Junkers J 1
Encyclopedia
The Junkers
J 1, nicknamed the Blechesel ("Tin Donkey" or "Sheet Metal Donkey"), was the world's first practical all-metal aircraft. Built early in World War I
, when aircraft designers relied largely on fabric-covered wooden structures, the Junkers J 1 was a revolutionary development in aircraft design, being built and flown only 12 years after the Wright Brothers
had first flown the "Flyer I"
biplane
in December 1903. This experimental aircraft never received an official "E-series" monoplane
designation from IdFlieg
and the Luftstreitkräfte, probably because it was primarily intended as a practical demonstration of Junkers' metal-based structural ideas, and was officially only known by its Junkers factory model number of J 1. It should not to be confused with the later, armoured all-metal Junkers J 4 sesquiplane
, accepted by the Luftstreitkräfte
as the Junkers J.I
, using a Roman numeral)
, who had already established his engineering credentials by the invention of a type of calorimeter
and in the construction of internal combustion engine
s, first got interested in aviation in 1907 when a colleague named Hans Reissner, a professor at the Technische Hochschule
in Aachen
, approached Junkers for assistance in aircraft construction. Five years later, Reissner, with Junkers' help, began construction of his all-metal canard
design, that he named the Ente ("Duck"). Junkers' firm built the flying surfaces of Reissner's design, and also built its radiator
. The problems encountered in creating the Ente got Hugo's active mind working on the problems of airframe
design, and solving the problem of eliminating the then-prevalent exterior bracing from airframes, placing all such structural elements within the covering of the airframe
. He patented the concept of the flying wing
aircraft in German in 1910. When World War I broke out his mind turned to military matters.
After the assassinaton of Archduke Franz Ferdinand precipitated the outbreak of World War I, Hugo Junkers and his company's research institute, or Forschungsanstalt, began the engineering work to realize Junkers' idea of creating aircraft designs that dispensed with drag-producing exterior bracing. His work on Reissner's Ente design had convinced him of the necessity to use metal as the main structural material, but since the apparently "ideal" metal alloy for aircraft construction, duralumin
, had only been invented some six years earlier in Germany, and was initially prone to flaking and other undesirable characteristics when worked in sheet metal form, Junkers had to use sheets of heavier electrical steel
instead for his first all-metal aircraft designs, similar to the types of ferrous sheet metals used in laminated-core AC electrical transformer
s.
The Junkers firm got its first aircraft construction contract in July 1915 from the German government, No. 96/7.17 A7/L, to produce an example of a two-seat all-metal aircraft that would be capable of a 130 km/h (81 mph) top speed, wing loading of 50 kg/m² (10.2 lb/ft²) and use a 75 kW (100 hp) engine for power. Junkers engineers Otto Mader, head of Junkers' Forschungsanstalt, and Hans Steudel, director of Junkers' structural materials and testing department, started the work on the design of what would become the Junkers J 1 in September of that year, and by November 1915 the completed J 1 was ready for initial flight testing.
, for support of the horizontal stabilizer
(which had a variable incidence feature built into it) and tailskid structures, and only two crossed bracing cables along the front vertical plane of the main landing gear struts, exposed outside the structure.
The fuselage
used welded strip-steel angle stock and I-beam sections along with some steel tubing to form its main internal structure, with 42 cm (17 in) wide sheet steel panels wrapped around the fuselage to form its covering. The innovative cantilever structure for the wings allowed their exterior surfaces to be strikingly smooth, being likewise covered in chord
wise sheet steel panels. The wing root
had a depth of about 75% of the height of the fuselage at the root's thickest point, and the wing had at least three airfoil changes, along with tapering of the leading
and trailing edge
angles between the wing's root and the wingtip. These changes in wing section would become a Junkers design hallmark on the later 1918 Junkers D.I single seat all metal fighter design, which was covered with corrugated duralumin. The J 1 also relied on steel panels with "spanwise" corrugations as a structural element, hidden under the smooth outer metal covering, to increase the wing's strength. This particular design element of the J 1 was used on later all-metal aircraft, such as the wings of the American B-17 Flying Fortress heavy bomber
design of 1935.
