Wikipedia talk:WikiProject Aircraft/Engines/Archive 11

Template:Rocket engine proposal.
Hey! It's me again! Thanks to all for helping me improve the rocket engine templates. I've been working on a nav template Template:Rocket engine (its in my user space) for the concept of rocket engine. Please note the dangerous similarity in name with the recently discusses Template:Rocket engines, which is plural and has different caps. I believe that now that the latter is better scoped, we should rename it to Template:Orbital launch vehicles rocket engines. But that is a different discussion.

This Template:Rocket engine is currently not ready to go into an article, but I believe that it is a good tool to navigate in a glimpse all concepts about rocket engines and, at the same time, to have an idea of areas to enhance regarding rocket engines in Wikipedia. Basically, everything in black should be worked on. This is a big undertaking, and I will need help. I will ping some of you just to get an opinion and post this same request on WikiProject Spaceflight, WikiProject Rocketry and WikiProject Aviation since all use rocket engines. As usual, please respond on the template's Talk Page. Baldusi (talk) 22:41, 28 July 2015 (UTC)

Calculator operator
Quiet in here?! There is a new specs section tweaker using a couple of Quebec based IP addresses. Obviously not reading the guideline shortcuts in my reversion edit summaries. Nimbus (Cumulus nimbus floats by)    00:39, 20 January 2016 (UTC)


 * This is the other IP address.Nimbus (Cumulus nimbus floats by)    00:40, 20 January 2016 (UTC)

Chaise engines
Is there a piston expert out there who could help me understand the point of the Chaise layout? It seems to have been basically an inverted 4 cylinder air-cooled motor but (probably, I've only found a head-on photo so far) with alternate cylinders forming a shallow V. French contemporary sources refer to it as "quinconcés", which I read as quincunxed; must refer to the crankshaft, I guess. But why this unusual layout? Balancing? Does it relate to Chaise engines previous main applications, motorbikes and cars? Cheers,TSRL (talk) 21:00, 23 March 2016 (UTC)

Having looked again at the photo, the cylinder axes clearly do not converge at the output shaft, as on a conventional V; this is telling us something, but what?TSRL (talk) 21:12, 23 March 2016 (UTC) There is another photo of a different (bigger) Chaise engine at an angle, which helps a bit; the first two cylinders seem to be almost in the same transverse plane. Maybe the cylinders are the corners of the "quincunx" for air-cooling, but what's at its centre?TSRL (talk) 21:34, 23 March 2016 (UTC)

Pardon my stream of conciousness. This three page article has some very helpful diagrams and photos on pages 2 and 3. The two staggered Vs are well separated so air-cooling will be improved as the last article suggested. Still don't understand this "quinconcés" description but they also describe some radials in the same way. Staggered? Puzzled, certainly.TSRL (talk) 22:06, 23 March 2016 (UTC)


 * Much to my surprise, "en quinconce" translates as staggered. So perhaps it was about cooling, inspired by the V-twin biker heritage. What are the implications for crankshaft vibration etc? Why did it not catch on?TSRL (talk) 22:57, 23 March 2016 (UTC)


 * So, for an aircraft article, is shallow angle inverted V-4 (which answers several questions) a reasonable description? V4s seem still to work on bikes. Which is where they came in ...TSRL (talk) 23:32, 23 March 2016 (UTC)


 * Interesting engine. Benefits from the text seems to be a short length (as a VR6 engine) and better cooling than an inline engine. It's possible that the cylinder offset to the crankshaft is due to a Desaxe design (can't see it in the text though), the Yamaha MT-09 uses this feature. Cheers Nimbus (Cumulus nimbus floats by)    12:38, 24 March 2016 (UTC)


 * Quincunx is an old (Roman) Latin term for "staggered". As opposed to Quincunx in medieval terms, which had come to mean cross-shaped (of 5 objects).
 * The Chaise was an interesting, although supposedly temperamental, engine. It was another solution to the old problem of "as much power as possible in the smallest space." This involved tricks like closely-set engine barrels (fine, unless you try to use all that power on takeoff and discover there's no cooling without airspeed), narrow angle Vs and most unusually but typically French, an undercut crankshaft.
 * You can work out the rest. Fresh from the factory it was expensive, but effective. Maintenance though was nightmare. A bottom end teardown in particular. Also the valve actuation was poor, with the rocker arm pillars and their unstable shafts getting a particularly bad reputation for getting out of order long before an overhaul was due. They were seen by English engine mechanics as a reason why the French should stick to cookery and by French pilots (I think St Ex. had some pithy comments) on the lines of "I'm not flying across Algeria with one of them".
 * Narrow angle vees BTW aren't too hard to balance, they're no worse than inlines. Andy Dingley (talk) 13:03, 24 March 2016 (UTC)


 * Thanks to your helpful comments, it's much clearer now. Cheers,TSRL (talk) 15:49, 28 March 2016 (UTC)

Propelling nozzle
Hello all,

Something I read on the article Propelling nozzle worries me. The first bullet point of 'Principles of operation' says that nozzles work using the throat to increase pressure by constricting airflow - which runs contrary to the Venturi effect and what is described in this diagram illustrating de Laval nozzles. It also mentions that the nozzle 'back-pressures' the engine; sure it does, but by underexpanding the airflow, not by constricting it. I pointed it out on the talk page, but nobody got back to me. I contacted MilborneOne, but this apparently isn't his area of expertise.

