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 W 34.
Like all Junkers designs from the J 7 fighter onwards, 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.
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.
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.
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 coamings.
Some examples, such as the transatlantic machines had an early enclosed cockpit.
The 228 kW (306 hp) 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 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, but in practice W 33s were equipped as either landplanes or seaplanes, as needed.
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.
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, near Moscow in the USSR.
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.
Variants
W 33
Prototype with Junkers L5 engine
Open cockpit, no windows in cargo compartment
W 33a
Modified prototype with Junkers L2 engine
W 33b
Enlarged cargo compartment, Junkers L5 engine
W 33ba
Enlarged cargo compartment, Junkers L2 engine
W 33be
Like W33a with BMW Va engine
W 33c
Strengthened centre wing,
Junkers L5 engine
W 33ce
BMW Va engine
W 33d
Enlarged wing swept
W 33f
Strengthened centre wing, less wing swept than d-version,
The Junkers W 34 was a German-built, single-engine, passenger and transport aircraft.
Developed in the 1920s, it was taken into service in 1926.
The passenger version could take a pilot and five passengers.
The aircraft was developed from the Junkers W 33.
Further development led to the Junkers Ju 46.
W 34a
Prototype with Gnome et Rhone Jupiter VI engine
W 34b
Initial production aircraft, strengthened wing
W 34ba
Bristol Jupiter VIII engine
W 34c
Strengthened centre wing structure
Jupiter VI engine
W 34ca
Bristol Jupiter VIII engine
W 34ce
Jupiter VII engine
W 34ci
BMW Hornet engine
W 34d
Junkers L5 or Siemens Sh20 engines
W 34da, de, di
Jupiter VI engine
W 34f
Enlarged wing-swept, modified undercarriage, strengthened centre section,
Jupiter VI engine
W 34fa, fe, fi
Jupiter VI engine
W 34fao
Siemens Sh20 engine
W 34fay
Wright Cyclone engine
W 34ffi
Junkers L5 engine
W 34fo
Pratt + Whitney Wasp engine
W 34fu
Armstrong Jaguar engine
W 34fy
Armstrong Jaguar Major U engine
W 34f1y
Armstrong Panther engine
W 34gi
BMW Hornet engine
W 34hau
Luftwaffe trainer aircraft
Bramo 322H-1 engine
W 34hi
BMW Hornet engine
1933 onwards on Luftwaffe aircraft.
Ju 46
The Junkers Ju 46 was a German shipborne catapult-launched seaplane derivative of the W 34, constructed for pre-war Luft Hansa‘s mail service over the Atlantic Ocean.
The first production models were delivered in 1932 and replaced the Heinkel He 58, which, along with the He 12, had pioneered these ship-to-shore mail delivery flights.
Ju 46fi
Catapult aircraft with Pratt + Whitney Hornet engine
T2D1 (485kW)
Ju 46hi
Ju 46fi with a BMW132 engine,1933 onwards
K 43
Military version of the W 34 built at Limhamn
Trp 2
Ambulance aircraft version of W 33, built at Limhamn
Trp 2A
Ambulance aircraft version of W 34, built at Limhamn