The 90 kW (120 hp) Mercedes D.II six-cylinder liquid-cooled inline engine
selected for the design had a simple, clamshell-like horizontally split cowling
enclosing the engine's crankcase
and lower cylinder block, and an advanced engine radiator layout, placing the radiator in a ventral position under the forward fuselage, with the front of the radiator housing's opening just behind the front gear strut's attachment points to the fuselage, and with the radiator's housing having a width equal to that of the fuselage above it.
Like the Fokker Eindecker
, the vertical tail surfaces were of an "all-flying" design (with no fixed fin) and the entire tail surface structure and covering also consisted of formed and sheet steel, much like the wings, with the stabilizer capable of having its angle of incidence
adjusted on the ground.
, the Inspektorat der Fliegertruppen, the aviation administration arm of the German army, required that static load tests be done on the J 1, with the usual early era static loading trials carried out on the J 1's structure with sand bags for weight, loading and strength tests, as well as a test of the static thrust that would be obtained with the chosen engine and propeller
combination. The static tests were completed on 3 December 1915, preceding the engine thrust tests. The Junkers factory did not yet have its own test field in Dessau
, so the completed J 1 was taken to the Fliegerersatzabteilung 1 (FEA 1) airfield in Döberitz
just west of Berlin for its flight testing program.
On 12 December, Leutnant Theodor Mallinckrodt of FEA 1 was assigned to taxi and briefly "hop" the J 1, which he managed to do successfully up to almost a 3 m (10 ft) altitude, but a gust of wind caught the starboard wing during the "hop" as the J 1 descended, with the port wingtip scraping the ground and the J 1's left side of the fuselage was bent inwards towards the rear of the wing mount. Repairs were made through the holiday period at the end of 1915, and more static load tests were carried out to check on the integrity of the repairs.
The second attempt at flight for the J 1 was carried out at Döberitz by Gefreiter
(Private) Paul Arnold of the FEA 1 unit, on 18 January 1916. This flight had the J 1 taken up to an altitude of only 80 m (260 ft) , following a 200 m (660 ft) takeoff run, and the variable incidence setting on the stabliizer had been mistakenly set to lift the tail excessively, in the belief that the J 1 was too tail-heavy. Later that day, after the stabilizer's incidence adjustment was corrected to give level flight trim, Leutnant Mallinckrodt took another turn at the J 1's controls for another attempt at flight, this time flying as high as 900 m (2,950 ft), with a shorter takeoff run than before. The in-flight handling of the J 1 was acceptable, and it was stable in flight, but upon landing the J 1's main landing gear wheels ran over a small ditch, fortunately only bending one of the landing gear struts, with no damage to the airframe itself.
On the following day, 19 January, Mallinckrodt once again took the J 1 up for its only known "high performance" flight test, which consisted of a 7 km (4 mi) course, at varying altitudes from 200–300 m (650–985 ft), and managed to get the J 1 up to a top speed of 170 km/h (106 mph), a speed which had never been achieved with a liquid-cooled 90 kW (120 hp) engine. The J 1 was compared to the popular Rumpler C.I
two-seat armed observation biplane, which was some 30 km/h (19 mph) slower in its top speed, even though the Rumpler biplane had the more powerful Mercedes D.III
engine, but due to the lighter weight of the Rumpler's wood-and-fabric structure it had a much better climb rate than the J 1.with its experimental steel structure.
By the end of January 1916, Junkers had been given a contract to further develop his all-metal concept, and the later Junkers J 2
single seat fighter, which would never see front line service, was the follow-on to the J 1.
Rumours have existed that an accurate scale display model, made of metal, of the J 1 had been built by the Junkers factory workers during the years following its initial flights, and exhibited at the Franklin Institute
in Philadelphia, Pennsylvania
after the close of World War I, but no word exists on the eventual fate of the miniature replica of the J 1, probably built by some of the same people at the Junkers factory that constructed the original aircraft.
. After that Junkers aircraft became smooth skinned though still as in the J 1, they were all metal. Almost all Junkers designs were aerodynamically clean cantilever monoplanes. Only Anthony Fokker
's aircraft were as advanced aerodynamically. Although Fokker briefly collaborated with Hugo Junkers, this was an independent development by Rheinhold Platz. The Fokker company's use of wooden cantilever wing structures started with Platz's Fokker V.1
and V 2 experimental aircraft of 1916-17, which led to later fighter aircraft such as the Fokker Dr.I
triplane and the Fokker D.VII
biplane.
