André Chapelon
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André Chapelon | |
|---|---|
| Born | 26 October 1892 |
| Died | 22 July 1978 |
André Chapelon (26 October 1892 – 22 July 1978) was a noted French mechanical engineer and designer of advanced steam locomotives. Engineer of Ecole Centrale Paris, he was one of very few locomotive designers who brought a rigorous scientific method to their design, and he sought to apply up-to-date knowledge and theories in subjects such as thermodynamics and gas/fluid flow to the field.
Life and career
André Xavier Chapelon was born in Saint-Paul-en-Cornillon, Loire, France on 26 October 1892, and was descended from an English immigrant, one of many who came to France in the 19th Century to teach steel production methods.[1]. He achieved a distinction in Mathematics and Science and served as an Artillery Officer during World War I before returning to the École centrale Paris in 1919 from which he graduated as Ingenieur des Arts et Manufactures in 1921. He joined the Chemins de fer de Paris à Lyon et à la Méditerranée (PLM) as a probationer in the Rolling Stock and Motive Power section at Lyon-Mouche depot, but foreseeing poor prospects he left in 1924 and joined the Société Industrielle des Telephones, soon becoming as assistant manager. In 1925 he joined the Chemin de Fer de Paris à Orléans (PO) and, along with Finnish Engineer Kyösti Kylälä jointly designed the Kylchap exhaust system. While his principles met with scepticism No. 3566, the first locomotive rebuilt to Chapelon's design was an outstanding success and from 1929 to 1936 several other locomotives were rebuilt to Chapelon's designs.[2]
In 1934, Chapelon was appointed Chevalier of the Legion of Honour and awarded both the Plumey Prize of the Academie des Sciences and the Gold Medal of the Société d'Encouragement pour l'Industrie Nationale. From 1938 he published the book for which he is most noted La locomotive à vapeur.
Chapelon's methods
He tested his experimental designs thoroughly to understand how they actually behaved, using the most accurate and complete testing and sensing equipment available, such as high-speed stroboscopic photography to watch steam flow.
Before Chapelon, few engineers and designers tried to understand why a certain design worked better than another—they merely worked by trial and error, trying to replicate the attributes of previous locomotives by rule of thumb, by guesswork, and from empirical theories and design rules that had rarely been given adequate testing.
Efficiency
Efficiency was one of Chapelon's primary concerns in design; some of his locomotives exceeded 12% efficiency, which for a steam locomotive was exceptional. With greater efficiency, Chapelon could achieve greater power in a smaller locomotive that burned less coal, rather than simply enlarging a locomotive for more power.
Compounding and steam flow
He was a major proponent of the compound locomotive; his other major work included optimising the steam circuit, including improving the steam flow by widening steam passages and paths, improving the flow through valve gear, and improved exhaust systems such as his Kylchap exhaust.
Wheel and rail
Chapelon realised that in order to produce an efficient, powerful locomotive every aspect of it had to be improved and dealt with scientifically. He studied locomotive behaviour at speed and the riding properties of the steel wheel on steel rail; his knowledge was put to use much later on the French TGV high speed trains.
Problems
His curse was that despite his abilities and track record, he never got to design a class of brand-new locomotives that actually got built in any number. He was continually stymied by railway management and politicians, and often his superbly performing locomotives were treated as embarrassments by his superiors—because they showed up the poor performance of the officially approved locomotives!
Chapelon's legacy
Chapelon's work lived on in the work of his friend Livio Dante Porta of Argentina, and others, and he was accorded the rare honour for a foreign railwayman of having a British Rail Class 86 (electric!) locomotive named for him.
Chapelon's locomotives
French locomotives
The first locomotive rebuilt to incorporate Chapelon's work was PO 4-6-2 3566 which was released from Tours works in November 1929.[2] As a result of this, three further series of Pacifics were similarly modified.[1]
This was followed by a more comprehensive rebuild of Pacific 4521 as a 4-8-0 which was completed in August 1932. The success of this work led to 11 more rebuilds to locomotives numbered 4701-4712 (later 240 701 - 240 712). These locomotives produced alost 40 ihp continuous per metric ton locomotive weight, which probably still is a world record.[2]
In 1936 he began the rebuild of a PO 6000 class 2-10-0 as a 2-12-0 with 2 high-pressure cylinders between the 2nd and 3rd couped axles mounted behind four low-pressure cylinders.[2] There was also an additional level of "superheat" between the high and low pressure cylcinders, allowing the loco to achieve a tractive effort of 83700 lb.[1]
The 242 A 1 was perhaps the pinnacle of Chapelon's development of the steam locomotive. The 4-8-4 was a rebuild of Etat 4-8-2 241.101 which retained the 3-cylinder layout, changed it into a 3-cylinder compound system and introducing more of Chapelon's improvements including a triple Kylchap exhaust, double high pressure valves and Willoteaux valves on the low pressure cylinders.[2] Completed in 1946 and with a continuous power output of 5500 ihp,[2] the locomotive was rather more powerful than contemporary French electric locomotives, resulting in a hasty redesign of subsequent electric locos, increasing their power by another 1,000 horsepower (750 kW).
It is considered a matter of enduring sadness that the locomotive was scrapped in 1960, probably as a consequences of French railway authorities not willing to be reminded of Chapelon's superiority in steam locomotive design.
Exported locomotives
The only locomotives he designed for use outside France were some metre gauge 2-8-4 and 4-8-4 locomotives for GELSA (Groupement d'Exportation de Locomotives S.A.) for export to Brazil. They were highly advanced locomotives with many modern American appliances as well as Chapelon's innovations. André Chapelon was much an admirer of American railroad innovation, even though his work tended to be ignored in the USA.
See also
References
- ^ a b c Stora, T. "André Chapelon". FRENCH COMPOUND LOCOMOTIVES' HOMEPAGE. Retrieved 2009-03-04.
{{cite web}}: Cite has empty unknown parameter:|coauthors=(help) - ^ a b c d e f Jones, Kevin P. "Andre Xavier Chapelon". SteamIndex. Retrieved 2009-03-04.
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