World's largest aircraft unveiled

Stratolaunch: Largest aircraft in the world unveiled

Microsoft co-founder Paul Allen has been quietly building the world's largest aircraft, Stratolaunch,  in the California desert. Once completed  it will be the world's largest airplane. With a wingspan more than that of Howard Hughes' Spruce Goose. It was wheeled out of its hangar for the first time on Wednesday.

 Stratolaunch  has some impressive stats:

Wingspan 117 ms
Height 15m.
Unfueled weight :226 800 kg
Fuel load : 113 400 kg
Total weight: 589 670kg.

Other extraordinary facts:  It has  28 wheels and six Boeing747 jet engines.

97 km of wiring.
It's so big that the county had to issue special construction permits just for the construction scaffolding.

It's so big that to truly get a sense of it, you have to see it from a distance - like a mountain.

Why so big?  Not to carry passengers, but rather low earth orbit payload carying rockets. The bigger the plane, the larger the rockets, or the greater the number.

Allen's Stratolaunch company has partnered with Orbital ATK to "air launch" the company's Pegasus XL, a rocket capable of delivering small satellites, weighing as much as 450kg, to orbit. The rockets would be tethered to the belly of the giant plane, which would fly them aloft, and once at an altitude of 10,668m or so, the rockets would drop and "air launch" to space.

"With airport-style operations and quick turn-around capabilities," the company said it believes "air launch" is a cheaper and more efficient way to get satellites into space than rockets that launch vertically and can be extraordinarily expensive.

For Allen, it's all about LEO, or low-Earth orbit. He, and others, such as Richard Branson's Virgin Orbit, are betting that they can reduce the cost of launching small satellites to space. And that, in turn, will lead to new ways to beam the internet all across the globe, provide better Earth sensing capabilities, better communication, and open up all sorts of avenues.

"When such access to space is routine, innovation will accelerate in ways beyond what we can currently imagine," Allen said in a statement a year ago. "That's the thing about new platforms: when they become easily available, convenient and affordable, they attract and enable other visionaries and entrepreneurs to realize more new concepts."

More than a decade ago, Allen had hoped to spark a revolution in space travel when he funded SpaceShipOne, which became the first commercial vehicle to cross the threshold of space. The project ultimately won the Ansari X Prize, and a $10 million award. He then licensed the technology to Branson and moved on to other pursuits. But with Stratolaunch, he is back in the space business.

"Thirty years ago, the PC revolution put computing power into the hands of millions and unlocked incalculable human potential," he wrote.

"Twenty years ago, the advent of the Web and the subsequent proliferation of smartphones combined to enable billions of people to surmount the traditional limitations of geography and commerce. Today, expanding access to LEO holds similar revolutionary potential."

Jean Floyd, Stratolauch's chief executive, said the company would be "actively exploring a broad spectrum of launch vehicles that will enable us to provide more flexibility to customers."

He added: "Over the coming weeks and months, we'll be actively conducting ground and flightline testing at the Mojave Air and Space Port. This is a first-of-its-kind aircraft, so we're going to be diligent throughout testing and continue to prioritize the safety of our pilots, crew and staff. Stratolaunch is on track to perform its first launch demonstration as early as 2019."

Original Article Washington Post

NASA concept for a similar concept, using a tow-plane 

Happy Xmas and Prosperous 2014

Wishing all my blog followers a Happy Xmas 2013 and Prosperity in 2014

A few Aircraft related festive photos:

Avro Shackleton MR3 in SAAF service (Part 2)

Avro Shackleton MR3 in SAAF service (Part 2)

35 Squadron Emblem

(Shaya Amanzi - From the Zulu: "Hit the Water")

To replace the Short Sunderland, the SAAF ordered eight Avro Shackleton MR Mk3 in 1954, and delivery took place in 1957. The SAAF operated (1957 to 1984) a total of eight Avro Shackleton Mk.3's with tail numbers 1716-1723.

One Shackleton was lost on operations when it crashed in the Wemmershoek (Stettynsberg) range of mountains during poor weather conditions on 8th August 1963 with the loss of life of all 13 crew:

All aircraft were deployed by 35 Squadron at AFB Ysterplaat Cape Town , after initially flying out of Congela , close to Durban harbour.

The Shackleton served as a Maritime Patrol Aircraft with both the SAAF and RAF and was later replaced in the SAAF by the C-47TP and Nimrod in RAF service. The SAAF however used only the Mk.3 variant without the Viper upgrade.

Procuring the Shackleton was a major step up from the previous use of Sunderlands and Catalinas and according to Wiki , even Harvards and Spitfires were used! Shackletons were used extensively until 23 November 1984 when it was officially withdrawn from service.

 Shackleton 1716 was re-furbished to flying condition for the SAAF Museum, but had the unfortunate experience to crash land in the Sahara desert near the border with Mauritania on 13 July 1994 whilst on a flight to Great Britain to take part in a number of air shows. It suffered a number of engine failures and was forced to land in the dark, without any loss of life to the 19 crew on board. (See separate post on this)

Another Shackleton 1722 has been re-conditioned to flying status and flies as part of the SAAF Historical Flight in Cape Town.

 Armament consisted of two 20-mm cannon in the nose, plus up to 10,000lb (4 536kg) of weapons in the underfuselage bay.

 From the book Avro Shackleton by Barry Jones:

The SAAF's Shackleton strength was reduced by one in August 1963. 1718 had previously suffered a hydraulic failure,resulting in a wheels-up landing at D. F. Malan on 9 November 1959, but the
required repairs were carried out in record time, in order to get the aircraft back into service. On 8 August 1963 the aircraft had been engaged in joint exercises with the RAF and was on a return flight to Cape
Town. In gusting winds and severe icing conditions down to 3,000ft (l,000m), 1718 struck high ground before crashing into the Wemmershoek mountain range outside the town of Worcester, some 60
mile (96km) east of its destination. The crash occurred about 25.8 km (16 miles from the nearest town, Worcester, in the Stettynskloof valley between Paarl and Stellenbosch.

All thirteen crew members were killed in the tragedy, that was hard to accept by the squadron for some time. The aircraft had made a total of 777 flying hours during the six years since its acceptance by the SAAF

On the other side of the coin, two years later 1722 took part in an impressive display of search and rescue. Eight Buccaneer S.50s were in loose formation on their delivery flight to the SAAF when one, SAAF No.419, had a flame-out in both engines at high altitude, about 500 miles (800km) south of the Canary Islands. The two crew members,Captains Jooste and de Kerk, ejected while Major A. M. Muller, who was leading the formation, relayed their position. 1722 was scrambled, and only a couple of hours into the mission picked up the 'blips' from the downed airmen's SARAH beacons.

Coloured flares were fired by both the Shackleton crew and the survivors in the Atlantic, to verify visual contact by all concerned.Another MRJ, 1721, was drafted into what was no longer a search, but a rescue
operation and two sets of Lindholme Gear were dropped to the Buccaneer crew.
The Dutch liner Randfontein was in the area and 1722 guided it to the rescue location, where a successful transfer from life raft to luxury was made. 1722, captained by Major Pat Conway, had flown nearly eighteen
hours on the AR mission, which had been undertaken as a text-book operation.

