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{{Short description|German single-engine low-wing monoplane transport aircraft}}
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{{Infobox aircraft
 |name=W 33
 |image=Junkers aircraft Bremen.jpg
 |caption=W 33 [[Bremen (aircraft)|''Bremen'']] after its historic Atlantic crossing.
 |type=Transport
 |manufacturer=[[Junkers]]
 |designer=Herman Pohlmann<ref name=Zoeller>{{cite web|last=Zoeller |first=Horst|title=Junkers – Who is Who?|url=http://www.geocities.com/hjunkers/ju_who_p.htm |access-date=2016-06-22  |publisher=The Hugo Junkers Homepage |url-status=usurped|archive-url=https://web.archive.org/web/20091027072819/http://www.geocities.com/hjunkers/ju_who_p.htm |archive-date=October 27, 2009 }}</ref>
 |first_flight=17 June 1926<ref name=Kay>Kay, 2004, p. 64</ref>
 |introduction=1927
 |status=retired
 |primary_user=
 |produced=1927–34
 |number_built=199
 |variants=[[Junkers W 34]]<br />[[Junkers Ju 46]]
}}

The '''Junkers W 33''' was a German 1920s single-engine low-wing monoplane transport aircraft that followed Junkers standard practice making extensive use of corrugated aluminium alloy over an aluminium alloy tube frame, that was developed from the similar but slightly smaller [[Junkers F 13]], and evolved into the similar [[Junkers W 34|W 34]]. One example, named [[Bremen (aircraft)|''Bremen'']], was the first aircraft to complete the much more difficult east–west non-stop heavier-than-air crossing of the Atlantic.

==Design and development==
Like all Junkers designs from the  [[Junkers J 7|J 7]] fighter onwards,<ref name=Turner/> it used a [[duraluminum]] aluminium alloy structure covered with Junkers' characteristic corrugated dural skin. While the Junkers W 33 was unusual when compared to the contemporary biplanes in use in the UK and the US, [[cantilever]] monoplanes were a popular design choice in continental Europe during the period, and the Junkers designs were unusual only in their extensive use of closely corrugated metal skins. Unlike the skins on the contemporary [[Rohrbach Roland]], those on the Junkers aircraft were not load bearing and it did not have a [[stressed skin]] structure. The Junkers W 33 was a direct evolution of the 1919 four-seat airliner, the [[Junkers F 13]].<ref name=Turner>{{Harvnb|Turner|Nowarra|1971|pages=39–40}}</ref> The F 13 was similar to the W 33, but slightly smaller and had some detail differences. Considerable evolution occurred in the structure of the F 13, so that later models shared more details with the W 33. The wings had the same span as the late F 13s, though the planform differed slightly, while the length was the same as the F 13fe.<ref name=Turner/>
[[File:Junkers W33 Tank.jpg|thumb|Cross section of the W33 wing]]
A slightly different fuselage cross section gave the W 33 a squarer cabin with a hunch-backed appearance compared to that of the F 13 and a door was provided on the port side to provide access to the freight compartment.<ref name=Turner/> Early examples of the W 33 had an open cockpit much like the F 13, although it lacked the structural member that divided the pilot and co-pilot, and the corresponding and very distinctive [[coaming]]s. Some examples, such as the transatlantic machines had an early enclosed cockpit.

The  {{cvt|228|kW}} [[Junkers L5]] upright inline water-cooled engine was also the same as used in the F 13fe, a more powerful engine than used in many of the F 13 variants. The W 33 differed primarily from the W 34 in normally using an inline engine (aside from the rare dGao variant, which served as a prototype for the W 34), while the W 34 generally used various radial engines and had some minor detail improvements, such as a larger enclosed cockpit.

As was common for the time, when a wheeled undercarriage was fitted, a [[conventional undercarriage|conventional fixed undercarriage]] was used with a tailwheel. Early examples had a similar undercarriage to that used on the F 13, in which a hinged cross axle connected the two main wheels, while later examples provided an independent three-legged structure for each wheel. The Junkers '''W''' letter may have denoted the type as a seaplane (for ''Wasserflugzeuge''), but in practice W 33s were equipped as either landplanes or seaplanes, as needed.<ref>{{Harvnb|Turner|Nowarra|1971|page=10}}</ref> As a floatplane, the W 33 was equipped with two main floats, braced to the fuselage with a forest of struts.

