Talk:Le Rhône

Rotary engine

The article mentions that this engine was a rotary - the first mention of this is linked. This is normally as far as we go in describing the basic operation of the category of engines in an article on a specific engine. For instance it is not necessary to detail the Otto cycle in describing every 4 stroke engine! More importantly, the reason for using the "blip" switch on a rotary was to substitute for the problematic throttle control, not directly because of its rotational inertia. --Soundofmusicals (talk) 10:08, 10 November 2017 (UTC)

• I definitely favour Hydrargyrum's text, although would move it down out of the lead: [1] Andy Dingley (talk) 10:21, 10 November 2017 (UTC)

But we have a very good, well referenced article on rotary engines that explains exactly why throttling a rotary engine was so problematic, and it is in direct contradiction to the sense of Hydrargyrum's text - which is, with all due respect, not factual. --Soundofmusicals (talk) 22:15, 10 November 2017 (UTC)

So which statement do you claim is inaccurate?

1. As the the crankshaft of this engine was fixed to the aircraft frame,
2. the entire crankcase and bank of cylinders rotated along with the propeller,
3. producing a significant gyroscopic effect.
4. Moreover, this arrangement meant the engine had high inertia,
5. making it slower to respond to speed change commands compared to engines in which the crankcase and cylinders are fixed to the aircraft frame.
6. Speed was usually regulated or reduced for landing by manually switching the magneto ignition on and off

Also the article at rotary engine is anything but "well referenced". You seem to be referring to Rotary engine#"Normal" rotaries here, which has a grand total of one citation, to a skimpy museum pamphlet.

Andy Dingley (talk) 22:49, 10 November 2017 (UTC)

Statement 5 is where it all breaks down, although statement 4 is also very ambiguous in this context, and not necessarily very useful. All the others are individually ok, but we might question their relevance to the case in point. Controlling "speed change" of a combustion engine (making it run faster or slower) is based on a increase in (effective) fuel supply (i.e. the throttle is opened). BUT rotary engines, while they have a "fuel valve" (basically a very simple (primitive) throttle - do not respond in the way a "stationary engine" does - as the air (oxygen) supply (vital to combustion) is quite separate from the supply of fuel. In fact moving the throttle tends to make the fuel/air mix become either very rich or very lean - instead of smoothy increasing or decreasing rpm the engine tends to either run very roughly or to stall. In a "normal" rotary (like a Le Rhône) the air mix can be independently adjusted to counter this tendency, but the response of the engine is erratic, even with an experienced operator, so at tricky moments, like when landing, the much more positive and predictable control afforded by the ignition switch is greatly preferred. I have tried to keep this explanation as simple as I can. There are several editors here who might be able to explain better to someone with a limited technical background.

Nahum is, alas, the only really comprehensive source for a lot of the above - it is possible that we do rely on him a bit too much. But are we referring to the same reference? How Nahum can be described as a "skimpy museum pamphlet" I am at a loss to determine. I own this text, and am sure you must be referring to something else.--Soundofmusicals (talk) 06:16, 11 November 2017 (UTC)

I thought #6 was going to be the issue (as it's more of an issue for monosoupapes). I really can't see how to contest 4 or 5. Try swinging one! Feel the weight of turning the whole cylinders, not just the pistons and crank.

The SciMus pamphlet is OK and it's one of the best around (there just isn't much anywhere on rotaries), but it's still awful thin. My own library on them is mostly original stuff (much of which was scanned for Commons, until they deleted nearly all), because there's little published post 1930s (a bit on the Bentleys). I'm sorry that you consider me to have such a limited technical background though.

So what's wrong with 4 /5 ? Andy Dingley (talk) 00:20, 12 November 2017 (UTC)

If you have a technical background what's wrong with reading my posts to this thread? And, if you have any objections, actually raising them instead of repeating your basic line? Of course the rotational torque is high, the point is that's not relevant to a (fallacious) statement that it's the torque that creates the throttling problem and the reason why the trick with the ignition is necessary. If anything the torque works as to mitigate the tendency of a rotary to "choke" on an overly rich (or lean) mixture if the rudimentary throttle's setting is changed without compensating changes to the so-called "fine-adjustment" - the engine can go on spinning for a few revolutions while the mixture problem sorts itself, whereas without the torque it would just plain judder to a halt. For all this, people used the ignition switch (in non-mono rotaries like the Le Rhône mostly a simple button cutout) rather than try to throttle back when they were doing something tricky like landing and risk losing power should they need to go round. Another way of putting it is that the problem was cutting POWER - an engine that is coasting on its own torque is simply not delivering any power. Third time lucky: 4 is correct in itself but not relevant - 5 is plain wrong. --Soundofmusicals (talk) 01:32, 12 November 2017 (UTC)

Caption

Le Rhône 9J mounted in the front of a Cierva C.6 autogyro replica, displayed in "Museo del Aire", Cuatro Vientos, Madrid, Spain

@Nimbus227:
Museo del Aire", Cuatro Vientos, Madrid, Spain should be OK. Peter Horn User talk 18:24, 21 October 2019 (UTC)

No need to ping me? That image was part of the original article creation in January 2007 by a retired Spanish Wikipedian (not added by me or edited by me). Objects/places in image captions are often wikilinked which is useful.

The answer to the formatting riddle in the 'Applications' section is to remove the engine photo (not an application and essentially the same as the other images) and use two columns. A full image of one of the aircraft types using the engine gives the reader a context of how the engine was used (time period/size of aircraft/type of aircraft etc). Rolls-Royce Kestrel#Applications is one example. Nimbus (Cumulus nimbus floats by) 17:00, 22 October 2019 (UTC)