Talk:Rolls-Royce Merlin/Archive 2

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Missing Application

There is no mention in the applications of the Merlin-powered Canadair DC-4M North Star, a variant of the Douglas DC-4 with certain DC-6 features, of which 71 were built under license by Canadair in Montreal in the late 1940s/early 1950s. One of the original customers, British Overseas Airways Corp. (BOAC) called it "Argonaut". Please see the Wikipedia entry "Canadair North Star" for more details. As a rare civil use for the Merlin, it should be mentioned.Viscount724 (talk) 03:58, 12 March 2009 (UTC)[reply]

As far as I can tell, it was just an oversight. Thanks for mentioning it, but it's OK if you add it yourself next time, in a similar case. But there's nothing wrong with getting another opinin first either. - BillCJ (talk) 04:31, 12 March 2009 (UTC)[reply]

A few things

I have been on the engine articles all day so excuse me if I am a bit crabby/short. I've archived six years of this talk page, hope you don't mind. This is a very high profile engine article, if not the highest. I would like to see it reach FA status eventually, we don't have a single GA aircraft engine article yet, but we are getting there! ;-).

A few things bother me in this article:

Duplicated specification section - Non project standard, the variant section should outline the differences between the early and late marks.
The 'mass flow' bit does not seem directly connected to the Merlin, the section is repeated verbatim in the Rolls-Royce Griffon article, it's a quote but is not formatted as such.
Variants - We now have text and a table, neither necessarily complete, one or the other?
Still some American spelling/word variations lingering, nowt against the 'Yanks', just has to adhere to WP:ENGVAR to pass higher scrutiny.

Editors may or may not be aware that there is an engine task force now and we have been steadily evolving guidelines and improving engine articles at the same time, the talk page is at WT:AETF, no edit warring, just constructive 'banter'! Very willing to put time into this article as long as there are no objections to the eventual aim. Cheers Nimbus (Cumulus nimbus floats by) 00:29, 5 August 2009 (UTC)[reply]

Changed the Lovesey quote to a quote and specified that the lecture and article was about the Merlin. Does that look better? Minorhistorian (talk) 22:51, 5 August 2009 (UTC)[reply]

Sorry, yes! I meant to say so last night. Only yourself replied to my comments so I understand that there won't be any objections to a clean up/improvement campaign. Needs some time and thought spending on it, will try to make a concerted effort soon. I spent roughly six hours each on two other British engines recently just to get them up to B class. Nimbus (Cumulus nimbus floats by) 23:46, 6 August 2009 (UTC)[reply]

Just noticed that there is very little on the actual technical description of the Merlin i.e. how it was constructed, internal workings etc, the article seems to assume prior knowledge of the preceding types like the Kestrel. The variants section is a bit messy, can I suggest that we split this to List of Rolls-Royce Merlin variants where we can make it as complete as possible if desired. I would leave some of the variant text behind and mention that it is a summary of representative variants (which it almost does). There are odd snippets of text in the article that are not directly related to the Merlin, maybe of passing interest but they should be trimmed out as 'padding'. For 'Good article' and above it is recommended that the lead has four paragraphs. Nimbus (Cumulus nimbus floats by) 10:08, 14 August 2009 (UTC)[reply]

Yep, definitely. The Lovesey article provides some good technical detail, particularly when describing some of the later modifications made internally.Minorhistorian (talk) 23:09, 14 August 2009 (UTC)[reply]

Who said that (unsigned)?!! Before we look at adding stuff there are other problems. The timeline in the first 'History' paragraph doesn't make sense, the Peregrine and Vulture first ran three to four years after the PV-12/Merlin. I doubt whether RR had settled on anything but they certainly persisted with the V-12 line. Nimbus (Cumulus nimbus floats by) 10:54, 14 August 2009 (UTC)[reply]

'Upgrade' seems to be a modern word (trying to capture the atmosphere of this engine and the period), in the Packard section it says 'checked out'! I think there is a missing sub-section on production which the Packard bit could go into although it could also be considered a variant. Nimbus (Cumulus nimbus floats by) 11:07, 14 August 2009 (UTC)[reply]

I signed but for some reason it failed to register (my name shows under history). Anyway there is a lot wrong with the article, including the timeline and a lack of technical detail. My time here will be limited for the next couple of weeks, when I will have a mid-semester break. Right now my priority is to complete a 3,000 word essay...Minorhistorian (talk) 23:09, 14 August 2009 (UTC)[reply]

B class checklist

Have completed a partial B class checklist (which makes it C class I notice), still needs some inline cites in places. To polish we need to look at the following areas (IMHO of course!):

Possible more detailed added section on technical description
First paragraph of 'Origin' section, timeline/relevancy problem. Done
Production - Expand if possible Done
Variants - Split off to 'List of' article Done

I think its getting there. Nimbus (Cumulus nimbus floats by) 14:37, 14 August 2009 (UTC)[reply]

I have split the variants section off to a new article, it all hinges on the 'origin' section now because the timeline and inferences are very wrong. I'm quite happy with the lead now, the King Arthur bit is not mentioned elsewhere in the article, needs a ref. I did read recently that the British public thought this was the link at the time, not knowing the RR naming convention but I can't find it again. Nimbus (Cumulus nimbus floats by) 00:23, 20 August 2009 (UTC)[reply]

PS Note: Apparently the King Arthur connection myth partly comes from the film The First of the Few where an actor says this is where the name comes from, acknowledged as a mistake/dramatism etc. Must watch that again, no 'pop culture' section here yet thankfully!

GA review (see here for criteria)

A review based on the 'Good article' criteria

It is reasonably well written.
a (prose): b (MoS):
It is factually accurate and verifiable.
a (references): b (citations to reliable sources): c (OR):
Spitfireperformance.com appears to be offline, the refs could probably be replaced
It is broad in its coverage.
a (major aspects): b (focused):
It follows the neutral point of view policy.
Fair representation without bias:
I believe so
It is stable.
No edit wars, etc.:
Article is generally stable barring recent improvement work
It is illustrated by images, where possible and appropriate.
a (images are tagged and non-free images have fair use rationales): b (appropriate use with suitable captions):
Infobox image is repeated although the second version has useful component labelling
Overall:
Pass/Fail:
Should nominate for featured article

On the basis of this I will complete the B class check list and will think about nominating the article for independent GA/FA review. Cheers Nimbus (Cumulus nimbus floats by) 15:30, 20 August 2009 (UTC)[reply]

Berger and Street

If Kurfurst wants to add this information he can provide some page numbers as well, otherwise the informtion is unverifiable. Minorhistorian (talk) 10:03, 20 August 2009 (UTC)[reply]

All I can say is that this is very frustrating and not at all helpful given the aim I am trying to achieve and the work I have been putting in recently, why would an editor add citation tags when they apparently have access to the reference source? I have similar references for the use of 100/150 fuel but they obviously do not support the specific dates etc. Although the fuel grade was a significant development step that section is starting to unbalance the article if not already, the last paragraph for instance does not seem directly related to the Merlin. I realise that this is spillover from the perpetual Spitfire/Bf 109 'which one was best' debate, personally I don't care which one was best, all I would like to see here is a neutral concise article that can be presented for Featured Article review sometime in the near future hopefully. Nimbus (Cumulus nimbus floats by) 18:56, 20 August 2009 (UTC)[reply]

First it must be stated that this is no new addition to the article, [you have recently removed the cite from Berger http://en.wikipedia.org/w/index.php?title=Rolls-Royce_Merlin&diff=306501272&oldid=306499134]. The cite was added almost a year ago, and back then you seemed to have no problems with it or considered it unverifiable. At that time, the page number (page 199) was also included in the reference. I have no idea where it got lost in the meantime - probably during formatting the refs. Since as I see you problem with this cite revolved around the lack of page number (in any case, it would have been wiser to tag it with 'page needed' rather than deleting it), and it can be provided, moreover it also gives dates and is properly referenced, I suppose you have now no trouble about its (re)inclusion? This at the same time also provides a reliable secondary source for the currently unsourced statements which you considered unverifiable because this lack of page number; unfortunately, both Price and Shacklady are very thin on this subject in their books, and I could not find suitable references there but for the anti diver use of this fuel.

