Talk:X engine

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Technology

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Vroom

Can it work on the side 111.65.38.115 (talk) 23:16, 26 September 2022 (UTC)[reply]

Meaningfully different from a radial engine?

I'm trying to grasp how this isn't essentially the same as a 4-bank radial engine layout. The only place the article as written differentiates this from a radial engine is where it says they have "greater weight and complexity as compared to a radial engine," which is unsourced. It having uneven spacing between cylinder banks seems like it would maybe qualify it as a distinct type of radial engine but not as a distinct layout itself. Cuyamas (talk) 01:51, 17 November 2023 (UTC)[reply]

First off, in what sense are you comparing them? As engines, or as manufacturing tasks? It's true that the main distinction is in their development origin and their manufacture: X engines have typically either developed from inline engines (usually vees) or have their constructional characteristics in common: monobloc cylinders for a bank, camshaft(s) in each bank, common water cooling in a bank. There's also usually a geometry difference in that radials have more banks than rows, X engines have more rows than banks.

There's also an intermediate group, inline radial engines such as the Armstrong Siddeley Deerhound and the Zvezda M503. These are radial engines, with radial engine crankshafts and timing, but constructed as linear banks. Radial engines have nearly all been air-cooled and the rows are staggered to improve airflow. Inlines have often been water-cooled (although not the Armstrong-Siddeley) and this is much easier with the banks aligned in-line. As the last radial US engines like the Wright R-2160 Tornado became truly enormous, their frontal area just couldn't capture enough airflow for cooling and so they moved to liquid-cooled engines with remote radiators, thus inline.

As engines, the main difference is the timing. Radials (nearly always) have odd numbers of cylinders in a row and these are evenly spaced. X engines have even numbers, either evenly spaced or not, because their timing and firing order is based within each bank.

In a further group, GM's somewhat infamous pancake diesels, the 16-184 and 16-338, these are inline radials where the distinction between radial and X engine is truly lost. They're evenly spaced and have an even number of cylinders, but as two-strokes they're a bit more flexible there anyway. They ended up as they are because they're uniflow diesels designed for marine installation, to resist depth charge and torpedo attack (where large rigid crankcases and long crankshafts are susceptible to damage) and as naval engines they had to be repairable in situ, with little working space. This encouraged a compact radial design on a minimal crankcase, but with no space for more than four banks.

Overall though, the true X engine (i.e. one that is distinct from radials) comes about from one of two reasons: it's either a doubled vee engine (and usually a failure, like the Vulture's big end design) or else it has non-even bank spacing, because it's trying to fit in an incredibly small space. Either an asymmetric X with improved ground clearance for aircraft, like the Napier Cub, or a low, wide X like the Armata's 12N360. Both suck. Massively. Andy Dingley (talk) 03:00, 17 November 2023 (UTC)[reply]

That seems like a pretty good analysis, I suppose I should have given some context to why I was asking. I've been looking at a lot of articles relating to engine designs and layouts and there seems to be a lot of superfluous articles with very little content. This is one of those, and I was trying to see if there was a really good argument against merging this article with radial engines. They still strike me as similar enough to warrant that. Cuyamas (talk) 03:14, 17 November 2023 (UTC)[reply]

Well, if the 12N360 truly sucks remains to be seen. For the time beeing it's (for what is known) installed only a few hundred times. OTOH the soviets were tinkering with the X-engine quite some time before they used it in a tank, at least thirty+ years. So one would asume that they had thought this through, would they? Markscheider (talk) 09:19, 17 November 2023 (UTC)[reply]

Simmering-Graz-Pauker Sla 16

Porsche's mid-war tank engine (a replacement for the overworked Maybachs) needs to go in too. Andy Dingley (talk) 21:08, 21 November 2023 (UTC)[reply]

Internet lore hast it that the russians simply copied this, 'cause they are not able to come up with something own. I don't think so. It would need a lot of wp:rs to put this alleged connection into the article. Beeing of the same basic configuration ain't enough. Markscheider (talk) 09:45, 22 November 2023 (UTC)[reply]

Sorry? You have a point here? Now I know you're an Armata fan, but are you seriously suggesting that the Sla 16 didn't exist? Or that it's in some way dependent on the 12N360? Andy Dingley (talk) 23:42, 22 November 2023 (UTC)[reply]

Armata fan: no, i'm not. But i would like to say sorry for confusing things. That was because someone brought up 12N360 in the section above. Feel free to do whatever you want to. Markscheider (talk) 10:34, 23 November 2023 (UTC)[reply]