Winds of Destruction: The Autobiography of a Rhodesian Combat Pilot

by Peter Petter-Bowyer

  The Air Force Commander made it clear that he was delighted with the first Madula Pan strike because it was our best single result to date. It had cost a fraction of the followup air weapons costs with no foreign currency implications. However his greatest concern at that time was to recover the bodies and bomblets from the downed Canberra, providing this could be done without further loss of life.

  For three days the Army made a number of attempts to get to the crash site but vastly superior FRELIMO forces, hellbent on protecting a prize that lay so tantalisingly close to our border, repelled these attempts.

  Then radio intercepts revealed that the bodies had been found, large quantities of ‘ball bombs’ had been collected and, together with Canberra wreckage, all was being loaded on vehicles for transfer to Maputo. In consequence, recovery attempts were called off.

  When we were still developing Alpha bombs, Bev and I decided to stamp the fuses with Chinese hieroglyphics that translated to ‘Made in North Korea’. Whatever the FRELIMO Government made of this when they studied bomblets, later piled next to aircraft wreckage, is not known but national radio and media coverage gave out that the bomblets had been manufactured in the ‘Racist Republic of South Africa’ and that the aircraft had been ‘a gift to the enemy from the British Colonialist Government’.

  Going back to the Alpha Project again—we had produced bomblets that would not detonate sympathetically if one happened to be set off by, say, an enemy bullet. Only a 100G shock could activate a pistol. Both characteristics gave protection against enemy fire and inadvertent mishandling of bomblets. In the case of Ian Donaldson’s crash, the Canberra fuselage had absorbed so much of the shock loading on impact that not a single bomblet had detonated; which is why all 300 ended up in Maputo.

  New Frantans

  MY PROJECT TEAM HAD SUCCEEDED in its most pressing task of providing the Canberras with an effective anti-personnel strike capability. By January 1977 we were already engaged in a number of new projects. These ran concurrently, imposing a huge load on Denzil and Bev who were still heavily involved in the production of Alpha bombs, officially designated Mk2 Fragmentation bombs. In spite of this they had been more than willing to take on new developmental work. Projects Bravo and Delta (pyrotechnics and 37mm Sneb boosters) had been finalised. Next priorities, Projects Echo and Foxtrot, were for new Frantans and high-pressure bombs.

  To provide the Lynx with an effective Frantan, we chose to move away from conventional napalm bomb designs. All those in use in the western world were simply metal tanks, most with small fins designed to pitch the unit nose-down at the moment of release to ensure positive separation from the aircraft. Otherwise, none possessed flight stabiliser fins.

  After release, the tanks behaved in haphazard ways causing them to follow unpredictable trajectories. Tumbling, flying sideways, oscillating and corkscrewing were characteristics that set napalm aside from aimable bombs and made accurate delivery difficult. For instance, if two tanks were released together, with one pitching nose-down and another nose-up, they could land so far apart that one might fall short of target whilst the other passed over.

  When Americans took on a target they dropped four or more napalm bombs from each of a number of aircraft to saturate large areas with flame and intense heat. Absolute accuracy and high costs did not bother them whereas we needed units that would follow a repeatable trajectory to make each unit aimable, accurate and highly effective. This meant we had to produce an aerodynamically shaped unit with low drag characteristics for carriage, but incorporating efficient stabiliser fins to ensure longitudinal stability for clean release and alignment in free flight.

  Metal containers were no good, as we had witnessed on hundreds of occasions. Burster charges coupled with unpredictable case rupture resulted in equally unpredictable distribution of burning napgel. Too often large quantities of the gel remained inside partially burst tanks or sticky blobs of unburned gel lay all over the ground and stuck to vegetation. This was no good at all! I decided we needed tanks that would shatter like glass on impact to free their entire gel contents in a huge fan-like spray of tiny droplets with inter-linking volatile gas. I had learned that the Hunter disposable long-range tanks were constructed from fibres with phenolic resin and that they shattered on impact. We followed this line and produced casings moulded from woven glass fibre and chopped asbestos set in a phenolic resin binder.