The prototype W 33, registered ''D-921'', first flew as a seaplane from [[Leopoldshafen]], on the river [[Elbe]] near Dessau on 17 June 1926.<ref name=Kay/> Production began in 1927 and ran until 1934 and most of the 198 production machines were built at the Junkers works at [[Dessau]], but a small number were assembled at Junker's Swedish subsidiary AB Flygindustri at [[Limhamn]] near [[Malmö]], and at [[Fili (Moscow)|Fili]], near [[Moscow]] in the USSR.<ref name=Gunston131>Gunston 1995, p. 131</ref> Both of these plants had originally been built to avoid Allied post-war restrictions on aircraft manufacturing in Germany following [[World War One]], that had been considerably eased by the time the W 33 was flying.

In 1934 a Junkers W33 was used to test the [[Junkers Jumo 210]] engine. It was flown with a 680 hp version on 5 July 1934.<ref>{{Cite book |last=Vajda |first=Ferenc A. |url=https://books.google.com/books?id=Elfmh6eJFrMC |title=German Aircraft Industry and Production, 1933-1945 |last2=Dancey |first2=Peter |date=1998 |publisher=McFarland |isbn=978-1-85310-864-8 |page=234 |language=en}}</ref>

==Operational history==
[[File:Junkers W33.jpg|thumb|Transatlantic W 33 on display at Bremen airport]]
[[File:Junkers W33 hydroplane.jpg|thumb|Junkers W 33 first prototype ''D-921'' at the ''Deutschen Seeflug'' competition, July 1926]]
Soon after their first flights the first two W 33 prototypes competed at the ''Deutschen Seeflug'' seaplane competition at [[Warnemünde]] in July 1926, with the first prototype W 33 competing as no.7, and coming in second in the contest while the second prototype, a W 33a, competed as no.8.<ref name=Kay/>

W 33s were used by many operators across the world in the late 1920s and 1930s,<ref name=Turner/> as transports and mailplanes. [[Deutsche Luft Hansa]] only had four that they used for mail from 1929. Others were flown as survey aircraft and crop-sprayers. Later, despite their obsolescence, the Luftwaffe would use some as trainers alongside W 34s.

The [[Colombian Air Force]] used Junkers W 33, W 34 and the militarized W 34, the K 43, during the [[Colombia-Peru War]] of 1932–1933.<ref name=Leticia>von Rauch 1984, pp. 3–4.</ref> The [[Ethiopian Air Force]] operated a single W 33c during the [[Second Italo-Abyssinian War]].

One Junkers W 33g was used by the Swedish Air Force from 1933 to 1935 as an air ambulance under the designation [[List of military aircraft of Sweden|'''Trp2''']]. This aircraft may have been assembled at Linhamm, as were four W 33s exported to Australia.<ref name=GY/> After World War II, this aircraft was used as a utility transport by the Swedish Air Force's [[Roslagen Air Corps|F 2 Hägernäs squadron]] and in June 1952, it participated in the search and rescue operation during the [[Catalina affair]], in which two Soviet [[MiG-15]]s shot down a Swedish [[Douglas C-47]] intelligence aircraft and the [[Search and Rescue]] [[Consolidated Catalina]] sent out after it.<ref>{{cite web|author=Flight Stories |url=http://fly.historicwings.com/2012/06/the-catalina-affair/ |title=The Catalina Affair, Part 1 of 3 ‹ HistoricWings.com :: A Magazine for Aviators, Pilots and Adventurers |publisher=Fly.historicwings.com |date= |accessdate=2022-04-04}}</ref>

Of the 17 W 33s assembled in Russia at Fili from imported parts at least 9 appeared on that country's civil register.<ref name=GY/><ref>{{cite web|last=Fitzpatrick|first=Peter|title=Junkers W33/W34|url=http://www.mojobob.com/roleplay/hero/pulp/resources/vehicles/junkers.html|accessdate=22 June 2021|archive-date=30 September 2018|archive-url=https://web.archive.org/web/20180930133352/http://www.mojobob.com/roleplay/hero/pulp/resources/vehicles/junkers.html|url-status=dead}}</ref> In Russian service, they were given the designation '''PS-3''' as the third  ''Passazhirskii Samolyot'' (passenger aircraft or airliner), while at least 17 Russian examples were built by GVF workshops with numerous improvements with the  designation '''PS-4'''.<ref name=Andersson95p161>Andersson, 1995, p. 161</ref>

===Flight records===
The Junkers W 33 set numerous records, and one example, named the ''Bremen'', made the first east-to-west crossing of the Atlantic by airplane.<ref name=Turner/>

