however, the operators should be able to give a good estimate of the wind and therefore the required aiming adjustments.

When adjusting, another key factor they need to take into account is the temperature of the launching rockets. When the explosive in the rockets is cold, it burns slower and therefore lasts longer - this leads to a reduced thrust but longer flight time. The opposite is true at the other extreme, the explosive burns quickly with an increased thrust and reduced flight time. The launch therefore should take place when the rockets are between roughly 7 and 27 degrees celsius (45 to 80F). The user handbook for the Giant Viper gives estimated times for warming and cooling the rockets at different ambient temperatures so that users can prepare them in time to reach this range. The explosive inside does change temperature very slowly in either direction however, so they should maintain their temperature for 12 hours, as long as they remain in their insulated containers.

Table of launch angle adjustments based on rocket temperature and wind speed/direction.

Although being dependent on such changeable factors such as wind and temperature is a definite drawback of the Giant Viper, it does have its strengths. It is both tactically easy and fast to deploy, which means fields can be cleared while maintaining the element of surprise. It is also possible to use two Giant Vipers in tandem - either to clear a wider or longer gap or a field set with deeper mines. The latter is especially useful as most mine clearance techniques have a finite depth at which they are effective. The concept is in fact so strong that it is still in use today, albeit in the form of the Python, which has improved on the Giant Viper’s design in terms of efficiency and safety. 

Information and pictures in this article are taken from E:03.0452.09, E:03.0452.18 and E:03.0673.28.

Published in The Craftsman, September 2024.

More from the series

• REME History: Deception at War
• REME History: Minefield Detection
• REME History: Flail Tanks
• REME History: The Scorpion
• REME History: The Crab
• REME History: The Crab II
• REME History: DD Tanks