Despite enduring a world-changing pandemic in 2020 and facing an uncertain future, I suspect it’s nothing compared to living in a country at war. Which is what I found myself contemplating recently as I flew what is now a civilian version of a South African military stalwart, the Aérospatiale Alouette III.
“My favourite helicopter sound,” one friend remarked.
“That high pitched turbine whine and whack of the rotors takes me straight back to the border,” said another. “Spine-chilling!”
It’s amazing how sights, smells and sounds all have that ability to awaken memories, especially when those memories were formed in times of heightened stress and fear. This month, as alluded to already, I’ll be writing about the machine behind the sound.
Picture the setting. The year is 1977 and South Africa is in the midst of the ‘border war’, a spin-off skirmish of the Cold War; a bitter battle in the bushland of the northern reaches of South West Africa (now Namibia) and into Angola.
It was no holiday for South African lads plucked, wet behind their ears, from their homes, barely old enough to drive their Ratel infantry combat vehicles, living on rat-packs and in fear of the inexplicable ‘rooi-gevaar’. I didn’t experience any of this myself, being too young to be called up to national service. But I remember one of my school teachers speaking of the utter terror of tracers zipping over his head, and of the relief at hearing Puma and Alouette helicopters roaring over them to engage a mostly-unseen enemy from the air.
The Border War has been chronicled in many books, including aviation books, which I had access to as a ‘laaitie’. It was easy to pick out the South African Air Force aircraft of the time. Most had similar bushveld olive drab/khaki camouflage, applied over the silver or blue schemes of the 1970s. One aircraft, the Alouette III, seemed to be in more pictures than any other, a ‘troepies’ friend as it were, unlike the high flying, more glamorous Mirage and Impala Mk2 fighters.
In the beginning of vertical-lift aviation, small numbers of helicopters made an appearance towards the end of World War II, most notably as war-time aerial support vehicles, for observation, transport and medical evacuation. Unlike fixed wing planes, they were able to do without a runway to insert or, more importantly, pluck a soldier out of a sticky situation. During the Korean War in the 1950s, Mobile Army Surgical Hospitals, or M. A. S. H. (immortalised by the 1970’s American TV show of the same name) were made possible largely thanks to Bell 47 (designated H-13 Sioux) helicopters, with their two medevac panniers fitted above the landing skids.
In addition, the Bell 47 was successful in its role as a medevac chopper because of its relatively light weight and its turbo-charged, 6-cylinder Lycoming engine, which had just enough power to take a pilot, nurse and two wounded men on stretchers. But ultimately, early helicopter designers realised that hovering a helicopter and making purely vertical take-offs and landings in a hot and high landing zone required more power than the available piston engines could offer.
The answer to the problem came from Joseph Szydlowski, a Polish-Israeli aircraft engine designer who developed a small gas-turbine engine, the Turbomeca Artouste, in the mid-1950s.
At around the same time and place, French state-owned aircraft manufacturer Sud-Est was developing its first commercial helicopter, the Sud-Est SE3130. The SE3130 was based on the Sud-Est Alouette (1) prototype, which shared many design ideas seen in the earlier Bell 47 helicopter, the main difference being a 3-blade, fully articulated, main rotor system, which was far more complex than the teetering or see-saw type semi-rigid rotor on the Bell. The design then morphed into the Alouette II helicopter, with many further refinements and a simpler main rotor system to facilitate large-scale production, also made possible because of a lighter 260 Shaft Horse Power (SHP) Turbomeca Artouste turboshaft engine. The performance of the world’s first turbine-powered mass-produced commercial helicopter made the Alouette II an overnight success.
By virtue of the success of the Alouette II, and after a merger between Sud-Est and Sud-Ouest to form Sud Aviation, Chief Engineer René Mouille set his sights on developing a more aerodynamic and more powerful turbine-powered helicopter with improved visibility. The design brief was for a military and civilian helicopter that could carry seven passengers or two stretchers internally. A tricycle undercarriage was selected to allow for running take-offs and landings, as well as for naval ship-borne operations.
The Alouette III’s design genius lay in its intricate use of a chrome-moly space-frame centre-cradle and aluminium-skin tension monocoque tail structure combination to achieve strength and light-weight performance. Initially designated as the SE3160, The Alouette III had a lighter Turbomeca Astazou turboshaft engine, originally rated to 880 SHP output, but then derated to 550 SHP. Much thought went into field serviceability, with access to all maintenance points. The Alouette III even has its own ladder access built into the main frame, making the dynamic components easily accessible for servicing.