The full quote goes as: "he noted [in his day's (apr 20 '45) operational summary]as well that two pilots had walked away-"more or less"-with only slight injuries from wrecked and flaming aircraft at B 116 [note: Wunstorf, Germany]. actually, it was a miracle either man survived. flying officer F R Dennison of 411(sqn)-a Grizzly Bear from Buffalo, NY-crashed while taking off and broke his back. later in the day, flt leiutenant E B Mossing of 401(sqd), who also had his engine cut during take off, scraped his spitfire's belly tank over an obstacle and came down so hard the impact ripped it's wings off, broke the fuselage at the instrument panel and left what remained of the aircraft a mass of flames-yet Mossing "extricated himself with one bone broken in his leg" the incidents followed a number of engine problems that were attributed to the introduction of 150-grade fuel in early feb. pilots mistrusted it, and were no doubt relieved when the AF brass decided to revert to 130-grade. "the vast majority of pilots, im sure, were beginning to wonder if the additional seven pounds of boost they got from 150-grade fuel were worth the price being paid." the matter was being dicussed at Wunstorf when, incredibly, a spark at the petrol dump ignited and two petrol bowsers containing almost two thousand gallons of the much-despised fuel burst into flames." Kurfürst (talk) 19:21, 20 August 2009 (UTC)[reply]

I should note that 'you' in the above post refers to Minorhistorian, I further note that there seems to be little acknowledgment that this issue may be damaging the article's chances at review. Nimbus (Cumulus nimbus floats by) 19:37, 20 August 2009 (UTC)[reply]

Can I suggest that this 'fuel section' is worked on in a sandbox until an amicably agreed version can be found? Nimbus (Cumulus nimbus floats by) 19:40, 20 August 2009 (UTC)[reply]

Yes, the above post refers to Minorhistorian, sorry to not make it clear before. Indeed it would be the best to find a mutually acceptable, solidly referenceable version. Fortuntely Berger's book seems to cover all what we need, and the section could be throughly referenced with it (as currently the article section has very few refs). The whole quote would be too long, so I suggest the following summary of the source:

In early February 1945 Spitfires of the 2 TAF also began using 100/150 grade fuel.^[1] Monty Berger, Senior Intelligence Officer of 126 (RCAF) Spitfire Wing, 2 TAF, noted that there were still problems being experienced with the new fuel, leading to several fatal accidents. Pilots were relieved when the AF brass to reverted to 130-grade by April 1945.^[2]

This could be added to the references section, if its not already there: Monty and Street, Brian Jeffrey.Invasion Without Tears. Toronto, Canada: Random House, 1994 (1st ed) ISBN 0-394-22277-6

I suppose this summary, given its properly sourced with page number, is acceptable? Kurfürst (talk) 19:50, 20 August 2009 (UTC)[reply]

P.S. Sorry I am not familiar with sandbox feauture. Kurfürst (talk) 20:04, 20 August 2009 (UTC)[reply]

Great, it's very acceptable to me as you were kind enough to type in the whole passage and provided page numbers, hopefully it will be acceptable to 'Minor' as well. Does this take care of the citation needed tags when the text is inserted? Nimbus (Cumulus nimbus floats by) 20:04, 20 August 2009 (UTC)[reply]

It seems to cover the entire of the 2nd TAF (introduction, use, troubles etc.). I am not sure but I can probably find something for the Mustang IIIs in some of my Osprey volumes. I recall something having been mentioned there about the use of 150 grade in them. Kurfürst (talk) 20:11, 20 August 2009 (UTC)[reply]

Yes, it was used in the Merlin 69 in the P51C Mustang III according to Lumsden, as the Merlin 69 was Packard built there is a perception that it was not a Merlin, this is causing separate problems in the article that I am trying to work out. If you create this page User:Kurfürst/Sandbox and bookmark it you will have your own sandbox that you can scribble and delete things at will, if you want more just add the subject or other name on the end such as User:Kurfürst/Sandbox/Merlin, there's no limit to how many that you can have to my knowledge. Nimbus (Cumulus nimbus floats by) 20:20, 20 August 2009 (UTC)[reply]

If the page number is given, no problem. A lack of page numbers in a citation indicates that the editor is not referring directly to the material cited, making it very difficult to verify. So far as I can tell this is the only place where this claim about the fuel problems is made; nothing like this is described in any of Price's work, nor in the very recent series on 2 TAF by Shores and Thomas; nor is it mentioned by Harvey-Bailey or any of the other publications on the Merlin. Minorhistorian (talk) 01:16, 21 August 2009 (UTC)[reply]

It is agreed then it seems. As far as Price and Shores go, I can find very, very little if any detail in their books about 150 grade fuel at all, so I am not surprised they don't go into details. Shacklady only mentions (in the context of summer 1944 and anti diver ops) that the exhaust burned out quickly but this was accepted; as far as I can see, he doesn't even mention the 2nd TAF use of the fuel.

The troubles on the other hand do not surprise me at all, several US publications mention the problems with 150 grade fuel with the Merlin Mustangs, especially the very short spark plug life (as little as 7-10 hours). I would not be surprised if these fatal accidents with the 2nd TAF would be related to similiar clogging of the spark plugs on Spitfires due to lead deposits from the new fuel. If the engine cuts due to this on take off or landing, it can be easily fatal.

Nimbus, can you add the reference via Lumsden? I looked in some the Osprey books, but can't find the reference yet about the anti diver Mustangs's use 150 grade. I will keep lookin'. Kurfürst (talk) 11:23, 21 August 2009 (UTC)[reply]

All Lumsden says is that the Mustang III used a Packard Merlin 69, I'm not quite sure what the citation tag is asking for, that the Mustang III flew in the ADGB or that it used the 100/150 fuel and/or a Merlin? If it's the fuel I can't confirm it directly with his book. If we can't confirm whatever is being asked for then we should just remove mention of the Mustang. Lumsden doesn't note any problems regarding the Merlin and the use of this fuel apart from the fact that American and British blends of it had a different composition. His coverage is quite comprehensive with 16 A4 pages on the Merlin and three pages on fuel. It would be good to get to the bottom of the problems mentioned, am I reading between the lines that it was exhaust valve failures. Spark plug life would be affected by the higher boost pressures allowed with the fuel, the lead fouling of the plugs mainly occurs on the ground when idling at low speed but would only cause rough running. Three different but connected problems. Arthur Rubbra, a key figure in Merlin development notes ongoing valve burning problems on all Merlins. An engine cutting on takeoff sounds more like a vapour lock problem to me, the higher octane fuel being more prone to this problem especially on a warm day, a magneto drop check and high power ground run would have been done by either the ground crew or pilot before a routine mission which should have revealed running problems but probably not on a 'scramble'. Will probably take the Mustang text out. Nimbus (Cumulus nimbus floats by) 13:26, 21 August 2009 (UTC)[reply]

The presumption that the accidents in 126 Wing can be directly attributed to the fuel seems to be unproven - if this was a universal problem surely there would have been mention of it elsewhere. As Nimbus has explained there were other possible causes for the crashes; a run of bad luck in one unit may not have affected others. Minorhistorian (talk) 22:55, 21 August 2009 (UTC)[reply]

I just happened to read this [1] currently used as cite note 27 as I was going to take that paragraph out as it didn't appear entirely relevant to the Merlin. I've clarified the relevance now and the reference does go into more detail about the problems, definitely mentions engine cuts and belly landings but no fatalities: In some instances, long periods of idling while waiting for take-off and a failure to use high power on take off resulted in loss of power during take-off run and in some cases caused complete cutting out with subsequent belly landing. The cases of cutting-out on take-off definitely attributed to excessive fouling were comparatively few, although numerous enough to list it as an effect of the extra lead. I don't want to use this ref against the other one, in a way it supports it. Probably best to let it settle now. Nimbus (Cumulus nimbus floats by) 22:55, 23 August 2009 (UTC)[reply]

<--A question: isn't fuel concern off-topic? Unless the Merlin had broad fuel issues, or was more sensitive to 150 v 130 than (say) V1710, this strikes me a fuel issue, not a Merlin issue. (Which isn't to say it's not interesting, but more for "Avn fuel of WW2", no...?) TREKphiler ^{hit me ♠} 15:35, 2 October 2009 (UTC)[reply]

As it relates to the Merlin the introduction of 100 octane and higher rated fuels obviously did have an effect on its performance (as it would have on other engines). The subject is mentioned enough in various Merlin references to warrant its inclusion I would say. I suppose that the Avgas article could be expanded to cover the wartime development of this fuel, it is briefly mentioned there already. Nimbus (Cumulus nimbus floats by) 16:19, 2 October 2009 (UTC)[reply]

Merlin production numbers

I checked my books and some good figures about the production totals of individual Merlin Marks; would this be a useful addition to the article, or simply too much detail? Kurfürst (talk) 19:27, 20 August 2009 (UTC)[reply]

Probably a bit much for this article but could it be used at List of Rolls-Royce Merlin variants ? MilborneOne (talk) 19:29, 20 August 2009 (UTC)[reply]

(Edit conflict) Exactly as I was just about to suggest: It could be added to the new List of Rolls-Royce Merlin variants article by all means, a summary of production totals is provided as a footnote in this (Merlin) article. Nimbus (Cumulus nimbus floats by) 19:33, 20 August 2009 (UTC)[reply]

I wonder if it would be practical to add it into that article's table (thanks for pointing out, didn't notice there is a seperate one) - by adding a new columns for each Mark there? Kurfürst (talk) 19:35, 20 August 2009 (UTC)[reply]

I think adding a column will squeeze the table, how about a separate new table for the numbers built? Can we copy this discussion over to the 'list' article talk page? Nimbus (Cumulus nimbus floats by) 19:44, 20 August 2009 (UTC)[reply]

I've copied this section of discussion over to the list article talk page. Nimbus (Cumulus nimbus floats by) 20:09, 20 August 2009 (UTC)[reply]

More review thoughts

I am copying in a section of discussion from WT:AETF because they are good points. I've put some comments in italics between the lines. Nimbus (Cumulus nimbus floats by) 20:43, 21 August 2009 (UTC)[reply]

A couple thoughts...

First, is it a normal practice to list the development engines? If that's the case, then I have a good source for the F414 article...

Don't see why not, as long as the section is not too long.

Second, the quote in the engine capacity section is way too long and, IMO, not incredibly important. That whole section seems to be responding to an unspoken challenge about the engine being undersized. If you're going to have a section that responds to that challenge, explicitly state the challenge as well. Something like "The Merlin is often overlooked because of its small displacement, but in fact..." (I have no idea if that is true or not, but that's what that section seems to be implying to me)

You could be right, the quote needs slotting in to the next section and have a lead in and summary of what Lovesey is saying.

In the tech improvements section, why are all the power ratings (2nd paragraph) at multiple altitudes. I know the technical use for that information, but why do they all have to be listed? Service vs Absolute ceiling? Something else? It's very difficult to read as is. I suggest either choosing one rating (max or takeoff or something) and sticking with that, or make a small table so the text isn't so messy.

