# Remanufacturing a Packard V12 engine



## petertha (Aug 1, 2017)

https://youtu.be/9BXYUjLJPdc


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## goldstar31 (Aug 1, 2017)

Surprisingly, the Packard Merlin was positively hated in the real world. 

At least there is one genuine Merlin engine basher left. Another 'Goldstar' out of RAF 31 Squadron from 1949 days- when we were conscripts or convicts. There wasn't much difference in the treatment.

There is still a Spit out in Canada somewhere. SL-721 and lettered JM-R after the then 'boss' of Fighter Command, James M. Robb.
Boothman of the Schneider Trophy Supermarine S6B 'bent it' and someone else 'bent our ears' with the unsilenced exhausts.

Probably worth a bit more research

Norm


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## DICKEYBIRD (Aug 1, 2017)

goldstar31 said:


> Surprisingly, the Packard Merlin was positively hated in the real world.


Hey Norm, watch the video.  It's about a Packard flathead V-12 auto engine; not an aircraft engine.  

Great video Peter, thanks!


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## 10K Pete (Aug 1, 2017)

goldstar31 said:


> Surprisingly, the Packard Merlin was positively hated in the real world.
> Norm



Rolls Royce made the Merlin, not Packard.

Pete


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## goldstar31 (Aug 1, 2017)

10K Pete said:


> Rolls Royce made the Merlin, not Packard.
> 
> Pete


 
Packard made Merlins under licence.


Britain was desperately short of engines to go into Spitfires, Hurricanes, Lancasters, Manchesters and Mosquitos. In the question of the P-51D, the Allison was crap and a further need was for Merlins for long range fighter escort for our bombers.

I can see a number in my head despite the passage of nigh 70 years. 
Perhaps a phone call to my Merlin mate might reveal what 266 means

Meantime

Cheers

N


It's actually 626. What about that?


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## goldstar31 (Aug 1, 2017)

A few corrections for JM-R and the Report by Vintage Wings of Canada.

There is a photo of a Percival Proctor and whatever and a write up regarding Robb's Spit. 

It was NOT a Metropolitan Communications Flight aircraft but one of a trio of Spitfires which RAF 31 Squadron stationed at RAF Hendon under the command of Group Captain Terence John Arbuthnott as Station Commander looked after. He was a former P-51 jockey before this. Sl/ldr Arthur Fane De Salis OBE was the Commanding Officer of RAF 31 Squadron and Commanding Officer of the Flying Wing of Hendon.

Of course, Hendon was the Taxi rank for the British Air Ministry officers who wanted to keep their log books of flying hours up to date.


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## 10K Pete (Aug 2, 2017)

Yep, you're right, Norman. Thanks for setting me right!

Pete


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## goldstar31 (Aug 2, 2017)

10K Pete said:


> Yep, you're right, Norman. Thanks for setting me right!
> 
> Pete


 
The important thing was that Packard was available to supply much needed engines- onto airframes that we- Brits hadn't got.

It meant that long range escort US aircraft were there to defend Allied bombers- and bring the final result.

So my kind regards-- and thanks

Norm


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## dairwin (Aug 2, 2017)

goldstar31 said:


> Packard made Merlins under licence.
> 
> 
> Britain was desperately short of engines to go into Spitfires, Hurricanes, Lancasters, Manchesters and Mosquitos. In the question of the P-51D, the Allison was crap and a further need was for Merlins for long range fighter escort for our bombers.
> ...




Please excuse a newby member butting in!  A Merlin 266 is a Packard version of the Merlin 66 (Spitfire low altitude/ground attack).  A Merlin 626 is a civilianised post-war transport engine benefitting from late improvements for longer service intervals.

Regards,

David


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## goldstar31 (Aug 2, 2017)

dairwin said:


> Please excuse a newby member butting in! A Merlin 266 is a Packard version of the Merlin 66 (Spitfire low altitude/ground attack). A Merlin 626 is a civilianised post-war transport engine benefitting from late improvements for longer service intervals.
> 
> Regard
> 
> David


 

 Thank you for reminding me of the relevance of seemingly obscure numbers. A gap of 67 long and very eventful subsequent years.

