The entries in the main stream of South African military history for 10 July 1942 deal with the end at El Alamein, of the Eighth Army's last humiliating retreat. On the Home Front, an entry mentions the end of a unique aircraft. At No. 23 Air School, Waterkloof Air Station, a Board of Survey sat to discuss the fate of a decrepit old aircraft which had flown for many hundreds of hours. Tt was an angular old bi-plane which had become an anachronism in the modern SAAF. The Board recommended that it be struck off charge and scrapped. The finding was confirmed on 1 December 1942, and by the beginning of 1943, the Gloster AS.31 Survey "250" had been broken up at Zwartkop Air Station.
I have often heard people ask what type of multi-engined aircraft was first used by the SAAF. On the strength of evidence available to me, it would seem that it was the Gloster Survey. The aircraft was taken on strength by the SAAF on 28 March 1933, and not in May 1933 or May 1935, as stated by some other sources. It is true that the South African Governusent bought a twin-engined Vickers Vimy bomber for use by Van Ryneveld and Brand during the first flight from Britain to South Africa in 1920. However, "Silver Queen" was purchased prior to the establishment of the SAAF on 1 February 1920, 11 days after which date it was put into service as a civil aircraft. It carried the puzzling early South African civil registration G-UABA. The second Vimy, in which Van Ryneveld and Brand flew from Cairo to Bulawayo was also evidently not taken on strength by the SAAF. One version says that the Prime Minister, General Smuts, authorised the British Air Force to place the second Vimy at the disposal of Van RyneveTd and Brand. British sources say that this aircraft, known as Silver Queen II, was a loan.
The second Silver Queen crashed at Bulawayo and its engines were sent to South Africa by rail. The historic flight was completed in a SAAF de Havilland DH-9.
These are the earliest contenders. After the Gloster Survey was taken on strength, the SAAF bought three de Havilland DH66/Hercules Tri-motor airliners from Imperial Airways. The first of these was the SAAF's "260" which was previously G-AAJH "City of Basra". It was taken over at the end of March, or at the beginning of April, 1934. The other two, 261 and 262, were received in June and November 1934, respectively.
It would thus appear that the Gloster Survey was the SAAF's first multi-engined aircraft. At the time of its purchase, the SAAF's inventory consisted of single engined trainers, reconnaissance bombers and one solitary Westland Wapiti liaison aircraft. The AS.31 was a versatile addition to SAAF strength. It could be used for photographic survey, as a trainer, as a bomber, as an ambulance aircraft or to transport passengers and freight. However, it was as a platform for photographic work that the Gloster Survey was best known.
Aerial photographs have two basic uses. Firstly they are invaluable in the field of military intelligence and secondly they furnish most reliable information for the drawing of maps. The story of the Gloster Survey is mainly concerned with the second. The technique goes back to 1851 when the Frenchman, Laussedat, made maps of mountain ranges from aerial photographs. Before the first aeroplane flew at the beginning of the century, the Austrian, Scheimpflug, and others perfected methods by which photographs, taken from balloons, could be used as the basis for manufacturing maps. The rapid development of aircraft and cameras during the First World War made extensive aerial mapping possible.
The techniques developed during the war were applied and improved upon after hostilities ceased. There were large areas which had heretofore defied the map maker who moved on foot and by boat. In New Guinea, for example, oil prospecting was hampered because the Dutch colonial authorities estimated that it would take a team of a hundred trained men 50 years to map an oil concession area of 10,000,000 hectares. The contract was given to a firm using aircraft. Only 24 months later, the oil company had a set of good 1:40,000 maps on which to base its prospecting programme.
Thus vast areas of Africa, Asia and South America were surveyed to pave the way for development. The South African Air Force received photographic equipment as part of the Imperial Gift granted to the Union after the First World War. The first experiments were carried out as early as 1921 and, during the next decade, the Air Force assisted several South African Government departments and the authorities in neighbouring territories by carrying out aerial surveys.
These included the Kalahari Irrigation Reconnaissance (1925), the Vaal-Harts Scheme (1929) and other areas for the Department of Irrigation as well as the Belfast-Waterval Onder line for the Railways (1929). Parts of the Transkei were also photographed to see whether native allotments could be allocated by using aerial photographs (1927). The Zambesi in the Livingstone area, the Chobe region and the Zimbabwe ruins were surveyed at the request of the authorities concerned (1925 and 1929). Large sections of the coast were done to assist the South African Naval Service's hydrographic survey.
The work was not easy and defects in the design of the aircraft used caused many a headache. Engine failure at best meant a long walk home for the crew, a difficult recovery operation to get the aircraft flying again and expensive delays in operations. Ants ate the wooden airframes which also had the tendency to warp in the hot African sun.
To keep costs down, war surplus aircraft were used. Most of them were single-engined, a poor safety factor, without sufficient power to operate at high altitudes.
The DH-9 was used for most of the surveying in South Africa. It was also used in the same role in many other parts of the world, but towards the middle of the 1920s it was realised that the type was nearing the end of the road. One of the private organisations using the DH-9 was the Aircraft Operating Company Ltd which had mapped vast areas of the British Empire, including parts of Southern Africa. To solve the problenn, they approached the de Havilland Aircraft Co. Ltd. of Edgware, Middlesex, England, with the request that a specialised design be produced to carry out the work.
A specification was drafted calling for the safety of two engines and the ability to struggle along on one if need be. It also stipulated that the airframe should be of metal and be designed in such a way that maintenance would be easy in the bush. Special mention was made of above average vision for the aircrew to replace the uncomfortable open cockpits of the DH-9.