In 1971, the treacherous currents around the Cape of Good Hope claimed another victim. The 70,000 ton oil tanker Wafra ran aground on rocks off Cape Agulhas, the most southerly tip of the African continent.
With its 60,000-ton cargo of crude oil threatening to cause an ecological disaster for the area's wildlife, not to mention the renowned holiday resorts that were located around that part of the country, an ocean-going tug was called in to tow the stricken vessel off the rocks. Good seamanship by the tug's crew got the Wafra
clear of the reef with very little oil spillage and the tanker was towed some 200 miles (300km) out to sea. As the vessel was unsalvageable in her existing state and there was no chance of transferring her cargo to another tanker, the SAAF was briefed to sink her, with the added instruction that, if possible, the ship's internal structure was not to be ruptured, so that she could take her cargo with her when she sank.
No. 24 Squadron's Buccaneer S.50s, armed with a pair of Nord AS-30 air-to ground missiles under each wing, carried out two sorties against the vessel, under the guidance of No. 35 Squadron, but the tanker remained intact. Consequently,MR.3s were called into action and a salvo of depth charges dropped alongside the Wafra had the desired effect. She sank onto the Agulhas Plateau, 2,300ft (700m) below the turbulent meeting place of the Atlantic and Indian Oceans, complete with her crude oil.

At least two SAAF MRJs are known to have returned to the UK. 1719 arrived on 25 February 1963 for a six-week training exercise with Coastal Command and it arrived back at D. F Malan on 1 April. The
following year, 1722 touched down at BalIykelly on 28 June, for a four-week course at the JASS, returning to Cape Town on 30 July 1964.

After the loss of 1718, the seven surviving MR.3s were all progressively modified to Phase III standard by Hawker Siddeley CWPs, except that the Armstrong Siddeley Viper jet boost (JATO) engines was never installed in any of the South African aircraft. The bases used by No. 35 squadron were deemed to be large
enough to get even a fully laden MRJ airborne. The Phase III modifications were implemented before the arms embargo and the full ECM suit was installed in all seven aircraft, so that they approximated to the
RAF's final MR.3 condition, apart from the Viper JATO.

Wing re-sparring was carried out on at least two aircraft, 1716 being out of service for the work between March 1973 and April 1976. Re-sparring on 1717 took a lot less time - no doubt the engineers had
learned from the work on 1716 - the squadron being without the aircraft from September 1975 to October 1977. At least two other aircraft, besides 1718 and 1723 already mentioned, had undercarriage
problems on landing. 1722's nose wheel refused to lock down on 7 June 1960 and the aircraft landed on a foam laid down at Langebaanweg, the nose-wheel assembly collapsing on contact with the runway. Two years later, on 10 September 1962, 1721 had to make a wheels-up landingat Ysterplaat, but the damage sustained was repaired in a comparatively short time.



One other mishap to the SAAF MRJ fleet occurred on 18 September 196 I, when 1720 was undertaking asymmetric landing practice. The pilot undershot the runway at D. F Malan and the aircraft was extensively
damaged. Rather than dismantling 1720 and taking it away for repair, a hangar was constructed around it for the work to be carried out where it was.

The arms embargo certainly had a detrimental affect on the SAAF's MR.3s, and the two re-sparrings already mentioned were quite an engineering accomplishment on the part of their maintenance engineers. Engine spares were impossible to obtain, as were new tyres and electronic replacements so, in November 1984, the Shackleton was officially withdrawn as an operational aircraft in the SAAF.

1723 had expended its fatigue life several years prior to this and had been grounded since 22 November 1977. It was stored in the open at Ysterplaat, until being purchased by Vic de Villiers, who acquired the aircraft via a triple deal involving both the South African Airways Museum and the SAAF Museum. De Villiers gave the airways museum Vickers Viking ZS-DKH, which he had held for many years, and
they let the SAAF Museum have a Lockheed Ventura. The SAAF completed the convoluted agreement by selling 1723 to de Villiers, who mounted it on the roof of his 'Vic's Viking Garage' on the Johannesburg
to Vereeniging road. For many years it remained in its service colours, but without national markings. However, by 1994,commercial advertising had taken over and the aircraft was repainted a vivid red,
over which' Coca Cola' logos were liberally displayed. A sign that is mounted beside the aircraft, incorrectly said 'World War Two Shackleton'; today this has been edited and the word 'Two' has gone, although
the legend is still inaccurate.

On 24 April 1978, five months after 1723 was grounded, 1719 followed suit and it too was stored in the open at Ysterplaat to begin with. Later the aircraft was moved on it own wheels to an airfield at Stellenbosch, in the South African wine region. Finally, in 1991, 1719 was moved, to the
Cape Town Waterfront complex, where it is displayed today.

1720 had reached the end of its fatigue life by 10 March 1983, so it was grounded.
It had been planned to mount the aircraft a the gate guardian at Ysterplaat, but someone 'pulled rank' and instead it was positioned outside the Warrant Officer's Club. For a reason that cannot be ascertained,
it was repainted to represent '1719', complete with the individual code 'L'. Maybe it was hoped to frustrate future aviation historians, but today the aircraft's proper identity has been restored.

In 1984,1717 too was grounded; it had only been kept flying to that date by courtesy of a technical team that ascended the Wemmershoek Mountains to where the wreckage of 1718 lay, in order to retrieve serviceable parts that could be used on 1717. After open-air storage at Ysterplaat, the aircraft was dismantled to be taken by sea to Durban. From there, in October 1987,it went by road to Midmar Dam and was reassembled for static display at the Natal Park Board Museum.

The nostalgia of the Shackleton' retirement was not lost on the SAAF and on 23 November 1984 the surviving trio of airworthy MRJ ,1716,1721 and 1722, took part in a ceremonial flypast at D. F. Malan
Airport. Twelve growling Griffons was quite a farewell note! Two weeks after the ceremony, 1716 and 1721 were flown to the AAF Museum at Swartkop, while 1722 was retained in ground-running condition
by No. 35 Squadron for the museum.

In November 1991, the aircraft was flown to Ysterplaat, which, by then, had developed into the second largest military aviation museum in South Africa.