Should I change it?

Regards, Hayazin (talk) 10:07, 31 May 2016 (UTC)


 * It is obviously wrong, so yes please do fix it. - Ahunt (talk) 21:27, 31 May 2016 (UTC)


 * It would good if you could include a suitable inline ref; several sections of the article, including this one, are distinctly short of such.TSRL (talk) 13:40, 1 June 2016 (UTC)

Musée aéronautique et spatial Safran
A number of images taken at this museum have recently been uploaded to Commons, they are predominantly aero engines. There is a French wiki article and I was considering creating an English version, just wanted to check the naming convention. We seem to use the French version with an English translation in parentheses in the lead section. Nimbus (Cumulus nimbus floats by)    14:39, 24 October 2016 (UTC)
 * That will work fine! We should link the English name as a redirect as well. - Ahunt (talk) 15:27, 24 October 2016 (UTC)
 * Good stuff, I see so many pages moved after creation which must be annoying for authors. Nimbus (Cumulus nimbus floats by)    17:10, 24 October 2016 (UTC)
 * Article is now live at Musée aéronautique et spatial Safran. It's a fairly direct translation of the French article, the exhibit sections could be expanded with more engines and photos, the museum page says they have restored at least 85 piston engines so far. There is a translation tool but it didn't work for me (just refused to translate} so I did it manually. There are a lot more French aviation museums that the Av project has not covered yet, another winter job! Cheers.Nimbus (Cumulus nimbus floats by)    10:39, 25 October 2016 (UTC)
 * Thanks for doing that. It could be a long winter! - Ahunt (talk) 13:38, 25 October 2016 (UTC)
 * Ogden's book lists 282 museums, collection and monuments which should occupy you til the clock go forward!TSRL (talk) 14:05, 25 October 2016 (UTC)
 * Yep! In the corresponding Commons category there are engine types on display that don't even appear in company navboxes so we have images but no info (yet). Nimbus (Cumulus nimbus floats by)    13:43, 25 October 2016 (UTC)
 * I was just looking at the wealth of photos there. User:Duch sure took a lot of great photos! - Ahunt (talk) 13:46, 25 October 2016 (UTC)
 * He did, and thankfully took care to identify them. I've been going through other images over there and there are plenty with no articles.Nimbus (Cumulus nimbus floats by)    13:54, 25 October 2016 (UTC)
 * I gave him some WikiWings for his great efforts! - Ahunt (talk) 14:09, 25 October 2016 (UTC)
 * The name seems to have changed since 2009, when Ogden's book was published; he has it as Musée Société Nationale d'Étude et de Construction de Moteurs d'Aviation. Not snappy!TSRL (talk) 14:21, 25 October 2016 (UTC)
 * Tres bon! Is that 282 French museums or worldwide? Nimbus (Cumulus nimbus floats by)    14:23, 25 October 2016 (UT
 * That name spells SNECMA who were the original museum creators. Nimbus (Cumulus nimbus floats by)    14:27, 25 October 2016 (UTC)
 * So it does. All 282 entries are French - bon appetite!TSRL (talk) 14:34, 25 October 2016 (UTC)
 * Oh dear, we're not doing well with only three covered!. Nimbus (Cumulus nimbus floats by)    14:43, 25 October 2016 (UTC)

I'm always surprised how difficult it can be to find out a museum's content from their website. Given that there is a fair amount of exhibit churn, Ogden's book (2009) really needs updating. One good but unstructured source is Air Britain News - useful if you're a member but in that case you'll know that anyway! At least they are fairly up-to-date.TSRL (talk) 15:40, 25 October 2016 (UTC) Sadly, neither of these cover engines. I see the French are ahead of us: they have 13 French museum articles.TSRL (talk) 16:15, 25 October 2016 (UTC)
 * There was a European version of the 'Wrecks and relics' book but I don't think it has been published for a long time, probably wouldn't have included engines anyway. Hey ho! Nimbus (Cumulus nimbus floats by)    16:36, 25 October 2016 (UTC)

Rolls-Royce red links
I've recently acquired a fairly rare book by Bill Gunston chronicling all the Rolls-Royce aero engines up to 1989. Our navbox has a few red links and these types are covered in the book, albeit only briefly. I think there are types in the navbox that are not covered by the book. They all appear to be design studies or possibly bench run engines only.

The question is how best to cover them here? Some unbuilt types get a mention in their related engine article but the remaining ones don't relate to built engines. So...they could have their own stub articles that would probably get Afd'd for notability or they could be grouped together in a section in an overview article that we don't yet have (that would be Rolls-Royce aircraft gas turbine engines). We already have Rolls-Royce aircraft piston engines.

