Canberra Type Tp52
Translation of an Article from the Swedish Aviation Historical Research Group's magazine "Kontakt"
Background
Some years after WWII began the Swedish Air Force a new activity, "research flying" with direction to the electronic branch, mostly radar and radio. The first aeroplane for this activity was a converted B 3 (Junkers Ju86K) which was given the designation Tp73. ("Tp" stands for "Transport). It was written off in January 1957.
After WWII the Air Force also began more seriously with Electronic Intelligence (ELINT). For the activity, two DC-3's were procured. The designation of these planes was Tp79. These Dakotas were specially equipped and were run by FRA (Foersvarets Radioanstalt = the Radio Establishment of the Defense). One of these (79002) disappeared over the Baltic Sea in June 1952, most probably shot down by the Russians. One of the Tp47 Catalinas, that were searching after the lost Dakota, was itself shot down by a MiG-15. The crew was fortunately saved by a merchant ship. This loss of the DC-3 led to procurement of a Vickers Varsity (Tp82).

Tp52 Canberra Joins the Swedish Air Force
When the research platform Tp73 was written off and also the demand of altitude performance of the ELINT aircraft increased, the Air Force began to look abroad to find an aircraft suitable for both missions. The choice fell on the EE Canberra. An agreement was made with English Electric concerning two used, but totally overhauled and partly modified planes. Also technician training and pilot training were included in the agreement.
The two aircraft EE intended to sell were available on a base in Australia and of the version Mk VII. They have not been used for seven months. Their earlier mission had been as measurement aircraft in connection with nuclear weapon tests. The both machines were flown to England and English Electric's works in Preston for overhaul and modification. During the work, severe corrosion damages were found. It was caused by the fact that the aircraft had been sprayed with water to clean them from radioactivity after the tests. Unfortunately salt sea water had been used, and after half a year the aircraft were so corroded that they were unusable.
EE managed to find two other airframes, however not Mk VII, but the older version B.2s. These two aircraft were soon to be called "The Swedes" and carried the RAF serials WH711 and WH905. They were given the Swedish FV-numbers (FV = Flygvapnet = The Air Force) 52001 and 52002 and the designation Tp52.
Except for the major overhaul, the aircraft were also modified (by Boulton-Paul Ltd). The original nose cone was replaced with nose of type AI17, and a radome adapted for the "S"-band. The same type of nose cone was also installed on the T.11 Canberra version and was nicknamed in Sweden as "the pencil". Furthermore most of the radio and navigation equipment was removed and replaced with more modern equipment of the Swedish Air Force standard. Also two spare engines type Rolls Royce Avon Mk 101C were included in the delivery.
In January 1960 was 52001 ready for delivery and a crew from the Wing F8 of Barkaby (near Stockholm, now closed) flew the Canberra from Preston home to Sweden and the F8 Wing. On the 5th of March, 52002 was flown home. The price for the both aircraft was about 3 million Swedish kronor. With training, spare parts and other equipment the final amount was about 4,5 million kronor. But with the delivery both research and ELINT were given much better conditions and also the step into the jet age was taken.

Modifications
Before the two aircraft could been taken in active service, they had to be modified and equipped for their respective duty concepts. Generally the two planes went through the same modifications, but with the reservation that 52001 should be used by the FRA for ELINT, while 52002 should be used for research both by the Air Force and for some civilian companies that had the Air Force as a customer. Except for earlier mentioned exchange of radio and navigation equipment, the electric alternators were changed to the type that was used in the SAAB J35 Draken, which gave a higher output. In the bomb bay a big "rack" of profiles and plating was build. On this rack different equipment could be installed; fixed equipment for FRA in 52001 and more occasional installations in 52002. As certain radar tests were to be carried out with 52002, an adapter of glass fiber was built so it would be possible to mount the antenna used for the radar developed for the all-weather attack plane SAAB A32 Lansen. 52001 was of course provided with a many and various antennas for ELINT with, amongst others, three bladed, dorsal antennas and a large antenna built into the fin.
At the beginning of December 1960, 52001 returned to the F8 Wing where it began its service for FRA together with Tp82 Varisity and occasionally with Tp83 Pembroke. Half a year later, the 25th of May 1961, 52002 was also ready to join 52001 with Kungliga Svea Flygflottilj (Royal Svea Air Force Wing), at the F8 Wing's home base at Barkaby.

