Tuesday, February 3, 2015

Junkers Ju 52 Series

The Ju 52 trimotor, like the USAF C-47, was first built in the 1930s and remained in service for more than a quarter century. This transport made its maiden flight in April 1931, and three years later, a heavy bomber version appeared. The latter aircraft formed the nucleus of the Luftwaffe’s infant bomber force in the mid-1930s, and it was used during the Spanish Civil War.

The Ju 52 was obsolete as a bomber by 1939, but because of its durability, simplicity of design and handling characteristics, it continued to serve throughout World War II as a versatile workhorse of the German transport fleet. For a period, Adolph Hitler used a Ju 52 as his private transport. Ju 52s delivered the attacking forces and their supplies during the German invasion of Norway, Denmark, France and the Low Countries in 1940. Almost 500 Ju 52s participated in the historic airborne assault on the island of Crete in May 1941, and Junkers later supplied Rommel’s armored forces in North Africa.

Approximately 30 different countries have flown Ju 52s. The aircraft on display was donated to the museum by the Spanish government in 1971. Note: This particular aircraft is a CASA 352L.

Ju 52 and the SST Concorde
I have a rather amusing incident to share re the restored Ju-52 of Lufthansa [1]. A number of years ago (back in 1990 plus or minus one or two years), the now restored Ju-52 made a goodwill tour to London’s Heathrow airport. When it was departure time, the Ju-52 found itself on the taxiway behind a British Airways Concord SST. Much to the amusement of the Ju-52 crew, the captain of the Concord requested permission to switch departure orders with the Ju-52. The captain of the SST did not want to miss seeing the Ju-52 take off – he obtained permission from the air traffic controller to let the Ju-52 pass him and take off first. It must have indeed been a wonderful sight to see.

[1] The Lufthansa Ju-52 with the famous registration D-AQUI is a confirmed classic. Strictly speaking, it doesn’t belong to Lufthansa anymore but to DLBS Deutsche Lufthansa Berlin Stiftung (German Lufthansa Berlin Foundation), and it now carries the registration D-CDLH.


Civil Use
The Junkers Company was an early constructor of aero-engines as well as airframes. In 1923 Junkers Motorenbau was founded, and in July 1936 the airframe and engine companies merged as Junkers Flugzeug-und-Motorenwerke.

Apart from designing and building orthodox gasoline engines, Junkers embarked on a long development programme of what were known as Schweral (heavy oil) or Rohal (crude oil) engines in other words diesels.

The five-cylinder FO-3 was produced in 1926 and this was followed in 1928 by the 750-hp six cylinder FO-4 also known as the Jumo 4 and later Jumo 204, and the 545-hp Jumo 5 of 1932. The Junkers diesel engines were flight-tested in a number of aircraft and in 1932

Jumo 4-powered Junkers F24s were put into service on Lufthansa’s Berlin-Amsterdam route and nine of the airline’s F24s were fitted with Jumos.

Jumo 204s were also installed in the Junkers G38 and later, Jumo 205s were used in a number of DLH flying boats and seaplanes and in the Junkers Ju 86. A Jumo 204 was also fitted to one of the single-engined Junkers Ju 52s.

Most of the many thousands of Ju 52/3ms were powered by air-cooled radial gasoline engines but two were fitted with 550-hp Jumo 205Cs. Changes to the airframe made them Ju 52/3mhs and, the Junkers suffix for the Jumo being the letter 0, the correct designation became Tu 52/3mho.

One of these aircraft was the landplane Emil Schaefer. Apart from its Jumo engines and two blade propellers it was a standard aircraft. Then at the 1934 Paris Air Show a Jumo-powered Ju 52 twin-float seaplane was exhibited. After the show it was converted to a landplane and entered Lufthansa service as W Hoehndorf. As far as is known these aircraft were identical and it is presumed that they were used to get operational experience of diesel engines and compare their performance with BMW-powered Ju 52/3ms.

