Hiero (aircraft engine)

from Wikipedia, the free encyclopedia
Hiero engine of a Phoenix J.1 fighter plane in a Swedish museum
Hiero N

Hiero is the name of a series of upright liquid-cooled aircraft engines from the former Austria-Hungary , which were designed from 1908 by the then famous racing driver Otto Hieronimus . The first versions from 1911 to 1914 were series-produced four-cylinder in - line engines that had limited military use. The following major series six-cylinder , which from 1915 in the First World War in various types of aircraft kuk Luftfahrtruppen were used were, design technology from a few years earlier highly regarded published Austro-Daimler Type 6 ( AD6 ) affected, but possessed more power and good also . After the war these engines were built in Czechoslovakia as one of the successor states of the disbanding Danube Monarchy in the two late versions L and N for a few years. In the newly founded Republic of Austria , only the new, small two-cylinder Hiero Type T was produced for a few years after 1918, but it was intended for small aircraft and had nothing in common with the large six-cylinder.

In the literature, the name Hieronimus or Hieroymus, which was taken over from the name of the designer (although incorrectly), can also be found in some cases . Furthermore, the four-cylinder versions are sometimes cited as Hiero 4 and the six-cylinder versions as Hiero 6 .

history

The beginnings

The Hiero mentioned aircraft engines were of Otto Hieronimus designed a famous in the early years of the 20th century Austrian racing driver, who for his airplane engine chose the first five letters of his family name as a brand name. Hieronimus, who was also interested in aviation but never learned to fly himself, was convinced that he could use his knowledge and experience as a racing driver or mechanic to construct a specially developed aircraft engine. In doing so, he wanted to replace the contemporary engines , which were mostly inadequate in terms of performance and often still prone to failure , and which were almost always derived from motor vehicle or automobile engines . With this idea, Hieronimus was one of the pioneers of aircraft engine construction in the true sense of the purpose and advanced to become a designer with his work. Since Hieronimus had capital and backing from politics and the military, but did not have his own factory facilities in order to be able to design and test corresponding engines, he looked around in his home country - what was then Austria-Hungary  - for a partner company with whom he could then immediately begin with the design work for his "airplane engines".

Hiero four-cylinder

His first design was upright, liquid-cooled, four-cylinder in-line engines specially designed for use in aircraft, which he began to develop in Mladá Boleslav from 1908 at the then Austrian car manufacturer Laurin & Klement (later merged into the Škoda works in the 1920s ) when he moved to Werner & Pfleiderer in Ottakring , the 16th district of  Vienna, in 1910. Serial production of the Hiero four-cylinder began in 1911 at Werner & Pfleiderer, with which Hieronimus produced the world's second series-produced aircraft engine from that year. The corresponding aircraft engines were always built and sold under the name "Hiero" without mentioning the actual manufacturer, although Hieronimus was only the designer and never had his own production facilities to manufacture his engines himself.

Hiero six-cylinder

At the same time as he was still developing the first engine version with four cylinders, the desire for larger and more powerful aircraft engines arose. Not least on the initiative by the since 1909 active with the first own aircraft kuk Luftfahrtruppen Austria-Hungary, Otto Hieronimus built between the years 1910 and 1913, a correspondingly larger and more powerful engine and its first liquid-cooled six-cylinder in-line engine called Hiero E . This was partly derived from the earlier in-line four-cylinder engines, but its design was influenced by the Austro-Daimler Type 6 aeroplane engine, which was constructed around the same time by the then well-known engineer Ferdinand Porsche and later highly regarded . The Austro-Daimler was the world's first series-produced aircraft engine from 1910 and was developed as such from the start. In contrast to the latter, however , the new Hiero had a lot more power from the start, which immediately made it interesting for the kuk aviation troops. With his new aircraft engine, Otto Hieronimus was one of the imitators of the Austro-Daimler 6 , which also inspired other well-known manufacturers abroad to later design and manufacture very similar aircraft engines, including Mercedes and Benz in the German Empire and Beardmore in Great Britain . The six-cylinder Hiero was then produced in large series from 1914 by the Werner & Pfleiderer company in Vienna (the company where Hieronimus was already completing and building his four-cylinder).

At the same time, in the same year, the production of the previous in-line four-cylinder, which in the meantime was no longer up to date in terms of performance and therefore not least because of the fatal assassination attempt in Sarajevo on the Austro-Hungarian heir to the throne, Archduke Franz Ferdinand and his wife Sophie , ended June 1914 the dramatically worsening political situation (which was soon to lead to a great war) was no longer considered as a power source for military aircraft.

First World War (1914-1918)

Subsequently, from the beginning of 1915, the Hiero six-cylinder as well as the Austro-Daimler 6  - the latter in numerous different power levels during its production period - powered various Austro-Hungarian military aircraft types from the First World War. However, the capacities of Werner & Pfleiderer in Vienna were soon no longer sufficient to meet the enormous war-related demand, so that the Hiero in Hungary at the company " Martha " in Arad (now in Romania ) and at " Ganz -Fiat “was made in Budapest under license. In the part of Austria itself, " Warchalowski, Eißler & Co. " in Vienna and "Breitfeld-Daněk" (later merged into ČKD ) in Prague were added. From 1917, due to increasing demand , the Hiero was even manufactured under license in the German Reich at the automobile factory " Loeb & Co. GmbH " in Berlin-Charlottenburg . The Hiero engines were tuned up under the pressure of war and due to continuous development twice, and they always than the comparable powerful Austro-Daimler 6 were and were considered to be at least as reliable.

The Hiero E , the first version of these in-line six-cylinders from 1915, had the typical features of a corresponding engine with vertically arranged cylinders such as crankcase made of aluminum , bolted-on cylinders made of cast iron , two valves per cylinder (one each for inlet and outlet) that over bumpers and rocker arms have been pressed, and double ignition with two Bosch - magneto .