1963 ACCIDENT SUMMARY ANALYSIS



Occurrence Date: 8 August 1963
Aircraft Involved: one Avro MR. Mk 3 Shackleton (serial 1718)
Aircrew & Aircraft Home Unit: 35 Squadron at DF Malan International Airport
Aircraft Damage Classification: Category IIIa
Accident Root Cause: human error (pilot error)
Total Human Involvement: 13
Total On-Board Human Involvement: 13
Total Human Attrition: 13 killed

Identity of Deceased:

Pilot, Capt Thomas Howard Silvertsen (P22051) attested in the SAAF 01/04/48
co-pilot, 2/Lt Charles Alwyn du Plooy (P1/48842/1) attested in the SAAF 25/01/61
3rd pilot, Capt Jaques Guillaume Labuchagne (P21805) attested in the SAAF 04/02/53
navigator, Lt Abraham Gert Willem Coetzee (P20965) attested in the SAAF 28/01/57
2nd navigator, 2/Lt George James Smith (P1/24862) attested in the SAAF 23/03/60
3rd navigator, CO Derek Ian Strauss (P50506) attested in the SAAF 07/01/63
flight engineer, WO2 Sydney Shields Scully (P4895) attested in the SAAF 01/09/36
2nd flight engineer, L/Cpl Marthienus Christoffel Vorster (P2/20554) attested in the SAAF 01/04/58
signals leader, Sgt David Hope Sheasby (P17877) attested in the SAAF 03/03/55
radio operator, L/Cpl Charl Paul Viljoen (P20356) attested in the SAAF 01/06/55
2nd radio operator, L/Cpl Matthys Johannes Taljaard (P17993) attested in the SAAF 06/03/57
3rd radio operator, L/Cpl Michel Adolf Brodreiss (P23845) attested in the SAAF 01/12/59
4th radio operator, A/M Johannes Chamberlain (P50083) attested in the SAAF 01/07/62

The tactical submarine phase of Operation CAPEX (Cape Exercise), a joint training exercise involving elements of Britain's Royal Navy and both the SA Navy and Air Force, commenced on August 7, 1963. During this phase, the Royal Navy submarine, HMS Alliance, would relocate from her existing position south of Port Elizabeth to a position further west, from where she would take part in further exercises with the SA Navy. During this transitional phase of the submarine, Shackleton 1718 was tasked by Maritime Group to conduct a CAPEX A exercise with the submarine.

Although 35 Squadron was based at the military section of DF Malan International Airport in Cape Town, the unit's headquarters was at nearby Air Force Station (AFS) Ysterplaat and it was at this latter facility that the flight crew of Shackleton 1718 received a full briefing at 12H30 on August 8, 1963. During this briefing, the Operations Officer on duty advised the Shackleton aircrew to head out over False Bay after take-off and to transit seawards towards the exercise area. He warned them that the direct overland route to Port Elizabeth should be avoided due to anticipated high icing levels on this route.

Forecast weather for the route over False Bay and then southwards was poor. Heavy icing conditions could be expected between 1 220 and 1 829 m ( 4,000 and 6,000 ft) above mean sea level (AMSL) and consequently the flight crew were further briefed that Maritime Group had granted them special clearance to transit to the exercise area under 915 m (3,000 ft) AMSL. A 244 m (800 ft) AMSL cloud base would exist with tops up to 6 707 m (22,000 ft). Heavy air turbulence could be expected with cumulonimbus clouds, hail and heavy rain throughout. Surface wind was 42 km/h (26 mph) at 340? and 92 km/h (57 mph) at 340? and 1 524 m (5,000 ft).
Even though the forecast weather over the eastern overland route was no better, at least the seaward route would eliminate the risk of the aircraft accidentally flying into high ground in the conditions of much reduced visibility. The aircraft commander, Captain (Capt) TH Silvertsen , when giving his own briefing, confirmed his route as south over False Bay and then seawards towards the exercise area. The flight had been authorised by Maritime Group to provide the Shackleton crew with training in the radar detection of a submarine. No special instructions were issued.

Shackleton 1718 was fully serviceable for flight even though the compasses had not been swung on their normal expiry date of July 19, 1963. Maritime Group gave authorisation for a month's extension provided that no major part of the aircraft was replaced. The compasses were therefore considered serviceable.

The Flight Office at Ysterplaat was uncomfortable about the weather conditions and telephoned the Maritime Group Operations Centre thrice prior to the departure of the Shackleton, in an effort to get the flight cancelled, but this request was not forthcoming.

Just minutes before take-off, Capt Silvertsen, notwithstanding his briefing instructions, informed Air Traffic Control (ATC) that he would climb to 2 896 m (9,500 ft) AMSL and head overland towards Port Elizabeth.

The aircraft lifted off Runway 34 at 15H06 and turned right on 350? for the climb out. Moments later, ATC informed the commander to come to 330? so as to safely avoid Tiger Mountain. Capt Silvertsen acknowledged this transmission and did accordingly. After the lapse of about a minute, he requested clearance to resume his original course of 350?. This was the last radio transmission received from Shackleton 1718.

At about 15H20 the radar technician at DF Malan requested permission to deactivate the radar for about ten minutes due to flooding of the radar installation on account of the heavy rain. This permission was granted, but before the radar was deactivated, 1718's location was given as a distance on the radar screen of about 40 km (25 miles) on a course of 100?. The ground course was about 145?.

Although the evidence suggested that the airplane had crashed, most likely in the Stettynskloof/Wemmershoek Mountains area, the adverse weather conditions, combined with the lateness of the hour, precluded any meaningful attempt at a search and rescue effort being mounted until the following day, August 9.

At 10H00 and again at 13H30 on August 9, helicopters were sent out to the Wemmershoek area to report on the weather, which remained completely adverse. Following a report of an aircraft having been heard, a further helicopter was despatched at 15H00 to search the mountains south of Simonstown. On August 10, another helicopter continued the search at Simonstown from 08H15, while a second aircraft was sent to report back on the weather in the Wemmershoek area. Here, the weather was still closed in, but hinted at the first signs of improvement. At 09H00 at aircraft was sent to fly high over the Wemmershoek Mountains to report on the cloud coverage. At 11H00 two aircraft continued a search in the same mountains and at 13H15 they were joined by a further pair of rotorcraft. The wreck was finally discovered from the air at 17H18 just over two days following the accident. It was evident from the almost complete destruction of the aircraft that nobody aboard could possibly have survived the crash.

The crash occurred about 25.8 km (16 miles from the nearest town, Worcester, in the Stettynskloof valley between Paarl and Stellenbosch. After inspecting the crash scene, the 35 Squadron Engineering Officer, Capt WJ Stiglingh decided to investigate the failures apparent on the port elevator and the upper section of the starboard rudder, both of which detached in flight, although the Board of Inquiry (BOI) officially convened to investigate the cause of the accident, was unable to establish which broke off first.

The section of the starboard rudder was found 1 620 m (5,314 ft) and the port elevator 1 250 m (4,100 ft) from the impact point. Following the disintegration of these two flight control surfaces, the aircraft would have been rendered uncontrollable. At this point (about 15H25) the pilot was heard to make his final radio transmission: “Mayday. Mayday,” but this was not recognised as such by the ATC. The timing of the transmission coincides exactly with the crash time.

At the same time that the starboard rudder and port elevator detached in flight, the port fuel tip tank also broke away removing a section of the port wing and both outer elevators. The outer most starboard elevator was found further forward than the impact point of the port tip tank. Clearly, it broke away shortly after the tip tank. The port elevator, which was complete, showed relatively little damage. Most of the damage sustained was consistent with it having fallen on to its inboard end and then on to some rocks. Signs were found, however, of excessive downward movement of this elevator to the extent that the hinges had damaged the steel spar, more so at the outboard hinge where the hinge arm had actually cut into the spar. It was official opinion that pilot applied force could not have caused this damage since the control column movement in restricted by stops strong enough to resist human force.