Tp52 in the service of Flygvapnet
52001, with the code 01 on the fin, was, as planned nearly exclusively used for ELINT purposes for the FRA. The crew then consisted of three; a pilot, a navigator and an operator from the FRA. The aircraft was all the time fitted with the English "T.11-nose cone" and extra fuel tanks on the wing tips. This arrangement gave it the range to patrol the Baltic Sea from North to South on "turn and return" missions. Alternatively, it could fly the borders between Norway, Finland and Denmark.
52002 worked of course under different conditions. The missions were short-time tests in the field of teletecnical research (ie radar, radio, data transmisson, recognizing of friend/foe and other projects of strictly secret nature). On these flights the crew of pilot and navigator, were joined by one or two researchers on the two rear seats. With these type of missions, the "Lansen" radome was nearly always used. But occasionally 52002 also flew with the T.11 radome. Extra fuel tanks were less usual than on 52001. The aircraft was very busy as a research platform, but when not on its missions, it was sometimes used as a "flying target" plane.
Both aircraft were often based on other places than F8 in Barkarby, for example F17 in Ronneby or F7 in Saatenaes. Also the large live firing area Vidsel in the north of Sweden could be used when secrecy demanded it.
Both aircraft were sometimes used in "ÖB-controls". These were very secret and must have been very exciting flights. These controls implied that the aeroplanes were flown on absolutely lowest altitude (sometimes under 10 meters) over the sea, eastward or westward. After some time, they changed direction and flew towards the Swedish coast before climbing fast to high altitude. Suddenly an echo could pop up on the radar screens in the underground centres. This was of course to check how alert the radar operators were. The extreme low flying altitude was used after it appeared that you could be discovered in certain sectors, even if you flew on 15-20 meters altitude. The navigation was of course important considering other nations borders and was carried out with the help of Decca Navigator. The pilot had a hard job. As there was no autopilot, he had to manually adopt a very "precision-flying" approach.

Painting and Marking
During all their service in Sweden, the Tp 52's were painted according to British standard, ie aluminum paint over a coat of zinc cromate primer. The roundels ("crown marks") were of 1300mm diameter on top and undersides of the wings. The roundels on the fuselage were of 960mm in dia Numbers for codes and flottilj (Wing) were painted black. During the time the aircraft were based at F8, the Wing numbers were of the older type (m/40), but when the code numers later were applicated, they were of the more modern type (m/64). When 52001 later was re-based on F3 wing on Malmen, the Wing number became of the new type and the new code on the fin (callsign) become "19".
The dorsal blade antennas (52001) were black, which also the "T.11"-radome was. The "Lansen" radome on 52002 could vary in colour from coffee brown to matt black. The adapter ring was of unpainted glass-fiber.
All instruction- and warning texts were of British typeface. Only exception was the "FARA"-signs. (Fara = Danger). They were of early rectangular type, yellow with red text.
The exhausts from the engines starting cartridges on the fore part of the engine cowling was "camouflaged" by a painted black tapered triangle.

The end for Tp52
In the beginning of the 1970's the Canberras had been too small and narrow for its purpose. FRA demanded a considerable larger space for their equipment. Two SE-210 Caravelle could be purchased from SAS (Scandinavian Airlines System) for a reasonable cost.
When wing F8 was laid down in 1973, the activity was moved to F3 (Malmen). Both Canberras were consequently re-based, but only 52001 would fly under the administration of F3, now with the code 19. In summer 1974 also this plane was taken out of service after 14 years of safe flying. The flying time of 52001 is not known, but 52002 logged in 2427 hours of flying (without an accident).
52001 (F3-19) was sold to Svedinos Car and Aircraft Museum in Ugglarp, south of Falkenberg on the west coast of Sweden. I saw it there a couple of years ago. It is placed outside and not in very good condition.
52002 (F8-02) was brought to Flygvapenmusem at Malmen, Linkoeping. Also this aircraft is unfortunately placed outside together with some other large aircraft. The aeroplanes inside the museum are in excellent condition, but, sadly, old faithful servants as Catalina, Dakota, Pembroke, Varsity and a lot of others are parked outside, exposed for the not always so pleasant Swedish weather.

Most of this information comes from the magazine "Kontakt", number 95, published in February 1990.
Lars Henricksson, 2000