The design team at Stag Lane produced two projects the DH-67 and the DH-67B. The first was an adaptation of the Hercules airliner, built for operation in tropical climates. The designs were not accepted and, as de Havillands were fully occupied at the time, the project was farmed out to the Gloster Aircraft Co. Ltd.
The famous aircraft designer, H. P. Folland, took over the project in December 1928 and made many changes. The new project designation was Gloster AS.3l which was far more versatile than the original de Havilland scheme. In addition to its specialised role as a survey aircraft, it could also be converted to carry up to eight passengers or an equivalent weight in cargo: equipped to serve as an ambulance aircraft or as a bomber with a defensive armament of three machine guns.
The airframe was of all-metal construction covered with fabric. To simplify work in the bush, the square-section fuselage consisted of three separate units which could be dismantled by removing a few bolts and pins. Dual controls were fitted to the open cockpit and all control cables were eliminated and replaced by push rods to guarantee better serviceability. The cockpit was reached through a door in the fuselage. In comparison with the DH-9, the cabin had ample space, and three separate camera positions were provided. A special Eyrie mounting in one position enabled the camera operator to lower the camera to a position in which it was clear of any projections on the aircraft.
The tail unit consisted of a single fins and rudder of typical Gloster outline. The undercarriage was designed to stand rough handling. It was built in the form of a triangulated "V" with an oleo shock absorber housed in the vertical leg.
The wings were of orthodox metal and fabric design with balanced ailerons of the Frise type fitted to the bottonn planes only. Two squat 525 h.p. Bristol Jupiter XI geared aircooled radial engines were fitted to the lower wings. Initially the aircraft was fitted with double bladed wooden propellers, but these were later replaced with wooden four bladers. In case the Bristol Jupiter might not always be available during operations in foreign countries, the engine mountings could be modified to take no less than five other types of British, French or American engine.
Only two examples of this versatile aircraft were eventually built. The first received the British civil registration G-AADO and was sold to the Aircraft Operating Company. The other was K2602 built for the British Royal Air Force. In a slightly modified form, it was used for wireless experiments at the Royal Aircraft Establishment at Farnborough until late 1936. In comparison with the staggering development costs of today, the AS.31 was an extremely cheap aircraft. The two exaniples were built at a total cost of only £13,000.
The Gloster AS.31 Survey "250" in service with the SAAF.
The delivery flight to Cape Town lasted from 20 March until 11 April 1930. The aircraft covered the 7,000 miles at an average speed of 128 m.p.h., only three miles per hour less than its maximum speed.
On board were the Chairman of de Havilland, Mr Alan Butler, his wife, a cameraman and a ground engineer.
The Aircraft Operating Company sent G-AADO to Bulawayo for use in a surveying programme in the Rhodesias and Central Africa which was to last just on three years. It flew about 500 hours and one area photographed was a 63,000 square mile slice of Northern Rhodesia. The AS.31 proved to be a very reliable aircraft, as only tyres and tailskid shoes had to be replaced during the period.
The Gloster AS.31 at a bush airfield somehere in the Rhodesias during survey
operations by the Aircraft Operating Compnay during the early 1930s.
War clouds were gathering, and in 1936 a Photographic and Survey Flight was established at Zwartkop as part of the SAAF's expansion plans. However, the AS.31 was already obsolete and destined to p]ay a minor part in the future. The Airspeed Envoy, a twin-engined monoplane with a retractable undercarriage, was bought to equip the new unit alongside other older aircraft.
At about this time, the Survey was fitted with two 525h.p. Bristol Jupiter lXFP engines to replace the geared Jupiter XIs. It was involved in an accident on 20 June 1937 during a tour of inspection by Col. L. Beyers. By then it had flown for 809 hours and 30 minutes. It was in the air again two months later but, by the end of the year, the SAAF was writing to Glosters for spares. These were not available, but they were evidently supplied after the SAAF sent the necessary drawings to Britain.
In March 1939, the Survey was involved in another accident while taking Lt. Gen. Andries Brink to Kuruman. By then its total flying hours stood at 1,301. It is suspected that the aircraft was again modified at this stage and the wooden four-blade propellers may have been fitted then. Records show that its maximum loaded weight increased by 430 lbs. to 9,000 lbs. and the fuel capacity rose by 14 gallons to 254 gallons. The top speed of 131 m.p.h. probably remained unchanged.
In April 1939, the Survey was overhauled again and cleared for another 360 hours flying. At some unknown date, it was transferred from Zwartkop to Durban to be used in the training of wireless operators at the Wireless and Electrical School. It is mentioned as being there in February 1940. One of the engines was unserviceable and the aircraft was grounded until mid-1940.
In May 1940, it was allotted to No. 67 Air School at Zwartkop. The date is interesting, as a month later No. 1 (Survey) Flight, equipped with two Airspeed Envoys and a B.A. Double Eagle, was raised in the unit for service in East Africa. The flight in turn became No. 62 and No. 60 Squadrons. The allocation evidently fell through, as in June there was a scheme to make the aircraft available to the South African Military College for signals instruction. Nothing came of this either, as the high-tension cables fitted to the engines would have caused interference on the sets. Parts to modify the engines were not available. The next move was to allocate it to No. 62 Air School, the Central Flying School in Bloemfontein. It evidently did not go there either, and showed up at the Photographic Flight, Zwartkop in August 1940. The engines were serviceable again, but the fabric covering was in a poor condition. The historic aircraft lingered on for another 11 months and then the Board of Survey sat to condemn it.
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