Le Rhône

[
La Cierva C-6 autogyro replica, displayed in "Museo del Aire", Cuatro Vientos, Madrid, Spain]

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 gave 130 hp, they were dependable rotary engines.

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 a remarkable method of connecting the link rods to the master rod. In the Le Rhône, the fuel mixture went first to an annular chamber at the back of the crankcase and thence, by attractive polished copper pipes, to conventional intake ports and cam-operated valves in the cylinder heads. The copper induction tubes had their crankcase ends located in different places on the 80 and 110 hp 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.

The Le Rhône used a complicated slipper bearing system. Its master rod had three concentric grooves to take slipper bearings from all the other cylinders. The master rod was a split-type to allow assembly of the connecting rods. 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 no's. 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 Rhones worked very well.

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 and a system of links and levers accomplished this. 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 before it can contact the intake. While this puts a limit on power output, it is not necessarily a fault. As it was, most Le Rhône models produced all the power that their structural strength and cooling arrangements could cope with.

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 by Germany (by Motorenfabrik Oberursel), Austria, United Kingdom, and Sweden.

Le Rhône 80 hp engines were made under license in the United States by Union Switch and Signal of Pennsylvania, and the 110 hp 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.

Variants

*80 hp Le Rhône

*Type J - 110 hp

pecification (Le Rhône 9J)

From Aviation history.com [ [http://www.aviation-history.com/engines/rotary.htm Le Rhone Rotary Engine - France ] ] pistonspecs

type=Rotary
bore=112 mm (4.41 in)
stroke= 170 mm (6.69 in)
displacement=15,074 cc (919.9 cubic inches)
length=
diameter=
width=
height=
weight= 149 kg (330 lb)
valvetrain=cam operated single rocker for both inlet and exhaust
supercharger=
turbocharger=
fuelsystem=
fueltype=
oilsystem=castor oil- Total loss
coolingsystem=air cooled
power=110 hp (82 kw, 113 bhp)
specpower=
compression=
fuelcon=
specfuelcon=
oilcon=
power/weight=

* Maximum rpm.: 1, 200
* Bore and Stroke:
* Displacement:

Trivia, variants and miscellanea

*

* Oberursel made the 110-hp model, supposedly without authorization in Germany. The Oberursel U.R. II was a straight copy of the Le Rhône but the Le Rhône was preferred over the Oberursel due to the superior materials used over the home product. However by July, 1918 that there was a shortage in Germany of castor oil which the rotaries required. A new Voltol-based lubricant 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 U.R. II rotary engine. It has been suggested that without the proper lubricants, the Le Rhône rotary would have been equally failure prone.

Uses

* Airco DH 5
* Avro 504
* Bristol M.1
* Bristol Scout
* Caudron G.3
* Caudron G.4
* Hanriot HD.1
* La Cierva C-6, autogyro, 1924.
* Morane-Saulnier N
* Nieuport 11 "Bebe"
* Nieuport 17
* Nieuport 27
* Sopwith Camel
* Sopwith Pup
* Standard E-1
* Thomas-Morse S-4C

ee also

*Gnôme Monosoupape
* Gnome et Rhône

External links

* http://www.aviation-history.com/engines/rotary.htm
* http://www.aviation-history.com/index.html

References

"Most of the original data, information and pictures of this article were taken from [http://www.aviation-history.com/index.html|The Aviation History Online Museum] ".