Would appreciate any thoughts. Related is the fact that Spirito Mario Viale was an RR engine designer (led the Pennine team) and he should be added to the navbox if there are no objections. Cheers Nimbus (Cumulus nimbus floats by)    20:14, 9 May 2017 (UTC)


 * If Spirito Mario Viale was a RR designer then he should be added! As far as the not-built projects go, I would suggest a single article on all of them together, just for sake of completeness. - Ahunt (talk) 14:20, 10 May 2017 (UTC)


 * Perhaps a List of Rolls-Royce aircraft engines that could give a brief overview of each and deal with the unbuilt projects. MilborneOne (talk) 16:10, 10 May 2017 (UTC)


 * We already have the main engine list, not sure if a separate list for RR would count as 'listcruft', there was a trimming of various engine lists a few years ago. A single article would work but what to call it? Nimbus (Cumulus nimbus floats by)    18:25, 10 May 2017 (UTC)


 * I was thinking more thank a simple list perhaps something more like Rolls-Royce aero-engine development rather than use the "List". MilborneOne (talk) 19:09, 11 May 2017 (UTC)


 * Yes, a list in prose form. There must be similar situations with unbuilt aircraft designs but I've not seen a single article covering multiple types (from the same manufacturer). They often have their own article which seems to indicate that unbuilt aircraft types are more notable than engine types. I'm sure the answer will come, in the meantime I could put something together in a sandbox. Nimbus (Cumulus nimbus floats by)    21:23, 13 May 2017 (UTC)


 * Here is one I did a few years back that is similar, dealing with a group of designs by a single manufacturer that were not built: Schweizer cargo glider designs - Ahunt (talk) 21:46, 13 May 2017 (UTC)

I can't see an easy way round this, was erring toward an overview article but because of the timeframe (1945-1970) that would involve an even longer title (Rolls-Royce Limited aircraft gas turbine engines). Will perhaps create a couple of stubs and see if they survive. Nimbus (Cumulus nimbus floats by)    12:33, 16 May 2017 (UTC)

Popular pages report
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Salmson 9U
Anyone know anything about this engine, possibly water-cooled? It appears in the Anatra DS article without much cite support and it's not in the water-cooled Salmson article explicitly.TSRL (talk) The table in the Salmson water-cooled engine article suggests it may have been the 9R.TSRL (talk) 20:05, 29 May 2017 (UTC) Think that's the answer, as the 9r is what a cited Russian website says. I've edited the articles accordingly.TSRL (talk) 15:39, 30 May 2017 (UTC)

Kuznetsov
There are two Kuznetsov company articles, Kuznetsov Design Bureau and JSC Kuznetsov. The navbox points to the newer article where many engines in the navbox belong to the older article. I think there is overlap between the two (i.e. the older article has an external link to the current company website). There is one category (Category:Kuznetsov aircraft engines).

No discussion on either talk page so I came here. Do we need two articles? Should we refine the scope of both articles? Should we rearrange the navbox to put the engines in era/company groups? Should we have two navboxes (per Rolls-Royce)? Just a few thoughts, it's difficult to decipher the 'big picture' with some of these Russian companies, who they are, when they were established etc. Russian editors (presumably) have been adding unknown, unlinked manufacturer company abbreviations to the more modern engines recently. Nimbus (Cumulus nimbus floats by)    14:07, 15 November 2017 (UTC)


 * In reading through them it does look like two articles can be justified as the Soviet-era design bureau and the later joint-stock company, but it does seem that some clean-up, coordination and rationalization needs to be done. - Ahunt (talk) 14:11, 15 November 2017 (UTC)


 * I would agree, just noticed that the newer article engine list is a duplicate of the older. From their website it seems the newer company was established around 2008/2009. Would the answer with the navbox be to unlink the manufacturer in the title but link the two in groups? Nimbus (Cumulus nimbus floats by)    14:25, 15 November 2017 (UTC)


 * That makes sense to me, plus make sure that the engine lists in the articles match the timeframe of the right manufacturer, to deconflict them. - Ahunt (talk) 14:34, 15 November 2017 (UTC)


 * It seems the new company is only maintaining (possibly building?) the original engines. There will be (may be?) a new build version of the Kuznetsov NK-32. I'll have a look at how some of the other language wikis are dealing with it. Nimbus (Cumulus nimbus floats by)    14:52, 15 November 2017 (UTC)


 * Cases like that do pose problems. I would say if the new company is building engines from the old design bureau (not just maintaining them) then the engine should be listed in both articles. - Ahunt (talk) 14:56, 15 November 2017 (UTC)


 * Yes, it's tricky. Russian WP has both articles, the newer one is quite thin with a brief history and the product section has a photo of a rocket engine (NK-33?). I suppose another way of dealing with the navbox is a 'see also; line which some of ours have. Nimbus (Cumulus nimbus floats by)    15:01, 15 November 2017 (UTC)


 * The NK-33 is an old Kuznetsov rocket engine design but it's still being developed and in production. Nimbus (Cumulus nimbus floats by)    15:06, 15 November 2017 (UTC)


 * I think the easy way to deal with Template:Kuznetsov aeroengines is to just add a "companies" section to it and leave the rest more or less intact. - Ahunt (talk) 15:36, 15 November 2017 (UTC)

I'll touch nothing at the moment, the key is the United Engine Corporation which has mopped up nearly all the old engine companies. There have been other changes going on recently, NPO Saturn is now UEC Saturn. Other articles like Shvetsov and Soloviev have either become redirects or were merged which wasn't necessarily the best way to do things. We either keep up or give up!!! All good fun. Nimbus (Cumulus nimbus floats by)    16:01, 15 November 2017 (UTC)

Russian designation navbox?
More Russian stuff! I have wondered about creating a navbox for the Russian M series of engines (Shvetsov M-11 etc), I remembered that the Russian wiki has had something like this for a while (includes all Russian engines) and spotted that there is an Italian version of it (far easier to translate). I think we've been left behind on this one. Just checking before I go ahead and create one that there are no objections, I think it would be very useful myself. Cheers. Nimbus (Cumulus nimbus floats by)    15:27, 11 December 2017 (UTC)


