Countering Strela missiles
AS I HAD PREDICTED, WE needed to lose aircraft to Strela missiles before the Treasury hurriedly provided funds for the research and modifications needed to protect helicopters and piston-driven aircraft. Flight Lieutenant Archie Ramsbottom was appointed the technical officer for the project. I became involved with him immediately on an ad hoc advisory basis and together we paid a visit to CSIR in Pretoria for discussions on Strela missiles and the steps to be taken to render them harmless.
A sensor that could ‘see’ objects radiating infrared energy in the 2-micron wave band controlled Strela flight. Highest intensity emissions were from the relatively small exposed sections of exhaust pipes and hot engine parts. However, the cumulative value of infrared radiating from an entire standard airframe, although apparently cold, presented a good target. Strela would initially home on the entire heat signature of an aircraft and only seek out the hottest spot late in its flight; hence the strikes on the exhausts of the two Trojans.
Exhausted gas plumes did not present any problem but it was quite obvious that hot exhaust stubs and any exposed sections of engines had to be shielded. This needed some clever design and engineering work, which our technicians managed quite easily. Surface paint was the bigger problem. We established that colour was not the main criteria in selecting a paint mix that exhibited low radiation properties in the 2-micron wave band. In fact, and surprisingly, it was easier to achieve this with white paint than in the camouflage colours we intended to retain.
Archie worked long hours with paint manufacturers and the Paint Shop at New Sarum to develop the ideal paint mixes for our camouflage colours. What they eventually produced virtually eliminated radiation of infrared energy in the critical wavelength sector, even when the surface was hot.
The dedication and enthusiasm of Air Force technicians and paint manufacturers made Archie’s job easier and the results were impressive. Provosts and Trojans looked the same as before except for strange-looking fibreglass fairings shaped like half cups that screened exhaust stubs that had been turned to face upwards. Simple screens were also used to disallow Strela from ‘seeing’ hot components through the cooling-gills under the engines.
Dakota exhausts required a different solution. This involved extending the exhaust pipes all the way to the trailing edge of the mainplanes where the pipes turned upwards to exhaust gases vertically. A wide tunnel-like fairing through which air flowed to keep the outer surface of the tunnel cool surrounded each long exhaust line. At the trailing edge of the mainplane, the tunnel fairing rounded upwards to screen the hot upturned outlet of the exhaust pipes.
Counter-Strela modifications for Alouettes and Cessna 185 aircraft were created by SAAF in conjunction with CSIR. The Cessna modifications were much the same as those developed for the Trojan. Alouette helicopters presented bigger problems because the entire engine and exhaust pipe were exposed. As with fixed-wing aircraft, it was necessary to modify the jet pipe to exhaust upwards and the entire engine was shrouded in a bath-like shield. This shield was without a top to allow access for engine servicing in the field. Because of this, the engine and jet pipe could be seen from the ground when a helicopter banked steeply.
All anti-Strela modifications were very successful and many Strela missiles were wasted against our slow aircraft.
Jets, however, could not be protected to the same degree. There was no easy fix to the exposed ends of jet pipes. All that could be done was to paint the airframes with the new paint to minimise total radiation, thereby limiting Strela’s ability to acquire target until a jet aircraft had passed its operator’s position.
When all the Strela protection work was completed, Archie and I paid a visit to Air Rhodesia’s top managers to suggest to them that their Viscount airliners should be protected along the lines of our Dakotas. The reason for our visit arose from tests we had conducted with a Strela missile that had been acquired by Air Force to evaluate our counter-missile work.
The missile’s firing mechanisms were neutralised and a battery pack replaced the regular pyrotechnic generator. As a mobile test bed, this modified missile worked very well. Our tests confirmed that our light aircraft and Dakota modifications were satisfactory, and that the missile could not easily ‘see’ Canberras and Hunters until after they passed abeam. During these tests we noted that, whereas a Viscount produced a stronger signature from its four exhausts than either a Hunter or a Canberra, its entire airframe and large under-wing exhaust pipes made the aircraft highly visible, irrespective of range and direction of travel.
We were told that Air Rhodesia’s engineers and upper management were fully aware of what had been done to protect Dakotas and they agreed that a similar style of engineering could be employed to shroud Viscount exhaust pipes. The matter of repainting the Viscounts presented no special problem. However, despite a very cordial meeting, both Archie and I sensed that there was no real interest because Air Rhodesia’s managers seemed unable to accept that Strela would ever be a threat to civilian airliners.
Army Sub-JOC commanders
ON 4 JUNE 1974, LIEUTENANT-COLONEL Dave Parker, the Army Commander at JOC Darwin, asked me to take him along on a recce flight. He had been impressed with air recce successes and wanted to gain first-hand knowledge of how we searched for CT camps and what ground patterns attracted a pilot’s attention. His open- mindedness and desire to learn from direct experience was very refreshing. Throughout our flight his questions and observations made it plain that he was very switched-on. Having shown Dave a few bases I had found previously we were fortunate to find a new one that appeared to be in use. Surprisingly he saw the base more easily than many of the pilots I had trained and his excitement was infectious.
Three helicopters brought in twelve RLI troops. Dave could see immediately that they were going to be too thin on the ground to have any chance of boxing in the area around a camp site that offered the CTs a number of escape routes in good cover.
I directed the lead helicopter to position 150 metres to one side of the CT base by calling “Camp centre 150 to your right… NOW.” Troops were put down simultaneously on three sides of the camp before the lead helicopter climbed to 1,000 feet to direct the troops towards the camp. The other two put in dummy drops in gaps between the troops in an attempt to make CTs uncertain of which way to break. They then returned to Mount Darwin for more troops.
Contact was made before Dave and I saw two groups of four CTs breaking at high speed through a huge gap between the soldiers. Being unarmed I could do nothing about this, and the orbiting helicopter was already engaging CTs inside the camp. We had to be content with two CTs killed and one captured wounded with no less than eight CTs seen to escape. This experience certainly highlighted for Dave Parker the reason why Air Force had