The North Atlantic had previously been crossed by the [[US Navy]] [[Curtiss NC-4]] flying boat, with numerous stops, and by [[John Alcock (aviator)|Alcock]] and [[Arthur Whitten Brown|Brown]] in 1919 in a [[Vickers Vimy]], nonstop, and by others, but all of these heavier than air aircraft flew the easier west to east route, which had the [[prevailing wind]]s helping them along with a tailwind. On April 12–13, 1928, the W 33 [[Bremen (aircraft)|''D-1167 Bremen'']] was flown by [[Hermann Köhl|Köhl]], [[Ehrenfried Günther Freiherr von Hünefeld|von Hünefeld]] and [[James Fitzmaurice (pilot)|Fitzmaurice]] from [[Baldonnel, Ireland]] near Dublin into the prevailing winds, to [[Greenly Island, Canada|Greenly Island]], off the coast of [[Quebec]] in the [[St. Lawrence River]], in 37 hours. Strong winds took them north of their intended destination, which was to have been New York, and they put down near the first settlement they found, but caused minor damage to the aircraft that required some time to repair before they continued. Their aircraft is now on display at [[Bremen Airport]] in Germany. The Bremen was one of two aircraft making the attempt, however the ''Europa'' never made it out of Germany.
[[File:DBP 1979 1007 Jugendmarke Junkers W 33 Bremen 1928.jpg|thumb|German Stamp commemorating the historic 1928 flight of the W33]]
A W 33 set class C world records for an endurance flight of 52 hours, 22 minutes and for covering a distance of ({{cvt|4661|km}}) during a single flight around Dessau between 3 and 5 August 1927, piloted by [[Johann Risztics]] and Edzard. Earlier Fritz Loose and W.N. Schnabele had set another Class C record for duration and distance, while carrying a {{cvt|500|kg}} load. For that flight they remained aloft for 22 hours 11 minutes and travelled {{cvt|2736|km}}. At about the same time, the W 33 set a similar pair of records in Class Cbis (Seaplanes).<ref>[http://www.flightglobal.com/pdfarchive/view/1927/1927%20-%200847.html ''Flight'', 3 November 1927, p. 763]</ref> A substantially modified W 33 fitted with a radial engine and so sometimes erroneously referred to as a W 34, flwon by [[Willy Neuenhofen]] set an altitude record of {{cvt|12740|m}} on 26 May 1929.<ref name=Turner/>

The first Swedish-assembled W 33 was completed in May 1930, and delivered two months later to Japan. With Eiichiri Baba flying under the command of Lt. Col. Kiyoshi Honma, and with Tomoyoshi as the radio operator, J-BFUB, named ''Third Hochi Japan-US'' departed [[Sabishiro Beach]] near [[Misawa, Aomori|Misawa]] on 24 September 1932 in an attempt to cross the Pacific Ocean to the US, but they disappeared en route. Their last radio transmission indicated that they were passing to the south of [[Etorofu Island]].<ref>{{cite web|last=Yukihiro|first=Torikai|title=ユンカースW33輸送機/W34/K43f水上機: 鳥飼行博研究室|trans-title=Junkers W 33 transport aircraft / W34 / K43f Seaplane: Torikai Yukihiro Laboratory|language=Japanese|url=http://torikai.starfree.jp/1933/w34.html|date=2018|location=Japan|accessdate=22 June 2021}}</ref> Neither wreckage nor survivors were ever found, despite an extensive search. (see also [[List of missing aircraft#1920-1939]])

==Accidents and incidents==
* 15 May 1932 – D-1925 ''Atlantis'' flown by Hans Bertram and Adolph Klausman landed on the [[Kimberley (Western Australia)|Kimberly coast]] of [[Western Australia]] while attempting to fly from [[Kupang]] to [[Darwin, Northern Territory|Darwin]] due to a navigational error, the crew were not [[1932 Kimberley rescue|rescued]] until June 1932.<ref name=Atlantis1932>{{cite book|title=Atlantis is missing... a true account. Australia's most bizarre air rescue|last=Winter|first=Barbara|year=1979|publisher=Angus & Robertson Publishers|location=Hong Kong|isbn=0207142335}}</ref>
* 29 October 1932 – D-2017 ''Marmara'' of [[Luft Hansa]] was on a freight flight from [[Croydon Airport|Croydon]] to [[Cologne]] when it crashed off the [[Kent]] coast.<ref name=Flight031132>{{cite magazine|title=Airport News – Croydon |magazine=Flight |issue=3 November 1932 |page=1027 |url=http://www.flightglobal.com/pdfarchive/view/1932/1932%20-%201107.html}}</ref>