 * Looking further this big navbox would duplicate our smaller manufacturer navboxes if used but the M series we don't have a navbox for. Nimbus (Cumulus nimbus floats by)    15:31, 11 December 2017 (UTC)


 * There are a random mixture of RD designated aircraft engines and rocket motors in this template: Template:Russian and Soviet military designation sequences which could be removed if incorporated in a dedicated engine template.Nimbus (Cumulus nimbus floats by)    15:36, 11 December 2017 (UTC)


 * I think the air breathing engines in that template are not supposed to be in there, outside of the scope of 'radar, missile and rocket systems'. Nimbus (Cumulus nimbus floats by)    15:41, 11 December 2017 (UTC)


 * It looks like a worthwhile project, might help readers find related articles, so I would say go ahead and create it and let's see how well we can make it work! - Ahunt (talk) 16:36, 11 December 2017 (UTC)


 * Good, I'll get on it. I have Kotelnikov's piston engine book which lists them. Nimbus (Cumulus nimbus floats by)    16:45, 11 December 2017 (UTC)


 * Super! Drop a note here when you get it done and we can all have a look at it. - Ahunt (talk) 17:35, 11 December 2017 (UTC)


 * It won't be a five minute job, they used some of the designations twice! Also some odd anachronistic entries (an M-1 in WWII for instance). It will be useful I'm sure, will get it up to a point where there aren't too many redlinks then make it live. Nimbus (Cumulus nimbus floats by)    18:13, 11 December 2017 (UTC)

Jet engine merge proposal
Hi, there is a proposal here to merge Airbreathing jet engine into Jet engine. The discussion is getting a bit bogged down, so more votes would be appreciated. &mdash; Cheers, Steelpillow (Talk) 16:59, 12 July 2018 (UTC)

Please help identify a problematic radial engine from an Indian museum.
( uploader of these images.)

I've come to my wits' end trying to figure this one out.

The following photos all show the same 9-cylinder radial engine located at the Birla Industrial & Technological Museum in Kolkata, India:

The file names come from the exhibit's current placard, visible in the two 2012 photos, "220 HP 9-Cylinder Continental Rotary Aero Engine". Obviously this engine is a stationary radial, not a rotary, and I got that corrected in most of the filenames. (I missed the last one because it wasn't in an engine category to start with.) "9-cylinder" is correct, as can be seen by counting, but the identification as a Continental is probably wrong, and I have no idea whether the power is correct. Most of these images were initially categorized as a Continental R-670, but that's obviously wrong because the engine has 9 cylinders, not 7. Since Continental also made versions of the 9-cylinder Wright R-975, I assumed it was that at first, but a comparison with R-975s shows that the valve pushrods (most of which have been removed, but a couple are still in place at the top) are in the wrong position: they are in front of the cylinders, whereas the R-975 had them behind the cylinders. Unfortunately, no data plate or manufacturers' label is visible, and size is hard to determine, so all I could think to do was to compare details of construction with other candidates. I've tried comparing with Commons images of all other U.S.-built 9-cylinder radials I know of: the Lycoming R-680, the Pratt & Whitney R-985, R-1340, R-1690, and R-1860, and the Wright R-1820. Each time I've come up dry, but it's possible that I just haven't found the proper versions to compare with. British radials don't seem to match either. Hence my plea. --Colin Douglas Howell (talk) 19:07, 17 October 2018 (UTC)


 * All good fun! It's quite a large engine, the schoolgirls give scale. Its design follows Pratt & Whitney, Continental license-built their engines (but not Wright engines apparently). It appears to be supercharged and would produce much more than 220 hp. The displacement of the R-1340 is 22 litres (220 hp?). In one of the images there is a placard on the wall that says Wright engine! I'll keep looking. Nimbus (Cumulus nimbus floats by)  22:48, 17 October 2018 (UTC)

10th anniversary
Tomorrow (11th December) is the 10th anniversary of the formation of this task force, the number of articles within its scope has also just nudged over 2,000. Many mysteries have been solved and others created! Work now seems to be mostly on maintenance and improvement, better images are available on Commons (10 years worth of uploads) but they are not necessarily easy to find. Cheers and Merry Christmas/Happy Holidays. Nimbus (Cumulus nimbus floats by)  13:50, 10 December 2018 (UTC)
 * - Ahunt (talk) 14:12, 10 December 2018 (UTC)