It is considered that at the time of the excessive downward movement of the elevator, the force, mainly due to leverage over the spar, was sufficient to cause failure of the hinge bolts in tension. Failure of the spar attachment upper lug clearly indicated that the outboard end of the elevator broke away first in a rearward direction. No evidence was found to suggest that this port elevator was attached to the airframe at the time of impact.

Examination of the starboard elevator indicated that its upward travel had been exceeded; this and other damage to this elevator being consistent with crash damage.

Regarding the section of the upper starboard rudder, the outboard skin at the break had failed in tension and the inboard skin was torn away from the front rearwards, this indicating that the broken off portion was first bent inwards and then backwards. Furthermore, apart from damage at the upper leading edge, which was inflicted when the rudder struck the ground, this portion of rudder was altogether undamaged. The rudder was probably detached from the aircraft before the point of impact.

As for the lower portion of the starboard rudder, failures on the outboard and inboard skins correspond to failure on the upper section. Damage on this section would appear to indicate that it did not strike the ground at the point of impact, but that it was flung forwards and carried further assisted by the strong winds prevailing at the time.

Considerable violence coupled with exceptionally strong winds and/or air turbulence was necessary to carry the port and starboard fin, port tailplane and several other pieces of empennage to their final positions. None of these parts, except the starboard fin, displayed any damage that could have occurred at the point if impact.

The port tailplane front spar had pulled out along its length, shearing all its rivets. Examination of the main impact zone indicated that the fuselage struck at right angles to the main mark down the slope and the sideways cartwheel or flick might have thrown empennage parts in to the air forward of, and to the right of, the impact area.

Examination of the point of impact of the port wingtip fuel tank indicated that the angle that the tank struck the ground was such that, had the tank been attached to the aircraft, the empennage should then have hit the ground. The tank was therefore most probably detached from the aircraft while still in the air. Positions of the No. 3 and 4 ailerons and part of the port wing support this reasoning.

The dump valves of both port and starboard tip tanks were found in the fully open position. As these valves are electro-mechanically driven, they were probably intentionally open and most likely before the port tip tank impact since this tank still had a considerable amount of fuel left over in it, judging by the flash fire area. The forward portion of the starboard tip tank, on the other hand, showed no signs of flash fire or explosion, indicating that its fuel content at the time of impact must have been low. The open dump valves appear to suggest that the pilot must have been busy dumping fuel in order to reduce the load on the airframe when it experienced the heavy turbulence and just before the aircraft began disintegrating. The aircraft weighed about 43 213 kg (95,242 lb) at the time of the accident.

In an attempt to reconstruct the events leading up to the crash, another Shackleton of the same weight and load as Shackleton 1718, took off from Runway 34 at DF Malan on August 22, 1963 to attempt to emulate as closely as possible the course and climb tempo of the stricken aircraft. Based on this emulation, it was ascertained that Shackleton 1718 was either at or very close to its intended cruise altitude of 2 896 m (9,500 ft) AMSL.

Instrument Flight Rules (IFR) flight had been authorised and the aircraft had been operating under IFR conditions at the time of its demise.

The Board was satisfied that the flight crew were under all circumstances both qualified and capable of performing the mission with which they had been tasked.

The accident occurred over State ground; property of the Department of Forestry. The terrain was unplanted, deforested and in its natural state. No claim could thus be made by the Department. There was no damage to private or other military property.

Shackleton 1718 was manufactured in August 1957. Although possessing a maximum take-off weight of 45 372 kg (100,000 lb), for its final flight it lifted off at 43 938 kg (96,840 lb). Since the aircraft was heavily laden with its maximum weight point close to the rearmost limit, the pilots would have experienced some instability in the yawing (left/right) plane.

The Board established that the impact speed of the aircraft was high and that this, combined with the resulting fire following the crash, caused almost complete destruction of the aircraft. There was no attempt by the crew to use parachutes and all aboard are assumed to have perished in the high G impact.

The Board established that the atrocious weather was a significant contributory factor in this accident. Wind was about 148 km/h (92 mph) due to the unstable air mass forming convection currents. Cloud cover extended from 305 m (1,000 ft) to 8 841 m (29,000 ft) AMSL with associated heavy precipitation. Due to the turbulence, the moist unstable air mass and low icing height resulted in unusually high icing conditions from 1 220 m to 1 829 m (4,000 ft-6,000 ft).

Air Force headquarters telephonically informed the Board that the maximum acceleration permitted on the Shackleton airframe was 2.4 G. It was thus theoretically possible to easily exceed this low limitation, especially under conditions of unusually high turbulence as in this case. Although it cannot be proved, it is not impossible that the pilot in control could have over controlled the aircraft on at least one occasion in response to the unusually heavy turbulence. This could have placed an additional load on the airframe.

It was considered a possibility that, due to the turbulence, the pilot found himself unwittingly between the mountain peaks and that either one wingtip or one of the tail surfaces skimmed the side of one of the mountains, the impact causing the aircraft to disintegrate in flight and causing the pilot to lose control. The Board, however, considered this scenario unlikely given the fact that the ATC heard the pilot's Mayday transmission clearly and the aircraft must have thus been flying above the mountain peaks under normal circumstances when the radio call was put out. Additionally, the fact that the dump valves were open does not correspond with a collision against a mountain.

The Board found Capt Silvertsen solely responsible for the accident. He displayed a complete lack of discipline by disobeying a direct order to rather route south over False Bay and instead routed over land, where the mountainous terrain exacerbated the already foul weather conditions. The aerodynamic effect of heavy icing, strong and turbulent winds, the heavy weight of the aircraft combined with the possible over control by the pilot in control, placed an unusually high loading on the airframe. This resulted in the airframe exceeding its design limits and initiated disintegration, leading to the loss of control and the consequent fatal crash. The accident was classed as an avoidable major flying accident.

All the evidence submitted by all the witnesses interviewed was considered credible by the Board.

Shackleton 1718 was delivered new to the SAAF valued at R 417 250.00. At the time of its demise it had completed 775.15 total airframe hours and, with depreciation, was valued with engines and propellers at R 266 109.45. The Rolls-Royce Griffon Mk 57A piston engines, like the airframe, were all classified as having sustained Category IIIa (write-off damage with no salvageable content). Engine numbers were 64411, 64412, 64416 and 64445.

This was the only Shackleton to be written off in 27 years of SAAF service from 1957 to 1984.

The Group Commander remarked that the ultimate load factor was 4 G. This figure suggests that the airframe was considerably stronger than the BOI was made to believe when they made their investigation. This information was, however, not available to the Board at the time.

The only flight crew member of the 13 that perished on board to have received any honours or awards was WO2 (Warrant Officer Class 2) Scully, recipient of the Africa Star with Clasp and the Union Medal (No. 285).