  Prototype sixteen-gallon units were made and fitted with Alpha bomb fuses (suitably modified to function at low-impact levels) imbedded in the large pocket of flash-compound that ignited the napgel. From Day One the new Frantans were a great success and, with small modifications, were cleared for operational use on Lynx and Provosts.

  Hunters used imported spun-aluminium fifty-gallon Frantans but these suffered all the limitations we sought to overcome. So I arranged comparative trials between our lowcost sixteen-gallon Frantan and the very costly imported fiftygallon units. The results were astounding. The Hunter pilots were able to deliver the local unit with great accuracy. In itself this was pleasing, but even more satisfying was the fact that the local unit, though only possessing one third of the napgel contents of a fifty-gallon unit, provided consistent coverage of ground that equalled the best of the imported variety. Foreign currency saving was another bonus.

  Golf Project

  IN PROJECT FOXTROT WE ATTEMPTED to produce fuel-air explosive (FAE) bombs, which American military journalists described as having ‘near-nuclear’ effect. One military article was supported by dramatic photographic records of the total destruction of an old US naval destroyer from just one of these FAE bombs. However, destruction of ships was not America’s real interest in FAE. The weapon had been developed to clear large pathways through enemy minefields by detonating hidden mines with excessive over-pressure of ground.

  Ethylene oxide was the medium we employed. There were two reasons for the choice of this liquid gas. Firstly, it explodes with as little as 2% of air inclusion and as much as 95% of air inclusion, whereas most other gases will only detonate within a very narrow gas to air ratio. The second advantage of ethylene oxide is that, when ignited, it produces gas volumes many times greater than any high-speed explosive, such as TNT.

  Each American FAE bomb was dropped at relatively low level and descended to ground on a parachute. A groundsensing device perforated a pressure disc to release the bomb’s pressurised liquid contents at about twenty feet above ground and simultaneously fired flares upwards. The upward and downward flight time of the flares allowed the ethylene oxide gas skirt to widen to around twenty-five metres in radius before the first of the flares contacted the gas skirt setting off a vicious explosion. Lethal over-pressure from a mere five gallons of ethylene oxide dispersed and detonated in this way extended way beyond the edge of the gas skirt.

  Very often the precise positions of CTs firing from dense bush were not known and we had no single weapon that could produce lethal effect over relatively large areas to cater for such situations. FAE seemed to offer a perfect solution to this ongoing problem.

  Considerable time, effort and cost went into Project Echo during which we succeeded in making huge expensive fireballs before, eventually, achieving two terrific detonations. The first of these broke many windowpanes in the Kutanga Range domestic area that was over 500 metres from the blast. What interested us about successful detonations were the sound effects they produced and the fact that they totally stripped vegetation, including substantial trees, up to forty-five metres radius from blast centre. The ground around was pulverised and powdered to a depth of several inches. The sound of each detonation was not a sharp bang, as from TNT, but a loud deepnoted ‘crruuump’ from an explosion, followed immediately by the ‘cruump’ of an implosion.

  Ethylene oxide is a very dangerous substance to store and with Rhodesia being under UN sanctions it was also very expensive and difficult to source. Considering these issues, and realising that weapons that descend on parachutes would be difficult to deliver ac
curately, even in the lightest of wind conditions, we decided to drop the FAE project. Nevertheless, I was still determined to produce high-pressure bombs. Denzil was just as determined and acquired information on the gas-generating properties of every known explosive and combustible liquid compound. His hope was to identify a readily available safe-tohandle explosive that would exhibit similar characteristics to ethylene oxide. When he recommended ANFO we all studied the data before agreeing it exhibited suitable gas-producing properties. This was a pleasing discovery because we could produce ANFO very cheaply and easily.

