Talk:Packard V-1650 Merlin

Moved below to this page
It should be noted that the project engineer at Packard was Nils Joel Skrubb, a Finn, educated in Engineering in Helsinki who emigrated to the US to work for the the Packard Motor Company in the 1930's. He completely revised the Rolls Royce design to American Standards after spending six months of detailed study and memorization and conversion. The Brits found it difficult to accept that the Packard version was superior. A common misconception was that it simply was the Rolls design. It was completely revised and redrawn.––71.238.187.240 (talk) 06:05, 25 December 2010 (UTC)

This may be correct but needs editing into an encyclopedic form and better references. 122.107.58.27 (talk) 08:21, 7 January 2011 (UTC)

Note that I've added several sentences to the lead paragraph that may address concerns about an adequate summary of contents and the need for an accessible overview.

˜˜˜˜ —Preceding unsigned comment added by Yankees98 (talk • contribs) 18:50, 21 May 2011 (UTC)


 * completely revised the Rolls Royce design to American Standards - then why did they feel the need to replicate completely the BSF and Whitworth nuts and bolts used on the engine. Packard was under a licence agreement with RR that precluded 'tinkering' without RR's agreement. All modifications, including those involved only in the method of manufacture, had to be submitted to the design authority - Rolls-Royce - and that meant everything. What the writer probably originally meant was that the drawings were re-drawn using American drafting standards so that an American-trained machinist would be familiar with the terms used. That is not the same as 're-designing'. Once you take a known good design and start making radical changes you enter the realm of the unknown, where everything needs re-testing to ensure that it is safe for flight and that adds considerably to the time needed to bring the engine into use. Aero-engines have to achieve mandatory Type Tests that certify the engine as being suitable for use in man-carrying aircraft, and only a fool would alter the design of a proven engine necessitating much lengthy and time-consuming re-testing. And RR had been designing and testing the Merlin engine since around 1935 so by 1940 when Packard came on the Merlin scene RR already had an accumulated time of around five years of the engine being in use.


 * ... and Rolls-Royce had built this engine, the Rolls-Royce R in 1929, when Packard hadn't built anything of note so quite what Packard had to teach RR about building high-performance aero-engines engines I don't know.


 * The only noticeable difference between the RR and Packard-built engines was that the Packard engines tended to be more nicely finished on the exteriors. Pilots didn't mind who made the engines as from their POV there was NO difference.


 * Packard were free to suggest possible modifications to RR and also to try them out on their own Merlin engines, but it was RR's responsibility to ensure that the engine still met it's certificating requirements, and so any alterations to either design or manufacture had to be approved by Rolls-Royce.


 * Oh and BTW, in 1946 when the F-82 Twin Mustang entered service the US Government were still having to pay RR royalties on the Merlin design, which is why North American were forced to change the later F-82s to use the Allison V-1710 engine. And you can bet your life that if Packard had made any notable design contribution to the Merlin the USGs lawyers would have found a way out of paying Rolls-Royce. — Preceding unsigned comment added by 86.112.68.219 (talk) 21:16, 15 June 2011 (UTC)

Yes... It's funny how Rolls-Royce are still in business and Packard aren't. Packard's manufacturing standards were excellent and RAF mechanics liked the Packard engines, particularly because of the toolkits supplied with them, but the performance of each Packard model was about the same as the Rolls-Royce pattern it was based on. Performance of the Spitfire LF.IX (RR Merlin 66) was rated exactly the same as the LF.XVI (Packard Merlin 266). On the Lancaster, the Pilot's and Flight Engineer's Notes: Lancaster, A.P.2062A, published by the Air Ministry (pp.27-33), show little difference between RR and Packard units. The bomber would perform just the same, and the only significant difference was that Packards gave slightly lower fuel consumption at low power (for instance 200 gallons per hour at 2,000rpm +7psi high altitude cruise compared to the Rolls-Royce unit's 212 gallons -- p.32) and markedly higher fuel consumption at high power (420 gallons per hour at 2,850 +9 maximum climb compared to the Rolls-Royce unit's 380 gallons -- p.33). Khamba Tendal (talk) 18:19, 17 August 2015 (UTC)


 * That was probably due to the different carburettors used - RR-built engines had SU Carburettors, Packard-built engines had ones of Bendix design. The carburettor is built-in to the induction system and to have ordered engines without carburettors would have delayed their use on arrival in the UK (or elsewhere, such as Canada or Australia) until carburettors could be fitted and adjusted. The fitting of Packard-built engines with a different carburettor is the reason that otherwise identical aircraft had different Mark numbers, e.g., the Lancaster I and Lancaster III. The Canadian-built Lancaster X also had a slightly different fuel system hence the new Mark number rather than simply being a Canadian-built Mark III.


