Le Rhône 9C engine scale 1

MODEL

This 3D model is a 1:1 scale reproduction of the Le Rhône 9C engine. It is as faithful as possible to the original engine in terms of the detail of the parts, the dimensions and the internal workings.
All printed parts have been designed for 3D printers with a maximum print volume of 20cmx20cmx20cm. For this reason, large parts (for example the engine crankcase) have been cut into several parts so as not to exceed the maximum print volume. Such parts are assembled with studs, screws and glue.
A certain number of parts (cylinders, crankcases, oil pump, magneto, etc.) are cut to allow their internal workings to be seen.
The characteristics of the model:
• Length: 120cm
• Width: 80cm
• Height: 98cm
• Total weight: 40kg
• Printed parts: 1,503 (27kg of filament)
• Printing time: 2,800 hours
• Accessories (screws, washers, springs, bearings, aluminum tube, etc.): 1,630
All parts of the model are mobile in the same way as the original engine:
• Rotation of the crankcase around the crankshaft
• Rotation of the propeller linked to the crankcase
• Movement of the pistons in the cylinders with movement of the connecting rods
• Rotation of the cams
• Back and forth of the rocker arms via the push/pull rods
• Back and forth of the intake and exhaust valves
• Oscillation of the oil pump driven by gear
• Rotation of the “Samlson AVIA H=45” magneto driven by gear with opening/closing of platinum screws
• Sliding drawer with needle of the "Tampier" carburetor

DOCUMENTATION

The following documents are published:
• Assembly.pdf: assembly documentation of the model
• PrintedParts.pdf: list of parts to print
• Accessories.pdf: list of accessories necessary for assembling the model
• Safety-Wire.pdf: documentation for making the propeller brake wire

VIDEOS

https://www.youtube.com/watch?v=VVMW-pRoDyE
https://www.youtube.com/watch?v=kvkDoHUGjag

WARNING

This 3D model is a very large project with a substantial budget; the filaments and accessories represent an expense of more than €1,000.
Before downloading it, make sure that you will have the space to store it (large volume) and that you will have the time to make it.

HISTORY

This engine model was built on a large scale; the "Le Rhône 9C" approved in 1914 was produced in more than 10,000 units. The oil consumption of this engine was significant; the "Le Rhône 9C" burned five liters of oil and 33 liters of fuel per hour. It was fitted to a large number of aircraft, Bristol M.1 and Scout, Caudron G.III, G.IV, C.43 and C.127, Farman HF.20, Grahame-White Type XV and G.W.E.6 Bantam, Morane-Saulnier G, H, L, N and P, Nieuport 10, 11 and 21, Pemberton-Billing PB.23, Ponnier M.1, Royal Aircraft Factory F.E.8 and S.E.4, Sopwith Camel, Dove and Pup, Thomas-Morse S.4 and Vickers F.B.12
It was fitted with high-strength steel cylinders screwed into the crankcase, hot-fitted cast iron liners; the distribution consisted of two valves controlled by a double rocker arm and a single linkage. The fuel supply was from inside the engine, the mixture being brought to the inlet valves by an external copper pipe. The carburetor was a semi-automatic Tampier and the ignition was done by magneto (one spark plug per cylinder).

The lubrication system was of the total loss type. Castor oil was injected by a pump driven by the engine into the carburetor. The oil mixed with the fuel and the air passed into the crankcase through the inside of the crankshaft, lubricated the bearings at the bottom, was projected towards the cylinders by centrifugal force before being transferred to the top of the engine. The unburned part of the oil then came out through the exhaust pipes. The engine turned on the right hand side, i.e. counterclockwise, when looking at it from the front. The order of operation of the cylinders was 1, 3, 5, 7, 9, then 2, 4, 6, and 8, and it took two revolutions for the engine for a cylinder to complete its four-stroke cycle. The timing of the distribution was as follows: intake opening 18° before passing to top dead center, intake closing 35° after passing to bottom dead center, exhaust opening 45° before passing to bottom dead center, exhaust valve closing 5° after passing to top dead center. The ignition advance was 26° before passing to top dead center.

The distribution, due to the single rod actuating the intake valve by pushing and actuating the exhaust valve by pulling, was complex. For each cylinder, the rod was actuated by a two-roller rocker, the first roller rotating on a first five-cam plate for the intake, the second roller rotating on a second five-cam plate for the exhaust, the rod operating in push and pull. These two plates were eccentric relative to the axis of rotation of the cylinders, their base was driven by a 50-tooth gear which was engaged on a 45-tooth gear secured to the false nose screwed to the engine block. In this way, the cylinders rotated faster than the cams in a ratio of ten to nine, that is, when the engine made ten revolutions, the two cams made only nine. The design of the cams was complex because it took into account this rotational offset and also the eccentric offset between the axis of rotation of the engine block and the axis of rotation of the cams.

CONTRIBUTORS

I would like to thank all the people who contributed to the realization of this project:
• Christian Faure (https://musee-aviation-saint-victoret.fr)
• Jean-Yves Gacon (https://musee-aviation-saint-victoret.fr)
• Gérard Hartmann (former historian at the Aéro-Club de France)
• Pierre Jansen (https://www.pjvision.nl)
• Fred Murrin (http://www.thevintageaviator.co.nz)
• Jean-Noël Passieux (http://jnpassieux.fr)

3D printing parameters

The printing parameters are indicated in the Assembly.pdf file.