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Le Rhone

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Template:Infobox Aircraft Engine

The Le Rhône was a popular rotary aircraft engine produced in France by Société des Moteurs Le Rhône around 1916. It powered a number of military aircraft of the First World War.

Although not powerful, the largest wartime version gave Template:Convert, they were dependable rotary engines.[1] The Le Rhône 9 was a development from the Le Rhône 7, a seven-cylinder design.

Operation

The Le Rhône had a conventional induction system and an unusual method of connecting the link rods to the master rod. In the Le Rhône, the fuel–air mixture went first to an annular chamber at the back of the crankcase and thence, via polished copper pipes, to conventional intake ports and cam-operated valves in the cylinder heads.[1] The copper induction tubes had their crankcase ends located in different places on the Template:Convert versions – the 80 hp versions had them entering the crankcase in a location forward of the vertical centerline of each cylinder, while the 110 hp version had them located behind the cylinder's centerline. This resulted in the 80 hp version's intake plumbing being "fully visible" from the front, while the 110 hp version had the lower ends of its intake tubes seemingly "hidden" behind the cylinders.

A complicated slipper bearing system was used in the Le Rhône. Its master rod was a split-type to allow assembly of the connecting rods, and had three concentric grooves to take slipper bearings from all the other cylinders. The remaining rods carried bronze shoes, shaped to fit in the grooves, at their inner ends. Counting the master rod as no. 1, the shoes of nos. 2, 5, and 8 rode in the outer groove, those of 3, 6, and 9 in the middle groove, and 4 and 7 in the innermost one. Although complex, Le Rhônes worked very well.[2]

The Le Rhônes employed an unusual method of valve actuation. A single rocker arm, pivoted near its center, was made to operate both the exhaust valve and the intake valve. Pulled down, it opened the intake valve; pushed up, it opened the exhaust. To do this, the rocker had to be actuated by a push-pull rod instead of by the usual pushrod. This, in turn, meant that the cam followers had to have a positive action, which was accomplished by a system of links and levers. This system works well enough – some makers used it up to the late 'twenties – but its use makes overlap of valve openings impossible. In an engine designed for high- power and speed, the intake valve begins to open before the exhaust valve is quite closed, but on the Le Rhône, the rocker arm must clear the exhaust valve before it can contact that of the intake. While this put a limit on power output, most Le Rhône models produced all the power that their structural strength and cooling arrangements could cope with.[1]

Production

As well as production by Société des Moteurs Gnome et Rhône, which had bought out Société des Moteurs Le Rhône, the Le Rhône was produced in Germany (by Motorenfabrik Oberursel), Austria, the United Kingdom, and Sweden.

Le Rhône 80 hp (60 kW) engines were made under license in the United States by Union Switch and Signal of Pennsylvania, and the 110 hp (82 kW) Oberursel UR.II rotary engine used by Germany in World War I, in such famous fighters such as the Fokker Dr.I triplane, was a close copy of the 110 hp 9J version.[1]

Variants

File:Oberursel-UR-2-engine.jpg
Oberursel UR.II, a clone of the Le Rhône 9J
  • 80 hp Le Rhône
  • Type J – 110 hp

Oberursel copy

  • Oberursel made the 110 hp model, supposedly without authorization in Germany.[3] The Oberursel UR.II was a straight copy of the Le Rhône, but the Le Rhône was preferred over the Oberursel due to the superior materials used in the French product. However, by July 1918 there was a shortage in Germany of castor oil,[1] a plant-derived lubricant that the rotaries required as it could not be easily dissolved into the fuel, and because it possessed lubrication qualities superior to mineral oils of the day.[4] A new Voltol-based lubricant, derived from mineral oil, was substituted and was blamed for a rash of engine failures on rotary-engined German fighters such as the Fokker E.V which used the Oberursel UR.II. It has been suggested that without the proper lubricants, the Le Rhône rotary would have been equally failure prone.[1]

Applications

File:La Cierva C-6 Engine Closeup.jpeg
Le Rhône 9J mounted in the front of a La Cierva C-6 autogyro replica, displayed in "Museo del Aire", Cuatro Vientos, Madrid, Spain

Specification (Le Rhône 9J)

File:Le rhone.jpg
More powerful Le Rhône Model J, general view
File:Le Rhône 9J 2.jpeg
Le Rhône 9J; crankshaft, pistons, rods, etc.

From Aviation history.com [5] Template:Pistonspecs

  • Maximum rpm.: 1,200

See also

References

Notes

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Le Rhone Rotary Engine Retrieved on 18 February 2009.
  2. Gunston 1989, p.93.
  3. Gunston 1989, p.73.
  4. General rotary engine lubrication information from Gnome Monosoupape Type N Rotary Retrieved on 18 February 2009.
  5. Le Rhone Rotary Engine - France

Bibliography

  • Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9

External links


Template:Gnome-Rhône aeroengines

cs:Le Rhône 9C

This article is licensed under the GNU Free Documentation License.
It uses material from the Wikipedia article "Le Rhone".