There is evidence to suggest that Emil Schaefer was re-engined with BMW 132 radial engines and that the Jumo 205Cs in W Hoehndorf were replaced by Jumo 206As, since these engines were listed as in the aircraft in 1940 and 1941.

The Jumo diesels, although having lower fuel consumption, were not an unqualified success and were noisy, heavy and smoky.

As history bears out, the Ford Tri-Motor AT and the Junkers tri-motor were on parallel courses. Hugo Junkers was a pioneer in the development of metal-skinned aircraft for Germany. His American analog was William B. Stout. Stout, with Henry and Edsel Ford as investors, was set to build his own metal-skinned planes. Still, Stout cast his eye overseas for ideas on how to improve his own designs. There is evidence that Stout incorporated Junkers’s innovations into his own designs. Ford eventually bought the company from Stout in 1925. Before Stout could adequately demonstrate a working prototype worthy of production, a fire destroyed part of the factory, and the prototype tri-motors. Afterwards, a Ford team (Stout eventually fell out of the picture) produced the Ford Tri-Motor 4-AT in 1926 (199 were built). The 5-AT was produced in much larger numbers after 1928. But this plane was not the same one that Junkers produced.

Hugo Junkers also began experimenting with the production of metal planes during the 1920’s. The first Ju 52 that Junkers rolled out in 1930 was, in fact, a single-engine model. By 1932, the Ju 52/3m version had the familiar tri-motor configuration.

Ford Motor Company, was the majority shareholder of a production plant in Cologne, Germany. Several years before the U.S. involvement in the war, and in hopes to appease the Nazis, Ford replaced the entire board of directors of that company with Germans, place Ford’s German operations in the care of a pro-Nazi caretaker, and changed the name to Ford Werke, AG. When I mentioned “nationalized”, earlier, this notion was mistaken–Ford Werke was never consolidated into the Hermann Goering Werke of nationalized German military industries. Instead, Ford Werke maintained its status as an independent company although Ford, Inc. contends that it lost control of Ford Werke in 1941 after the U.S. declared war. Nevertheless, under National Socialism, the state dictated the product lines that a privately-owned enterprise could sell; at Ford Werke, this product was: TRUCKS for the Wehrmacht (only German-made parts were used in their assembly, even prior to the War).

I did not find a connection between Ford Werke or any of Ford’s other subsidiaries in Nazi-occupied countries as far as aircraft parts production is concerned–but this was not an exhaustive search, so please weigh the evidence accordingly. Did Ford Inc. sell any tri-motor aircraft to the Germans in the 1930’s prior to, or even after the rise of totalitarianism? That I do not know, although Ford did supply tri-motor aircraft to each of the U.S. Services.

Besides the obvious similarity of having three powerplants and being monoplanes, the Ford Tri-Motor 4/5-AT has an overhead wing design, and Junkers Ju 52 has its wing integrated into the lower part of the fuselage. Interestingly, both used a Pratt & Whitney radial engine at some time in their development (5-AT, P&W Wasp; Ju 52/3mce, P&W Hornet). Later, a BMW radial replaced the P&W engines in the Ju 52.



1 comment:

  1. The Ford trimotor was a near copy of the Dutch Fokker Trimotor. History records that at the time Ford's designers were involved in designing their Trimotor but not making much progress, a Fokker happened to land for an overnight stop at the airfield where the Ford design team was located. Ford's design team spent the entire night pouring over and recording every detail and dimension of the Fokker with the end result that a near identical copy of the Fokker eventually emerged from the Ford design office. Apart from the use of a corrugated duralin metal skin as opposed to the Fokker's steel tube and fabric skin, the Ford design had minor changes made to the shape of its flying surfaces [mainly the rudder and fin] and a few altered dimensions in order to avoid being sued by Fokker for design infringement. The Ju 52 was originally a single engine design and the story goes that it was given two extra engines as a result of the request of buyers for the aircraft who intended it for use in gold mining operations in NEW GUINEA. The existing single engined Ju 52 not being powerful enough to carry freight in that country. That was also the reason Junker devised the double flap system as New Guinea airfields were very short.