View source for Saab 17

{{Short description|Swedish dive bomber}}
{{Use dmy dates|date=September 2016}}
{{Use British English|date=August 2022}}
{{Infobox aircraft
|name=Saab 17
|image=SAAB B17-20 - Flickr - Ragnhild & Neil Crawford.jpg
|type=[[Reconnaissance aircraft|Reconnaissance]]-[[dive bomber]]
|national_origin=Sweden
|manufacturer=[[Saab AB|SAAB]]
|designer = 
|first_flight=18 May 1940
|introduction=March 1942<ref name=Annerfalk58>Annerfalk, 1999, p.58</ref>
|retired=1977 ([[Ethiopia]])
|primary_user=[[Swedish Air Force]]
|more_users=[[Imperial Ethiopian Air Force]]<br>[[Royal Danish Air Force]]
|produced=1941–1944
|number_built=326 (including 2 prototypes)<ref name=Annerfalk59/>
}}
The '''Saab 17''' is a [[Sweden|Swedish]] single-engine monoplane reconnaissance dive-bomber aircraft of the 1940s originally developed by [[AB Svenska Järnvägsverkstädernas Aeroplanavdelning|ASJA]] prior to its merger into [[Saab AB |Saab]]. It was the first all-metal stressed skin aircraft developed in Sweden.

==Design and development==
[[File:Assembly-Halls-with-B17-planes-in-Trollhättan-142370502302.jpg|thumb|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 C.V|Fokker S 6 (C.Ve)]] [[sesquiplane]]. Design work began at the end of the 1930s as the '''L 10''' by [[AB Svenska Järnvägsverkstädernas Aeroplanavdelning|ASJA]], but once accepted by the ''[[Flygvapnet]]'' 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#Aircraft|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 [[duraluminum]]. It could be fitted with wheels or skiis, 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.<ref name=Karlström>Karlström, 1988, p.52</ref> A retractable tailwheel was provided. A floatplane version was built in small numbers for coastal reconnaissance to replace the obsolete [[Heinkel HE 5|Svenska Aero 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]]. 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. 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. [[Flap (aeronautics)#Split flap|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 a {{cvt|880|hp}} [[Bristol Mercury XII]] [[radial engine]] built by [[Nohab]] in Sweden, and the second with an imported {{cvt|1065|hp}} [[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 [[Pratt & Whitney R-1830 Twin Wasp|STWC-3]] (Swedish Twin Wasp C-3), an unlicenced 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 {{cvt|1060|hp}} [[Piaggio P.XI]] radial from Italy.<ref name= avro>{{cite web|title= B 17 – Saab 17 (1941–1955) |url= http://www.avrosys.nu/aircraft/Bomb/157-b17/157B17.htm |website= Avrosys |access-date= 3 September 2015|pages= 1–5}}</ref> The [[United States]] government denied a request to purchase a licence 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 licence.<ref name=Annerfalk84>Annerfalk, 1999, p.84</ref> Until production caught up with 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.{{cn|date=December 2020}}

==Operational history==
[[File:Saab B 17B on ground.jpg|thumb|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]]
[[File:Saab B17B in the air.jpg|thumb|Saab B 17B in flight]]
The first flight was on 18 May 1940 and first deliveries of dive bombers to the ''Flygvapnet'' began in March 1942,<ref name=Annerfalk58/> while deliveries of reconnaissance versions began in June 1942, and the type was operational by September 1942 when the first exercises were carried out.<ref name=Annerfalk59/> 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.<ref name=Annerfalk59/> The final aircraft was delivered on 31 August 1944.<ref name=SaabsFirst>{{cite magazine|title=Fpl 17 – Saabs första konstruktion|magazine=Svensk Flyghistorisk Tidskrift |publisher=Svensk Flyghistorisk Tidskrift (Swedish Aviation History Journal)|date=June 2020|language=sv|page=8|issn=1100-9837}}</ref>

A B 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.<ref name=Annerfalk95>Annerfalk, 1999, p.95</ref>

[[Stig Wennerström (colonel)|Stig Wennerström]] gained some fame in Sweden for successfully bailing out from a B 17 from low altitude, with his gunner, but would later become a spy for the Soviet Union.<ref name=Annerfalk144>Annerfalk, 1999, p.144</ref>