 * The original 1940 British engine order to Packard was signed under "Cash and carry" and paid for with cash (before Lend-Lease) by the UK so Packard was required to build the engines just as the customer - the MoS - ordered. To have done otherwise would have constituted a breach of contract by Packard.


 * All Packard-built engine "dash numbers" had a corresponding Rolls-Royce designation denoting the engine upon which they were based, IIRC the V-1650-1 was the US-built version of the Merlin XX. The only other changes between Rolls-Royce and Packard engines were in the reduction gear ratio and propeller shaft, this differing depending on the aircraft/propeller combination the engine was intended for. UK-destined engines had a standard SBAC 'Universal' propeller shaft for Rotol/de Havilland propellers, US ones a shaft for a Curtiss Electric or, IIRC, Aeroproducts propeller.


 * BTW, if someone orders something from you to a specific design, and pays you in advance for it, and then you "redesign" it you risk the "redesigned" engines being rejected by the customer as unsuitable and losing the order. Thus if the "redesigned" engines had arrived in the UK and the fitters who would be working on them found that they now needed a whole new range of spare parts, specialised tools, spanners/wrenches, etc., they would not have been pleased. This simple fact ought to be fairly obvious.


 * Taking out a licence for something is different if you are making it solely for your own use. Both Curtiss-Wright and Westinghouse took licences for world-beating British jet engines post-war that if simply built as-designed might have saved the companies. Instead both decided they could "improve" them, and now no-one has ever heard of the J67 (Bristol Olympus licence) or the XJ54 (RR Avon licence), and the Wright J65 (Armstrong Siddeley Sapphire licence) only just made it, being delayed two years by its "redesign". Neither Curtiss-Wright nor Westinghouse are still in the engine-making business. With these engines they were offered potential lifelines that they then chose to throw away. Luckily Packard in 1940 chose not to. BTW, the Avon (designed in 1945), in its industrial version is still being built and sold today, in 2015..


 * So no, the Merlin wasn't "redesigned" by Packard. It would have been a very stupid thing to do. Packard OTOH may have suggested improvements to RR who would then have evaluated the ideas back in Derby and if thought desirable, after extensive testing, incorporated them into the design issuing updated drawings to all the factories, including Packard's in the US. — Preceding unsigned comment added by 2.29.18.231 (talk) 13:05, 20 December 2015 (UTC)

I think at one point Packard were allowed to make a change to the oil-feed piping and it didn't work and RR had to make them change it back. At another point Packard Merlins started blowing up and RR found that the Americans had never implemented a conrod mod that they were ordered to make because RR had detected a potential cause of failure. The failure would only occur if there were slight metallurgical flaws in manufacture, but RR ordered a design mod to stop it happening and Packard ignored it. RR looked at some Packard conrods and found that not only did they not conform to the mod, but they were pointlessly over-polished. They looked great, as if anyone was going to look at them when they were powering a Lanc over Germany, but the over-polishing increased the chance of metallurgical failure. So words were had, and Packard had to agree to behave in future.

The idea that Packard 'improved' the Merlin is rah-rah stuff and is not correct. When they chose the Wright blower drive for the two-stage version (which is why Mustangs and Spit XVIs whistle in that weird way) it wasn't any worse, but it wasn't any better either. Later they tried to design their own blower drive and, if you've ever seen the drawings for that thing, you will have concluded, 'Either the bloke who drew that was on drugs or I am.' Only two of those engines were ever actually built, and they never flew, which is probably just as well. Khamba Tendal (talk) 19:43, 2 November 2016 (UTC)


 * The actual 'redesign' consisted of taking the Rolls-Royce design drawings drawn in the first-angle projection used in the UK and re-drawing them using the third-angle projection that is commonly used in the US.  — Preceding unsigned comment added by 95.149.173.74 (talk) 19:55, 30 May 2016 (UTC)


 * " ... because of the toolkits supplied with them" - Packard had to later provide tool kits with each engine as US users would not have had any tools that fitted the BSF and Whitworth fittings on the engine. The RAF already had the specified tools so the included tools would have been a nice 'bonus' for the fitters. — Preceding unsigned comment added by 95.150.10.186 (talk) 09:52, 19 September 2016 (UTC)


 * IIRC, Rolls-Royce didn't charge the USG for royalties on the Merlin until the war had ended. That's why the USG had NAA re-engine the F-82 with the Allison after 1945 as from then on royalties would be due. — Preceding unsigned comment added by 95.150.18.249 (talk) 08:43, 1 July 2018 (UTC)