==Variants==
[[File:Ahrenbergs-Atlantic-Flight-1929-142361190574.jpg|thumb|W33 floatplane]]
;Junkers W 33:-b.-c,-dd and -f powered by a {{cvt|310|hp|order=flip}} [[Junkers L5]] water-cooled inline engine.
;Junkers W 33:-c3e and -he powered by a {{cvt|340|hp|order=flip}} [[Junkers L5G]] water-cooled inline engine.
;Junkers W 33:-dGao powered by a {{cvt|540|hp|order=flip}} [[Siemens Sh 20]] radial engine.
;[[Junkers W 34]]: A 6-passenger development powered by a variety of [[radial engine]]s.<ref name=Turner/><ref name=Kay2/>
;[[Junkers K 43]]: Bombing and reconnaissance version built in Sweden, equipped for machine guns in the cabin roof and floor.<ref name=Kay2/>
;PS-3: Soviet designation for German built examples.<ref name=Andersson95p161/>
;PS-4: Soviet designation for locally produced modification.<ref name=Andersson95p161/>
;Trp2: Swedish Air Force designation.<ref name=Kay2/>

==Operators==
[[File:Flughafen Bremen, Ausstellung der Bremen D 1167 (Typ Junkers W 33).jpg|thumb|The W33 Bremen aircraft of the atlantic crossing]]
===Civil operators===
;{{flag|Brazil}}
* [[Syndicato Condor]]<ref name=Turner/>
;{{flag|Canada|1921}}
* [[Canadian Airways]]<ref name=Grant>Grant, 2004, pp. 70–75.</ref>
;{{CHN-ROC}}
* [[Eurasia (airline)|Eurasia]]<ref>Andersson, 1994, p. 6</ref>
;{{flag|Colombia}}
* [[SCADTA]] One registered as C-33, sold to [[Colombian Air Force]] in 1932.
;{{GER}}
* [[Deutsche Luft Hansa]]<ref name=Turner/>
;{{flag|Iceland|old}}: One on civil register<ref name=GY>{{cite web|url=http://www.airhistory.org.uk/gy/reg_index.html|title = Registration index}}</ref> W.33d, "Súlan" (The Gannet)
;{{JPN}}: Two on civil register.<ref name=GY/>
;{{SWE}}: Three on civil register.<ref name=GY/>
;{{USSR}}
* [[Deruluft]]<ref name=Gunston131/>
* [[Dobrolyot]] operated 7<ref name=Gunston131/><ref name=Gunston127>Gunston, 1983, p. 127</ref>
* TsARB (Центральная авиационная ремонтная база – Central aviation repair base) operated 10<ref name=Gunston127/>

===Military operators===
;{{COL}}
* [[Colombian Air Force]] operated 1 W 33 from 1932 to 1939,<ref name=Turner/> acquired from [[SCADTA]]
;{{flag|Ethiopia|1897}}
* [[Ethiopian Air Force]] operated 1 W 33c from 1929 to 1936<ref>{{cite web |url=https://www.nevingtonwarmuseum.com/abyssinian-airforce.html |title=Abyssinia 1935–1936|publisher=Nevington War Museum}}</ref>
;{{flag|Germany|Nazi}}
* ''[[Luftwaffe]]''<ref name=Kay2/>
;{{flag|Iran|1925}}
* [[Imperial Iranian Air Force]] operated 3 W 33d from 1929 to 1943.{{citation needed|date=June 2021}}
;{{flag|Mongolia|1924}}
* [[Mongolian People's Army|Mongolian People's Army Air Force]] operated 5 aircraft from 1931.{{citation needed|date=June 2021}}
;{{SWE}}
* [[Swedish Air Force]] operated 1 W 33g from 1933 to 1938 and 2 W 34h from 1934 to 1953.<ref name=Kay2>Kay, 2004, pp. 72–75</ref>
;{{USSR}}
* [[Soviet Air Force]] operated 25<ref name=Gunston127/><ref name=Gunston131/>