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 [[End of World War II in Europe|German surrender on 7 May 1945]], the aircraft were no longer needed and were returned to ''Flygvapnet'' control a couple of months later.<ref name=Annerfalk100>Annerfalk, 1999, p.100</ref>

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,<ref name=Annerfalk59/> 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 [[Imperial Ethiopian Air Force]] bought 47 B 17As which were operated from 1947<ref name=Annerfalk59/> until 1977.<ref>Cooper, 2014, p.9</ref> Ethiopian B 17s were used to suppressed the [[1960 Ethiopian coup attempt|1960 coup attempt]] in [[Addis Ababa]].<ref>Cooper, 2014, p.12-13</ref> Several aircraft were stationed at [[Kebri Dahar]] in Ogaden during the [[1964 Ethiopian–Somali Border War|1964 conflict with Somalia]].<ref>Cooper, 2014, p.16</ref> By late summer 1977, the 3rd Squadron based at [[Dire Dawa]] was deactivated and its remaining twelve B 17s were stored at the airbase.<ref>Cooper, 2014, p.26</ref> During the [[Ogaden War]], eight B 17s that were stored at Dire Dawa airbase were destroyed by Somali bombardment in August 1977.<ref>Cooper, 2014, p.39</ref><ref>Cooper, 2014, p.58</ref>

From 1951, 19 B 17s were loaned to ''[[Svensk Flygtjanst]] AB'' and AVIA for use as [[target tug]]s and painted yellow with civilian markings.<ref name=Annerfalk59/> One of these, a B 17A SE-BYF was sold to the Austrian [[Austrian Air Force|''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 [[Finnish Air Force|''Ilmavoimat'']] in 1959 and 1960, also as target tugs. Neither of the Finnish aircraft lasted long before being destroyed in accidents.<ref name=Saab17iFlygvapnet>{{cite magazine|title=Saab 17 i flygvapnet, Spaningsplan och dykbombflygplan – S17, B17 |magazine=Svensk Flyghistorisk Tidskrift |publisher=Svensk Flyghistorisk Tidskrift (Swedish Aviation History Journal)|date=June 2020|language=sv|issn=1100-9837|page=14}}</ref>

==Variants==
===Company designations===
;L 10
:internal ASJA/Saab designation; two produced
[[File:Saab S 17BS.jpg|thumb|Saab S 17BS mounted on floats]]
;L 10A 
:internal ASJA/Saab designation for 17A, B, and C
;L 10BL 
:internal ASJA/Saab designation for S17BL
;L 10BS 
:internal ASJA/Saab designation for S17BS

===Flygvapnet designations===
;P 7<ref name=Annerfalk59/>
:L 10 development prototypes

;B 8
:Preliminary designation for bomber version of L 10, not used
[[File:Saab B 17C.png|thumb|Saab B 17C in flight. The three main versions could be distinguished by their intakes and exhausts. The 17A had a single intake centred on the top of the cowling, the 17B had a single intake offset to [[starboard]] along with a prominent exhaust on the same side, and the 17C had two intakes on either side of the top]]
;B 17A 
:Bomber with {{cvt|1065|hp}} [[Svenska Flygmotor Aktiebolaget|Svenska Flygmotor Aktiebolaget (SFA)]]-built [[Pratt & Whitney R-1830 Twin Wasp|STWC-3 (Pratt & Whitney R-1830-S1C3G Twin Wasp)]] radial engine; 132 built
;B 17B
:Bomber with {{cvt|980|hp}} SFA-built [[Bristol Mercury XXIV]] radial engine; 55 built
;B 17C
:Bomber with {{cvt|1060|hp}} [[Piaggio P.XI|Piaggio P.XIbis R.C.40D]] radial engine; 77 built

;S 15
:Preliminary designation for reconnaissance version of the L 10, not used
;S 17BL
:Reconnaissance version of B 17B with wheeled or ski landing gear; 21 built
;S 17BS
:Reconnaissance version of B 17B with floats, powered by a Bristol Mercury XXIV engine; 38 built