I suspect that it is all to do with something called 'Pelmanism'

Thanks for the memory

Norman


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## goldstar31 (Aug 9, 2017)

The news broke that 'more than 20,000 workshop drawings have been discovered for the Wooden Wonder, the De Havilland Mosquito which used two R.R.Merlins.

Few aircraft could equal this aircraft in many, many roles in WW2. 

Amazing what could be done with seaweed and balsa wood. 

Cheers

Norman


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## kvom (Aug 9, 2017)

The Packard plant in Detroit, where the engines were assembled, is a still-standing ruin that occasionally serves as a movie set.

It was the first automotive plant that used steel reinforced concrete for the structural components, the main reason it has resisted demolition since the plant closed in 1958.


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## dairwin (Aug 9, 2017)

goldstar31 said:


> The news broke that 'more than 20,000 workshop drawings have been discovered for the Wooden Wonder, the De Havilland Mosquito which used two R.R.Merlins.
> 
> Few aircraft could equal this aircraft in many, many roles in WW2.
> 
> ...




Hi Goldstar,

The Mossie was certainly a multi-role aeroplane and the fastest for 2 years during WW2.  Hosted both RR built and Packard Merlins.

DAI

ps I had to look up Pelmanism!


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## dairwin (Aug 9, 2017)

kvom said:


> The Packard plant in Detroit, where the engines were assembled, is a still-standing ruin that occasionally serves as a movie set.
> 
> It was the first automotive plant that used steel reinforced concrete for the structural components, the main reason it has resisted demolition since the plant closed in 1958.



The Packard factory produced nearly a third of all Merlins made: 55,523 of a grand total of 168,176.  The three RR plants in the UK and the UK-Ford factory at Trafford Park manufactured the remainder.

I understand that on VJ day, newly machined crankshafts were being tossed out the Detroit factory window into loading bins for recycling :-(

DAI


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## Hopper (Aug 10, 2017)

So, did the US-made Packard Merlins use BSW/BSF threads and fastener hexagons, or UNC/UNF threads and AF hexes? Either way, one side or other would have been cursing that their spanners did not fit.


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## dairwin (Aug 10, 2017)

Packard fully adopted the thread forms as defined by Rolls-Royce (BA, BSF, BSP and BSW).  BA (1BA and 2BA) and BSF (1/4 BSF, 5/16 BSF) extensively used.

Some ancillary devices (e.g. internal screws of the later magnetos made by North East) did use US threads.

Additionally, RR modified some threads to their own spec which I have found an occasional challenge (e.g. the outlet union adaptor of the supercharger changeover valve has BSP one side and RR thread the other) .

Inter-compatibility was key during the war years, hence the Packard adoption.

DAI


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## kvom (Aug 10, 2017)

One reference I read said they used Whitworth threads too, and ended up making all their fasteners, as they were unavailable in the US in quantity.


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## ShopShoe (Aug 10, 2017)

Maybe it was here, maybe it was on a TV documentary, but supposedly RR experts visited Ford and Packard and decided that the machining capability at Packard would be better able to handle the work.


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## dairwin (Aug 10, 2017)

kvom said:


> One reference I read said they used Whitworth threads too, and ended up making all their fasteners, as they were unavailable in the US in quantity.



There are some BSW as mentioned. Two that come to mind is the drain  fitting to the fuel pump, and the ullage drain pipe from the priming rail to the carb (on RR built engines).

DAI


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## kvom (Aug 10, 2017)

ShopShoe said:


> Maybe it was here, maybe it was on a TV documentary, but supposedly RR experts visited Ford and Packard and decided that the machining capability at Packard would be better able to handle the work.



Actually Henry Ford refused to make the engines in the US (although a Ford plant in the UK did so).  Whether it was Packard or RR that initiated the deal I hadn't discovered, but in any case Packard had to redraw all the plans.  That took a year.


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## dairwin (Aug 10, 2017)

kvom said:


> Actually Henry Ford refused to make the engines in the US (although a Ford plant in the UK did so).  Whether it was Packard or RR that initiated the deal I hadn't discovered, but in any case Packard had to redraw all the plans.  That took a year.



There are differing reports on this; however RR did set up a US based subsidiary to source components and machine tools before 1939.  This subsidiary did have discussions with Packard before the war, and before discussions with Ford-USA.