 * "' .... Packard Built Merlins


 * An often asked question is; "did Packard replicate the British thread system when they built Rolls-Royce Merlins under license during World War II?" The answer is yes; all threads that were used on the Merlin were accurately replicated by Packard. This would include BSW (British Standard Whitworth), BSF (British Standard Fine), BSP (British Standard Pipe) and BA (British Association). Having said that, however, Packard Merlins used U.S. built Bendix injection carburetors; PD-16 for single stage engines and PD-18 for two stage engines, both of which used U.S. Unified threads. British built Merlins employed S.U. carburetors using Whitworth threads. The job facing Packard when they undertook manufacture of the Merlin was daunting to say the least. It’s bad enough having to build a complex product like the Merlin but exacerbating the situation was the fact no tool maker in the U.S. made Whitworth taps or dies. Therefore, Packard were forced into making their own. Although this created a significant hurdle to overcome, the effort was well worth it, Packard and Rolls-Royce components were interchangeable."


 * From here:  — Preceding unsigned comment added by 95.144.50.228 (talk) 08:50, 23 May 2021 (UTC)

Boost Pressures
The +6 figure in the table figures seems to be a bit off. The conversion factors shown would support this.

The others are close. AMCKen (talk) 20:05, 26 May 2011 (UTC)

Odd turn of phrase
"and Packard Motor Car Company was eventually chosen because the parent British company was impressed by its high-quality engineering"

What does this passage mean, who is the "parent company" and what are they parent of? It seems to be implying that Packard had a parent company in the UK, or that Rolls was that parent, yet I do not believe either is true. I believe the statement is simply trying to say that Rolls was impressed by Packard, but the wording implies something else. Maury Markowitz (talk) 13:57, 29 July 2011 (UTC)


 * This is the neutrally worded summary on the V-1650 from the Rolls-Royce Merlin article (cites removed):


 * As the Merlin was considered to be so important to the war effort, negotiations were soon started to establish an alternative production line outside the UK. Rolls-Royce staff visited a number of North American automobile manufacturers in order to select one to build the Merlin in the U.S. or Canada. Henry Ford rescinded an initial offer to build the engine in the U.S. in July 1940, and the Packard Motor Car Company was subsequently selected to take on the $130,000,000 Merlin order. Agreement was reached in September 1940, and the first Packard-built engine, designated V-1650-1, ran in August 1941.


 * I can re-check some sources but I seem to remember reading that Rolls-Royce visited several companies in the US and eventually chose the one best able to take on the task. There is probably a lot more to the decision than is included here. Perhaps 'parent company' should be replaced with 'Rolls-Royce' for clarity, that phrase is not cited. Current cite three is probably just for the first run date, which I probably added looking at the source. Nimbus (Cumulus nimbus floats by)    20:05, 29 July 2011 (UTC)


 * The contract was originally intended to have been awarded to Henry Ford but he was a noted Anglophobe and pro-German, and refused, so it went to Packard instead. — Preceding unsigned comment added by 80.7.147.13 (talk) 19:38, 23 January 2013 (UTC)


 * Ford instead responded with a similar V12 aero engine of their own design but no-one bought it so it was redesigned and cut-down to a V8 for vehicle use as the GAA. — Preceding unsigned comment added by 80.7.147.13 (talk) 12:58, 21 December 2013 (UTC)


 * Before the Fall of France the French government were intending to use the Merlin in a French fighter, poss. the Dewoitine D.520, and arranged with Britain for Merlin drawings to be supplied to them, and it was they, France, who initially contacted Ford, supplying Ford with a set of drawings. I suspect it was the French surrender that influenced Henry Ford into refusing the order, for the only country they would then be supplied to was Britain. With this, Britain carried on with the order alone, and offered it instead to Packard, who accepted. — Preceding unsigned comment added by 95.144.50.240 (talk) 09:37, 22 September 2016 (UTC)

Purpose of scheme?
The second sentence of the very first paragraph is at variance with my understanding.

