BORN OUT of “duress” from the United Nations Arms Embargo imposed on South Africa during the 1970s, the Atlas C4M Kudu was spawned in response to an operational requirement from the SA Air Force for a light re-supply/medevac capability during the Angolan conflict.
With the C47-Dakota fulfilling the light transport role and the C160/C130 aircraft fulfilling the medium lift component, the nature of bush warfare required an even lighter airlift capability with the specific ability to get into and out of remote, unprepared strips.
The operational requirement, in fact, called for four different transport roles. The first was for a cargo load of two 44-gallon drums for fuel placements at remote locations to provide mobility to the logistic support lines in what was then South-West Africa (now Namibia) and Angola. The other three were for the casevac role, a stretcher plus medic; for the transport role, four passengers, and for the paratrooping role, six paratroopers. Contrary to popular belief, the Atlas C4M Kudu was not a spin-off designed from the AM- 3C Bosbok by Atlas just modifying the AM-3C Bosbok and replacing the fuselage with the wider and larger volume fuselage of the Kudu.
In fact, the prevailing duress left local industry with very little alternative but to take the Italian designed AL-60 light civil utility aircraft of the early 1960s, originally designed by Al Mooney, of Lockheed, and certify it against the SAAF’s operational requirements. The AL-60 had been manufactured in small quantities in Mexico and Argentina and under licence in Italy. Aermacchi then purchased a licence to produce the type, first in its original configuration as the AL-60B, for some African customers, then in a modified version as the AL-60C.
This latter version changed from the original tricycle undercarriage to a tail dragger arrangement and it was this aircraft that was manufactured by Atlas under licence. The basic specification was thus for a generalpurpose, light utility transport, accommodating a crew of two and up to six passengers in the cabin or 560 kg of freight. The first civilian prototype (ex SAAF #999) used by Atlas Aviation for the certification of the Kudu to Federal Aviation Regulations Part 23, flew on February 17, 1974, and the first military prototype flew on June 18, 1975, entering SAAF service in 1976.
More than 40 Kudus had been built when production ended in the early 1980s with the prototype, Kudu #999, eventually being assigned to the Test Flight and Development Centre. The question within the SAAF at that time was: Was there sufficient excess horsepower to accomplish the mission? In the early 1970s, the then Rhodesian Air Force’s AL-60B Trojans, had at odd intervals visited AFB Pietersburg in support of RhodAF weapons exercises on the Roodewal bombing range, and already the Trojan was derogatively referred to by the fighter pilots as a “noise generator, converting fuel into noise”. The Kudu and Bosbok were yet to be introduced to inventory.
SAAF Kudu pilots will readily attest to the fact that the Kudu was, in fact, underpowered, which meant that high skills, judgement and knowledge levels were required as was respect for the environmental factors that governed density altitude to safely maximise output from the Kudu in the hot and high conditions that prevailed in Namibia and Angola.
The concept of fitting a turboprop to the Kudu, though, is not new. During 1976, the discussion around the crew room among the fixed wing test pilots and flight test engineers at TFDC often breached the subject and, in fact, Lt Col Arrie Meulman drew up a concept design for a turboprop equipped Kudu.
The flight test fraternity, more than anyone else, understood the implications of releasing an underpowered Kudu to service and expressed empathy with Kudu pilots having to accomplish the mission in hot and high conditions from rough fields in the middle of nowhere. The logisticians, however, not really understanding the implications, were having none of it – the Bosbok had an Avco Lycoming GSO-480- B1B3 flat-six piston engine and for purposes of standardisation of equipment and training, they were not going to have their world complicated by the logistics support efforts required to provide pilots with a more powerful aircraft.
The Kudu was not only performance challenged, but also in some cases, the flying qualities demanded above average skills. However, despite its performance and handling shortcomings, the Kudu shouldered a large portion of the light utility and transport requirements for the SAAF ‘in theatre’. At the operational level, the slow speed of the Kudu cruising along at approximately 110 KCAS, made it highly vulnerable to enemy ground fire and man-portable surface-to-air missiles.
What is certain, though, is that the rather limited performance and handling qualities challenges of the Kudu, produced high calibre pilots. The SAAF’s training syllabus adequately prepared the mostly young and inexperienced pilots with the necessary skills to fly the aircraft safely. On the one hand, survival was ensured by clever utilisation of the aircraft through flight tactics to counter the ground threat and, on the other hand, squadron pilots developed standard operating procedures to deal with performance and handling shortcomings.
The primary challenges posed by the Kudu from a handling perspective, was the landing, particularly in crosswind conditions with its large keel surface area aft of the centre of gravity. In addition, the downwash from the full flap landing configuration reduced the tail plane’s pitch authority to bring the aircraft into the three-point attitude for landing which resulted in squadron pilots ‘stealing’ two notches of nose-up trim to reduce the pull force required for the round out.
Not a bad idea for compensation, but any balked landing overshoot at full power produced a strong nose-up pitching moment from the all-moving stabilator, that would have to be overcome by a pitch trim rate that was not very quick and, as a result, the cockpit could become very busy trying to get the aircraft trimmed out, flaps raised and deal with the directional control challenges imposed by full power.