Fair point, I note multiple different reference sources is probably the culprit although even in Alec Lumsdens book the powers are given at different altitudes, takeoff power at sea level is a constant though and he gives that for every variant. Might not show the power at altitude which is where the supercharger had the most effect, will look at it.

That's tough if they sources have it inconsistently as well. Plus there's the obvious (to me now) answer that as power increases, so does ceiling. Maybe emphasize the increase ceiling and take off power for each variant? Or maybe list the rated power "at altitude"? I don't know if I like my latter suggestion, "at altitude" is a bit nebulous... Maybe just a mini table. (Or how about a nice, easy to read graph what plots the increase in power over the variants... that could be an elegant solution...) -SidewinderX (talk) 23:18, 21 August 2009 (UTC)[reply]

Also in the tech improvements section, the emergency boost part confused me (3rd paragraph). I first read that to mean that the supercharger boost was increased, only then to find out that it's only for emergencies at 5 minutes max. Maybe reword it to first introduce the new emergency boost, and then describe it.

Agreed, that needs fixing.

The beginning of the article mentions several production locations and the "Production" section barely adds any more information about most of those locations. Can that be fleshed out some?

Possibly, I do have more info on that, the company built new houses and there are backround management decisions recorded about the need for increased production capacity.

The Applications section writing is jarring to me... the first thing you read is about a Spanish Bf-109... quite unexpected! Maybe an intro paragraph in that section leading the reader through common, aforementioned uses before the odd ones?

Agreed, another paragraph is needed there.

Can the citations be split into two columns for readability?

Erm..I don't think so! We are stuck with the MoS unfortunately, we did try a collapsible ref list in the F-4 Phantom featured article and got wrapped knuckles from the FAR team.

Anyway, those are my critical thoughts... it seems like this is a good bet for a FA. - SidewinderX (talk) 17:18, 21 August 2009 (UTC)[reply]

Re Lovesey: if this is to be kept my thoughts are that this could provide a lead to a section on supercharger development, rather than worriting about engine displacement. The article as is has little detail on the evolution of more efficient superchargers, nor is there much indication of the importance of supercharger development to the Merlin. What about transferring and modifying the section on superchargers in Supermarine Spitfire variants: specifications, performance and armament to this article instead, bearing in mind the Merlin wasn't just used in the Spitfire? If anything the section on fuels could be trimmed? Minorhistorian (talk) 23:00, 21 August 2009 (UTC)[reply]

From Spitfire performance and armament etc:

The original Merlin designs used single-stage superchargers. For engines equipped with a single-stage supercharger the air being forced through the supercharger air intake was compressed by the supercharger's impeller. In the case of the Merlin II/III, XII and 40 series as the air was being compressed it was mixed with fuel which was fed through an SU carburettor before being fed into the engine's cylinders. The Merlin III produced 1,030 hp (770 kW) at +6 pounds of "boost" (the "boost" is the pressure to which the air/fuel mixture is compressed before being fed to the cylinders). The limitation of the single stage supercharger was that the maximum power dropped quickly as higher altitudes were reached; because air pressure and air density decreases with altitude the efficiency of a piston engine drops because of the reduction in the weight of air^[3] that can be drawn into the engine; for example the air density, at 30,000 feet (9,100 m) is 1/3rd of that at sea level, thus only 1/3rd of the amount of air can be drawn into the cylinder and only 1/3rd of the fuel can be burnt.

A supercharger can be thought of either as artificially increasing the density of the air by compressing it - or as forcing more air than normal into the cylinder every time the piston moves down.^[4]

One of the most fundamental changes made to the later Merlin engines was the incorporation of a two-stage, two-speed supercharger, which provided a considerable increase in available power, especially at higher altitudes. As a result of this, in respect to the Merlin 61 series, used from the Mk IX on, two sets of power ratings can be quoted because these engines were fitted with two-stage, two-speed superchargers. As an example, the maximum power generated by the Merlin 61 was 1,565 hp (1,167 kW) at 12,250 feet (3,730 m) (critical altitude) in the first stage of the supercharger or Medium Speed (Better known as M.S, referring to the speed at which the impellor was driven) stage, using + 15 pounds "boost"^[5].

Once the aircraft reached and climbed through the critical altitude the power would start to drop as the atmospheric pressure, hence the weight of air dropped; a second stage compressor was needed to allow the engine to continue to perform at higher altitudes. When the aircraft reached an altitude of 20,000 feet (6,100 m) for the Merlin 61 the second Fast Speed (F.S) stage of the supercharger was started; the air/fuel mixture coming through the M.S stage then flowed through an intercooler and then into the second stage to be compressed again. An intercooler was required to stop the compressed mixture from becoming too hot and either igniting before reaching the cylinders (preignition knocking), or creating a condition known as knocking or detonation. ^[6] This second stage blower required approximately 200 hp (149 kW) to drive it. As a result the maximum power generated by the Merlin 61 in F.S was 1,390 hp (1,036 kW) at 25,900 feet (7,900 m), using + 15 in of boost^[5]^[7].

The Merlin 66 used in the L.F Mk IXs produced slightly more power but, because of the use of slightly different gear ratios for the impellers, the critical altitude ratings of the supercharger stages were lower, 7,000 feet (2,100 m) and 18,000 feet (5,500 m) respectively. This allowed the L.F Mk IX to produce its optimum performance at altitudes where experience showed most air-to-air combat over Europe was taking place.

Thoughts on incorporating this? Minorhistorian (talk) 23:10, 21 August 2009 (UTC)[reply]

AFAIK: M.S. = Moderate Supercharging F.S. = Full Supercharging Imho the bit starting 'Once the aircraft...' is a bit too descriptive and lenghty, and the full text would be better placed in an article describing internal workings of an engine; I suggest describe shortly the supercharger system on the Merlin (seperately actived s/c stages, ie. opposed to some US engines where both impellers were runnin' and FS only meant a higher speed for both stages), and assume people know how superchargers and intercoolers are related, or wikilink and/or expand the proper articles. BTW I have the exact weights for the whole Merlin 61 system weight breakdown in the Spit IX if its useful for the article. Kurfürst (talk) 23:17, 21 August 2009 (UTC)[reply]

I'm a little busy working at the moment to take this all in and comment properly but I like the smoother incorporation of the Lovesey quote, I made him a redlink as I intended to write a new article on him soon (redlink has gone?). I would err on not including any more technical detail at the moment, if the FA review suggests that the article is too short we could add it in. Would agree that the 'S' in MS/FS refers to the level of supercharging as this is how it used in various references and Ar Publications, the form 'MS Gear' etc. is also seen. Have not actually looked at the supercharger article yet, if it doesn't curently cover what we need then it can be expanded using all our ref sources. Cheers Nimbus (Cumulus nimbus floats by) 19:32, 22 August 2009 (UTC)[reply]

The supercharger article has not satisfactorily addressed the variations and uses by military aircraft for at least two years. It definitely could use some work by experts—not me. Binksternet (talk) 20:13, 22 August 2009 (UTC)[reply]

Not me either although I did attend a five-week aircraft piston engine theory and practical course about 10 years ago, would have to dig out the notes! I've had a quick look at that article now, it does appear to cover the basics and has an aircraft section, it is quite thin on references though and could well be wrong in places. It's one of those strange articles that deals mainly with road vehicle applications and has a section on aircraft use. It has been tagged as coming under the aviation project and more recently been adopted by the aircraft engine task force. I suspect if we try to turn it into more of an aircraft engine related article that the automobile/car contributors would complain. It's possible that we could create Supercharger (aircraft) but then others might complain that it is an unnecessary split. Would need to be discussed there but I think we do owe it to readers by using the supercharger link that they get what they might be expecting to see i.e. much more information. There's just too much to do sometimes! Nimbus (Cumulus nimbus floats by) 20:49, 22 August 2009 (UTC)[reply]

I like your idea of starting Supercharger (aircraft) or maybe with another title that includes turbo, and letting the ground-huggers have their article back. The advantage would be that supercharger and turbocharger could come together under one application. I'm not certain, but I think that there were some aircraft charging systems (perhaps on Allisons?) that included a little of both methods: shaft-driven superchargers augmented by exhaust-driven turbine chargers. If that notion of mine is correct, no article on Wikipedia appears to explain it. Binksternet (talk) 21:45, 22 August 2009 (UTC)[reply]

This bit about superchargers copied to a new topic at Wikipedia_talk:WikiProject_Aircraft/Engines#Turbo-_and_supercharging_in_aircraft. Binksternet (talk) 21:53, 22 August 2009 (UTC)[reply]

(Edit conflict) Great. I just ventured into Talk:Supercharger, very 'interesting'! I see the split proposal has been mentioned before. There are obviously a lot of misconceptions in there. Sounds like it is time for an Aircraft superchargers, turbochargers turbo-superchargers and other thingies article. Something useful I did get from that discussion relevant to the Merlin article is the use of ejector exhausts, currently not mentioned at all and should be included with a possible mention of their other use for gun heating. Nimbus (Cumulus nimbus floats by) 22:00, 22 August 2009 (UTC)[reply]

Err, my fault deleting redlink, have restored...Minorhistorian (talk) 00:00, 23 August 2009 (UTC)[reply]