Junkers' methods of using metal for aircraft structures inspired both American engineer William Stout
and Russian aviation designer Andrei Tupolev
each to adopt Junkers' developments for the creation of all-metal aircraft in the 1920s and early 1930s.
Junkers
Junkers Flugzeug- und Motorenwerke AG , more commonly Junkers, was a major German aircraft manufacturer. It produced some of the world's most innovative and best-known airplanes over the course of its fifty-plus year history in Dessau, Germany. It was founded there in 1895 by Hugo Junkers,...
J 1, nicknamed the Blechesel ("Tin Donkey" or "Sheet Metal Donkey"), was the world's first practical all-metal aircraft. Built early in World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
, when aircraft designers relied largely on fabric-covered wooden structures, the Junkers J 1 was a revolutionary development in aircraft design, being built and flown only 12 years after the Wright Brothers
Wright brothers
The Wright brothers, Orville and Wilbur , were two Americans credited with inventing and building the world's first successful airplane and making the first controlled, powered and sustained heavier-than-air human flight, on December 17, 1903...
had first flown the "Flyer I"
Wright Flyer
The Wright Flyer was the first powered aircraft, designed and built by the Wright brothers. They flew it four times on December 17, 1903 near the Kill Devil Hills, about four miles south of Kitty Hawk, North Carolina, U.S.The U.S...
biplane
Biplane
A biplane is a fixed-wing aircraft with two superimposed main wings. The Wright brothers' Wright Flyer used a biplane design, as did most aircraft in the early years of aviation. While a biplane wing structure has a structural advantage, it produces more drag than a similar monoplane wing...
in December 1903. This experimental aircraft never received an official "E-series" monoplane
Monoplane
A monoplane is a fixed-wing aircraft with one main set of wing surfaces, in contrast to a biplane or triplane. Since the late 1930s it has been the most common form for a fixed wing aircraft.-Types of monoplane:...
designation from IdFlieg
Idflieg
The Idflieg was the bureau of the German War Office that oversaw German military aviation prior to and during World War I....
and the Luftstreitkräfte, probably because it was primarily intended as a practical demonstration of Junkers' metal-based structural ideas, and was officially only known by its Junkers factory model number of J 1. It should not to be confused with the later, armoured all-metal Junkers J 4 sesquiplane
Biplane
A biplane is a fixed-wing aircraft with two superimposed main wings. The Wright brothers' Wright Flyer used a biplane design, as did most aircraft in the early years of aviation. While a biplane wing structure has a structural advantage, it produces more drag than a similar monoplane wing...
, accepted by the Luftstreitkräfte
Luftstreitkräfte
The Deutsche Luftstreitkräfte , known before October 1916 as Die Fliegertruppen des deutschen Kaiserreiches , or simply Die Fliegertruppen, was the air arm of the Imperial German Army during World War I...
as the Junkers J.I
Junkers J.I
-See also:-References:NotesBibliography* Flight 18 March 1920* Grey, C. G. Jane's All the World's Aircraft 1919. London: Putnam, 1919.* Grosz, P.M. Junkers J.I, Windsock Datafile 39. Hertfordshire, UK: Albatros Productions Ltd., 1993. ISBN 0-948414-49-9.* Taylor, Michael J. H. Jane's Encyclopedia...
, using a Roman numeral)
Design and development
Hugo JunkersHugo Junkers
Hugo Junkers was an innovative German engineer, as his many patents in varied areas show...
, who had already established his engineering credentials by the invention of a type of calorimeter
Calorimeter
A calorimeter is a device used for calorimetry, the science of measuring the heat of chemical reactions or physical changes as well as heat capacity. Differential scanning calorimeters, isothermal microcalorimeters, titration calorimeters and accelerated rate calorimeters are among the most common...
and in the construction of internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
s, first got interested in aviation in 1907 when a colleague named Hans Reissner, a professor at the Technische Hochschule
RWTH Aachen
RWTH Aachen University is a research university located in Aachen, North Rhine-Westphalia, Germany with roughly 33,000 students enrolled in 101 study programs....
in Aachen
Aachen
Aachen has historically been a spa town in North Rhine-Westphalia, Germany. Aachen was a favoured residence of Charlemagne, and the place of coronation of the Kings of Germany. Geographically, Aachen is the westernmost town of Germany, located along its borders with Belgium and the Netherlands, ...
