Talk:Rolls-Royce Mustang Mk.X

Article name

Rolls-Royce Mustang Mk.X is a bit of a made up name it should either be the unofficial nickname "Rolls-Royce Mustang" or the official North American Mustang Mk X not a mixture. MilborneOne (talk) 19:46, 12 November 2013 (UTC)

Support change to North American Mustang Mk.X, its original location before being moved here. "Rolls-Royce Mustang" could apply to all Merlin-engined models, even those with Packard-built engines, so is somewhat vague. - BilCat (talk) 20:13, 12 November 2013 (UTC)

No, the Mustang X was a Rolls-Royce project, which produced the first Merlin-engined Mustangs. Although the USAAC had reserved two Mustang airframes from the British order at British expense for testing with the Packard Merlin (airframes 93 and 102) in 1941, this had still not been done at the time when Rolls-Royce tried it. The first North American XP-51B, a Mustang I with a Merlin 60-series and Hamilton four-blade prop, flew on 30 November 1942, weeks after the first flight of a Mustang X in England. And the subsequent production aircraft required fuselage strengthening to absorb the Merlin's power. Khamba Tendal (talk) 18:27, 22 June 2023 (UTC)

Bilcat please see attached reproduced documentation showing the Mustang X designation in official reports. These are PRIMARY sources. The Rolls Royce Mustang X name applied to 5 airframes that remained in the possession of RR for the entire war.

If you insist on 'North American Mustang that's fine but then its designation must be Mustang X not 'MK X' as there is no evidence in any official documentation of it being called this. (See AFDU reports attached below.) It was a Rolls Royce project on behalf of the Ministry of Aircraft Production with no NAA involvement beyond RR sending reports back to NAA and supplying engineers to help with their installation of the Packard built Merlin.

In effect, Rolls-Royce was the design authority for this aircraft (which was not a P-51 either, but rather a Mustang 1 (Model NA 83). RR had been developing the Mustang 1 since its arrival in the UK in late 1941 and sending reports back to NAA regarding problems and improvements. This is long before the A-36 (NA 97) and then P-51A (NA 99)existed or were in service with the USAAF.

Birch's book Rolls Royce and the Mustang (Rolls Royce Historical Society) is very clear on this with multiple official documents reproduced. Completeaerogeek (talk) 21:47, 16 March 2024 (UTC)

• Mustang Mk X seems simplest and avoids assigning a 'manufacturer' to the article title, where one doesn't exist as such. GraemeLeggett (talk) 09:14, 14 March 2024 (UTC)

  Graeme- where is the 'official NAA designation Mustang Mk X? What is the source? None of the citations in the article are NAA. NAA did not even name the aircraft Mustang. The RAF did that. In fact it took until 13 JULY 1942 until NAA requested to adopt the name Mustang in a letter to the USAAF PR Office from Dutch Kindelberger. Matthew Willis reproduces this text on P-58 of Mustang the untold Story. Completeaerogeek (talk) 21:32, 16 March 2024 (UTC)

The Merlin-Mustang project was never an NAA initiative but rather a Ministry of Aircraft Production project given to Rolls-Royce after it requested permission to experiment with a Merlin installation on the Mustang 1 following Rolls-Royce service liaison pilot Ronnie Harker's flight in the aircraft n 30 April 1942. The project was not run by, coordinated by or in any other way influenced by NAA.

In fact numerous letters from RR and MAP show that instead RR influenced NAA with NAA representatives (Lee Atwood amongst others) visiting Hucknall repeatedly and RR sending engineers to NAA. RR at Hucknall on behalf of the MAP, had been experimenting with and modifying and improving Mustang 1s and sending data back to NAA since the aircraft's arrival in the UK in late 1941. It was the de-facto development arm of NAA for this aircraft as the RAF was using the aircraft in combat long before the USAAF.

Accordingly, the correct name of the aircraft is the Rolls-Royce/MAP applied designation - Rolls Royce Mustang X or simply Mustang X. Rolls-Royce and the Mustang (Birch, David - Rolls Royce Historical Society 1987 shows in multiple places, using reproductions of original documents that the aircraft is never referred to as the 'MK anything'. Every letter and performance chart and evaluation (p 118-135) including a reports on p 129 signed by WGDCDR D.O. Finlay, CO of the Air Fighting Development Unit, the primary testing organisation evaluating the Mustang X and the many developments and modifications involved, shows this to be the case.

I am happy to be corrected if any one can find a primary source i.e. from Rolls-Royce that says otherwise.

This is akin to calling the RAF Mustang 1 and 1a, P-51s (NAA Models NA-73, 83 and 91) which they were not, as the P-51 was a distinct design, (Model NA 99) only came into existence after the A-36 and the P-51A.

There is a significant difference between applying a designation for convenience to a pre-existing aircraft (i.e. Mustang 1 to XP-51/P-51/F6A) and having nomenclature for an aircraft designed to a contract specification (NA 99-P-51A) Otherwise all Douglas Dauntlesses could be called A-24s.

The Mustang X was a Rolls-Royce development project for the Ministry of Aircraft Production and Rolls-Royce is in effect the manufacturer or design authority for this purpose. The aircraft never served with the RAF and so is not subject to the usual vagaries of the RAF numbering system. They remained with RR for the entire war. Rolls-Royce, AFDU, AA&E and RAE all have official documents describing it as the Mustang X and nothing else. These are primary sources, particularly Rolls-Royce as the design authority.

NAA was constantly informed of the developments to the Mustang X including having representatives on-site at Hucknall and RR sending engineers to NAA to help integrate the Packard Merlin. Birch's book contains numerous letters between NAA management and RR and other British agencies.