A small point: beware equating inches & pounds of boost. I can't recall the conversion, but I do know they aren't 1:1. Also, as air temp drops, burn efficiency would improve, in some % to the density change which cuts efficiency. I confess not knowing the value of the second stage; all auto blowers are 1-speed, 1-stage... I do know drive speed governs max boost. And there's an issue of how strong the internals are; to much boost risks popping the heads off! (Of course, there's always the issue of popping the blower, too; in a/c, maybe less so, & maybe also for not using nitro...) As for the intercooler, can you confirm the risk of detonation? At 15psi boost (which is comparatively low) on 130 octane, I wouldn't expect it. There would be an issue of loss of performance in the charge heating. I'd bet (not knowing better...) the jolt is the 2d stage blower drive kicking in. My $0.02. TREKphiler ^{hit me ♠} 01:39, 4 October 2009 (UTC)[reply]

Inches (of Mercury) and pounds are different, inches is not in use (or should not be) in this article as it is a British engine, Cyril Lovesey would have been the person to ask about Merlin superchargers, his lecture paper is very informative, it had to be removed from the article unfortunately. Nimbus (Cumulus nimbus floats by) 01:54, 4 October 2009 (UTC)[reply]

Production section

I've added a promised expanded production section, lots of interesting research. By eye it is about the same length as the 'fuel' section, I have sold Manchester short, there is some interesting stuff to add there as they complained that RR's engineering tolerances were too slack! Please feel free to copy edit/tweak etc., grammar is not my strong point but it is factually correct AFAIK. Would like to add some info on the ejector exhausts and then it will be about 43 kb which is the ideal length I believe. There is of course tons more info but it's probably not wise to add it at this stage. Might need some more images to break up the text, I will try to get to a museum this week as there is not a lot on Commons to choose from at the moment. Cheers. Nimbus (Cumulus nimbus floats by) 23:44, 24 August 2009 (UTC)[reply]

Forgot something! Cost is missing from the infobox, I just can't find a good reference. In 1939 a Merlin was about £6,000 deduced from the referenced price of a Spitfire airframe (also c.£6,000) and a complete Spitfire for export (c.£12,000). Would be the 'icing on the cake'. Nimbus (Cumulus nimbus floats by) 23:53, 24 August 2009 (UTC)[reply]

Didn't Hooker ([Not Much of an Engineer.]) write that Ford of Manchester was the factory that regarded R-R's tolerences as being too sloppy? It must have been galling for Rolls-Royce to have a plebian company like Ford complaining about sloppy engineering. (BTW I don't have a copy but I know where I can find one.) Looking good Nimbus, cheers Minorhistorian (talk) 03:53, 25 August 2009 (UTC)[reply]

Just googled "rolls-royce merlin costs" and found this [The Case for the Carburettor]. I have now downloaded the four page article (not counting ad for de H prop) and will use it as a reference in the "Carburettor" section, with added info. Not that it has much to do with the price of a Merlin! Minorhistorian (talk) 04:21, 25 August 2009 (UTC)[reply]

I've been googling as well but not finding much on cost apart from what they cost now! Must get the Hooker book. Strangely enough in 'Magic of a Name' a passage from Hooker's book is used verbatim. The story goes that one day the Ford chief engineer appeared in Cyril Lovesey's office, Lovesey assumed that he was going to say that he couldn't meet the RR tolerances to which the Ford engineer replied 'on the contrary, the tolerances are not tight enough'! The Ford factory redrew the drawings which took a year and then produced 'very good' engines according to Hooker. There was a possible French Ford production option but Hives had his doubts and it didn't happen. Nimbus (Cumulus nimbus floats by) 09:54, 25 August 2009 (UTC)[reply]

Just picked up Sir Stanley Hooker's book from the local library; appendix IV is "Supercharging the Merlin Engine"...there is also a whole chapter on the Merlin. More to come...stay tuned...Minorhistorian (talk) 10:28, 25 August 2009 (UTC)[reply]

"Not Much of an Engineer"? The important text for the supercharging aspect is his technical report at the time, which is one of the RRHT reprints. Andy Dingley (talk) 11:33, 25 August 2009 (UTC)[reply]

FA nomination?

Well I think it is just about there, noting Minorhistorian's offer to expand the supercharger section. The article now has a good structure, covers all the major points adequately, if not comprehensively, the grammar, spelling and compliance with the MOS are pretty good and it has a reasonable number of images to break up the text and I now believe it meets the criteria subject to review. It is a requirement prior to nomination to discuss it's suitability for promotion review (see Wikipedia:Featured article candidates). I have already posted this proposal at WT:AETF but the discussion came back over here, no matter. There is a formal voting process just to agree to the nomination (by adding a template to this article). This would be the first step if everyone is in agreement. Thanks to all editors who have constructed this article since February 2002 (this is what the 'embryo article' looked like back then BTW [2]) and the editors who have contributed recently to bring it up to a high standard. Cheers Nimbus (Cumulus nimbus floats by) 13:06, 25 August 2009 (UTC)[reply]

I'll start! Support as nominator and reasons given above. Nimbus (Cumulus nimbus floats by) 13:13, 25 August 2009 (UTC)[reply]
Support. It's certainly come a long way since 2002! Could perhaps do with fresh eyes to iron out any further wrinkles though. --Red Sunset 13:47, 25 August 2009 (UTC)[reply]
Comment It looks like a fine article, but I notice it hasn't been through a Wikipedia:Peer review which would "iron out any further wrinkles" before the FAC. You don't want any minor problems causing it to fail. - Trevor MacInnis ^contribs 07:32, 26 August 2009 (UTC)[reply]
Comment I have considered that and note that a peer review is recommended but not mandatory. I'm more than prepared to edit the article further as the FA team sees fit. I posted that this preliminary vote was taking place in the aircraft project and engine task force and am still hoping that more independent editors will drop by, read and check the article and then add their vote either way here, a form of peer review in itself. If it appears that a major rewrite is needed then we can take it from there but at the moment comments appear to be positive. I am also concerned about the length of time a peer review takes which is a problem we have discussed elsewhere, we should put some kind of time limit on how long articles remain under peer review so that there 'is light at the end of the tunnel' for nominating editors (either good or bad light!) Cheers Nimbus (Cumulus nimbus floats by) 11:46, 26 August 2009 (UTC)[reply]
Comment It is certainly a much better article than it was even a few months ago. Right now I am tied up with university work so my contributions will be strictly limited for some time yet. All credit to Nimbus for his recent hard work. Minorhistorian (talk) 21:51, 26 August 2009 (UTC)[reply]
On hold, have submitted the article for peer review as suggested. Nimbus (Cumulus nimbus floats by) 15:02, 1 September 2009 (UTC)[reply]
Support. I made a few minor changes, but otherwise found little to fault in the article. - Ahunt (talk) 20:12, 7 September 2009 (UTC)[reply]

Request

Could I ask that we limit new additions to the article at this stage please, the article is currently undergoing a peer review at Wikipedia:WikiProject Aviation/Peer review/Rolls-Royce Merlin, I am trying to deal with the points raised. Recent additions need work to comply with points already raised and I have to check them again. Many thanks. Nimbus (Cumulus nimbus floats by) 14:54, 4 September 2009 (UTC)[reply]

Could I ask once again that changes to the article are limited at the moment to copy editing and small improvements, I admit that I have been 'nervously dabbling'! The article is currently under formal review, the analogy is if we keep changing it every five minutes that it is akin to a teacher trying to mark an exam paper and the pupil keeps asking for it back to change something, in fairness to the FAC review team it just can't be done. Patience is a virtue, I do promise that when it is all over I will haunt another article. Cheers Nimbus (Cumulus nimbus floats by) 23:43, 17 September 2009 (UTC)[reply]

Formal FA Nomination

I have closed and archived the peer review after nine days where few negative comments were indicated. I have now formally nominated the article for Featured Article status: Wikipedia:Featured article candidates/Rolls-Royce Merlin/archive1. Nimbus (Cumulus nimbus floats by) 08:43, 10 September 2009 (UTC)[reply]

There's been no comments on the FA review page by anybody but you in the last week or two. Any idea on long will this stay open? -Fnlayson (talk) 20:16, 1 October 2009 (UTC)[reply]

The whole process is a bit of a mystery to me, I can only guess that the backlog of articles waiting review is causing the delay. There are no negative indications so far there that I can see. My last post there (Sept 23) was to note that I had informed the reviewer who questioned the web references that I had removed them from the article and that they could be struck (it suggests to do exactly this in the FAC instructions). For some reason this was not actioned. I don't want to chase reviewers although I note some nominators are doing it. Just have to sit tight I suppose. Nimbus (Cumulus nimbus floats by) 20:36, 1 October 2009 (UTC)[reply]

I asked that because the Boeing 777 FA review last December was closed after a couple weeks of inactivity. -Fnlayson (talk) 20:47, 1 October 2009 (UTC)[reply]

Mmmm..interesting, I can't clearly see the reason given there just 'not promoted'. In the case of the Merlin the points raised so far have all been adressed to my knowledge, to sit watching a nomination that has an unseen outstanding problem without saying anything (if that is what is happening) is not on. I am convinced that it is just down to the number of articles under review, I have done what I can so far as nominator and fixed things as promised. Some more 'support' votes wouldn't go amiss but it does say that these are not necessarily taken into account, which is a fair point if an article isn't actually ready, or is this all part of 'consensus being reached for promotion'? I'll give it a couple of days then ask nicely somewhere if there is a problem. Nimbus (Cumulus nimbus floats by) 21:18, 1 October 2009 (UTC)[reply]