, approached Junkers for assistance in aircraft construction. Five years later, Reissner, with Junkers' help, began construction of his all-metal canard
Canard (aeronautics)
In aeronautics, canard is an airframe configuration of fixed-wing aircraft in which the forward surface is smaller than the rearward, the former being known as the "canard", while the latter is the main wing...
design, that he named the Ente ("Duck"). Junkers' firm built the flying surfaces of Reissner's design, and also built its radiator
Radiator (engine cooling)
Radiators are used for cooling internal combustion engines, mainly in automobiles but also in piston-engined aircraft, railway locomotives, motorcycles, stationary generating plant or any similar use of such an engine....
. The problems encountered in creating the Ente got Hugo's active mind working on the problems of airframe
Airframe
The airframe of an aircraft is its mechanical structure. It is typically considered to include fuselage, wings and undercarriage and exclude the propulsion system...
design, and solving the problem of eliminating the then-prevalent exterior bracing from airframes, placing all such structural elements within the covering of the airframe
Airframe
The airframe of an aircraft is its mechanical structure. It is typically considered to include fuselage, wings and undercarriage and exclude the propulsion system...
. He patented the concept of the flying wing
Flying wing
A flying wing is a tailless fixed-wing aircraft which has no definite fuselage, with most of the crew, payload and equipment being housed inside the main wing structure....
aircraft in German in 1910. When World War I broke out his mind turned to military matters.
After the assassinaton of Archduke Franz Ferdinand precipitated the outbreak of World War I, Hugo Junkers and his company's research institute, or Forschungsanstalt, began the engineering work to realize Junkers' idea of creating aircraft designs that dispensed with drag-producing exterior bracing. His work on Reissner's Ente design had convinced him of the necessity to use metal as the main structural material, but since the apparently "ideal" metal alloy for aircraft construction, duralumin
Duralumin
Duralumin is the trade name of one of the earliest types of age-hardenable aluminium alloys. The main alloying constituents are copper, manganese, and magnesium. A commonly used modern equivalent of this alloy type is AA2024, which contains 4.4% copper, 1.5% magnesium, 0.6% manganese and 93.5%...
, had only been invented some six years earlier in Germany, and was initially prone to flaking and other undesirable characteristics when worked in sheet metal form, Junkers had to use sheets of heavier electrical steel
Electrical steel
Electrical steel, also called lamination steel, silicon electrical steel, silicon steel, relay steel or transformer steel, is specialty steel tailored to produce certain magnetic properties, such as a small hysteresis area and high permeability.The material is usually manufactured in the form of...
instead for his first all-metal aircraft designs, similar to the types of ferrous sheet metals used in laminated-core AC electrical transformer
Transformer
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...
s.
The Junkers firm got its first aircraft construction contract in July 1915 from the German government, No. 96/7.17 A7/L, to produce an example of a two-seat all-metal aircraft that would be capable of a 130 km/h (81 mph) top speed, wing loading of 50 kg/m² (10.2 lb/ft²) and use a 75 kW (100 hp) engine for power. Junkers engineers Otto Mader, head of Junkers' Forschungsanstalt, and Hans Steudel, director of Junkers' structural materials and testing department, started the work on the design of what would become the Junkers J 1 in September of that year, and by November 1915 the completed J 1 was ready for initial flight testing.
Pioneering design features
When the Junkers J 1 was first rolled out for government examination by the Kaiser's military aviation experts in November 1915, they were looking at what was the pioneering example of future aviation design-a sleek, well-thought-out low drag design that had completely eliminated the need for major exterior bracing struts, except on the empennageEmpennage
The empennage , also known as the tail or tail assembly, of most aircraft gives stability to the aircraft, in a similar way to the feathers on an arrow...
