Figure # 8, Page # 12 of the French 200 H.P. Hispano-Suiza Aero Engine, Instruction Handbook. June 1917
We know, by observation, that the large oil pipe goes up the left side of the crankcase, pilots view, and extends forward to the front edge of the crankcase where a hole extends upwards to the bottom edge of the crankcase main bearing. The sketch on page # 12 Figure # 8 shows a passage way (H) up to the propeller shaft and then the oil goes into the center of a large weight reduction hole of the propeller shaft in which it appears to have four holes drilled. Then it is passed into the center web of the gear wheel and into the holes drilled into the gear, there is no mention of how many of these holes are drilled into the gear. Arrows also show the oil is directed into these holes and also into holes lubricating the front ball bearing.
There is no explanation of this process in the written text that I have been able to find except this text written herein, above and below
In the document that I have of the, “ Report upon Troubles with the 200 H.P. Hispano in Service”, was the following on page #3 I believe, as I haven’t the complete document. As follows is the statement.
It is necessary that the diameter of the lubricating jet of the reduction gear be 10/10 mms. (some are still 6/10). No other thing is mentioned as to the location of the jet or any other placement of the jet.
The only place I found that even closely resembles the description if the jet and the copper oil pipe is a projection into the propeller shaft from the front of the engine into the and sprays oil into the propeller shaft and then into the four holes in the shaft and the gear wheel where centrifugal force throws it into the tooth area of just the one tooth per hole. One must remember that there are only four holes that I can see in the sketch.
1.0mm diameter = .785square mm
.6mm diameter = .287 square mm
A difference of .498 square mm or an increase of 49.3% on the square area, just why this was done I don’t know and isn’t revealed in the text. Was it to increase the oil flow to the gear and pinion or was it to decrease the pressure in the piping, which was the primary purpose I don’t know and they who did know didn‘t reveal the true purpose.
We do know that the oil that was forced into the teeth which are on the outer side from the gear wheels web. The driving but smaller pinion wheel does not get any direct spray of oil and seems to get the lubrication only from indirect sources. Remember that it is on the bottom side of the two wheels and gravity may take care of it’s lubrication most of the time altho this may not be sufficient lubricant in combat maneuvering.
Page # 11 Lubrication Paragraph # 5; From the front end bearing housing of the crankshaft oil is forced under pressure through an oil duct H in the crankcase upward to the propeller inside diameter. The shaft is hollow for weight reduction and just how many of the teeth are drilled for oiling I cannot state for sure. I don’t believe every tooth can be drilled due to a weakening of the hub area of the larger gear. Visually imagine 41 or 59 holes drilled thru the hub area for each tooth!
Is this just a bad design? It doesn’t seem to provide enough oil spray on the teeth to cool the gear and pinion sufficiently under all circumstances of maneuver. Of course this gets into the real reason that Wolseley took off the reducer which we really also don’t know for sure. Possibly the Oil Pressure Relief should have been directed into the Gear and Pinion box area near the tooth disengagement area.
After finishing a sketch of the Oil Pipe I believe that this must be the pipe of the, “Broken Copper Pipe Story”. It seems to be less than half the diameter of the steel pipe which is given as ½”. and around 2” long and projecting out of the front face of the upper crankcase. The only mention in the Manual is the resizing of the jet mentioned above. The sketch is very bad on this view and I had to increase the magnification 500 to see a two very faint lines showing the tube itself.
Yours, M. L. Anderson