Agreed – the reviewers are up to their necks, but at the same time I note that several later candidates are getting more attention than the poor old Merlin; and more Supports, or even Comments would indicate that there is at least some interest in the article! However, it is worrying that the lack of activity might lead to an early closure – I suppose we could try and spice it up with some sex and violence (all reliably referenced of course ;-) ), but failing that I think I'd give someone a polite nudge after the weekend. --Red Sunset 21:48, 1 October 2009 (UTC)[reply]

I think that canvassing for support is generally frowned upon and the apparent lack of interest in the aircraft project when I mentioned the nomination puts me off going back there. I was hopeful (and still am) that the article stands on its own merits. Unfortunately it is difficult to spice up what is effectively a 75 year old, 3/4 ton, seven foot long lump of metal and oil, although we have tried! Nimbus (Cumulus nimbus floats by) 21:59, 1 October 2009 (UTC)[reply]

Add a notice about this FA review at WT:WikiProject Aviation. I don't think one was added there. -Fnlayson (talk) 22:03, 1 October 2009 (UTC)[reply]

Ok, will do. Nimbus (Cumulus nimbus floats by) 22:10, 1 October 2009 (UTC)[reply]

Nudging someone on the FAC talk page was my intended meaning, but a note at WT:WikiProject Aviation might liven things up a bit. BTW, I can't believe there are people out there that don't find a 75 year old, 3/4 ton, seven foot long lump of metal and oil interesting LOL! --Red Sunset 22:26, 1 October 2009 (UTC)[reply]

Have added a short unbiased note at WT:AVIATION. Aircraft engines are not the most exciting things to 99.9% of the planet's population at a wild stab although the Merlin must be known to some! There is a video on 'the tube' of a working scale model of a Merlin, beggars belief. There was a company selling castings of a similar working model engine intended for scale model aircraft but there was a lot of fiddly machining left to do. Nimbus (Cumulus nimbus floats by) 22:38, 1 October 2009 (UTC)[reply]

Was thinking of adding some words to the end of the second lead paragraph '...although its most numerous application was with the Avro Lancaster.' This is a fact noted in the infobox and would remove any possible comments of bias towards the Spitfire. Is this like a Weasel or a fair comment?! Nimbus (Cumulus nimbus floats by) 00:34, 2 October 2009 (UTC)[reply]

Suggests to me there were more Lancasters than Spitfires. Maybe you should specify "the four-engined Avro Lancaster". Kaiwhakahaere (talk) 01:54, 2 October 2009 (UTC)[reply]

Yes, there is too much about the Spitfire, nothing about any other aircraft...hmmm

First run in 1933, a series of rapidly applied developments, brought about by wartime needs, improved performance markedly. In military use the Merlin was eventually superseded by its larger capacity stablemate, the Rolls-Royce Griffon. The first aircraft to use the Merlin were the Fairey Battle, Hawker Hurricane and Supermarine Spitfire: although the engine (Merlin?) is most closely associated with the Spitfire, the (equally famous?) four-engined Avro Lancaster was the most numerous application.

Thoughts? Minorhistorian (talk) 02:15, 2 October 2009 (UTC)[reply]

It's a tricky one to get right, will probably leave it for the moment. Nimbus (Cumulus nimbus floats by) 09:30, 2 October 2009 (UTC)[reply]

Not forgetting that any detail added to the lead must be mentioned, and possibly expanded on, in the body of the article as well, I can see merit in the comments made by Minorhistorian and Kaiwhakahaere as well as the revised example of the paragraph. However, I would suggest changing the order slightly to:

First run in 1933, a series of rapidly applied developments, brought about by wartime needs, improved performance markedly. The first aircraft to use the Merlin were the Fairey Battle, Hawker Hurricane and Supermarine Spitfire: although the engine is most closely associated with the Spitfire, the four-engined Avro Lancaster was the most numerous application. In military use the Merlin was eventually superseded by its larger capacity stablemate, the Rolls-Royce Griffon.

But at the end of the day, best left for Nimbus to decide what to do since he is the nominator (and has two sets of wings as well – so there!!! :-)). --Red Sunset 18:36, 2 October 2009 (UTC)[reply]

Very true about things mentioned in the lead needing to be in the body text, probably another good reason for leaving it as it is. The only indication of application numbers is in the infobox where I wrote down the number of main aircraft types built, multiplied this number by the number of engines they used (was quite easy for the Spit and Hurricane!) to work out the total number of engines used by type and then arranged them in descending order and added a footnote. I don't think this needs to be mentioned anywhere in the article. Fingers crossed that some positive words are added to the FAC page in the near future. Cheers Nimbus (Cumulus nimbus floats by) 18:52, 2 October 2009 (UTC)[reply]

I've been bold and added this stuff to the article and reworded the lead slightly to go some way towards addressing recent FAC comments. Of course, I have no problem if the consensus is to remove it. I've cited Lumsden 2003 since that's where the info came from (?), but I wasn't able to give page number(s). --Red Sunset 09:56, 4 October 2009 (UTC)[reply]

Jimbo says that we must be bold if it improves the encyclopaedia!! I've added cites and page numbers. Thanks to everyone for your thoughtful additions and patience. Nimbus (Cumulus nimbus floats by) 23:48, 4 October 2009 (UTC)[reply]

Update (for those who are wondering like me!). I noticed that the article had been removed from the current FAC list, fearing the worst due to recent criticism I went digging to see what had happened. It had been removed with three other candidates with the edit summary [3] of pr-first pass. I don't know what this means but it sounds positive. I intend to provide some constructive feedback on the process to the FAC team however it turns out as it is a complete mystery to me as to how it works and I have been here for a while now. Just a note on the recent IP edits, I always check when an IP who is not obviously a vandal changes something and reverts it twice just in case they are right, in this case he was wrong and you guys were right to revert. Cheers Nimbus (Cumulus nimbus floats by) 01:13, 7 October 2009 (UTC)[reply]

Very positive. See bot edit from a little while ago. :) -Fnlayson (talk) 01:32, 7 October 2009 (UTC)[reply]

Another update

Crikey! The Star of Bethlehem shineth now in the top right corner of this article!!! I really can't describe how I feel at the moment. After many miles on a motorbike to four museums with a camera on my back, thumbing through stacks of books, and staring at a computer screen for more hours than I care to mention, it was all worth it!! Absolutely fantastic effort guys. Special thanks to 'Red' for correction of my spelling mistakes, grammar etc. and 'Minor' for recent technical additions. The task now will be to maintain the standard, lest it end up in the 'Sin Bin.' Simply wonderful! Cheers. Nimbus (Cumulus nimbus floats by) 01:44, 7 October 2009 (UTC)[reply]

Excellent!!! Now, given some spare time the section on Superchargers can be finished. Great work all round, especially Nimbus, who got the ball rolling (may Jaffa cakes and Triumph Bonnies be yours forever); Red, Snow, Fin deserve more than honourable mention...not to forget the editors who reviewed the article. Now, as Nimbus says, lets keep the quality up and any (small) revisions tidy, informative and useful. Cheers Minorhistorian (talk) 02:50, 7 October 2009 (UTC)[reply]

Congrats. Well done!! TREKphiler ^{hit me ♠} 05:00, 7 October 2009 (UTC)[reply]

Excellent, thorough, patient work! Well done! --TraceyR (talk) 09:37, 7 October 2009 (UTC)[reply]

I would suggest any future additions should be tested in a sandbox rather than going directly to the article - that way Nimbus and others can inspect, accept or reject. I still have some work to do on the superchargers; right now I want to keep this as brief as possible. Useful help/advice will be welcome. Minorhistorian (talk) 13:20, 7 October 2009 (UTC)[reply]

Well it says in the new FA header on this page 'even so, if you can update or improve it, please do so'. A sandbox probably isn't necessary though I agree that any additions have to be high quality with 'squeaky clean' formatting, spelling and referencing. I don't intend to add anything although I noted that none of the reviewers thought that it was too long (or that any particular section was too long). I would still like to revisit the Supercharger (aircraft) idea, just too much to do sometimes. Would also like to apologise at this point for appearing to control or even own the article recently, I was just 'giving the boat a rudder' which was necessary for the FAC process. The FAC team have encouraged me to leave some feedback after I posted a note over there. Cheers Nimbus (Cumulus nimbus floats by) 14:02, 7 October 2009 (UTC)[reply]

Wow – that's brilliant news to come home to! Fantastic work done by all concerned, and a special mention to Captain Nimbus for maintaining a true course. Pass the Jaffas then!!! :-) --Red Sunset 18:33, 7 October 2009 (UTC)[reply]

Sorry, they're all gone! Thought that you might be a tad pleased, while we are gratuitously 'back slapping' don't forget that you added most of the en dashes and nbsps and a large technical section from Jane's! Cheers Nimbus (Cumulus nimbus floats by) 18:49, 7 October 2009 (UTC)[reply]

No apologies necessary. A single overseer (for lack of a better word coming to mind :( ) is not a bad thing, & I got no sense of "ownership" claimed, only a fervent desire to make it the best, which is what IMO we all aspire to. (Except the blasted vandals, curse them!) Amstels on me. Salud! TREKphiler ^{hit me ♠} 21:12, 7 October 2009 (UTC)[reply]

Thanks, I did feel at times that I was being a bit autocratic but as you say leadership is needed at times, there is only one editor in charge of the FA team 'the director'! Amstel, well I have not had one of those for a few years, the Heineken brewery trip was an annual pilgrimage for us in RAFG, 10 minutes guided tour round the site then two hours of 'free sampling', hic!! Happy days. Nimbus (Cumulus nimbus floats by) 21:22, 7 October 2009 (UTC)[reply]