A special feature, however, was - as with the Austro-Daimler Type 6  - the valve control and thus the presence of two camshafts , one on the left side of the crankshaft driven by this in the crankcase via bevel gears , which actuated the exhaust valves via push rods and rocker arms ( OHV ), as well an overhead camshaft driven by a vertical shaft, which actuated the intake valves directly via short tappets ( OHC ). A characteristic distinguishing feature of the Hiero engines compared to other OHV and / or OHC in-line engines of the Central Powers as well as the Allies was the arrangement of the inlet side on the right and the outlet side on the left - a configuration that clearly went back to contemporary engines from automobile racing.

The Hiero E 1915 made at a stroke ratio of 135/180 mm up to 200  hp (147  kW ) at 1,400 min -1 , he was kg with a dry weight of 316 but slightly heavier than the comparable Austro-Daimler 6 (in that year 160 PS (117.68 kW) at 1300 min -1 kg and a weight of 262).

The Hiero L , which appeared in 1916, possessed with the same stroke ratio and engine capacity of over a slightly higher output of 205 hp (149 kW) at 1,400 min -1 , however, had for a larger full-pressure level and thus improved considerably height performance.

The Hiero N , from 1917 built in series production and also in the German Reich, made in a further exact same stroke ratio due to various refinements maximum of 230 hp (169 kW) at 1,500 min -1 and was mainly for the newer particularly fast Phoenix -Jagdflugzeuge intended.

During the First World War, Hiero six-cylinder engines were installed in reconnaissance aircraft such as the Phönix CI as well as in fighter aircraft, including the latest Austro-Hungarian types such as Phönix DI , D.II and D.III . The engines subsequently proved their worth and were extremely valued by the pilots for their performance and reliability. Production continued in both parts of Austria-Hungary and in the German Reich until the end of the war in mid-November 1918.

Hiero six-cylinder after 1918

Czechoslovakia

After the war and the subsequent dissolution of the multi-ethnic state Austria-Hungary, the highly regarded Hiero engines were sold to Breitfeld-Daněk (during the war one of the allies) after their production in Austria, Hungary and Germany was banned by the Allies Manufacturer with the appropriate license) in the newly founded Czechoslovakia (which was supported by the Allies and to which no restrictions were imposed) in the last versions L and N continued to build for a few years. These engines, now known as Breitfeld & Danek Hiero , then powered a number of early Avia and Letov aircraft and were also exported in limited numbers.

Sweden

The Hiero six-cylinder came after the war outside a successor State Austria-Hungary used as Sweden a license from the Phoenix-aircraft works for reconstruction of 30 general-purpose biplanes of the type Phoenix CI received (Swedish name: Phoenix J.1 ). These aircraft remained in service with Flygvapnet until the end of the 1920s , and the Hiero engines also proved their worth here.

The two-cylinder Hiero T from 1918

Also after the war, in what was now the Republic of Austria from the end of 1918, the Viennese company Warchalowski, Eißler & Co. (also one of the license producers during the war) was the last engine type named Hiero based on a design by Otto Hieronimus the air-cooled two-cylinder Hiero T (also: Hiero Type T ) with 35 or 40 HP at 1400 min −1 (dry weight 176 kg) for small aircraft, depending on the version . The Allies did not object to this small engine, as it had nothing in common with the war engines and was neither intended nor suitable for use in military aircraft. For a few years he mainly drove small aircraft from Austrian and Czechoslovak production. On the one hand, the Treaty of Saint-Germain forbade Austria to manufacture larger aircraft engines; on the other hand, the low demand for aircraft would not have made series production economically viable anyway. The two-cylinder Hiero therefore remained the only aircraft engine that was mass-produced in Austria until the 1930s.

Versions

Before 1914

Four-cylinder in-line engines:

  • Hiero airplane engine (Hiero 4)

First World War (Austria-Hungary)

Six cylinder in-line engines:

  • Hiero E  (Hiero 6E)
  • Hiero L  (Hiero 6L)
  • Hiero N (Hiero 6N)

After 1918 (Czechoslovakia)

Six cylinder in-line engines:

  • Breitfeld & Danek Hiero L
  • Breitfeld & Danek Hiero N

After 1918 (Austria)

Two-cylinder in-line engines:

  • Hiero T (Hiero Type T)

Applications

First World War (Austria-Hungary)

After 1918 (Czechoslovakia)

Technical specifications

  • Type: six-cylinder in-line engine
  • Bore × stroke: 135 × 180 mm
  • Displacement: 15.40 liters
  • Compression:
    • from 1915: 7.0: 1
    • from 1917: 7.5: 1
  • Cooling: liquid cooling, forced circulation with water pump and cooler
  • Valves per cylinder: 2
  • Valve control: Two camshafts, inlet side OHC / exhaust side OHV
    • an overhead driven by a vertical shaft, actuation of the inlet valves via short adjustable tappets
    • one on the left side of the crankshaft driven via bevel gears, actuation of the exhaust valves via bumpers and rocker arms
  • Mixture preparation:
    • from 1910: A double ascending flow carburetor
    • from 1917: Two double riser carburettors
  • Power:
    • 1915: 147 kW (200 hp) at 1400 min -1
    • 1917: 169 kW (230 hp) at 1500 rpm -1
  • Weight (dry):
    • from 1915: 316 kg
    • from 1917: 331 kg
  • Fuel: gasoline (at least 75 octane)

literature

  • Bill Gunston: World Encyclopaedia of Aero Engines , 1986, Patrick Stephens: Wellingborough, p. 23

See also

Web links