, for support of the horizontal stabilizer
Tailplane
A tailplane, also known as horizontal stabilizer , is a small lifting surface located on the tail behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed wing aircraft such as helicopters and gyroplanes...
(which had a variable incidence feature built into it) and tailskid structures, and only two crossed bracing cables along the front vertical plane of the main landing gear struts, exposed outside the structure.
The fuselage
Fuselage
The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...
used welded strip-steel angle stock and I-beam sections along with some steel tubing to form its main internal structure, with 42 cm (17 in) wide sheet steel panels wrapped around the fuselage to form its covering. The innovative cantilever structure for the wings allowed their exterior surfaces to be strikingly smooth, being likewise covered in chord
Chord (aircraft)
In aeronautics, chord refers to the imaginary straight line joining the trailing edge and the center of curvature of the leading edge of the cross-section of an airfoil...
wise sheet steel panels. The wing root
Wing root
The wing root is the part of the wing on a fixed-wing aircraft that is closest to the fuselage. On a simple monoplane configuration, this is usually easy to identify...
had a depth of about 75% of the height of the fuselage at the root's thickest point, and the wing had at least three airfoil changes, along with tapering of the leading
Leading edge
The leading edge is the part of the wing that first contacts the air; alternatively it is the foremost edge of an airfoil section. The first is an aerodynamic definition, the second a structural one....
and trailing edge
Trailing edge
The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge rejoins. Essential control surfaces are attached here to redirect the air flow and exert a controlling force by changing its momentum...
angles between the wing's root and the wingtip. These changes in wing section would become a Junkers design hallmark on the later 1918 Junkers D.I single seat all metal fighter design, which was covered with corrugated duralumin. The J 1 also relied on steel panels with "spanwise" corrugations as a structural element, hidden under the smooth outer metal covering, to increase the wing's strength. This particular design element of the J 1 was used on later all-metal aircraft, such as the wings of the American B-17 Flying Fortress heavy bomber
Heavy bomber
A heavy bomber is a bomber aircraft of the largest size and load carrying capacity, and usually the longest range.In New START, the term "heavy bomber" is used for two types of bombers:*one with a range greater than 8,000 kilometers...
design of 1935.
The 90 kW (120 hp) Mercedes D.II six-cylinder liquid-cooled inline engine
Inline engine (aviation)
In aviation, an inline engine means any reciprocating engine with banks rather than rows of cylinders, including straight engines, flat engines, V engines and H engines, but excluding radial engines and rotary engines....
selected for the design had a simple, clamshell-like horizontally split cowling
Cowling
A cowling is the covering of a vehicle's engine, most often found on automobiles and aircraft.A cowling may be used:* for drag reduction* for engine cooling by directing airflow* as an air intake for jet engines* for decorative purposes...
enclosing the engine's crankcase
Crankcase
In an internal combustion engine of the reciprocating type, the crankcase is the housing for the crankshaft. The enclosure forms the largest cavity in the engine and is located below the cylinder, which in a multicylinder engine are usually integrated into one or several cylinder blocks...
and lower cylinder block, and an advanced engine radiator layout, placing the radiator in a ventral position under the forward fuselage, with the front of the radiator housing's opening just behind the front gear strut's attachment points to the fuselage, and with the radiator's housing having a width equal to that of the fuselage above it.
Like the Fokker Eindecker
Fokker Eindecker
The Fokker Eindecker was a German World War I monoplane single-seat fighter aircraft designed by Dutch engineer Anthony Fokker. Developed in April 1915, the Eindecker was the first purpose-built German fighter aircraft and the first aircraft to be fitted with synchronizer gear, enabling the pilot...
, the vertical tail surfaces were of an "all-flying" design (with no fixed fin) and the entire tail surface structure and covering also consisted of formed and sheet steel, much like the wings, with the stabilizer capable of having its angle of incidence
Angle of incidence
Angle of incidence is a measure of deviation of something from "straight on", for example:* in the approach of a ray to a surface, or* the angle at which the wing or horizontal tail of an airplane is installed on the fuselage, measured relative to the axis of the fuselage.-Optics:In geometric...
adjusted on the ground.
Operational history
Before the Junkers J 1 could fly for the first time, IdFliegIdflieg
The Idflieg was the bureau of the German War Office that oversaw German military aviation prior to and during World War I....