Prototype engines

I am a bit puzzled about how to describe the Merlin I and Merlin II. The article lists them as prototypes, but the text says that they went in to production and were used to fly aircraft. Snowman (talk) 20:48, 3 October 2009 (UTC)[reply]

Lumsden describes only the PV-12 as a prototype engine as such, the basic design layout of the engine was effectively fixed at the Merlin G (military designation - Merlin II). The types included in that section are correct, what may be required is an alternative header such as 'Early engines, Development engines, Pre-production engines, Test engines, Evaluation engines etc.' Of all the choices 'prototype' may still be the best way to describe them. They all flew. Nimbus (Cumulus nimbus floats by) 01:29, 4 October 2009 (UTC)[reply]

What I am clear about is that there is an internal inconsistency in this section, because the heading says "Prototype" and two of the engines are described as production engines. This wikipage might help; Prototype#Differences_between_a_prototype_and_a_production_design. Snowman (talk) 17:02, 4 October 2009 (UTC)[reply]

I was bold and adjusted the section label to Early engines as you suggested, Nimbus/Gary. Also, added developmental to the first sentence after that. Please adjust that as needed. -Fnlayson (talk) 17:24, 4 October 2009 (UTC)[reply]

Looks good to me. Nimbus (Cumulus nimbus floats by) 18:49, 4 October 2009 (UTC)[reply]

Image suggestions

Re: File:Avro Nene Lancastrian VH742 Coventry 06.54.jpg. Is this image any good for the article? Did they do any engine testing in Coventry? Snowman (talk) 11:49, 6 October 2009 (UTC)[reply]
Re:What is this place and this place? Snowman (talk) 11:57, 6 October 2009 (UTC)[reply]
Quite a few pics of Merlin production/repair at Hillington here. --TraceyR (talk) 14:13, 7 October 2009 (UTC)[reply]

Interesting, one of those is in the article (the women on the production line). It clearly states Hillington as the location where at the IWM collection (and our Commons version) states 'location unknown', I think it would be safe (and more informative) to add the location to the caption now. I am personally not a fan of too many images in an article, galleries appear to be discouraged generally though I can see occasions where they might be useful. Have a look at Rolls-Royce Limited for 'image explosion'! The article is supposed to be about the company, not just the cars, I have noted this myself over there but nothing happened, sure as eggs are eggs that I would get reverted if I removed any of them. Nimbus (Cumulus nimbus floats by) 15:20, 7 October 2009 (UTC)[reply]

A bit of light relief.

File:Female workers who works in Rolls Royce Factory.jpg

Ada to Flo: "Keep this to yourself, but our Stan toasted the lawnmower engine last weekend and I'm smuggling one of these out bit-by-bit to replace it. Any suggestions where I can stick the crankshaft?"

Here's a priceless alternative to the lead section that Nimbus unearthed recently:

This is the story of the Merlin, the unseen, but by no means unheard, wizard that brings victory among the stars. Hidden beneath the cowling of the British fighters, its mighty roar rose triumphant when the last Nazi went whining down to earth in the battle of Britain . Now, in Bombers as well as in Fighters, from dawn to dusk and through the night, in the skies above Europe and the world, it sings a paean to the oppressed, roars a dirge to their oppressors. Spitfires, Hurricanes, Lancasters and Halifaxes are among the list of mechanical stars that draw their power from the Merlin engine. Into the Rolls-Royce works come the feather-light alloys, the bar-metal, the forgings, and other raw materials of victory. Through fire and water and a mechanical wonderland, the brains and hands of men and women guide them and shape them into a gleaming light compact unit - a wizard of the air, a Merlin with Power beyond the wildest dreams of King Arthur's mighty magician.

Why didn't we think of something like that?!

So, is anyone sufficiently bold (suicidal) to slip this into a "Popular perception" section? ;-) --Red Sunset 20:08, 7 October 2009 (UTC)[reply]

Very good, much needed relief indeed! Interesting that whoever wrote this gem refers to the magician. We'll save it for next April 1. Nimbus (Cumulus nimbus floats by) 20:18, 7 October 2009 (UTC)[reply]

Re Smith references

Ah, yes the Smith February 1942 article flummoxed me because it didn't use page numbers; it looks like this was a supplementary article, added to the magazine after the layout had been edited and set for print - this is the first time I have struck an article using an alphabetical system. I meant to add this info to the Edit Summary. Apologies for the heart flutters Nimbus...the Flight articles, BTW, are brilliant; well written, comprehensive and published in wartime! Minorhistorian (talk) 00:59, 9 October 2009 (UTC)[reply]

I did twitch! I wondered why you included the month but can see that there are two similar references from the same year. I have some good books at home that do not have page numbers, they never thought of Wikipedia! I did notice a timeline problem in there which has been fixed and I had been dying to add the 'clipped, clapped and cropped' bit for ages! I am a tiny bit worried about the impeller rpm figure precision, I have not looked at the references because I always assume trust but they would be related to a specific engine rpm which is not given, would be tempted to round them to the nearest ten even if it is not what the reference says, bordering on excess detail for an encyclopedia. I noted your interesting conversion of Imperial height units to metric power units!! We just have to be doubly careful with any future additions. I am hoping to back off from this article now as it is effectively complete and I have a lot of work to do with the lesser mortal engines.

I don't know if you guys have WT:AETF on your watchlist but this morning (GMT) a comment [4] was posted expressing dismay that the engine was not named after a bird of prey, he must have missed the blue Merlin link in the lead and the expansion further down! It was retracted after three minutes, bless! Nimbus (Cumulus nimbus floats by) 02:08, 9 October 2009 (UTC)[reply]

Is there much more to come? The supercharger section is getting very long and we might have to split it off to a new article to avoid unbalancing the article IMO. I am trying to maintain a timeline in that section, granted there is overlap but the reader is now seeing later mark numbers at earlier dates. Nimbus (Cumulus nimbus floats by) 02:31, 9 October 2009 (UTC)[reply]

I was going to suggest an agreed self-policing 60 kb article size limit, we are at 59 kb now. Nimbus (Cumulus nimbus floats by) 02:38, 9 October 2009 (UTC)[reply]

This newly inserted unreferenced paragraph is unclear: The two-stage Merlins were further refined with the introduction of the Merlin 66, which used "cropped" impellers for increased power ratings at low altitudes, and the Merlin 70 series which were designed to deliver increased power at high altitudes. The 70 used a higher gear ratio. Nimbus (Cumulus nimbus floats by) 02:59, 9 October 2009 (UTC)[reply]

Aw come on; I'm working bloody hard at other things and I am still taking some time out to finish this section. Have a heart Slave driver...anyway, I've done all I'm going to do on the article ;) Minorhistorian (talk) 14:43, 9 October 2009 (UTC)[reply]

Great, better let 'Red' look over the additions in this area. I'm not sure about the use of three full stops, I have seen it somewhere in the MOS but can't remember what it is called. I am busy with the RAF museums after a split, was not expecting to end up there but that's how it happens sometimes. Very good engine collection at Cosford. Cheers Nimbus (Cumulus nimbus floats by) 14:59, 9 October 2009 (UTC)[reply]

WP:ELLIPSES is what they are! Used when words are intentionally removed from a quote, marvellous idea! The guideline indicates that there should be a space inserted before and after one except on leading and following punctuation marks, I tried to insert spaces but got in a mess due to full stops etc. (do we end up with four dots there?). Might be trivia but it is important to keep it straight and I would like to know how to use them properly in other articles. Cheers Nimbus (Cumulus nimbus floats by) 17:22, 9 October 2009 (UTC)[reply]

Re ellipses: IIRC, when you drop the end of a quote, you finish with 4. FYI. TREKphiler ^{hit me ♠} 19:28, 9 October 2009 (UTC)[reply]

That's right – tricky chaps these ellipses! ;-) I'm not a great fan of them personally, but if they help keep the size of the article down all well and good. On that note, it looks like 'Minor' has been very busy today – the supercharger section is quite comprehensive now and progresses logically, but is perhaps a little long though!?--Red Sunset 20:10, 9 October 2009 (UTC)[reply]

Sigh!* I'm starting to get a little frustrated, after all the work I have put into this - how much information is too much, huh? Minorhistorian (talk) 20:40, 9 October 2009 (UTC)[reply]

I understand your thoughts, for an encyclopedia though more is sometimes less, the main points can get lost in details, the difficulty is striking the right balance between not enough and too much information. I do believe in the case of the supercharger section that you had finished adding. Try putting an article through the FAC process for some 'frustration'!!! I would like to do it again sometime however difficult it might have been. On that note Red has suggested a paragraph (see below) which I have just tweaked and would be happy to add as it was noted as an omission at FAC, might sound contradictory to add even more material but it would be going into a different section. Remember that Supercharger (aircraft) has still not been created and will need reams of material when it does appear. Cheers Nimbus (Cumulus nimbus floats by) 20:54, 9 October 2009 (UTC)[reply]

Undent: I apologise Minor, I know you have put lots of hard work into this! As I said, the section covers every aspect of the topic comprehensively – all excellent stuff :-) – and it would be good if we could bring the other sections up to this level, but then the article would be half as long again unfortunately. Having said that, I think that any cuts in it might only introduce omissions. --Red Sunset 21:27, 9 October 2009 (UTC)[reply]

No problem - trying to balance what to leave out, with the information I've been digging out of those fabulous Flight articles, versus the requirements of an encyclopedia article, was an exercise in restraint; I know I get caught up in the wealth of technical detail ( I'm also fascinated by the amount of information the Brits were prepared to print in wartime BTW was there an American equivalent to Flight?). My thinking is that supercharger development was at the core of what made the Merlin such a successful engine; without this development the Merlin might have been an "also-ran". The reason I quoted specific figures on impeller speeds is to give lay-readers (?) some idea of how fast they needed to run. Minorhistorian (talk) 09:57, 10 October 2009 (UTC)[reply]

PS found a lurvly photo taken at Rolls-Royce Derby "And you see this long thing? It goes round and round because these whatsits go up and down when those thingummies go bang."