Commons categories
A user is adding engine type powered aircraft categories to engines over at Commons, The Walter Pollux is an example. I think they are misguided. Would appreciate thoughts before I wade in and delete them (no point discussing at Commons, it's full of tumble weeds!). Nimbus (Cumulus nimbus floats by)  22:30, 29 January 2019 (UTC)
 * I agree, that is going to create a big mess over there and, to the point, it is not going to help the readers sort things out. - Ahunt (talk) 14:04, 30 January 2019 (UTC)
 * Categories of "Aircraft powered by ..." would be just about supportable, but not a great deal of use. Placing them within the engine type category itself - unless the engine depended on that aircraft in some way (i..e SSME) - no. Andy Dingley (talk) 14:20, 30 January 2019 (UTC)
 * I think they've realised it's not right and have self-reverted. I just cleared the Walter Pollux category. Nimbus (Cumulus nimbus floats by)  17:49, 30 January 2019 (UTC)
 * Oh good! - Ahunt (talk) 18:31, 30 January 2019 (UTC)
 * Mmmm, it's quite messy actually. Same user has been creating new categories that don't follow convention and all words are capitalised, by removing the original category to empty it the original categories are getting deleted. I am trying to sort it out, hopefully it is just the Walter engines. Nimbus (Cumulus nimbus floats by)  19:19, 30 January 2019 (UTC)
 * I am not sure Commons can get any more disorganized. It seems to have reached peak entropy. - Ahunt (talk) 19:26, 30 January 2019 (UTC)
 * It is hard work over there. Whoever the deleting admin is they are not looking at what is really going on. I think I've fixed the Walter piston engines, the parent category has been capitalised since creation, not quite right but will probably leave it. User is an ex-Motorlet employee apparently, they are having trouble proving copyright for a lot of images uploaded. Nimbus (Cumulus nimbus floats by)  19:41, 30 January 2019 (UTC)
 * I have been running into admin issues over there too. Some are very aggressive on copyright vios, while others seem to write obvious copyright vios off as "de mininimis". Need a copyright lawyer as that is all buried in US case law. Working on Commons is quite disheartening, really. I would be happy if we could get around them filing aircraft photos under their registrations, as it makes it so hard to find good images for use here. - Ahunt (talk) 19:47, 30 January 2019 (UTC)
 * The individual registration categories can often mean that there are no images at all in the parent category, just links to registrations. One way round the difficulty of finding the best images or view all of them would be to have a duplicate image in the parent category but not sure that change would be recommended. Nimbus (Cumulus nimbus floats by)  20:30, 30 January 2019 (UTC)
 * I did think of that, too. It would make our job here much easier! - Ahunt (talk) 03:41, 31 January 2019 (UTC)
 * Rather than having a duplicate image, which would create the problem of keeping the two files in sync, I think it would be better to declare a special-case exception to the Commons over-categorization policy and require images of non-notable aircraft categorized by registration to also require other, more visually significant parent categories, such as aircraft type and/or user. One argument further supporting this is that, although military aircraft serial numbers tend to be permanent and unique, civil aircraft registrations are not: the same registration may be sequentially reassigned to multiple aircraft of different types. --Colin Douglas Howell (talk) 05:38, 31 January 2019 (UTC)
 * The main problem at Commons is that it has developed with virtually no leadership or consensus ways of doing things, there is an aviation project of sorts over there but I'm not even sure if it's still running. I check this page frequently for new engine images being uploaded, it runs from January 2015 and has never been split into handy size chunks (years/months), bonkers! Even if things were organised there would still be editors wanting to do it 'their way' exactly as it is here. It is true that American civil registrations can be reused but in the UK they are not, aircraft can be re-registered at a cost for 'personal plates' if the letters are available i.e. G-FRED, G-SEXY etc., the original registration can't be used even though it has been freed up. Nimbus (Cumulus nimbus floats by)  06:28, 31 January 2019 (UTC)

Bypass duct AFD and sources
Bypass duct currently have no sources. I think it should be merged or deleted and thus raised an AFD request Articles for deletion/Bypass duct --Tyw7 (🗣️ Talk) — If (reply) then (ping me) 10:16, 24 April 2019 (UTC)

Discussion on notability of Aluminum internal combustion engine on the reliable sources noticeboard
There is a discussion on the notability of the Aluminum internal combustion engine on the reliable sources noticeboard. The discussion involves the reliability of Russian news sources, including TASS. If you're interested, please participate at. —  Newslinger  talk   06:02, 10 June 2019 (UTC)

Template:Jetspecs - units of measurement.
The template page Template:Jetspecs states: ''For American and British designs, the format is imperial (metric). For all others, it is metric (imperial).''

Is this sensible advice? I can't help feeling that it should be changed a bit. At least to:

''For older American and British designs, the format is imperial (metric). For all others, it is metric (imperial).''

I'd prefer to see reference to SI rather than the somewhat vague term metric.

There is also the point that US engineers historically used what we now call US customary units which differ from imperial standards in various ways including screw threads and fluid measures.

Certainly all aircraft designers these days use SI units and have done for some decades. I'm not sure about the USA, but I suspect UK aircraft design work has been done pretty much entirely in SI from some time in the 1960s for all that imperial units, thread standards, and so on had to be used for supporting older designs.

There is also the anomalous case of Concorde, which was designed entirely using SI units but gave fluid capacity specifications (e.g., for oil, hydraulic fluid, and so on) in US fluid measures (not imperial) in an attempt to improve its attraction to US buyers (the point is mentioned in the Concorde Haynes manual: I can give a precise reference and quote if anyone's interested).

I've had a look. British science has been largely metric since the start of the 20th century according to

Also from the same page:


 * 1965: In February, the President of the Federation of British Industries (now the CBI) tells Ministers that the majority of its members are in favour of the adoption of metric as the primary measurement system.


 * 1969: Examinations for students starting higher education courses in science, engineering or technology are set in SI units.


 * 1971: Decimal currency is introduced on 15 February. All examinations conducted under the auspices of the Council of Engineering Institutions are in SI units.

The UK has been working in SI units in education and engineering pretty much entirely from some time in the 1970s as far as I can tell. Even ancient crumblies like my 1930s born dad can think in SI when they have to and anyone under the age of 50-55 ish has been brought up using metric (for all that some of us of around that vintage still think in feet and inches and stones and pounds when it comes to measuring people. And yes I have noticed we still do beer and milk in pints and roads in miles).