  Project Golf was initiated by making a direct comparison between an imported 500-pound TNT-filled mediumcapacity bomb and an ANFO-filled 6mm steel casing having equal mass. Both units were mounted vertically on three-foot stands pointing nose down for command detonation from a safe distance. The imported bomb was detonated first. It went off with the usual bright flash, black smoke and a very loud bang with plenty of dust drifting away on the wind. The ANFO bomb was nothing like as impressive to the eye or ear. The explosive flash was nowhere near as bright as the TNT bomb and pasty-grey smoke mingled with dust was drifting off before a deep ‘crrrrump’ was followed immediately by a second ‘crrump’.

  Inspection of the sites showed clearly that we had a winner in ANFO. Loud bangs, such as thunder from lightning, are the product of huge energy releases to atmosphere. In the case of bombs filled with high flame-rate explosives, bright flashes and loud bangs of surface bursts are products of wasted energy following the disintegration of steel casings. When used against buildings, bunkers and other targets where detonation occurs within confined structures, the same energy is highly destructive, but not so in the unconfined conditions of open bush.

  In the case of ANFO, the steel containers swell in size, as do the high-explosive containers; but ANFO, having a much slower flame-rate, continues its heaving detonation well beyond case disintegration. An ANFO mix, when confined in a steel container and given a hefty thump by an initiator charge such as Pentolite, ignites spontaneously to generate enormous amounts of high-pressure gas in a heaving EXplosion which forces air outwards from the generated gas bubble. The gas cools immediately, creating a void into which the air flows at supersonic speed, causing an IMplosion.

  Digressing for a moment, the implosion following an atomic bomb blast causes more damage to structure than the initial explosion. In the case of ANFO, explosion and implosion are equally damaging—a double dose of no good.

  The production of ANFO, a commonly used mining explosive, simply involves the thorough mixing of a small quantity of diesel fuel into prilled ammonium nitrate fertiliser. In the beginning we did this with a shovel in a wheelbarrow. Later we progressed to a simple motor-driven concrete mixer for large-quantity production.

  ANFO offered a special advantage. From the start we realised that it would not be necessary to use special ammunition dumps for the safe storage of ANFO bombs. Unlike standard high-explosive units that had to be filled in specialised conditions, ANFO bombs could be stacked in the open and only filled when they were needed.

  Digressing again and returning to the Mao Tse Tung ‘ground cannon’ mentioned in conjunction with the CT ‘air ambush’ system, I decided to test this ‘cannon’ using ANFO as the explosive. A one-metre round hole was dug to a depth of one metre. At the base we placed a 20kg charge of ANFO then filled the hole with rocks.

  Kutanga Mac places the final rocks watched by, Bev, with head down and Ron Dyer second from right.

  Waiting for the explosion and ensuing rockfall.

  The project team was over 1,000 metres away when the ‘ground cannon’ went off with a dull thunderclap. Whilst the rocks remained close together, their rapid passage up to around 1,000 feet above ground was obvious. Thereafter we could see nothing of individual rocks that soared on to greater heights. We watched the ground ahead for ages waiting for the rocks to land but neither saw nor heard anything. I was heading for my vehicle when a peculiar sound, which I can only describe as something like static electricity, developed all around. Everyone dived under vehicles in time to avoid the rocks that came crashing down.

  Used in multiples around airfields, this crude device would have been devastating to enemy paratroopers and ground-attack fighters. Fortunately however, there was never a need to employ Mao Tse Tung’s crude but effective ‘ground cannon’.

  Further static 500-pound ANFO trials were conducted before making a direct comparison between an imported 1000-pound bomb and an ANFO unit of equivalent mass. For this we acquired specially bred white guinea-pigs with black ears. They were placed in wire-mesh cages, set in deep holes (to protect them from shrapnel) next to which pressure pots and pressure discs were laid in a line at five-metre intervals from fifteen metres outwards to fifty metres from point of detonation.

  Inspection the hole from the small charge of ground cannon trial. PB 2nd from left, Bev 5th with hand over eyes and Kutanga Mac in dark shirt 9th, view the large hole made by the small ANFO charge of our ‘ground cannon’ test.

  The imported bomb explosion had no noticeable effect on the pressure pots and pressure discs beyond fifteen metres. In the fifteen minutes it took us to get to the test site, every guinea-pig, including the two at fifteen and twenty metres, had recovered from the big bang and were munching away at the feed in their cages.