Yes, I see your thinking – the supercharger's role in the development of the Merlin needs to be reflected in the depth of its coverage. I think you've touched on all the bases now, and Nimbus' suggestion re writing a Supercharger (aircraft) article would be right up your street – have you given it any thought? I have to agree that it does seem strange that stuff like this would be open for all and sundry to see during wartime – rather playing into enemy hands don't you think! BTW, that's a great photo you've found – I reckon it deserves a place in there somewhere; maybe in "Basic component overview"?

Alternative caption: OK chaps; I think we need to down-size the assembly teams – there's not enough room for everyone to work and it looks nothing like the drawing on the blackboard! --Red Sunset 17:16, 10 October 2009 (UTC)[reply]

Comparable designs

In consideration of comments made during the FAC review I've put a paragraph together here that briefly puts the Merlin into context relative to selected comparable contemporary engine designs. I'm mindful of the length of the article so comments/corrections/improvements are invited before (if) it gets slotted in. It would also give meaning to the "little" engine referred to in the Production engines section. Cheers --Red Sunset 19:52, 9 October 2009 (UTC)[reply]

I just nipped in there, sorted a few redirects and rounded the capacity figures to align with what is already in the article. I think this should go in the article (at the end of 'origin'?) as it would clearly improve it and it was noted as an omission, my only concern is that it might attract certain editors who have a bias in another direction shall we say. I hate to think that all this is upsetting people, I am trying to be very diplomatic, will also repeat that I would like to back well off from the article now in the hope that we can all keep an eye on it for IP vandalism etc. There are many other articles that we could improve with the experience. Will be a bit quiet for the next few days as I serve my penitence in the 'coal hole'. Cheers Nimbus (Cumulus nimbus floats by) 21:07, 9 October 2009 (UTC)[reply]

Thanks Nimbus. The rounded figures do look better – more fitting since they are there mainly for comparative purposes rather than absolute measurement. My initial thoughts were at the end of "Origin", but I'll look around to see if it might sit better elsewhere before introducing it. However; as I mentioned above, I'm mindful of the size of the article and am loath to add anything more to it, but in this case I think there is a valid reason for its inclusion. As you say, it might attract some unwanted attention though – we'll just have to see! Standing back from the article now is probably the best idea – if it ain't broke, don't fix it! ;-) --Red Sunset 21:52, 9 October 2009 (UTC)[reply]

Looking at this, I'm not entirely convinced it's needed. IMO, the German engines suffer as much from bureacracy & lack of materials as anything, so the Merlin's edge over them isn't design but development. In comparo to the V1710, maybe...which I've always thought suffered from bad press over being fitted in P-39s & P-40s, plus the Merlin being really good... TREKphiler ^{hit me ♠} 02:47, 10 October 2009 (UTC)[reply]

I think a mention of contemporary comparable engines to put the Merlin into some sort of context is justified; not just with respect to other British offerings, but to those of other countries as well. I also feel that its relative size is an important point to note, and I attempted to show that it was a "really good" engine (without being POV) by providing an example of the relative power of early examples. It seemed to me that if figures for early types were used, the bureacracy and lack of materials that you mention would not have had sufficient time to significantly impact on their development, and we would be comparing the basic or intrinsic merits of the designs. Having said that, my source doesn't provide figures for the earliest Jumo 211 sadly! You may well be right: given the time and freedom to fully develop the German designs they likely would have become more efficient, but at their inception they were basically not as powerful relative to capacity as the Merlin. I thought this might give rise to comment and I'm ready to be corrected, which is why I posted my original note rather than write it straight into the article. So please feel free to provide an alternative, and a possibly better comparison example. :-) Cheers. --Red Sunset 18:11, 10 October 2009 (UTC)[reply]

Comparison sections and even articles are a bit of a minefield, they are not generally encouraged in the aviation/aircraft projects, comparison articles have not survived AfD, mainly because they were unreferenced original research or the figures were referenced but the comparison 'theories' were not. Looking at the exact same Jane's all they give is the raw numbers with no commentary, strictly the 23% size difference could not be referenced to them as they don't mention it. I went back to Bill Gunston's engine encyclopedia to see if he mentions comparisons, he does in a way. He mentions a 'racing Merlin' that ran in 1937 that produced 1,800 hp for 15 hours with bursts up to 2,160 hp, after this he states "This amazing achievement confirms that the 27-litre Merlin would probably be adequate to beat the much bigger German engines." That is fair and citeable. In his other book (Development of Piston Aero Engines) he notes that the extra 300 hp available from 100 octane fuel was needed to "offset the greater weight of the British fighters", swings and roundabouts then! He doesn't compare either of the German engines to the Merlin apart from mentioning their advantage of fuel injection that "embarassed the RAF in the Battle of Britain." Arthur Rubbra makes no comparison in almost 50 pages on the Merlin but notes, the same as Bill Gunston, the fuel injection advantage. If and when we do include a comparison section (and there is no rush) it has to be 'bombproof' with no bias. I think there is a general expectation on WP to provide comparisons or 'more meat' than can actually be found in reliable sources on a subject, all we are doing is the same as any other reference source, providing accurate facts with, in the case of the Merlin article, some very carefully chosen and hopefully interesting words between them. Cheers Nimbus (Cumulus nimbus floats by) 20:09, 10 October 2009 (UTC)[reply]

Very strangely I just found this by accident as an example: Talk:Battle of Britain#Speed without context, it appears to have been answered by someone adding a couple of words in the article, could be fair but personally I would go looking in the aircraft article for more detailed info, presuming that it is there of course!! Nimbus (Cumulus nimbus floats by) 21:09, 10 October 2009 (UTC)[reply]

(ec) No a big fan of comparison section or articles they tend to be a breeding ground for NPOV. But would a article on pre-war piston engine development that covered British, German, American, Italian, Japanese and Russian piston engine development be better. It would not need to compare just summarise the development of each countries piston aero-engine development in the early 1930s. The reader could then do their own original research. MilborneOne (talk) 21:15, 10 October 2009 (UTC)[reply]

That's a good idea – put all the bare facts together in one place that can then be linked to. It sounds contradictory but I wasn't attempting to create a full-blown comparison section, just a few words to place the Merlin in the scheme of things. The 23% figure was a simple calculation that I thought would not be controversial, and was therefore written after the ref point. However, a reword taking out the power comparison seems fair if there is any dispute, but still leaving a mention and brief description of the other designs as I still think the relative size of the Merlin should be noted. To be completely unbiased, perhaps both Gunston quotes could be worked in? The second quote mentions heavier fighters though, which indicates the Merlin was powererful enough to overcome the extra weight, albeit with higher octane fuel – still swings and roundabouts? Good points about urgency and being bomb-proof – what we're talking about is not a lengthy addition by any means, but it does need to be worthy and fit for inclusion. :-) --Red Sunset 21:29, 10 October 2009 (UTC)[reply]

(EC) Yes, I think that is a very good idea (Milb's suggestion), writing it though is a different matter as it is a fair sized subject! Gunston's 'Development' book has more than enough material for something like this. It could answer questions that I have in my head and others probably do too like 'why were most of the WW II engines V-12s?' The more I look at early engines from differing countries and manufacturers, the more similarities I can see. They were all looking at what everybody else was doing at a guess. Still happens today. Might bring this up at WT:AETF to see if there are any volunteers! Cheers Nimbus (Cumulus nimbus floats by) 21:37, 10 October 2009 (UTC)[reply]

We had a big problem in the engine task force until recently where an editor was adding a simple calculation in the specification sections (it actually was not that simple and involved many variables), the problem was that it was to add a figure not asked for and deemed OR after a long discussion by all the task force members. At times the tiniest innocent self-calculation to 'advance a position' can cause problems, I agree that a simple percentage figure clarifies the capacity difference, the reality I think is that all we are effectively allowed to say is 'bigger' or 'smaller' and let the reader work it out for themselves if they want to. That's how I understand it but the bottom line is that we or anyone else can ignore all the rules! It's all fun for sure. Nimbus (Cumulus nimbus floats by) 21:51, 10 October 2009 (UTC)[reply]

Okey-dokey – no problem! :-) --Red Sunset 21:55, 10 October 2009 (UTC)[reply]

Was just thinking about Gunston's comment, it was not necessarily R-R's fault that the engine ended up in 'fat fighters'! I should have looked at his book a bit harder, there is some info on the decision to privately fund the engine, it was voted for by the board, could be added in at the expense of a few words, apparently Hawker did the same with the Hurricane so he says. Anyway, I have new e-mail from 'Irina' in Russia (about 40 of them in fact), I wonder what she might want!! Nimbus (Cumulus nimbus floats by) 22:13, 10 October 2009 (UTC)[reply]

Would Irina be sending info on Russian aero engines? Some more interesting Flight articles: Merlin I 1937, - 2845.html2845.html Engines at Milan 1937, "Some Trends in engine design 1938,German Aero Engines 1939. "Some Trends" describes some engines which were -um- interesting. Hispano Suiza's Type 82 & 90 which used two superchargers and TWELVE carbies apeice (how would you like to balance 12 carbies - on an open airfield in the middle of winter?) or the Lorraine Sterna driving an extension shaft and two bladed contra-rotating props. Who has memories of the "2,000 h.p. Allison Xs for the projected Seversky transatlantic seaplane"? Minorhistorian (talk) 22:38, 10 October 2009 (UTC)[reply]