I'm not at all sure that there are many British designed and made complete aircraft in current production.

But: Rolls Royce is still British and has been making SI-designed aero engines for decades, and aircraft components are still made in the UK such as Airbus wings at Broughton and all that's done in SI units.

Anyone got any thoughts?

Michael F 1967 (talk) 17:45, 10 August 2019 (UTC)


 * US and Canadian aircraft are still designed and built using US customary measures (imperial) even today. If you check a typical current production US aircraft, like the Cessna 172 you will see all the measures given in imperial (metric). - Ahunt (talk) 18:00, 10 August 2019 (UTC)


 * The units used for specifications in marketing material tell you nothing at all about the units used by the engineers who designed the aircraft - although such information is a useful guide as to how to express units in specification lists on Wikipedia.


 * As I understand it, Canada's been mostly metric for quite a long time although obviously has to deal with the not-entirely-metric USA rather more than most.


 * I do assume that some aircraft being built at the moment are built using non-SI units at least in part since some aircraft are updated versions of decades-old designs - that Cessna 172 is a case in point, dating back to 1955. But I am certain that new designs are all done in SI. Consider: the aviation industry is global. Boeing buys stuff from Europe; Airbus buys stuff from the USA. Once you start doing that, SI is the only sensible way to go and has been for decades.


 * I'd bet a reasonable sum, for example, that a modern Cessna 172 has a cockpit instrument panel which is laid out in SI and uses metric thread standards for fastening the instruments in place, since modern instrumentation is (as far as I know) all designed in SI and uses metric thread standards. However, the instrument panel might well be sized to fit airframe mounting points still specified in inches, given the age of the aircraft design.


 * If you're selling an aircraft like that outside the USA, it might be awkward if the nuts and bolts accessed during servicing weren't metric so they might have been changed. Then again, aircraft servicing is generally done with manufacturer supplied parts.


 * Any actual experts out there?


 * The O-360 engine used is also a very old design and so also might still be made in US customary units. But I'm still pretty certain that no-one's coming up with fresh aviation engineering in anything but SI.


 * Please note that US customary measures are distinct from imperial units. Michael F 1967 (talk) 18:31, 10 August 2019 (UTC)


 * Just running though the parts catalogues for the Continental and Lycoming aircraft engines and they are all in inches, old and new models. On the other hand Rotax engines, being European, are all metric. Check them yourself. - Ahunt (talk) 19:20, 10 August 2019 (UTC)


 * This is all rather getting a long way away from the point - which is about the advice given on using Template:Jetspecs so the piston engines you're referring to aren't relevant in any case.


 * Yes, old aviation engineering from the USA was always done using US customary units and so designs from the days before metrication are still made in US customary units - such as those piston engines you've linked to. After all, once you've got your design in production with jigs, tooling, supply chains, and all that, if you want to change things to metric, that's a really huge effort which will also require all the new parts and engines and so on to be re-tested, re-qualified, and re-certified for no obvious reason. Those engines you linked to - as far as I can tell - are all developments of designs from the pre-metric era so you'd expect them to adhere to pre-metric units, standards, and so on. After all, you don't want to have to completely re-work the entire design and replace all your tooling (while requiring the same of your suppliers) just because you've developed your engine a little.


 * I'm sure that you'll find that all modern US gas turbine aero engine designs - that is, fresh designs not developed from engineering that was done in the days when metric simply wasn't used - are done entirely in metric.


 * But back to my original query: the text guiding the use of the Template:Jetspecs says that US and British designs should have their units given first in imperial and then in metric.


 * I think that this should be changed given that only older jet engine designs were produced using imperial (UK and Commonwealth) and US customary units (USA and maybe Canada in some cases).


 * This link to a US museum on-line catalogue shows a Rolls-Royce engine with specifications provided in metric with US customary units following in brackets. RB-211 Smithsonian


 * RB-211 brochure doesn't provide much in the way of tech specs, but does give information in metric and then in US units. The spelling indicates that it's intended for a non-UK audience.


 * RB-211 project mentions that a Rolls-Royce RB211 engine which seems to have come from a Lockheed Tristar, is equipped with 1 inch UNF mounting bolts which the bloke doing the restoration describes as "non-standard" (by which he means "you don't find threads to that standard over here"). UNF is defined by the Unified Thread Standard (UTS) which as far as I know has never much been used outside the US and Canada, and not one which Rolls-Royce would have used unless there had been a reason: in this case, I assume it was to match the thread standards used on the Tristar - a US aircraft designed in the 1960s (first flight 1970), which was before metrication began in US engineering.


 * Apparently, UK industry began the switch from traditional UK thread standards to metric in the 1960s. UK metrication


 * According to Screw_thread, with respect to UTS: In the U.S., where UTS is still prevalent, over 40% of products contain at least some ISO metric screw threads. The UK has completely abandoned its commitment to UTS in favour of ISO metric threads, and Canada is in between. Globalization of industries produces market pressure in favor of phasing out minority standards. A good example is the automotive industry; U.S. auto parts factories long ago developed the ability to conform to the ISO standards, and today very few parts for new cars retain inch-based sizes, regardless of being made in the U.S.


 * None of this really gets us anywhere: I'd expect US engineering in the 1960s to be generally done in US customary units and according to US thread standards and so on. But the point is, here and now, what should the advice for the use of Template:Jetspecs be?