, the Inspektorat der Fliegertruppen, the aviation administration arm of the German army, required that static load tests be done on the J 1, with the usual early era static loading trials carried out on the J 1's structure with sand bags for weight, loading and strength tests, as well as a test of the static thrust that would be obtained with the chosen engine and propeller
Propeller (aircraft)
Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...
combination. The static tests were completed on 3 December 1915, preceding the engine thrust tests. The Junkers factory did not yet have its own test field in Dessau
Dessau
Dessau is a town in Germany on the junction of the rivers Mulde and Elbe, in the Bundesland of Saxony-Anhalt. Since 1 July 2007, it is part of the merged town Dessau-Roßlau. Population of Dessau proper: 77,973 .-Geography:...
, so the completed J 1 was taken to the Fliegerersatzabteilung 1 (FEA 1) airfield in Döberitz
Dallgow-Döberitz
Dallgow-Döberitz is a municipality in the Havelland district, in Brandenburg, Germany.-Geography:It consists of the villages Dallgow-Döberitz, Rohrbeck and Seeburg. To the east it shares border with the Spandau borough of Berlin. Neighbouring Brandenburg municipalities are Falkensee in the north...
just west of Berlin for its flight testing program.
On 12 December, Leutnant Theodor Mallinckrodt of FEA 1 was assigned to taxi and briefly "hop" the J 1, which he managed to do successfully up to almost a 3 m (10 ft) altitude, but a gust of wind caught the starboard wing during the "hop" as the J 1 descended, with the port wingtip scraping the ground and the J 1's left side of the fuselage was bent inwards towards the rear of the wing mount. Repairs were made through the holiday period at the end of 1915, and more static load tests were carried out to check on the integrity of the repairs.
The second attempt at flight for the J 1 was carried out at Döberitz by Gefreiter
Gefreiter
Gefreiter is the German, Swiss and Austrian equivalent for the military rank Private . Gefreiter was the lowest rank to which an ordinary soldier could be promoted. As a military rank it has existed since at least the 16th century...
(Private) Paul Arnold of the FEA 1 unit, on 18 January 1916. This flight had the J 1 taken up to an altitude of only 80 m (260 ft) , following a 200 m (660 ft) takeoff run, and the variable incidence setting on the stabliizer had been mistakenly set to lift the tail excessively, in the belief that the J 1 was too tail-heavy. Later that day, after the stabilizer's incidence adjustment was corrected to give level flight trim, Leutnant Mallinckrodt took another turn at the J 1's controls for another attempt at flight, this time flying as high as 900 m (2,950 ft), with a shorter takeoff run than before. The in-flight handling of the J 1 was acceptable, and it was stable in flight, but upon landing the J 1's main landing gear wheels ran over a small ditch, fortunately only bending one of the landing gear struts, with no damage to the airframe itself.
On the following day, 19 January, Mallinckrodt once again took the J 1 up for its only known "high performance" flight test, which consisted of a 7 km (4 mi) course, at varying altitudes from 200–300 m (650–985 ft), and managed to get the J 1 up to a top speed of 170 km/h (106 mph), a speed which had never been achieved with a liquid-cooled 90 kW (120 hp) engine. The J 1 was compared to the popular Rumpler C.I
Rumpler C.I
-See also:- References :* Munson, Kenneth - Bombers, Patrol and Reconnaissance Aircraft 1914 - 1919 ISBN 0 7537 0918 X* Munson, Kenneth - Fighters, Attack and Training Aircraft 1914 - 1919 ISBN 0 7537 0916 3...
two-seat armed observation biplane, which was some 30 km/h (19 mph) slower in its top speed, even though the Rumpler biplane had the more powerful Mercedes D.III
Mercedes D.III
The Mercedes D.III, or F1466 as it was known internally, was a six-cylinder, liquid cooled inline aircraft engine built by Daimler and used on a wide variety of German aircraft during World War I. The initial versions were introduced in 1914 at 160 hp, but a series of changes improved this to...
engine, but due to the lighter weight of the Rumpler's wood-and-fabric structure it had a much better climb rate than the J 1.with its experimental steel structure.