A total of 326 Saab 17 aircraft of all types were produced, and some bombers were converted into reconnaissance aircraft.<ref name=Annerfalk59/>

==Operators==
[[File:17320 Danmarks Tekniske Museum.jpg|thumb|Saab B 17A displayed in [[Helsingør]] in Danish markings]]
;{{AUT}}
*[[Austrian Air Force|''Österreichische Luftstreitkräfte'' (Austrian Air Force)]] - operated one target tug
;{{DEN}}
*[[Royal Danish Air Force|''Flyvevåbnet'' (Royal Danish Air Force)]] - operated 15 on loan while in exile with the [[Danish Brigade in Sweden|''Den Danske Brigade'' Danforce]] in 1945.
;{{flag|Ethiopia|1897}}
*[[Imperial Ethiopian Air Force|''Ye Ithopya A yer Hayl'' (Imperial Ethiopian Air Force)]] - operated 47 examples<ref name=Annerfalk59/>
;{{FIN}}
*[[Finnish Air Force|''Ilmavoimat'' (Finnish Air Force)]] - operated two target tugs
;{{SWE}}
*[[Swedish Air Force|''Svenska Flygvapnet'' (Swedish Air Force)]]
**[[Roslagen Air Corps|F 2 Hägernäs/Roslagen Air Corps Naval Support Wing]] ([[Hägernäs]], near [[Stockholm]]) - S 17BS floatplanes only<ref name=Annerfalk59>Annerfalk, 1999, p.59</ref>
**[[Jämtland Wing|F 4 Frösön/Jämtland Wing]] ([[Frösön]])<ref name=Annerfalk59/>
**[[Västgöta Wing|F 6 Karlsborg/Västgöta Wing]] ([[Karlsborg]])<ref name=Annerfalk59/>
**[[Skaraborg Wing|F 7 Såtenäs/Skaraborg Wing]] ([[Såtenäs]])<ref name=Annerfalk59/>
**[[Kalmar Wing|F 12 Kalmar/Kalmar Wing]] ([[Kalmar]])<ref name=Annerfalk59/>

==Surviving aircraft==
[[File:Saab B17A Fv17239 1.jpg|thumb|Saab B 17A flown by the [[Swedish Air Force Museum]]. A second B 17 is displayed in the museum.]]
Five Saab 17s are known to be in existence today, three of which are on public display.

The [[Swedish Air Force Museum]] in [[Linköping]] has two aircraft in their collection, a S 17BL '5', serial 17005 which is on static display in the museum, and a B 17A '7', serial 17239, the latter being kept in airworthy condition and which is periodically flown.<ref>{{cite web|last=Poelstra|first=Jack|url=http://avia-dejavu.net/photo%20SE-BYH.htm|title=SE-BYH Saab B 17A c/n 17239 - Swedish Air Force Museum - Groningen Airport Eelde in Holland - 7 July 2005|access-date=27 December 2020}}</ref>

Another B 17A 'E', serial 17320 which was donated by the Flygvapnet after having served as a target tug is on display at the Danish Museum of Science and Technology in [[Helsingør|Helsingør/Elsinore]].

Two former Ethiopian B 17As were recovered in the 1990s and purchased by a South African collector as a part of a large batch of ex-Ethiopian aircraft. These were shipped to [[Lithuania]] but  their current status and location is unknown following the collapse of the collector's business interests.<ref name=lae>{{cite web|title=Baltbound Bombers – 2|url=http://lae.blogg.se/2013/february/baltbound-bombers-2.html|website=Lae – inte bara en stad på Nya Guinea|access-date=3 September 2015|language=sv}}</ref>