  Following detonation of the ANFO unit, we rushed back to the little creatures with a forensic pathologist in tow. I had persuaded this medical specialist to assist us in our ANFO tests by examining the bodies of snakes and frogs we found on the surface following every single ANFO detonation. All these cold-blooded creatures, though dead, appeared perfectly normal until dissected. Over-pressure had destroyed their lungs and other vital organs without any damage to outer skin. The frogs, which lived more than one foot below surface, were always found on top of the powdered earth, lying belly up.

  At the 1000-pound ANFO detonation site we found every guinea-pig hunched up, motionless and covered in thick fine dust. Those at fifteen, twenty and twenty-five metres from blast had perished through overpressure. Those at thirty and thirty-five meters had perforated eardrums; the remainder recovered quickly enough but would not eat for more than ten hours. The pressure pots within twenty-five meters suffered distortion with permanent set and satisfactory over-pressure readings extended out to thirty-five metres.

  The guinea-pigs that survived the ANFO blast were kept in a large pen separate from those that had been subjected to the imported bomb blast and Kutanga Mac looked after these little fellows better than any private home could. For reasons we never established, the guinea-pigs in the ANFO pen grew larger than the others and became enormously fat. The two deaf animals were the happiest, fattest and hungriest. All were eventually found good homes.

  Our first ANFO bombs weighed 450kg, which was equivalent to the imported 1000-pound bombs. Canberras and Hunters released these in a series of tests. Although the tests themselves were successful, we were not at all happy with the loss of energy evidenced by large craters in the ground where they detonated.

  Operational considerations clearly identified Hunters as the main user of high-pressure bombs, so we turned all attention to fighter/bomber style steep-dive (sixty-degree) profile attacks. To maximise blast effect each bomb was fitted with a one-metre-long proboscis to ensure airburst. To minimise energy losses downward and upward, and to maximise ground overpressure, simultaneous initiation of Pentolite booster charges at the front and rear of the ANFO charge resulted in a very satisfactory ‘squeeze’ effect. In doing this, each bomb flattened everything around the point of contact and no energy was lost to punching out ground craters. The entire tailpiece was usually found at the centre of detonation proving that almost no energy was going skyward.

  Golf bomb.

  During early tests each pair of bombs landed close together; so we decided to improve the ninety-metre diameter bush-clearing effect by retarding one bomb to force it to fall short of the unretarded one. Spring-
loaded metal paddles were used initially but these were clumsy and inefficient. They were discarded as soon as we learned how to absorb the high shock loading involved in deploying our own designed and manufactured drogue chutes. The drogue chutes worked well and forced the retarded bomb to fall about thirty-five metres short of the streamlined unit. From then on a pair of ANFO bombs gave a bush flattening-pattern ninety metres wide by 135 metres in the line of attack.

  450kg Golf bombs were cleared for operational use in March 1977. Testing continued for some time thereafter, resulting in the ANFO bombs being upgraded with double steel cylinders sandwiching thousands of pieces of chopped 10mm steel rod to give lethal shrapnel effect beyond the over-pressure boundaries. Although officially termed 450kg HP bombs, the project title stuck and everyone knew them as ‘Golf bombs’.

  Cavalry Fireforce

  IN MARCH 1977, OZZIE PENTON asked for my temporary release from project work to conduct recce training camps for all PRAW crews. To make this manageable and to minimise disruption to my own work, I arranged for four separate five-day camps to be run in March, April, May and June. I chose Marandellas Airfield for the first recce camp and had Cocky Benecke, Francois du Toit and Norman Maasdorp along to assist me. Francois had resigned from the South African Air Force to join our force and was keen to get back to air recce work.

  John Blythe-Wood, as lead K-Car pilot operating out of Mtoko, had been having a run of first-class successes in which he had twice called for Canberra Alpha bomb strikes. My wish was to find a target for John’s Fireforce in the hope that he might use Canberras again because I had not personally witnessed an Alpha bomb strike from the air.