At the technical museum in Helsingør hangs a single SAAB airplane with Danish markings. The problem is that it has never been in the air force.

The Saab 17  is a  Swedish  single-engine monoplane reconnaissance dive-bomber aircraft of the 1940s originally developed by  ASJA  prior to its merger into Saab. It was the first all-metal stressed skin aircraft developed in Sweden.

B 17s in  Trollhättan  assembly hall in 1944

The project was initiated in response to a 1938 request from the  Flygvapnet  (Swedish Air Force) for a reconnaissance aircraft to replace the obsolete  Fokker S 6 (C.Ve)  sesquiplane . Design work began at the end of the 1930s as the  L 10  by  ASJA , but once accepted by the  Air Force  it was assigned the designations  B 17  and  S 17  for the bomber and reconnaissance versions respectively, and it became better known as the Saab 17.

The design chosen was a conventional  mid-wing  cantilever  monoplane  with a long greenhouse canopy and a single  radial engine  in the nose. Control surfaces were covered in fabric but the remainder was stressed-skin  duralumin . It could be fitted with wheels or skis, both of which retracted straight to the rear along the underside of the wing, leaving prominent fairings, and when fitted with wheels the undercarriage doors could be used as dive brakes. [3]  A retractable tailwheel was provided. A floatplane version was built in small numbers for coastal reconnaissance to replace the obsolete  Svenska S 5 , with massive fairings joining the floats to the wings where the wheels would have been. To maintain stability small vertical fins were added to the  horizontal stabilizer . The wings were reinforced so that it could be used as a  dive bomber  and bomb racks were provided under the wings, along with a small bomb bay below the cockpit, although some examples used a conventional rack on the centreline, while on the bomber versions, a crutch was fitted to swing the bomb clear of the aircraft in vertical diving attacks, when the bomb could otherwise have passed through the propeller. The reconnaissance versions lacked the crutch.  Split flaps  broken into four segments were fitted to the underside trailing edge of the wing.

Two L 10 prototypes were ordered, the first being powered by an 880 hp (660 kW)  Bristol Mercury XII  radial engine  built by  Nohab  in Sweden, and the second with an imported 1,065 hp (794 kW)  Pratt & Whitney R-1830 Twin Wasp  C radial.

Supplies of suitable engines remained a major problem, and resulted in the aircraft being built in three versions with different engines. The definitive  B 17A  used the Swedish-built  STWC-3  (Swedish Twin Wasp C-3), an unlicensed copy of the R-1830. The  B 17B  used a  Bristol Mercury XXIV  built by  Svenska Flygmotor  AB (SFA) in Sweden, and the  B 17C  used an imported 1,060 hp (790 kW)  Piaggio P.XI  radial from Italy. [4]  The  United States  government denied a request to purchase a license to build the Twin Wasp, so an unlicensed, reverse engineered copy was built instead as the STWC-3 (Swedish Twin Wasp C-3) to supplement and replace the lower powered Mercury radials already being built under license. [5]  Until production caught up to demand, the earliest aircraft being delivered were flown to their destinations, the engines were removed and shipped back, to be used on the next aircraft to be delivered. [ citation needed ]

Saab B 17B showing bombing crutch under the fuselage needed to allow the bomb to clear the propeller during a dive, and the large undercarriage doors which acted as dive brakes

Saab B 17B in flight

The first flight was on 18 May 1940 and first deliveries of dive bombers to the  Air Force  began in March 1942, [1]  while deliveries of reconnaissance versions began in June 1942, and the type was operational by September 1942 when the first exercises were carried out . [2]  Problems immediately arose with wing failures, and additional modifications were needed before it could be cleared for dive bombing, which remained limited to shallow attacks thereafter. [2]  The final aircraft was delivered on 31 August 1944. [6]

AB 17 was used to test the  ejection seat  Saab had developed for use in the  Saab 21  pusher fighter, which was first successfully fired on 27 February 1944 with a dummy. [7]

Stig Wennerström  gained some fame in Sweden for successfully bailing out of a B 17 from low altitude, with his gunner, but would later become a spy for the Soviet Union. [8]

For several months in late 1944 and early 1945 fifteen B 17As were operated by the  Danish Brigade in Sweden  (Danforce) a unit of 5000 men (including 50 airmen) in Sweden which had been formed to assist in liberating occupied Denmark from the Nazis, and preventing the retreating German soldiers from using civilians as human shields, and carrying out  scorched earth  tactics as they had done elsewhere. However, due to the  German surrender on 7 May 1945 , the aircraft were no longer needed and were returned to  Flygvapnet  control a couple of months later. [9]

Rapid advances in aviation related to improved aerodynamics, higher engine power and finally the introduction of jet engines, resulted in it having a short career, and it was gradually withdrawn from frontline service between 1948 and 1950, [2]  while the last examples were retired from secondary roles by 1954. Over the next few years, examples would be sold off to various operators.

Due to the efforts of  Carl Gustaf von Rosen , the  Ethiopian Air Force  bought 47 which were operated from 1947 [2]  until 1968.

From 1951, 19 B 17s were loaned to  Svensk Flygtjanst  AB  and AVIA for use as  target tugs  and painted yellow with civilian markings. [2]  One of these, a B 17A SE-BYF was sold to the Austrian  Österreichische Luftstreitkräfte  in 1957, where it continued to be used as a target tug until retired in 1963. Two B 17As were also sold to the Finnish  Ilmavoimat in 1959 and 1960, also as target tugs. Neither of the Finnish aircraft lasted long before being destroyed in accidents.  

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