Individual Aircraft History:

1716 / J - c/n1526, first flight 29th March 1957, accepted at the Woodford Airfield by 35 Sqdn on the 16th May 1957, ferried to RAF St Mawgan for SAAF air-crew work-up exercises on the 21st May 1957, Departed for South Africa on the 13th August 1957, arrived Waterkloof on the 18th August 1957, Progressively modified up to Phase III standard. Wing re-sparring took place in South Africa, from March 1973 to April 1976. The aircraft took part in the retirement ceremony flypast at DF Malan airport, Cape Town, on the 23rd November 1984. 

She was ferried from Cape Town to the SAAF Museum Swartkops on the 4th December 1984, with Capt Louis van Wyk as aircraft Captain. Restored to airworthy status in 1994, for planned attendance at a series of airshows in the UK. 1716 departed Cape Town International RW01 on the 8th July 1994, for the United Kingdom, routing via Libreville, Gabon, - Abidjan, Ivory Coast, - Lisbon, Portugal for intended entry into the UK via Brize Norton. Crashed 13th July 1994, in the Western Sahara Desert (22.38N, 03.14W) en-route to the UK.

Shackleton 1720 - painted as 1717 - which was on static display in front of the NCO's mess at 

Ysterplaat AFB in Cape Town for many years, was sadly broken up on 12th March 2013.

Speculation has it that it was due to corrosion - it had been considered a safety hazard

1717 / O - c/n1527, first flight on the 6th May 1957, accepted at the Woodford Airfield by 35 Sqdn on the 16th May 1957, ferried to RAF St Mawgan for SAAF air-crew work-up exercises on the 21st May 1957, Departed for South Africa on the 13th August 1957, arrived Waterkloof on the 18th August 1957, from where 1716, 1717, & 1718 departed to Cape Town. The a/c was progressively modified up to Phase III standard. Wing re-sparring was done from September 1975 to October 1977. The aircraft was withdrawn from service & placed in storage at AFB Ysterplaat. During October 1987, she was dismantled & transported by sea to Durban, & then via road to the Midmar Dam, for static display at the Natal Parks Board transport museum. Financially the Natal Parks Board were unable to keep funding the museum, and all the exhibits were disposed of. With the subsequent closure of the Midlands Historic Village, where the aircraft was displayed, she was bought on auction by Mr Desai, a private businessman from Stanger in Kwazulu Natal. As of 2006, the airframe had been cut up for scrap, with only the engines remaining, potentially being sold to the UK.

1718 / K - c/n1528, first flight on the 13th May 1957, accepted at the Woodford Airfield by 35 Sqdn on the 16th May 1957, ferried to RAF St Mawgan for SAAF air-crew work-up exercises, Departed for South Africa on the 13th August 1957, and arrived Waterkloof on the 19th August 1957, from where 1716, 1717, & 1718 departed to Cape Town. The a/c had a wheels-up landing at DF Malan airport on the 9th November 1959, and was repaired during 1959-1960. She crashed in the Wemmershook mountains during poor weather, on the 8th August 1963. The aircraft was taking part in a CAPEX exercise, when severe icing caused loss of control, and the aircraft crashed inverted into a mountain valley, killing all 13 onboard. The crew were: Capt Thomas Howard Sivertsen , Capt Jaques Guillaume Labuchagne, Lt George James Smith, Lt Abraham Gert Willem Coetzee, CO Derek Ian Strauss, 2/Lt Charles Alwyn du Plooy, WOII Sydney Shields Scully, A/Cpl Charl Paul Viljoen, A/Cpl Marthienus Christoffel Vorster, T/A/Cpl Matthys Johannes Taljaard, A/Cpl Michel Adolf Brodreiss, F/Sgt David Hope Sheasby, Air Mech Johannes Chamberlain.

1719 / L - c/n1529, first flight on the 6th September 1957, accepted by 35 Sqdn in January 1958, departed for Cape Town on the 8th February 1958, arrived Cape Town on the 13th February 1958. Returned to the UK for training with Coastal Command on the 25th February 1963 and returned to South Africa on the 1st April 1963. Progressively modified up to Phase III standard. She was withdrawn from service on the 24th April 1978 & in storage at AFB Ysterplaat. Static display outside clubhouse at Stellenbosch airfield. Static display at the V&A Waterfront in Cape Town, cut up for scrap.

1720 / M - c/n1530, first flight on the 26th September 1957. Accepted by 35 Sqdn in January 1958. departed for Cape Town on the 8th February 1958, arrived Cape Town on the 13th February 1958. During asymmetric practice on the 18th September 1961, landed in undershoot at DF Malan airport, and was badly damaged. Repaired on site, with a hangar being constructed around the aircraft whilst repairs were carried out. Progressively modified over the years up to Phase III standard by March 1973. Tthe aircraft was withdrawn from service on the 10th March 1983, after reaching the end of its fatigue life. Initially allocated as a gate-guard at AFB Ysterplaat, she is displayed outside the WO's club, now having been sprayed in the1957 delivery colours & marked as 1717-O. Due to the airframe deteriorating & being a safety concern, she was cut up for scrap 2013. 

1721 / N - c/n1531, first flight 12th December 1957, accepted by 35 Sqdn on the 30th January 1958, departed for Cape Town on the 14th February 1958, and arrived cape Town on the 26th February 1958, damaged in a wheels-up landing at AFB Ysterplaat on the 10th September 1962. Progressively modified over the years up to Phase III standard, has the distiction of being the Shackleton which using depth charges, sunk the damaged tanker Wafra in March 1971. This after attempts by the Buccaneers of 24 Sqdn to sink the ship had failed. Took part in the retirement ceremony flypast at DF Malan airport on the 23rd November 1984. Ferried to SAAF Museum Swartkops for static display in December 1984. She was used as a parts donor for the restoration of 1716.

1722 / P - c/n 1532, First flown on the 7th February 1958. Departed for South Africa on the 14th February 1958, arriving Cape Town on the 26th February 1958. On the 7th June 1960 the aircraft nosewheel assembly refused to lock down, and she landed on a foam strip at Langebaanweg. The nose undercarriage collapsed on touchdown resulting in slight damage. The aircraft was repaired and progressively brought up to Phase III (non-Viper) standard. She returned to the UK on the 28th June 1964 for Joint Anti Submarine School (JASS) course, flying from RAF Ballykelly. Returning to Cape Town on the 30th July 1964. Took part in final retirement ceremony, overflying DF Malan in formation with 1716 and 1721 on the 23rd November 1984. Retained by 35 Sqn at DF Malan in ground running condition for the SAAF Museum. Her last public flight was on the 24th September 2006, at the Africa Aerospace & Defence airshow, after which the Chief of the Air Force, felt the value of Shackleton 1722 was too high to risk by continuing to fly the aircraft, and she was grounded. This ended the famous "Pelican22"'s flying career, which had spanned an impressive 48 years! Still not 100% sure of her final flight date though?