 * Currently, it states: For American and British designs, the format is imperial (metric). For all others, it is metric (imperial).


 * I think it should read more like: For older American and British designs, the format is imperial (metric). For all others, it is metric (imperial).


 * But what to do about the facts that in the case of the USA, the system of units was (and still is, when used) US customary units, not imperial. Also, what about Canada and Australia (which did make aircraft in the days before they went metric): surely they should be mentioned?


 * A suitable formulation might be more like For older American, British, and Commonwealth designs, the format is imperial (metric). For all others, it is metric (imperial).


 * How about it? Michael F 1967 (talk) 19:09, 11 August 2019 (UTC)


 * I recognize that this talk page deals with jet engine specs, but you commenced by discussing aircraft in general, which is why I brought up aircraft examples and piston engines. Sure today most British jet engines are mostly metric. But I think I have adequately illustrated though example that current production US aircraft (airframes) and current production piston engines are designed, produced and sold in US units (ie inches). So let's look at current production US jet engines, since you have not actually given any examples of those to back up your claim that these must all be metric today. It only takes one example to prove you wrong. Here is the first one I looked up, the General Electric GEnx, first run in 2006 and which currently is produced for the Boeing 787 and Boeing 747-8. GE doesn't make the parts or maintenance manuals public, but you can note the official company specs page is in inches only (no metric at all). All the information I have provided supports that the current project parameters for US engines are in fact justified and correct. - Ahunt (talk) 13:00, 12 August 2019 (UTC)


 * You've provided no information about the units used for designing and producing current US aero engine designs. The fact that US piston engines (and maybe US light aircraft designs) dating back to the 1950s are still made in US customary units is irrelevant.  Likewise, the units provided by GE on a marketing page intended solely for a US audience doesn't tell you what the units used for the engineering design and production are.  And yes, it has to be intended for a purely US audience because it's the only country in the world which still makes widespread use of non-SI units.  Everyone else expects SI - if GE wanted non-Americans to understand that page, they'd've provided conversions to SI units.  Even here in the UK, hardly anyone much younger than about 50 understands anything but metric.


 * (I did a bit of secondary level maths and science teaching about 20 years ago here in the UK. The curriculum required the students to learn about imperial units. Many of them complained because they had no idea about feet and inches and so on and couldn't see the point.)


 * You're right that I've not found any specific information to back up my claim that all modern aero engine designs are fully metric - I've looked, and I can't find anything on-line to do so.


 * On the other hand, you've provided no information indicating that modern US aero engine designs are NOT done in metric.


 * It's worth bearing the following point in mind. Metrication Timeline states, regarding the year 2000:


 * 2000 In the USA, the automotive, pharmacy, earth moving machinery, refrigeration, electronics hardware, IEEE standards, University and Olympic sports, military training and operations, highway construction, federal building construction, nutritionists and many others have changed to a metric system, or to SI. However, this was often 'hidden metric' in that the fact that they operated in metric units was hidden from their suppliers and their customers.


 * So that's a reference stating that about two decades ago, an awful lot of US sectors had switched to SI - but hid the fact by using US customary units externally. I realise that aero engine design isn't explicitly mentioned, but many others is. And I cited a source above stating that in the US, very few parts for new cars retain inch-based sizes.


 * Bearing all that in mind, I think it's unreasonable to assume that recent US gas turbine aero engines aren't designed with SI parameters.


 * Think a little more. I have provided sources which indicate that UK engineering firms were switching to metric in the 1960s - more than half a century ago. Do you really think that any of them haven't made a full transition?  And do you really think that given the global nature of the aviation business that US firms wouldn't have followed suit and switched to metric for all new aero engine designs?  Seriously?  Do you really think the US aviation industry wants to isolate itself by not going along with the other 96% of the world?


 * Bear in mind the above referenced statement that an awful lot of the US had switched to working in metric twenty years ago, but made a point of hiding the fact by continuing to use US customary units for outward facing purposes.


 * By the way, I see no reason to think that it is the case that today most British jet engines are mostly metric.


 * To my mind, it seems far more reasonable to assume that all the engineering inside all recently designed gas turbine aero engines - British (I think they're actually more like British/German, British/US, British/French, and so on), US, Russian, Chinese, all of them - is entirely metric and has been for decades. The example of the RB211 I cited above using UNF threads refers to the mounting bolts provided to connect the engine to a 1960s US aircraft (or support frame when taken off the aircraft).


 * But all that is perhaps besides the point. What units should be used in Template:Jetspecs? There is a possible argument for using US customary units for recent US designs if that is what is expected by a US audience (analogous to the convention of using US spelling for US topics) - arguing that it's because the engineering is done in US customary units doesn't make sense to me because without evidence, I don't think it's reasonable to make that assumption these days.


 * Then again, how do younger Americans think? I've been watching Odd Squad recently and when measurement units are used, they're always purely SI. I gather it's aired in the USA.


 * So, the current wording is this: All parameters should be written in both imperial units and metric units. For American and British designs, the format is imperial (metric). For all others, it is metric (imperial).


 * I think it should read more like this: All parameters should be provided in both SI units and imperial (or US customary) units using the convert template. The primary units should be SI in general. For older US, British, and Commonwealth designs, US customary units or imperial units should be used.


