Pyrotechnics and boosted rockets
TARGET MARKING BY FIXED-WING aircraft using phosphorus rockets had been on going and all Army units carried smoke grenades and flares to mark FLOT and enemy positions. However, helicopters lacked the ability to put down markers from which to give other aircraft and ground troops direction. Rocket launchers were considered but discounted on the basis of weight and the fact that they would hinder rapid emplaning and deplaning of troops. Normal smoke grenades were unsuitable because they disintegrated when dropped from height.
I read all ASRs and, having noted pilot requests for a longduration, pyrotechnic marker device, I took this on as a project to run concurrently with the Alpha Project. Besides, there was another pyrotechnic project already in hand for a RAMS requirement.
Air Force technicians at New Sarum had recently developed a ground marker system for night bombing by Canberras. The system, known as RAMS (Radio Activated Marker Service), involved two ground flares, one of which was ignited by a radio receiver in response to a coded signal from an attacking aircraft. The other flare was manually ignited by troops on the ground. The purpose of RAMS was to give ground troops the ability to call for precision bombing of CT targets at night. This involved placing one flare as an inner marker within 300-500 metres of a live target. Having placed the inner (radio activated) marker, a bearing was taken from it to the centre of the target. The second (manually activated) flare was then sited as an outer marker on a reciprocal bearing that might be as much as 1,000 metres from the target.
To prepare for a RAMS attack, a Canberra crew needed a fairly accurate grid reference of the target itself, the magnetic bearing from outer flare to inner flare and the distance from inner flare to target. For this type of attack, bomb-aimers (Canberra navigators) used a method known as ‘off-set aiming’. It involved calculating the difference between the normal direct aiming angle at the planned bombing height and the steeper angle given by the inner flare position. The bombsight was then depressed to the calculated ‘off-set’ angle. There was nothing to prevent a reciprocal attack-line being used, in which case the sighting angle would be shallow, but it was more comfortable to over-fly the outer marker before bomb release.
When approaching target on the assigned attack heading, the pilot instructed the Army callsign to activate the outer flare for initial line-up. Thereafter the coded radio signal from the aircraft ignited the inner flare on the ground. Final adjustment to flight path was made to ensure correct alignment of the aircraft with the flares and bombs which were released the moment the bombsight crossbar reached the inner marker. 5 Squadron had practised and perfected the offset bombing system, all of which had been done at fairly high level.
Randy du Rand was happy enough with the existing RAMS system but felt it necessary to improve on the intensity of the flares for low-level night attacks. He was looking ahead, having visualised the need to use the proven offset bombing method for low-level delivery of Alpha bombs. Randy’s initiative was surprising on two counts. Firstly, the Alpha system had not yet been proven when he asked for brighter flares and, secondly, the new flares only became available in the nick of time for Randy’s first night attack with Alphas.
Bev introduced me to an eccentric American pyromaniac who revelled in flames, smoke and big bangs. He was an extremely difficult man to give direction to because he kept going off at a tangent to any subject being discussed. Nevertheless, he was a real boffin when it came to producing prototype smoke generators and immensely bright flares.
Bev made the steel containers into which the American loaded his concoctions. When we were satisfied with results we asked for repeat samples, but none gave identical results because the crazy fool kept changing ingredients without ever recording them. To pin him down was impossible and he refused point-blank to allow Bev to assist him so that Bev could establish precisely what chemicals were being used, and in what quantities. Much messing around occurred before it was realised that the man, already receiving good money for his work, sought to make a fortune from his secrets; so he was dropped, but not before Bev had established the primary chemical ingredients he had used.
It took some time for Bev to perfect a very robust smoke generator for helicopters to use as a ground-marker device. These manually activated generators were dropped over the side of helicopters from as high as 1,500 feet above ground, which subjected them to immense impact forces. It was essential to ensure each unit could survive high-speed collision with solid rock and still generate three minutes’ worth of dense white smoke. Many failures occurred and it took many weeks before reliable smoke markers became available.
A modification to the pyrotechnic composition for existing RAMS flares achieved the intensity of flame Randy sought. Here again much trial and error was involved along the way and without Bev’s incredible effort and technical expertise we would not have been ready for the first low-level night attack on Madula Pan. This attack will be discussed shortly.
One simple project Ron Dyer and I took on was to rectify the poor returns Lynx pilots were getting from their 37mm Sneb rockets. All we had to do was ask our engineering colleagues to manufacture in steel the same extension tubes used for phosphorus marker rockets. These tubes were then filled with RDX-TNT.
Tests showed the heavier 37mm (boosted) rockets were noticeably slower in flight than the lighter smoke markers, but they were just as stable. More importantly the shrapnel effect of boosted 37mm SNEB showed a ten-fold improvement over standard ones. Thousands of 37mm extension pieces were produced and filled at Thornhill over the next three years.
CS pellets
MOST FIREFORCE ACTIONS OCCURRED ON hills, in forested areas and riverine vegetation because this is where CTs enjoyed best cover. Most of the hills (kopjes) possessed huge granite boulders and vast granite surfaces. When CTs managed to get into good cover between or under granite boulders they became a dangerous menace and were almost impossible to flush out. Cannon fire and Frantans were seldom effective and too many soldiers were killed or wounded when attempting to kill or dislodge them. On two occasions I recall dogs attempting to flush men from hiding but they were killed.
I considered many possibilities in trying to find a way to incapacitate or force CTs into the open and even looked into firing rockets or dropping containers filled with anaesthetising fluid, but none of these ideas was practical. Then I came upon information about talc pellets impregnated with CS (teargas). I cannot recall where I read about this but remember the effects CS pellets exhibited on trials.
Teargas grenades employ a pyrotechnic cake from which CS is released when the charge burns. The resultant gas is hot and initially visible but its spread tends to be upward and the resultant gas cloud is wholly subject to wind drift. Irritation effects are short-lived and affect some people more than others. Dogs can tolerate CS gas because they do not possess the irritable sweat glands of human skin. CS pellets act differently in that they release invisible gas over a long period of time. The unheated heavier-than-air gas spreads out at ground level and migrates into every nook and cranny. Above all its presence makes it quite impossible for any human to remain where pellets are present.
I discussed the matter with John de Villiers and Vernon Joynt of CSIR and asked if they could produce CS pellets. They liked the concept and thought it possible providing they could establish a suitable talc powder binder to form pellets. I left the problem with them and returned to Rhodesia to design and manufacture an appropriate dispenser that would disperse the pellets over large areas. The dispensers worked well but unfortunately the CS pellets never materialised because CSIR had more urgent matters to attend to.