27 points on the main rotor require greasing every 15 flight-hours
The Alouette was designed before Teflon anti-friction materials found in modern rotor-craft clevises were available, meaning that it is imperative to wear a flight suit when flying it, what with all 27 points on the main rotor requiring greasing every 15 flight-hours or so. A messy job indeed! It did, however, introduce composite material structures to helicopter design and manufacture, like the light-weight fiberglass engine and airframe panels.
The control system was also a first for helicopters. With its fully-articulated, hydraulic-servo assisted controls, the Alouette III needs the softest touch to dance through even complex g-loaded or negative-g manoeuvres. The flat floor cockpit layout is spacious and ergonomically designed with the commander’s station on the traditional right-hand side. The co-pilot is positioned in the middle front station with dual controls, while an observer/passenger seat is aligned to the left. In the rear of the cabin is a bench-type seat for four passengers. Sliding doors, also a first for helicopters at the time, allow generous access to the rear cabin on both sides.
Engine start and management is accomplished by a complex electro-mechanical interface, enabling single button operation for start and stop – amazing for a 1960’s turbine aircraft. The main rotor is engaged after engine start via a centrifugal clutch, with a specific spool-up timed procedure. All of these design elements helped to create a helicopter with excellent manoeuvrability and superb hot and high performance.
So successful were both iterations of the Alouette, that in 1968 Sud Aviation began designing the SA315 ‘Lama’ for use in extreme mountain ranges, such as the Himalayas in Asia and the Andes in South America. By combining the II’s lightweight airframe with the III’s superior dynamic components, the company created a rotorcraft that was the undisputed champion of mountain work – until the AS350 B3 Squirrel arrived on the scene.
The first-ever Lama constructed still holds the absolute altitude record for its class of 40,814 ft (12,442m), which it set way back in 1972. At the same time, it also set an unintended record for the longest successful autorotation in history, after its turbine shut down because of the freezing temperatures (measured at -62° Celsius) at the peak of its record-breaking feat.
But back to the specific subject of this article, the Alouette III, which I was fortunate to fly at the Remembrance Day Memorial Service at Pretoria Boys High School on the 11th of November this year. The aircraft was originally manufactured as an SE316B by Aérospatiale (the company created out of the merger of several French aviation companies, including Sud Aviation) in 1970, with construction number 1746. The (B) denotes the last production version of the Alouette, which boasts a longer tail and main rotors, and added modifications for better hot and high performance.
C/N 1746 left the factory in Marignane, in the south of France, bound for the USA, where it was used primarily for firefighting and power line inspections. The helicopter was then sold, disassembled and shipped to South Africa to join the South African Airforce as SAAF Alouette 617 in 1975.
Not much is known about her active-duty history, except that she finished her service at 87 Helicopter Flying School at AFB Bloemspruit (Bloemfontein) in 1990. She then spent a number of years gathering dust at 10 Air Depot in Thaba Tshwane before being sold to the public as surplus by Denel. Her latest registration is ZS-RNV, after being nut-and-bolt restored in 2009 at Wonderboom Airport by specialist Johan Lok. Rare for a 1970 Alouette, she boasts a Certificate of Airworthiness, rendering her type-certified for commercial operations. Her current owners, daughter and father Hayley and Paul Cumming from Helivate, keep her in immaculate condition while allowing her to do what she does best; fly.
As part of the memorial service, we obtained permission from the South African Civil Aviation Authority (SACAA) to do a fly by, before scattering over 8,000 paper poppies from the air in remembrance of the South African lives lost during World War II, now 75 years on. After the sortie, we duly landed and joined the guests, including representatives of all of the SANDF’s arms, as well as military attachés stationed in Pretoria, and “old boys” who had served in the military.
They will never forget the unique sound of the Alo
The many people I have met who served in the South African armed forces, and specifically ‘on the border’, all tell me they will never forget the unique sound of the Alo. And on 11 November, old boys recounted stories interspersed with tears and laughter, tales dragged from their memories by the distinctive turbine whine of Aerospatiale Alouette III, number 1746.