Talk:Siemens-Halske Sh.III

Rotary operation
I couldn`t understand the operation description for this particular engine. I can realize that any engine must be fastened to the airframe in some way. Usually, this implies on the case being static and the crankshaft rotating, or vice-versa (as is the case on early rotaries). How - if someone can ellucidate - this Siemens-Halske Sh.III engine can operate with BOTH parts turning on opposite directions? Is there any internal gearbox to allow such uncommon operation? Or what? The text wasn`t sufficiently clear, what turns me really curious about. Someone? RobertoRMola (talk) 0042UTC, 16 August 2010


 * I too am unable to understand how this engine can have its crankshaft rotate one way and its casing the other. Indeed I would be keen to see a diagram added similar to http://en.wikipedia.org/wiki/File:Radial_engine_timing-small.gif that shows the internal operation both for this engine and for the standard rotary engine. 122.148.95.177 (talk) 22:51, 8 January 2013 (UTC)


 * It is strange, Bill Gunston's 'Development of Piston Aero Engines' book has a cross section view on p. 115 but it's still not entirely clear from that. The gearing was achieved with large bevel gears, described as an 'epicyclic differential gearbox', we have epicyclic gearing and differential (mechanical device). The gears were positioned inside the rear engine mount, in front of them the diagram shows two large roller bearings, presumably one for the cylinder assembly and one for the crankshaft. Hope that helps. Nimbus (Cumulus nimbus floats by)    08:10, 9 January 2013 (UTC)


 * This image is quite good, if you zoom in the bevel gears can be seen (I think some have been removed) and diagrams under the exhibit show the system. Nimbus (Cumulus nimbus floats by)    08:19, 9 January 2013 (UTC)

"Throttling"
A rotary engine (in the sense that the Sh.III was one) can't have "normal" carburetion - this is one of the principle drawbacks of this type of engine of course. In fact a "Monosoupape" rotary (which the Sh.III was NOT) could only be "throttled back" at all through the ignition system, by either momentarily cutting the ignition altogether ("blipping") or changing the timing so that each cylinder fired every second or third revolution. A "non-mono" rotary, such as the Sh.III, had a full set of Otto-cycle valves, and could be throttled by controlling the flow of fuel, but it was necessary to adjust the air supply through a separate control (in the RFC this was known as the "fine adjustment"). This of course was closer to a "true" throttle than in a mono rotary, but still lacking the action of a normal carburettor, in which the mixture of fuel and air entering the engine is (more-or-less) constant. Since this is a feature that the Sh.III shared with (for example) the Clerget and B.R. rotaries it is not actually a unique characteristic, and if it is to be mentioned at all here this needs to be made clear. --Soundofmusicals (talk) 15:01, 20 June 2018 (UTC)


 * Fixed. See Update.  Stivushka (talk) 17:41, 11 November 2022 (UTC)

Rewrite
Design section of article rewritten to comply with Wikipedia inline citation requirements for WP:Class B.

Description now makes it clear that the propeller and cylinders rotated in the same direction with the crankshaft rotating in the opposite direction. I have tried to keep the description as straigtforward and readable as possible while remaining true to the source material ... frankly this engine is a bit of a mind bender!

Happy reading

Stivushka (talk) 18:50, 11 November 2022 (UTC)