By the end of January 1916, Junkers had been given a contract to further develop his all-metal concept, and the later Junkers J 2
Junkers J 2
The Junkers J 2 was the first all-metal aircraft intended as a dedicated military aircraft design, the first all-metal aircraft meant to be a fighter aircraft, and was the direct descendant of the pioneering J 1 all-metal aircraft technology demonstrator design of 1915.-Development:Only some two...
single seat fighter, which would never see front line service, was the follow-on to the J 1.
Ultimate fate of the J 1
The Junkers J 1 was probably not flown again after January 1916. However, it survived World War I and was placed on display in a Berlin aviation museum. Sadly, it met its end during one of the earliest Royal Air Force bombing raids on Berlin, during World War II.Rumours have existed that an accurate scale display model, made of metal, of the J 1 had been built by the Junkers factory workers during the years following its initial flights, and exhibited at the Franklin Institute
Franklin Institute
The Franklin Institute is a museum in Philadelphia, Pennsylvania, and one of the oldest centers of science education and development in the United States, dating to 1824. The Institute also houses the Benjamin Franklin National Memorial.-History:On February 5, 1824, Samuel Vaughn Merrick and...
in Philadelphia, Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
after the close of World War I, but no word exists on the eventual fate of the miniature replica of the J 1, probably built by some of the same people at the Junkers factory that constructed the original aircraft.
Legacy
The 1915 design of the J 1 was a revolution in the technology of airframe structure. By the time of the Junkers J 4 in early 1917, the metallurgy of duraluminum had improved to the point where it was able to replace the much heavier steel as a primary airframe structural material, except for the armored steel "bathtub" forward fuselage structure enclosing the engine and crew, and this aircraft was all metal apart from a fabric covered rear fuselage. The late-1917 J 7 experimental fighter monoplane prototype was entirely duraluminium and both these aircraft had the corrugated stressed skinning that characterised all subsequent Junkers designs up to the 1932 Ju 60Junkers Ju 60
|-References:* *...
. After that Junkers aircraft became smooth skinned though still as in the J 1, they were all metal. Almost all Junkers designs were aerodynamically clean cantilever monoplanes. Only Anthony Fokker
Anthony Fokker
Anton Herman Gerard "Anthony" Fokker was a Dutch aviation pioneer and an aircraft manufacturer. He is most famous for the fighter aircraft he produced in Germany during the First World War such as the Eindecker monoplanes, the Fokker Triplane the and the Fokker D.VII, but after the collapse of...
's aircraft were as advanced aerodynamically. Although Fokker briefly collaborated with Hugo Junkers, this was an independent development by Rheinhold Platz. The Fokker company's use of wooden cantilever wing structures started with Platz's Fokker V.1
Fokker V.1
-References:* Weyl, A.J. Fokker: The Creative Years. London: Putnam, 1965....
and V 2 experimental aircraft of 1916-17, which led to later fighter aircraft such as the Fokker Dr.I
Fokker Dr.I
The Fokker Dr.I Dreidecker was a World War I fighter aircraft built by Fokker-Flugzeugwerke. The Dr.I saw widespread service in the spring of 1918...
triplane and the Fokker D.VII
Fokker D.VII
The Fokker D.VII was a German World War I fighter aircraft designed by Reinhold Platz of the Fokker-Flugzeugwerke. Germany produced around 3,300 D.VII aircraft in the summer and autumn of 1918. In service, the D.VII quickly proved itself to be a formidable aircraft...
biplane.
Junkers' methods of using metal for aircraft structures inspired both American engineer William Stout
William Bushnell Stout
William Bushnell Stout was an inventor, designer whose work in automotive and aviation fields was notable. Stout designed an aircraft that eventually became the Ford Trimotor and was an executive at the Ford Motor Company.-Early years:William Bushnell Stout was born March 16, 1880 in Quincy,...
and Russian aviation designer Andrei Tupolev
Andrei Tupolev
Andrei Nikolayevich Tupolev was a pioneering Soviet aircraft designer.During his career, he designed and oversaw the design of more than 100 types of aircraft, some of which set 78 world records...
each to adopt Junkers' developments for the creation of all-metal aircraft in the 1920s and early 1930s.