Quote:

So the last flying Shackleton in the world was certainly 'Pelican 22', whose final flight happened on March 29, 2008. This was a typical flight which took it over the city of Cape Town, and then out over the Atlantic Ocean, then back over Robben Island to Ysterplaat AFB. This final flight was piloted by Captain Peter Dagg. The crew included flight engineer Bronkhorst and ground engineer Potgieter.

1723 / Q - c/n1533, First flown on the 10th February 1958. Departed for South Africa on the 14th February 1958, and on arrival at AFB Ysterplaat on the 26th February 1958, the aircraft suffered a hydraulic failure. The undercarriage and flaps were lowered using emergency air, but the brakes were inoperative and the aircraft ran off the runway, colliding with a brick building. The damage to No. I engine was repaired. Progressively modified up to Phase III standard. The aircraft was retired on the 22nd November 1977, having expended her fatique life. Ironically she was the last aircraft delivered, but the first to be retired. She was stored in the open at AFB Ysterplaat until sold, and in March 1987, was put on display on top of Vic de Villiers 'Vic's Viking', garage in Johannesburg. This was a three way swop, with the Shackleton replacing a Vickers Viking, ZS-DKH, which went to the SAA Museum, and the SAA museum then gave the SAAF Museum three Ventura's. 1723 was initially kept displayed in her SAAF colours, but was subsequently over the years sprayed red/white in Coca Cola colours, then blue/white in SASOL colours.

Read more about this particular aircraft 1723 and Vick's Viking Garage (click on link)

No copyright infringement intended. Happy to credit you, link or delete images. Just contact me. Not my work, just collated.

Dassault Mirage III (Part 2) Progeny: The Cheetah and Kfir

Mirage III Progeny: The Cheetah program


During the early 1980's, the SAAF faced modern Soviet aircraft and weapons in Angola. Being handicapped by a UN arms embargo, the SAAF had to act urgently to improve its capabilities. 
The SAAF never had a large number of combat aircraft to spare. It only had about forty combat-ready 1970's-vintage Mirage F1's. If it was to take them out of service to upgrade them, it had no replacement other than the  even older, 1960's-vintage Mirage III's. These were shorter-ranged, had less powerful engines and obsolete combat systems, and could carry less ordnance. This meant any upgrade would have to be applied first to the older Mirage III's, as they were the only aircraft that could be spared from combat operations for that purpose.

Fortunately, this wasn't a bad choice in the end. Two major aircraft programs had demonstrated what could be done by building on the foundation of the Mirage III, probably one of the most successful proven combat aircraft of it's day. First, Dassault Aviation was by then producing the successor to the Mirage F1, the Mirage 2000, which returned to the delta-wing format of the Mirage III.

Mirage III D

Israel agreed to supply systems and components, and the green light for the Cheetah project was given in the early 1980's. In order to provide a measure of diplomatic and political 'cover' for Israel, it was decided (as with  many South African weapons projects) to claim that it was an purely indigenous development. Despite huge similarity between the Kfir and the Cheetah, officials in on both sides  steadfastly deny that the two aircraft had anything in common. 

The SAAF provided Israel a two-seat Mirage IIID as the prototype air frame for conversion. It was stripped down completely and all components subject to metal fatigue or stress were replaced, effectively returning the air frame new condition. An extended nose cone was fitted, derived from the Kfir TC.2 model, which housed advanced electronic systems, and small canard wings were fitted above the air intakes to improve low-speed handling and angle of attack. (The canards on the D and E model Cheetahs were smaller than those used on the later Cheetah C's, reportedly because it was too difficult to reinforce the fuselage frames in the engine intake area to accommodate the larger units. The Cheetah C's used the same full-size canards as the Kfir; but their air frames were supplied by Israel, as noted below. Presumably they weren't subject to the same limitations as the French-air frame-based Cheetah D's and E's.)

Israel Aircraft Industries (IAI), together with several other companies in that country's defense industry, had already produced a series of Mirage derivatives. Israel had purchased Mirage III aircraft from France prior to the Six-Day War of 1967, and had ordered a further 50 Mirage 5's (a simplified version of the Mirage III). However, these were embargoed by France after the conflict. Undaunted, Israel stole the plans to the Mirage III from Switzerland, which was license-manufacturing the aircraft (Swiss engineer, Alfred Frauenknecht, would later be sentenced to 4½ years imprisonment for his collaboration with Israel).

Israel used these plans to develop its own fighters. The first  was the Nesher, almost an exact copy of the Mirage 5 (indeed, it's so exact that some sources suggest IAI actually assembled Mirages, clandestinely supplied in kit form by France, rather than manufactured the Nesher itself). A total of 60 Neshers appear to have been manufactured, most sold to Argentina at the end of the 1970's under the name of Dagger 

These aircraft confronted British forces during the Falklands War. Israel went on to produce the Kfir, a considerably upgraded Mirage derivative with Israeli electronics with a US J79 turbojet engine (As on the F-4 Phantom II fighter-bomber, also operated by Israel at the time).

Argentine "Dagger"

The IAI Nammer ("Leopard",  frequently mistranslated as "Tiger") was a fighter aircraft developed in Israel in the late 1980s/1990s as a modernised version of the Kfir for the export market. Although a prototype was built and flown, buyers were not forthcoming and development was ceased. The avionics of the Nammer were those of the cancelled Lavi project.

The Nammer promised an upgrade package for existing Mirage III and Mirage 5 air frames. Two configurations were proposed, one based around re-engining with a General Electric F404, the other around retaining the Mirage's SNECMA Atar engine. Elta EL/M-2011 or EL/M-2032 fire-control radar was to be fitted. The first of these options maximised performance and range, the second maximised the aircraft's air-to-air targeting capability. As development progressed, the Nammer came to be advertised as a new-build aircraft with the EL/M-2032 an integral part of the package, and customers able to choose their preferred engine out of the F404 (or its Volvo derivative, the RM-12), the SNECMA M53, or the Pratt & Whitney PW1120. The design strongly resembled the Kfir C-7,but was easily distinguished by its longer nose and lack of a dorsal air scoop under the tail fin

Details of the weapon and control systems fitted to the Cheetah have never been publicly revealed by the SAAF, but it can probably assumed they were close to or identical to those found on various models of the Kfir. IAI lists them as including, in the latest Kfir version:

The radar used in the Cheetah D and E models (and in the Kfir C.7) was the simple Elta EL/M-2001Bunit. The Cheetah C, the last development of this project, possibly had the much more advanced Elta EL/M-2032 . The Cheetah C's electronic systems were probably on a par with those of the F-16C/D fighter-bombers of the USAF at the time.

The intermediate single-seat Cheetah E model:

Here's the final iteration of the Cheetah, the 'C' model:

The SAAF's two-seat Mirage IIID variants were the first to be converted. This was probably for two reasons. First, and most pragmatically, the two-seat air frames could be most easily spared from operational duties. Second, they were probably urgently needed to replace the worn-out two-seat Buccaneer aircraft in the nuclear strike role (South Africa had six nuclear weapons, developed at the height of its political isolation and military struggle, which were dismantled in the early 1990's). The Buccaneers had not been updated with modern strike systems, which limited their usefulness; so the upgraded Cheetah D's would have been welcome in this role.