==Specifications (Landplane)==
[[File:Junkers W 33 'Bremen' 2-view L'Aérophile May,1928.png|thumb|Junkers W 33 'Bremen' 2-view drawing from L'Aérophile May,1928]]
{{Aircraft specs
|ref=Junkers: an aircraft album No.3<ref name=Turner/>
|prime units?=met
|crew=Two
|capacity=cargo hold volume {{cvt|15.7|m3}}
|length m=10.5|span m=17.75|height m=3.53|wing area sqm=43
|airfoil=Göttingen 256<ref name=Selig>{{cite web |last1=Lednicer |first1=David |title=The Incomplete Guide to Airfoil Usage |url=https://m-selig.ae.illinois.edu/ads/aircraft.html |website=m-selig.ae.illinois.edu |access-date=16 April 2019}}</ref>
|empty weight kg=1220|max takeoff weight kg=2500|max takeoff weight note=
* ''Maximum Load:'' {{cvt|830|kg}}
|eng1 number=1|eng1 name=[[Junkers L5]]|eng1 type=6-cylinder water-cooled in-line piston engine|eng1 kw=228
|prop blade number=2|prop name=fixed-pitch propeller|prop dia m=
<!--Performance-->
|max speed kmh=180|cruise speed kmh=150
|range km=1000
|ceiling m=4300
}}

==References==
{{Commons category}}

===Citations===
{{Reflist}}

===Bibliography===
* {{cite magazine|last=Andersson|first=Lennart|title=Chinese 'Junks': Junkers Aircraft Exports to China 1925–1940|magazine=Air Enthusiast|number=55|date=Autumn 1994|issn=0143-5450|pages=2–7}}
* {{cite magazine|last=Andersson|first=Lennart|title=Histoire de l'aéronautique persane, 1921–1941: La première aviation du Chah d'Iran|trans-title=History of the Persian Air Force, 1921–1941: The First Aircraft of the Shah of Iran|magazine=Avions: Toute l'aéronautique et son histoire |date=July 1998|issue=76  |language=French|issn=1243-8650|pages=2–12}}
* {{cite book|last=Andersson|first=Lennart|title=Soviet aircraft and aviation, 1917–1941|publisher=Putnam|location=London|year=1995|isbn=978-0851778594|pages=159–161}}      
* {{cite magazine|last1=Andersson|first1=Lennart|title=Round-Out |magazine=Air Enthusiast |date=March–April 1999 |issue=80 |page=80 |issn=0143-5450}}
* {{cite book|last1=Andersson|first1=Lennart|last2=Endres|first2=Günter|last3=Mulder|first3=Rob J.M.|title=Junkers W 33, W 34 and K 43, Workhorse in Peace and War|publisher=EAM Books|year=2015|isbn=978-0957374416}}
* Grant, Robert S. "Metal Marvels: Junkers W 33s and W 34s in the Canadian Bush". ''Air Enthusiast'' No. 110, March/April 2004. pp.&nbsp;70–75. {{ISSN|0143-5450}}.
* {{cite book|last=Gunston|first=Bill|title=Aircraft of the Soviet Union: The Encyclopaedia of Soviet aircraft since 1917|publisher=Osprey|location=London|year=1983|isbn=978-0850454451|page=127}}
* {{cite book|last=Gunston|first=Bill|title=The Osprey Encyclopedia of Russian Aircraft 1875–1995|location=London|publisher=Osprey|year=1995|isbn=1855324059}}
* {{cite book|last=Hotson|first=Fred W.|title=The Bremen|publisher=Canav Books|location=Toronto|year=1988|isbn=978-0921022022}}
* {{cite book|last=Kay|first=Antony|title=Junkers Aircraft & Engines 1913–1945|year=2004|publisher=Putnam Aeronautical|location=London|pages=28–38|isbn=0851779859}}
* {{cite book |last = Munson |first = Kenneth |title = German Aircraft Of World War 2 in colour |location = Poole, Dorset, UK |publisher = Blandford Press |year = 1978 |isbn = 0-7137-0860-3}}
* {{Cite book|last1=Turner|first1=P. St. John|last2=Nowarra|first2=Heinz|year=1971|title=Junkers: an aircraft album No. 3|publisher=Arco Publishing Inc| location=New York|isbn=0668025069}}
* von Rauch, Georg. "A South American Air War...The Leticia Conflict". ''[[Air Enthusiast]]'' Number 26, December 1984 – March 1985. pp.&nbsp;1–8. {{ISSN|0143-5450}}.

{{Junkers aircraft}}
{{RLM aircraft designations}}
{{Soviet transport designations}}
{{Swedish military aircraft designations}}
{{Authority control}}

[[Category:Junkers W33]]
[[Category:1920s German airliners]]
[[Category:1920s German cargo aircraft]]
[[Category:Junkers aircraft|W33]]
[[Category:Single-engined tractor aircraft]]
[[Category:Low-wing aircraft]]
[[Category:Transatlantic flight]]
[[Category:Aircraft first flown in 1926]]
[[Category:Aircraft with fixed conventional landing gear]]