< The engine was licensed in order to provide a 1500 hp-class design at a time when US engines of this rating were not considered ready for use. . . >

It says (to me) that the engine was licensed by Packard from R-R for the US. I suggest that it is nearer the mark to say that it was licensed from R-R to Packard for the UK. 86.18.201.189 (talk) 00:34, 15 June 2012 (UTC)

I don't have cites, so this appears on the discussion page. In 1940 the number of engines required was more than RR could produce. They contracted Packard to copy their engines, as they found the Packard parts were interchangeable with their own. (This engineering requirement is not as simple as it sounds.) The State Dept intervened in Jan 1942, stopping the export of all supercharged engines. It was ploy to confiscate many hundreds of engines which had already been paid for by the British govt. RR ceased Merlin production in Aug 1944, and all subsequent Merlins were made by Packard. RR had taken the jet engine contract from Rover, and they were also retooling their factories for the Griffon engine. 220.244.76.70 (talk) 10:30, 24 November 2012 (UTC)


 * At the time (1940) Rolls-Royce's Merlin factory in Derby was a target for German bombers and significant damage would have halted Merlin production completely. The Merlin was essential to the defence of the United Kingdom as it powered the two main British fighters involved in the Battle of Britain - the Hurricane and Spitfire. It also powered the Defiant.


 * The Merlin licence was for Britain to obtain US production of an essential engine away from the possibility of bombing - all the Merlins used in the Battle of Britain were produced at Derby. The Packard-produced Merlins were only originally intended to be used in British aircraft, and the US government had no interest in the design - they had the Allison V-1710 - until much later when it started to be used in the Kittyhawk and later the Mustang.


 * And the two-stage Merlin 60-series - built by Packard as the V-1650-3 - was devised by Stanley Hooker and intended for the high-altitude Wellington VI and had little to do with Packard. The original test rig used a Vulture supercharger in-series with the  Merlin's own supercharger.  — Preceding unsigned comment added by 80.7.147.13 (talk) 10:07, 24 January 2013 (UTC)


 * A 1943 Flight article about misleading US reporting of the Merlin 61 and Packard;  — Preceding unsigned comment added by 80.7.147.13 (talk) 16:12, 3 February 2014 (UTC)

Postwar use
Some false credit to the Luftwaffe for intake cooling design and its MW 50 used during WW2. The did use water/alcohol in some planes during the war but infact the master of this technology was Pratt & Whitney who got better results than the Germans. The German system (Wassereinspritzung) was direct injection of water/alcohol into the cylinders which did give benefits but not as good as the Pratt & Whitney system which injected into the intake just down stream of the supercharger. This allowed the fluid to evaporate in the intake and cool the incoming charge creating a denser charge of the cylinder and resulting in more power. The ADI (Anti-Detonate Injection) system in the entry is injection into the intake, as the P&W system was so any reference to the MW 50 (Wassereinspritzung) system is completely mis-credited. A Pratt & Whitney engineer, Frank Walker did most of the development work on this and if you look you will find this well documented www.enginehistory.org/Frank%20WalkerWeb1.pdf .66.159.206.125 (talk) 01:54, 28 January 2013 (UTC)


 * I believe the largest post-war use of the Packard Merlin was in the Avro Lincoln and the Canadair 4.

Design and development
Pontiac Division of GM is given credit for the Indium coated bearings. This is an innovation usually credited to Pratt & Whitney. I'd like to see some documentation on this. If Pontiac Division of General Motors did develop this, don't you think that Allison (another division of GM) would have been the first to get it? Actually I suspect that people at Pontiac were the go-betweens from P&W and Allison and this was transfered to the Packard-Merlin program as well.Corumplex (talk) 02:34, 28 January 2013 (UTC)

Edit to lede
The lede has been trimmed down of the following content, which goes beyond the scope of the lede for the subject of the article. Either it should remain excised or a section on the V-1650's use in the Kitty Hawk and Mustang integrating it should be created.


 * By 1944, P-51B, P-51C and P-51D "Merlin" Mustangs were able to escort Allied heavy bombers in daylight to and from Berlin yet were still capable of dogfighting with German fighters en route. By late 1944, the Allies had won air supremacy over the whole of Germany, and Germany's defeat in World War II became inevitable.

User BilCat please note editing changes made to the above improving the original passage.

Wikiuser100 (talk) 12:07, 14 June 2014 (UTC)


 * I'm still trying to figure out how 1944 is "postwar". Lol. - BilCat (talk) 12:17, 14 June 2014 (UTC)


 * It was transitional, trying to avoid just this sort of edit war by someone insisting that content belonged back in the lede.
 * The situation is clear here: either stop reverting and accept the edit or do something (as suggested above) to appropriately integrate it elsewhere in the article. One more revert and you know we're going to have to bring an Administrator in, and nobody wants or needs that.
 * Do note again that the content at question has been edited to improve its thrust and flow before cut-and-pasting it into a new section if that proves your intention. Yours.  Wikiuser100 (talk) 12:25, 14 June 2014 (UTC)


 * The situation is clearer: you were bold, I reverted you, then came here to discuss it, per BRD, only to find you reverted again. Frankly, the previous version is better than the transitional one. Do a complete job, not that I think anything is necessary, or leave it alone. - BilCat (talk) 12:36, 14 June 2014 (UTC)