'Irina', was sadly not my type although I did tell her that I had recently bought a very interesting and comprehensive book on Russian piston engines, at that point she hung up for some unknown reason!! There is so much stuff out there, like the universe, too much to take in sometimes. Even harder to write it all down here for future generations overnight. I believe strongly in the idea of Wikipedia and get mildly annoyed when people scoff at our efforts. To get swiftly back on topic (slipped there for a second!) we can be justifiably proud that this article is recognised as one of the finest, even if it is not finished or absolutely perfect yet! Nimbus (Cumulus nimbus floats by) 22:59, 10 October 2009 (UTC)[reply]

In agreement with certain editors who consider it a minefield - It seems the adding of 'context' is really about adding a section about adding POV content about how the Merlin compared to the contemporary competition, by using red herrings like comparing displacements, and forgetting about the contenxt. The displacement is fairly irrelevant (in fact, the greatest handicap for the Merlins development, recognized by RR as well but the 35 liter Griffon did not managed to replace it), as what mattered in terms of engine effiency was size and weight. And as far as these go, the 'small' Merlin was not smaller or lighter than the 'bigger' engines out there; the early single stage Merlins weighted around 610 kg, the same as the 33 liter DB 601s and was of similiar size; the French equivalant, the 36 liter Hispano-Suiza 12Y weighted as little as 465 kg, and was somewhat smaller in its dimensions, despite being 23% 'bigger'. The comparison in the sandbox neither mentions the consumption of the engines, where as the war progressed, the small displacement Merlins compared increasingly poorly to the larger displacement engines, as with small displacement the only way to increase output was to increase supercharging capacity; and driving a supercharger of that size did not came free either, it consumed fuel, and power. Advancing a non-NPOV, based on dubious OR arguements into the article just to boast about the favourite engine does it disservice IMHO and as per experience. If this *must* be done (although it seems to be fairly uncommon in other aero engine articles), it would probably require proper discussion beforehand, steady sources, and avoiding conclusions. For example, comparing the main specs for these engines in a table of sorts, using reliable sources, using engine variants of comparable timeframe, instead of picking certain statistics out of context to put it into 'proper' context. Kurfürst (talk) 23:22, 10 October 2009 (UTC)[reply]

In re the comparo article, I'm whole-heartedly in agreement. Esp if it'll include the lesser-known (to me, anyhow...) Russian engines. Some discussion of the engineering resources would probably be appropriate, too; it's one reason (certainly not the only one) Japanese engines didn't get much beyond the 940hp Sakae 12.

In re the comparo tween Merlin & co, Nimbus, it appears I mistook your point. I don't disagree with a "gen 1" comparo; just needs to be clear (to avoid complaints from the likes of me who don't read carefully enuf ;D).

In re the fuel consumption & boost, IMO that's an interesting issue that a) should be mentioned here & b) deserves fuller attention elsewhere. Ditto the choice of V12. (I have a vague recollection it's both EZr to balance a V12, & get hi revs, =hi hp, than other types.) There's also the question of choice of supercharger over turbo & why the respective parties chose 1 over another. (OT, there's a question why the U.S. was so far behind on jets when there was early emphasis on turbos...)

And not to open another can of worms, but coolant & cooling system pressures are also a factor. With fuel, I'm a bit leery of giving it too much attention; it's not directly an engine design issue, IMO, tho things like increased CR to take advantage, or (less directly) plug fouling, are. Ditto coolant; not directly a factor, but taking advantage of better coolant is, & pressurinzing the cooling system definitely is. (Which this suggests wasn't common on earlier German engines, but was on Brits, maybe 1 reason why they outperformed.)

One last point, FWIW, there's a historical context: WW1, Germans had the best engines, WW2 the Brits did. If there's an "aeroengine development" page, IMO, why that happened would be very interesting... (Dare I suggest Versailles worked...?) TREKphiler ^{hit me ♠} 00:50, 11 October 2009 (UTC) (P.S. Do you suspect each of 12x1bbls was tuned to provide exactly the fuel each cyl needed? And the erks still hate the designer?;p)[reply]

Wow! This has turned into a very interesting debate. It seems that any form of power comparison is going to cause problems one way or another, and will be a constant source of unrest if added to this article. The issue is obviously too complex to cover in what was supposed to be a brief indication of where the Merlin stands in relation to V-12s developed at the same time in other countries (Not boasting about my favourite engine!), so best leave power out of it. To that end I've written an adapted version ready and waiting to be blown out of the water! However, there is a general feeling that a comparison article could properly cover all the issues commented on above. My knowledge in this area leaves much to be desired, though I do understand each and every argument here and am learning all the time. Notwithstanding, it is evident that within this distinguished assembly there are those that do have the knowledge and sources, so how about it?! --Red Sunset 17:28, 11 October 2009 (UTC)[reply]

From the wiki-technical point of view, the problem I see with such an article is the lack of reliable sources. This is an extremely complex subject, and from what I have seen, not very much covered by literature.. which probably leaves the OR the only option (I am not sure if we can technically write such an article, even if all editors agree the content.. or can we?). If we go into the why and ifs I dont think it can work out, but perhaps it is possible to show some trends (ie. the choice of V12s, pressurized coolant, boosting, new solutions applied to engines such as DFI, supercharger solutions - turbos, intercoolers, Planiol, DVL type etc.) primitive electro-mechanic "computers" etc.) and a neutral comparison of the major specs of these engines (for which there ARE reliable secondary sources)...? Still, I can't escape the feeling that such a work, however well written it could be, belongs more to websites rather than wiki. Regardless, I would be happy to share my considerable collection archive sources (I have probably around a couple of thousend pages worth on WW2 aero engines, manuals, original datasheets, evaluations and such). Kurfürst (talk) 18:24, 11 October 2009 (UTC)[reply]

I think that Gunston's 'development' book has most of the answers, I have had it for a while but not really read it properly, I just found more Merlin/German engine comparison statements in there but they are quite general, he does say that the British trend of V-12s stems from the Schneider Trophy which makes sense. One thing that occurs to me is that types of piston aero engine are not yet categorised, Category:V12 aero engines would be a quick link to round them all up (where readers could 'surf' them for their own comparison studies). It would help as well when looking for 'Comparable engines' for the 'See also' sections as I see some strange entries sometimes. Categorisation of engine articles has fallen behind due to the use of navboxes but it is something else we need to look at in WP:AETF (we've only been going for 10 months!), there are some people who delight in deleting categories, if they are 'tight' enough though I think that they are very useful. Our aircraft articles are categorised in many ways, role, nationality, decade etc. It's in my head to fix it for the engines eventually, cheers Nimbus (Cumulus nimbus floats by) 19:44, 11 October 2009 (UTC)[reply]

I don't think we need OR. When I say "why", I'm thinking, maker/designer considered ishs of revs, friction, balance, so forth, & said, "I think an X23 makes most sense." No OR, assuming there's a record, & I presume the design histories say that much. Yep, it's a biggie, but doable, I think. And if this is to be a comprehensive encyclopedia, this is the place. (Of course, that's always my excuse.. ;D)

On categories, agreed. I don't find them useful, myself (generally more specific in searches), but I can see how they can be. I like the "see also" & "comparable type" headings better.

One final note: this is the period of change from pen & paper, guesswork & experience design to wind tunnels & computers & careful engineering: the airframes & engines started to have to be pared to the bone, & to do that, it became necessary to know exactly what was needed & no more, where before, a "fudge factor" was OK. This also should be addressed, IMO.

Do we need more server capacity for this yet? ;p TREKphiler ^{hit me ♠} 21:28, 11 October 2009 (UTC)[reply]

One minor comment: The era of wind tunnels (originally called wind channels) began much earlier, at the UK NPL amongst other places, certainly in 1919, maybe even earlier. The early report subjects of the Advisory Committee for Aeronautics give insights into the research topics of the time. Well worth a look for those interested in the development of aviation research. Not so many on aero-engines, if my memory serves me correctly. Another thought on the use of computers - surely that came some time after WWII? --TraceyR (talk) 20:32, 13 October 2009 (UTC)[reply]

You've lost me there! Wind tunnels are not mentioned in the article, might have been mentioned here, I can't remember. As a 'coal hole' worker there is no substitute for 'proper' testing in the air or on the track. Aware of this page turning into a forum I would like to archive this page for ease of navigation if there are no objections. Fantastic achievement folks. Nimbus (Cumulus nimbus floats by) 23:26, 13 October 2009 (UTC)[reply]

^ Berger&Street, 1994. p. 199
^ Berger&Street, 1994. p. 199
^ The air at higher altitudes weighs less per cubic centimetre than it does at sea-level
^ Smallwood 1995, p. 133.
^ ^a ^b Price 1995, p.14
^ Note: The second stage starting was often accompanied by a noticeable jolt, which inexperienced pilots often mistook for some type of engine malfunction.
^ Smallwood 1995, pp.132–136.

[1] Berger&Street, 1994. p. 199

[2] Berger&Street, 1994. p. 199

[3] The air at higher altitudes weighs less per cubic centimetre than it does at sea-level

[4] Smallwood 1995, p. 133.

[Price_1995,_p.14-5] Price 1995, p.14

[6] Note: The second stage starting was often accompanied by a noticeable jolt, which inexperienced pilots often mistook for some type of engine malfunction.

[7] Smallwood 1995, pp.132–136.

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