Sixteen two-seat Cheetah D's were produced, as well as 16 single-seat Cheetah E's, the latter mostly converted from Mirage IIIEZ air frames (although some were reportedly converted from air frames supplied by Israel, due to a shortage of suitable South African Mirages). All had been delivered by 1991. Finally, 38 Cheetah C's were produced under the auspices of 'Project Tunny'. 
The Cheetah C's were reportedly based on stripped down Kfir air frames supplied by Israel, modified to accept the French Atar engine rather than the US J79.  Most of the SAAF's Mirage III's had been delivered during the 1960's. Some had reached the end of their fatigue lives, and were thus unsuitable for conversion. Others had been lost in accidents, and the Cheetah E conversions had absorbed many of the remainder.

Given these two facts, there would not have been enough usable single-seat Mirage III air frames left in the SAAF inventory to produce 38 Cheetah C's.  one can safely assume that the reports that say Israel supplied the fuselages for the latter is accurate. Apart from the prototype Cheetah D, most of the conversions were carried out in South Africa by Atlas Aircraft Corporation (today part of Denel Aviation), with Israeli technical assistance (which decreased as local industry gained experience and competence).

The C models were delivered from 1993-1995, replacing the Cheetah E's, which were retired. Some of the two-seat Cheetah D's were retained in service as lead-in trainers for the C versions, and to provide a specialist strike function if required. A single experimental Cheetah R version was produced, using a Mirage IIIR2Z airframe, but no other reconnaissance versions were converted, and the Cheetah R did not enter squadron service, being retired soon afterwards. The reconnaissance function was taken over by Cheetah C's fitted with pod-mounted cameras.

The first ACW prototype was tested on the only Cheetah R, and a more evolved model was tested on a two-seat Cheetah D. The latter improved the Cheetah's sustained turn rate by 14%, and permitted maximum takeoff weight to be increased by well over half a ton. It also permitted angles of attack up to 33 degrees at low speeds, with much greater stability, at the expense of a reduction of approximately 5% in the aircraft's maximum supersonic speed. However, for budgetary reasons the SAAF declined to upgrade their Cheetahs with the ACW, and it was never put into production.


If it lost aircraft due to combat or accident  it could not replace them, due the embargo; and it had to keep its combat planes as up-to-date as possible, to ensure they did not become so obsolete that they risked being shot down in large numbers by more advanced enemy aircraft. 

Mirage 2000-5F of the French Air Force

South Africa had friendly ties with Israel, particularly in the military field.  South African technological institutions such as the Council for Scientific and Industrial Research (CSIR), and local defense companies such as Kentron (today Denel Dynamics), Reutech and others, were developing advanced radar and electro-optical detection and guidance systems. The latter companies in particular often collaborated with their Israeli counterparts (up to and including producing Israeli components and systems under license in South Africa). It would therefore be entirely feasible for the advanced combat systems of the Kfir to be 'transplanted' into the Mirage III's of the SAAF, including local assembly and partial production if necessary.

AI Kfir, in US Navy colors under the designation F-21A,

where it served as an adversary aircraft for Dissimilar Air Combat Training

The Cheetah had a considerably more powerful and more economical engine, greatly improved avionics and weapons systems, and a fly-by-wire control system, which rendered it far superior to the Mirage III from which it stemmed. (It's generally accepted that the French Mirage 2000 is roughly comparable, in terms of its overall capability, to contemporary models of the US F-16 Fighting Falcon or the Soviet MiG-29.) The SAAF reasoned that if Dassault could develop the Mirage III into a fully modern warplane, they could do likewise. This was aided by the fact that in the 1970's, South Africa had purchased a license to manufacture the Mirage III and F1, as well as the latter's Atar 09K-50 turbojet engine. All the necessary plans were thus already on hand.



Given that the Cheetah prototype was converted in Israel, it's very interesting to note the proposed IAI Nammer aircraft of the late 1980's. Wikipedia info:




You can't help but notice that the line drawing above is virtually identical to the pictures of the Cheetah C and Kfir 2000 . Also note that the translation of 'Nammer' is the name of a big cat. A co-incidence? Did the prototype' of the Nammer become the prototype SAAF Cheetah C ?  It would certainly have been a good cover story to disguise IAI's involvement with the latter program. 

SAAF Cheetah C in Service Ysterplaat AFB

Pilot friendly advanced "Glass" Cockpit;Hands On Throttle And Stick (HOTAS) operation;
Advanced multi-mode Fire Control Radar (FCR) with SAR; State-of-the-art weapons delivery, including Beyond Visual Range missiles; Digital Moving Map (DMM); Electronic Warfare (EW) Suite.


The Israeli lineage of the Cheetah is clearly demonstrated by comparing the aircraft side-by-side. The SAAF Cheetah D, the initial two-seat version of the aircraft:

Kfir TC.2 of the Israeli Air Force:




Note identical extended and slightly downward-sloping nose cones, housing the electronics; the canard wings above the engine air intakes; and the strakes on the nose cone. Note the second curved strake running from the base of the nosecone down and back along the bottom of the fuselage. The Cheetah has an air refueling probe on the starboard side of the cockpit, which is absent from the Kfir TC.2, but an identical probe may be seen on other Kfir models, as shown below. The rear fuselage is different as the Cheetah uses a French Atar engine, while the Kfir uses the US turbojet; but from the engine forward, there's virtually no difference.


And the single-seat Kfir C.7:

Note that both have small strakes at the tip of the nose cone, identical instrument probes beneath it, and an in-flight refueling probe that goes to the starboard air intake, rather than behind the cockpit, as in the later Cheetah C. The Cheetah E also incorporates the Kfir C.7's additional two weapons stations beneath the air intakes. I therefore consider the Cheetah E and the Kfir C.7 to be essentially identical from the engine forward.



      IAI publicity photograph of their Kfir 2000 


The refueling probes are different, but the noses of the two aircraft are, again, almost identical. (Note, too, their similarity to the IAI Nammer mentioned above.) As far as its weapons and electronic systems are concerned, the Cheetah C is the functional equivalent of the Kfir 2000 (also known as the Kfir C.10.

The first sixteen Mirage III's supplied to the SAAF were 'C' model interceptors, with a shorter fuselage than subsequent models - too short to be converted into Cheetah C's, which have a longer fuselage. They could not have been lengthened without a reconstruction so extensive (and expensive) that it would have effectively meant producing a new air frame.

Vinten Vicon 18 Series 601 reconnaissance pod mounted beneath a Cheetah C

Some of the Cheetah D aircraft had been converted from Mirage IIID2Z airframes, which had been delivered with Atar 09K-50 engines in the 1970's. Naturally, they retained these more powerful engines in their Cheetah guise. The remainder of the D's, and the Cheetah E models converted from Mirage IIIE's, retained their 1960's-vintage Atar 09C turbojet engine, as local production of the more powerful Atar 09K-50 (used in the Mirage F1) had proved economically unfeasible - South Africa's technological base was insufficiently advanced to manufacture all of the required components. In any event, due to changing circumstances , the lower-powered Cheetah models would all be retired within a few years.