 * To this point, we can call our previous edits "revert-discussing" and try to hammer out an acceptable compromise before making any further changes. But please note that if you report me for edit warring, you'll likely be blocked by the admin at the same time, so tread carefully. - BilCat (talk) 12:43, 14 June 2014 (UTC)
 * I'm thinking the comment belongs on the P-51 page, not here, since the V1650 alone didn't do the job. (I didn't look to see if the V1650's use in the P-40 is here, but I agree, it should be.)  TREKphiler   any time you're ready, Uhura  20:58, 16 June 2014 (UTC)

The lead is all wrong in any case, since the Packard Merlin was not built because of a lack of American engines in that power class but simply because the customer, the British Ministry of Supply, wanted a shadow plant to produce Rolls-Royce Merlins beyond the range of German bombing and without making calls on British manpower. (And Packard was about to go bust and needed the work, so the hands across the sea weren't only extended one way.) The lead is also wrong to suggest that the original use of the Packard Merlin was the insignificant P-40F when the original Packard Merlins were actually built, to British order and at British expense, to power RAF Lancaster Mk IIIs. Khamba Tendal (talk) 19:19, 13 April 2016 (UTC)


 * At the time of the Merlin contract in 1940 the US had the Allison V-1710 of around the same horsepower so that statement isn't true either. And in 1940 the production Merlin wasn't developing 1,500 hp, it was producing around 1,030 hp. — Preceding unsigned comment added by 95.149.247.101 (talk) 08:42, 9 May 2017 (UTC)
 * Exact hp is a problem, since it wasn't like the Merlin only produced that much or Packard was buidling V1650s to a "1500hp spec", so I've removed that. As for the P-40, that's first use & deserves mention, however historically trivial it was.  TREKphiler   any time you're ready, Uhura  18:32, 9 May 2017 (UTC)

Does not make sense
I edited a paragraph which said "The engine also filled a gap in the U.S. at a time when similarly powered U.S. made engines were not available." I changed it to similarly powerful. Engines are not powered, they create power. But engines can be similarly powerful. My edit was reverted. Maybe it wasn't optimal, but I believe it was light years better than the original. Any comments. Moriori (talk) 02:34, 6 February 2018 (UTC)


 * You could try 'similarly rated' or 'of equivalent rated horsepower' but that might be too technical for some. In any case, the full statement isn't true, the Allison V-1710 being of similar power in 1940, and anyway the Packard contract was a private one between Packard and the UK solely for producing engines for the UK. The contract was signed in 1940 when Cash and Carry was in force. — Preceding unsigned comment added by 95.149.173.5 (talk) 12:24, 13 March 2018 (UTC)
 * I'd agree it needs fixing. I'm not a fan of "similarly", & "equivalent" implies too close a match. What about "U.S. engines of comparable power"?  TREKphiler  any time you're ready, Uhura  13:16, 13 March 2018 (UTC)
 * In terms of US defence procurement, the significance is that, until the British set up the Packard Merlin production line in Detroit, there was only one large inline US aero-engine and that was the Allison V-1710. There were various high-powered air-cooled radial engines -- an American speciality -- but only the one high-powered liquid-cooled inline engine. The Packard Merlin offered an alternative, which was why, in 1941, Lt Ben Kelsey at US Army Pursuit Projects earmarked two future Mustang airframes for trials with the Packard Merlin someday. (You really couldn't put a radial engine on a Mustang.) Of course, by the time North American got around to those trials in late 1942, Rolls-Royce and the RAF had already dropped a Spit F IX's two-stage Merlin 60-series into a Mustang and proved the concept. Packard duly produced the Merlin 61 as the V-1650-3, creating the P-51B, and the rest is history. Khamba Tendal (talk) 20:17, 22 May 2019 (UTC)


 * Actually there were other inline high power designs in development in the US such as the Wright Tornado, Pratt & Whitney X-1800, Chrysler IV-2220 etc., but they were cancelled or development was slowed after the prototype Vought XF4U achieved 400 mph on a radial engine in 1940. — Preceding unsigned comment added by 95.149.53.142 (talk) 09:06, 12 June 2019 (UTC)


 * These were not comparable at all, at best experimental designs, far too complicated to build, operate and maintain. --Denniss (talk) 09:13, 12 June 2019 (UTC)


 * You are correct, however after the XF4U flew in 1940 the US Army cancelled or reduced all support (funding) of new inline high-power aero engines. — Preceding unsigned comment added by 2.30.162.216 (talk) 14:34, 9 November 2019 (UTC)