 * BUT! perhaps a note could be added regarding modern American designs? Along the lines of For modern US designs, use your judgement?  I know that's not very good, but: it does seem that there is a current convention in the USA to use US customary units for general consumption (although I have provided a counter-example from the Smithsonian, above); then again, one of these days even the US will be rather more metric than non-metric. Michael F 1967 (talk) 18:55, 12 August 2019 (UTC)


 * We have a lot of discussions about si first or imperial in different parts of wikipedia but at the end of the day the reader can easily work out whats going on when both are presented (and I suspect they dont care which order they are in). My only support for one or the other really depends on the source of the information, which comes first should relate to the source. You get stupid examples where the first figure is rounded up so you 304.8 m when it is fairly obvious the imperial figure is the source. I would not worry about it, do what is sensible for the article and nobody except the purists and nationalists will get excited, the reader is clever enough to work it out. MilborneOne (talk) 19:10, 12 August 2019 (UTC)
 * I am good with that approach. - Ahunt (talk) 19:13, 12 August 2019 (UTC)


 * It's a sensible approach from one point of view. One problem is that imperial units and US customary units are not the same.


 * The main thing is that currently we have advice on Template:Jetspecs which states: All parameters should be written in both imperial units and metric units. For American and British designs, the format is imperial (metric). For all others, it is metric (imperial).


 * That does not align with the recently suggested approach and glosses over the imperial/US customary difference. Also, I suffer pains when I see units like kiloponds being used. Yes, I checked, it was in the cited source - but argh!  Who on Earth knows what they are these days?


 * Anyway, I'm suggesting that the advice given needs changing. The question is what should it be changed to?


 * And by the way, if fussy people like me weren't 'purists' about units of measurement, far more aeroplanes would drop out of the sky, bridges collapse, space probes crash, and so on. I don't see that nationalism could have any bearing on matters, but then again what would I know?


 * More relevant to Wikipedia: advice needs to be clear for this sort of thing or you'll get people messing things up. I only ended up looking at this due to the activities of User_talk:Petebutt. I don't know that all the thrust/weight ratio entries incorrectly given units were due to him, but I've corrected quite a lot. Well over a hundred.


 * So I'm suggesting that to reduce the incidence of future problems, it would make sense to change the advice on Template:Jetspecs. What to, is the only real issue.  I've made a definite suggestion.  Does anyone else have a better idea? Michael F 1967 (talk) 19:41, 12 August 2019 (UTC)


 * The simplest that would also conform to what MB1 said above, would be All parameters should be written in both imperial units and metric units. Which system of measure comes first should be in accordance with the ref cited for the specs. - Ahunt (talk) 19:57, 12 August 2019 (UTC)


 * That makes sense. Simple is good. I have one reservation: the primary system of units as listed in an article is not necessarily best given by the reference. A case in point would be the Fieseler Fi 103R where the specs in English-speaking publications tend to be given in non-SI units, but those were obviously not the units in which it was designed (granted, SI units as such weren't called that until 1960, but never mind).


 * All parameters should be written in both SI units and imperial/US customary units. - yes, but note that SI should be mentioned first since it's the primary system of measurement these days and metric is a bit too woolly a term (I should have picked up on that earlier).


 * Then perhaps add: The parameters should be entered in the units provided by the reference, converted as needed using the convert template. Use order=flip to place the most appropriate system of units first when needed, and sigfig=N to ensure appropriate precision when needed.


 * (I've just corrected a conversion of a landing speed which specified - explicitly - 9 digits after the decimal point as the precision to use)


 * I think maybe leave it at that. I think it's best to leave it up to the judgement of the editor as to which system of units should be placed first. That allows for evolution over time without proscription from the past leading to silliness in future.


 * Any thoughts? Michael F 1967 (talk) 20:01, 19 August 2019 (UTC)


 * That probably makes the greatest sense. - Ahunt (talk) 20:07, 19 August 2019 (UTC)

Walter Mars
Hi all, could someone have a look at Walter Mars please, I have no time at the moment. Recent edits have deleted the specification section completely and added bare Wikipedia URLs. Confusion seems to have set in when incorrect specs were added. Cheers Nimbus (Cumulus nimbus floats by)  19:27, 27 September 2019 (UTC)


 * Thanks, I've managed to clear the confusion hopefully, the IP was right but as a newcomer didn't know how to fix it properly. The source used in the CZ article is this online archive which looks similar to the Flight archive, there's probably much more useful info in there (if you can read cz!). Nimbus (Cumulus nimbus floats by)  06:16, 30 September 2019 (UTC)

Request for information on WP1.0 web tool
Hello and greetings from the maintainers of the WP 1.0 Bot! As you may or may not know, we are currently involved in an overhaul of the bot, in order to make it more modern and maintainable. As part of this process, we will be rewriting the web tool that is part of the project. You might have noticed this tool if you click through the links on the project assessment summary tables.

We'd like to collect information on how the current tool is used by....you! How do you yourself and the other maintainers of your project use the web tool? Which of its features do you need? How frequently do you use these features? And what features is the tool missing that would be useful to you? We have collected all of these questions at this Google form where you can leave your response. Walkerma (talk) 04:23, 27 October 2019 (UTC)

Safran EngineUS for deletion
Hello project members. I recently created Safran EngineUS, an electric engine family comparable to the Siemens SP90G/SP260D or MagniX. The article was proposed for speedy deletion. If you think it does not deserve it, feel free to add your voice in its talk page.--Marc Lacoste (talk) 17:48, 29 October 2019 (UTC)