I am unsure as to how any other source or 'opinion' can take precedence over a primary source...

Stacking citations of opinions does not equal a fact. This kind of thing damages WIKI's credibility.

Also, how does not having the manufacturer in the title work? The WIKI article for the Boeing 747 is Boeing 747 not just '747'.

The article should be titled Rolls Royce Mustang X, as the official documentation shows. I have uploaded documentation below for Talk page purposes that confirms this. I am not sure how this shows on a 'talk page and it does not seem to allow me to upload more than one image.) https://wiki.riteme.site/wiki/File:AFDU_Mustang_X_report.png#file]] — Preceding unsigned comment added by Completeaerogeek (talk • contribs) 20:54, 16 March 2024 (UTC)

• Oppose removing "Mk." - Completeaerogeek's insistence on using primary sources over secondary sources is, in my opinion, a good example of why the WP:OR policy exists in the first place. They seem to have WP:INTERPRETed the absence of "Mk." or "Mark" in certain primary sources to mean that it was an exception to the British military aircraft designation system, or that the designation did not fall under the system in the first place; claims that I have seen no reliable secondary source support. I have provided Completeaerogeek with several secondary sources which refer to the aircraft as "Mustang Mk X" (pages 46 and 49 of P-51 Mustang: Seventy-Five Years of America's Most Famous Fighter by Cory Graff and page 19 of Warbird History: P-51 Mustang by Robert F. Dorr), but they have so far failed or refused to get the point and insisted on preferring primary sources. Wikipedia is not a credible source, nor does it claim to be. It is a user-generated encyclopedia built "largely on reliable secondary sources". "Mustang Mk.X" is demonstrably the WP:COMMONNAME for the variant, with a vast majority of reliable Google results using that form of the designation over "Mustang X". I have no comment at this time on the inclusion or exclusion of the manufacturer, nor whether North American or Rolls-Royce should be used. - ZLEA _T\^C 23:40, 16 March 2024 (UTC)

Also note that the AFDU report is possible WP:COPYVIO. I've tagged the file in Commons, and it will be deleted in 7 days if proper licensing information is not provided. - ZLEA _T\^C 23:43, 16 March 2024 (UTC)

I also suggest that Completeaerogeek opens a formal move request to get more eyes on this discussion. - ZLEA _T\^C 23:46, 16 March 2024 (UTC)

• Comment the AFDU says "Mustang X" in the report, but it also says "Spitfire IX" which we know is shorthand for "Spitfire Mark XI", so the AFDU report can be interpreted as evidence for the use of Mark in the title.GraemeLeggett (talk) 11:07, 17 March 2024 (UTC)

As there's no evident reason why the Air Ministry or Rolls-Royce would have applied such a high mark number at the time (the RAF only had the Mustang I, IA and II, and the P-51B would later become the Mk III), and as 'Mk' does not appear in contemporary documentation on the aircraft, it's possible that the 'X' stood for 'Experimental' and not the Roman number ten. It's also worth bearing in mind that, although Lt Ben Kelsey at USAAC Pursuit Projects originally set aside two Mustang airframes from the British order for trials with the Packard Merlin, which, once it later became available, would be the only large US-produced liquid-cooled inline aero-engine apart from the Allison, this came to nothing because Packard were at first only making single-stage-supercharged Merlin XXs for Lancasters. The whole point of the Merlin Mustang was to use a two-stage-supercharged Spitfire 60-series engine, so the project had to originate in England. The engines for the first two North American prototypes were shipped over to Inglewood by Rolls-Royce. NAA had to carry out the final proving stage on the installation and revised airframe, but it wasn't their initiative. And only then were Packards licensed to produce 60-series engines. Khamba Tendal (talk) 17:49, 5 September 2024 (UTC)

Evident reason or not, most reliable secondary sources agree that "X" was a mark number. Per WP:INTERPRET, we must not use the apparent lack of "Mark" in contemporary primary sources to override the consensus of reliable secondary sources. Also, the idea that "X" might have stood for "experimental" is purely WP:OR as it is not supported by any reliable sources, primary or secondary, that have been provided so far. - ZLEA _T\^C 18:21, 5 September 2024 (UTC)

Wiki is mainly a digest of secondary sources, but then secondary sources often embody mistakes and misunderstandings, and 'Mk X' is probably a back-formation from the plain 'X' found on contemporary paperwork. The highest Air Ministry mark number for the Mustang at that time was Mk II, applied to the yet-to-be-delivered P-51A (as the USAAF called it), a slightly modified Mustang I with the V-1710-81 engine, fixed radiator scoop and reduced armament of 4x.50-cal. When the Merlin-powered P-51B/C entered service with the RAF in 1944, it became the Mustang III. It is, to put it mildly, unlikely that the Air Ministry would have suddenly, randomly jumped eight mark numbers for no particular reason (if you know anything about the Air Ministry bureaucracy of those days), and there is no record of an intervening seven potential Mustang developments with mark numbers booked in, so this project, which could not directly result in a production aircraft, the production base being 6,000 miles away, was pretty obviously titled 'X' for 'Experimental'. You can call it the Mk X if you like, and people do, be my guest by all means, but the X clearly wasn't part of a numerical series. Khamba Tendal (talk) 19:04, 4 November 2024 (UTC)

If it were a mistake, surely there would be at least one reliable secondary source calling it out. You have still provided no sources for your claim that "X" meant "Experimental", and it was not uncommon for experimental variants of British aircraft to be assigned non-sequential mark numbers beyond the expected number of production variants (for example, Spitfire Mk XX). Unless you can provide such sources, I suggest you WP:DROPTHESTICK. - ZLEA _T\^C 20:09, 4 November 2024 (UTC)