==Specifications (B 17C)==
{{Aircraft specs
|ref=Saab Aircraft since 1937<ref name =Andersson>Andersson, 1989, pages 59–65</ref> 
|prime units?=met
|crew= Two
|capacity=
|length m=10
|span m=13.7
|height m=4.5
|wing area sqm=28.5
|airfoil=
|empty weight kg=2680
|gross weight kg=3870
<!--Powerplant-->
|eng1 number=1
|eng1 name=[[Piaggio P.XI|Piaggio P.XIbis R.C.40D]]
|eng1 type=14 cylinder air-cooled radial piston engine
|eng1 hp=1060
|prop blade number=3
|prop name=Piaggio P.1001 variable pitch propeller
|prop dia m=
<!--Performance-->
|max speed kmh=435
|cruise speed kmh=370
|minimum control speed kmh=125
|range km=1700
|ceiling m=9800
|climb rate ms=10
|wing loading kg/m2=139
|power/mass={{cvt|0.220|kW/kg}}
<!--Armament-->
|guns=<br>
**2 × fixed forward-firing {{cvt|8|mm|3}} [[M1919 Browning machine gun#Flygplanskulspruta m/22|Flygplanskulspruta Ksp m/22F (M1919 Browning AN/M2) machine guns]]
**1 × rear cockpit flexible {{cvt|8|mm|3}} Flygplanskulspruta Ksp m/22R (M1919 Browning AN/M2) machine gun 
|bombs=<br>
**{{cvt|700|kg}} of bombs could be carried. Racks were provided under the wings, in an internal bomb bay and externally on the fuselage centreline.
}}

== See also ==
{{Aircontent
|related=
|similar aircraft=
*[[Aichi D3A]]
*[[Blackburn Skua]]
*[[Caproni Ca.355]]
*[[Curtiss SB2C Helldiver]]
*[[Douglas SBD Dauntless]]
*[[Mitsubishi Ki-51]]
*[[Naval Aircraft Factory SBN]]
*[[Northrop A-17]]
*[[Sukhoi Su-2]]
*[[Vultee Vengeance]]
|lists=
*[[List of bomber aircraft]]
*[[List of military aircraft of Sweden]]
|see also=
}}

==References==
{{Commons category}}

===Citations===
{{reflist}}

===Bibliography===
*{{cite book|last=Annerfalk|first=Anders|title=Flygvapnet An Illustrated History of the Swedish Air Force|publisher=Aviatic Förlag|location=Ljungsbro, Sweden|year=1999|isbn=91-86642-049}}
*{{cite book |last=Andersson|date=1989 |first=Hans G. |title=Saab Aircraft since 1937 |publisher=Smithsonian Institution Press / Putnam|location=Washington, D.C. / London, UK|isbn=0874743141|pages=59–65}}
*{{cite book |first=Tom |last=Cooper |year=2014 |title=Wings Over Ogaden: The Ethiopian-Somali War 1978-79 |publisher=Helion & Company Limited |location=Warwick, England |isbn=978-1-913336-8-51 }}
*{{cite book|last=Karlström|first=Björn|title=Flygplans - Ritningar 3 Svenska Flygvapnets Bombflygplan 1926-1986|publisher=Allt om Hobby|location=Stockholm|year=1988|isbn=9789185496259}}

===Further reading===
* {{cite book|editor=Bill Gunston|title=Jane's Fighting Aircraft of World War II |year=1989|edition=2001 |publisher=Military Press & Crescent Books |location=New York & London |isbn=1851704930}}
* {{cite book|last1=Widfeldt|first1=Bo|last2=Hall|first2=Åke |title=SAAB 17; Den Forsta Egna Konstruktionen|publisher=Air Historic Research|year=1997|isbn=9789197160582|language=sv}}
* {{cite magazine|last1=Edlund|first1=Ulf|last2=Andersson|first2=Lennart|last3=Berns|first3=Lennart|last4=Stridsberg|first4=Sven|title=Svensk flyghistoria under 1900-talet|magazine=Svensk Flyghistorisk Tidskrift |location=Stockholm|publisher=Svensk Flyghistorisk Förening|year=2003|issn=1100-9837}}

{{Saab aircraft}}
{{ASJA aircraft}}
{{Swedish military aircraft designations}}

[[Category:Saab aircraft|17]]
[[Category:1940s Swedish bomber aircraft]]
[[Category:Single-engined tractor aircraft]]
[[Category:Mid-wing aircraft]]
[[Category:Aircraft first flown in 1940]]
[[Category:Aircraft with retractable conventional landing gear]]
[[Category:Single-engined piston aircraft]]