Efforts were mounted to obtain additional 9K-50 engines to equip the Cheetah C models. The Mirage F1 was operated by a number of other countries, including Jordan, Iraq, Morocco and Qatar, all of whom also purchased armaments from South Africa. It is possible that one or more of those nations made Atar 9K-50 engines available to South Africa in return for arms shipments. The most likely candidate would have been  Iraq.

They bought over 80 Mirage F-1's from France, and, as mentioned above, obtained 100 G5 howitzer cannon from South Africa. (Iraq was engaged in a war with Iran from 1980-1988). 

Since combat operations would naturally impose greatly increased wear on the engines of its aircraft, it could order large numbers of replacement engines without arousing suspicion. I have little doubt that some of these replacements were swapped for South African artillery and/or ammunition - probably at a very favorable 'rate of exchange', because South Africa needed the engines very badly.)

The retirement of the SAAF's Mirage F1 fleet in the 1990's was partly (although by no means exclusively) caused by the need to transplant at least some of their engines into the Cheetah fleet. The surviving F1CZ interceptors were retired in 1992. 

Some of their engines went into the Cheetah C program. The Cheetah D and E versions (which had all entered service by 1992) took over from them until the Cheetah C's were ready. The last of the Mirage F1AZ's were retired in 1997, after all the Cheetah C's had entered service.

Mirage F1

If the Cheetah aircraft had a major weakness, it was their engines. The Atar 9C engines used by Mirage III's were rated at a maximum of 13,240 pounds static thrust with afterburner. The Atar 9K-50 engine of the Mirage F1 was rated at 15,873 pounds static thrust with afterburner, an increase in power of almost 20%. 

The core technology of both these engines was based on the German BMW 003 axial-flow turbojet developed during World War II, and was becoming increasingly dated. Technology that old simply couldn't keep pace with more modern developments. The Atar 9-series turbo jetengines weren't nearly as powerful (or as economical) as the turbofan engines installed in more modern military aircraft such as the F-16 or the MiG-29 (using two Klimov RD-33 turbofans, each rated at 18,285 pounds static thrust with afterburner. Such engines weren't available to South Africa at the time the Cheetah program was developed, so the SAAF had to make do with what it could get.

The Cheetahs used an upgraded wing, offering improved aerodynamic qualities compared to that originally fitted to the Mirage III. The wing design from the Carver program was experimentally adapted to fit the Cheetahs as the Advanced Combat Wing, or ACW. The diagram below shows how more advanced Cheetah wings evolved, from the initial production variant to a final design with missile stations on the wingtips. The ACW was flight-tested, but never entered service. 



The ACW had a fixed, drooped leading edge. An early iteration (Version 2 as shown above) had a simple notch in the leading edge at mid-span, while a later model (Version 3 above) had a much wider slot. This permitted underwing mounting of the SAAF's standard 500-liter (about 132 US gallon) drop tanks, which would otherwise have struck the lowered leading edge. Additional fuel tanks were incorporated into the drooped leading edge, which were claimed to improve the Cheetah's radius of action by almost 100 kilometers (just over 60 miles).

Official and unofficial South African sources claim that the Cheetahs were very successful, and popular with their pilots. Compared to the earlier Mirage III's and F1's, this is probably true. 
The Cheetah C's were  more capable than anything preceding them in the SAAF inventory. In terms of their electronics and weapons systems, they could certainly have matched the 1980's-vintage MiG-23's and -27's, and Sukhoi Su-20/22's, that the SAAF encountered in Angola. 

Due to the lower power of their engines, I don't believe they could have matched the Soviet aircraft in acceleration or top speed. One cannot believe claims from some South African sources that the Cheetah C was comparable in performance to the US F-15 Eagle. 

SAAF Cheetah C over USS Forrest Sherman, Cape Town 2007

Despite its limitations, the Cheetah program was a success, albeit at a very high price. Including all research, development, tooling, purchase and production expenses, and averaging them across the 71 aircraft produced (16 D's, 16 E's, 38 C's and a single R - the latter not entering service), each Cheetah cost South Africa well over twice the price of a brand-new contemporary equivalent (e.g. the Mirage 2000) on the open market. Operating in a sanctions environment, there was no alternative. 

The program updated obsolete third-generation jet combat aircraft to fourth-generation standards as far as their weapons and electronic systems were concerned, and provided the SAAF with an aircraft capable of handling any regional threat at the time. Fortunately, with the end of the Angolan War in the late 1980's, the collapse of the Soviet Union in the early 1990's, and the end of apartheid in 1994, no more sophisticated threats arose that would have required a more technologically advanced response.

During the 1990's the SAAF found itself in a budgetary crisis. Not surprisingly, the first democratically-elected post-apartheid government prioritized restoring balance to political, economic and social structures Funding was directed largely to such efforts. Furthermore, the military threats facing the country had almost completely evaporated, compared to the days of the Border War and international sanctions, which had driven the Cheetah program from its inception. 

There was no longer a pressing need for combat aircraft, but a need to conserve the SAAF's much more restricted budget. The number of front-line aircraft was therefore slashed. Only one squadron was retained, operating 28 Cheetahs (a mixture of single-seat C's and two-seat D's, all powered by Atar 09K50 engines). The remainder of the Cheetah fleet was retired from SAAF service. A couple were used as development aircraft, but most were placed in storage. Some were later sold to other nations. The last Cheetahs were retired in 2008, and are presently being replaced by 26 Saab Gripen multi-role fighters.

SAAF Saab Gripen fighters

Sadly, these reductions in force and budgetary constraints caused major problems for the SAAF in retaining the services of its highly qualified and skilled pilots. Many of them saw no future for themselves in the new climate of politically correct restructuring, and resigned to pursue more lucrative opportunities elsewhere. Some became mercenary pilots of combat aircraft for other nations and/or organizations, where their superior flying skills and combat experience were greatly appreciated and well compensated. 

The SAAF's budgetary and personnel problems have not abated since. It has been rumoured that only 8 trained pilots for its Saab Gripen fighters remain , down from 30 pilots in 2005 and 20 in 2008. 

The SAAF is presently in the midst of a crisis as far as trained personnel are concerned . . . a very sad situation for a service that only two decades ago boasted pilots equal to, if not better than, those of most first-class air forces, including the USAF. The SAAF will probably never regain the very high standards it had attained by the end of the Border War in the 1980's.

And the sad end of the road for some Cheetahs:

More info on SAAF Mirages:

The Mirage F1 (click to follow links) 3 Parts, including the Border war:
Part 1 History of the F1
Part 2 The Border War: F1s in Combat
Part 3 Combat record and First Hand Account (Arthur Piercy)

(Source Wings and Wiki, other Internet sources. Not for gain, just a fan blog. No copyright infringement intended)