It seemed to be an evolving story with Packard initially trying to drive a stiff deal, but with war under way and the need for more Merlins, by the spring 1940 the UK government approached the US government directly to source a US manufacturer.  Ford-USA was then approached with Henry Ford refusing to comply, so Packard was then approached through the US government and the deal was secured.

Ford-UK was also approached.  Both Packard and Ford-UK had to redraw the RR provided drawings into US projection (RR use first-angle projection, and the US use third-angle).  The Packard redraw was completed in late November 1940, with the fist prototype Packard engine running in July 1941 and the first production engine in October 1941.

DAI


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## kvom (Aug 10, 2017)

What I read is that the drawings were redone for reasons of tolerances.  One wouldn't think a redraw was needed for first vs. third angle projection alone.


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## goldstar31 (Aug 11, 2017)

kvom said:


> What I read is that the drawings were redone for reasons of tolerances. One wouldn't think a redraw was needed for first vs. third angle projection alone.


 
In a way, I would agree but not for the reasons given.

Whilst Spitfires were all of £5000 then, they were expendable and so were the little fellows that had come out of University Air Squadrons and supported by a tiny handful of fine US volunteers, the lads from the Commonwealth and Eastern European stalwarts that had seen it all before.
That was 1940 and by 1945, only a handful- and I mean handful would be left and all the Merlins lovingly constructed by RR personnel would have been scrap or perhaps lying in the English Channel. War dictated different standards- both pilots and machines might only last a scant single fill of 100 octane. In my spot of the firmament, it was 1949 and I stood as very young RAF corporal watching the first Avro Shackleton take off on three Griffons and then maintain height on one. Shackleton was designed as a wartime aircraft designed to last 168 hours and by then was expected to have gone- one way or another. In a few scant months, I too, would either be dead or trying to keep whoever it was whilst somebody piled our wounded into an aging Anson 12. Where I would be at the end of things was not important- I would probably get out with the Commandos but who cared?

In war or whatever my little lot would be, I was a 6 week wonder-- and there were more important things to consider.

To win a war, preconceived notions of Rolls Royce quality had to be swept away. Britain and later the US needed men and machines which would work on the day. Tolerances had to be relaxed. Henry Kaiser was making things called Liberty ships that were under engined, had welds which would crack but provided that they could be loaded up in Halifax NS harbour and get to Liverpool without being 'tin fished' , the ends justified the means.

If a Packard Merlin was not quite what one would expect- on the Good Old Days-so what? If it took its share of 12000 lbs of bombs to the target, another Goldstar- Arthur Harris was doing what Churchill expected him to do.

My view, gentlemen, and rather nearer to cold reality.

Norm


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## dairwin (Aug 13, 2017)

Hi Norm,

I agree with much of what you have said.  Your view of the expectations of war at that time strike resonance with the reality learned from two RAF pilots I knew who were on ops from 1942.

Regarding tolerance; it is a fact that Packard (and Ford) defined tolerances in more detail than RR, and machined to tighter tolerance as well.  There is a well know anecdote that Packard had questioned machining tolerances with RR, which they assumed meant the RR tolerances were too tight; Packard replied that even their cars were made with smaller tolerance.

By 1939, the Merlin was being manufactured at Derby in relatively small numbers in a pre-war environment, with production rates of 30 per month.  They were hand built, machined, assembled and fettled to make good.  Within two years, there was no time for the expert machinist; we needed mass production by lesser skilled personnel, on a far larger basis.

Packard's initial frustrations (beyond the drawing details) included their observation that webs, castings and thicknesses varied between engine sections.  Subassembly drawings were not RR normal practice, neither were parts lists.  Thicknesses of sections varied without documentation as RR engineers had changed these areas based on results of engines on operations.

I understand that sample engines sent to Packard were dismantled and sections cut through castings to determine thickness variations which were then documented.

Tighter tolerances resulted in more inter-compatibility of engine parts swapping during maintenance.  Packard parts could be used on RR engines are well, which could not have happened without Packards mass production approach to tolerance control.

However, RR did adopt the practice of defining tolerances and I have several RR manuals for my engines that provide this detail.

Productions rates for Packard were over 1,200 engines per month by late 1943, all with tight tolerances!

DAI


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## goldstar31 (Aug 17, 2017)

So the Battle of Britain Memorial Flight's Spits, Hurri's and Lanc have been grounded.

Engine problems but no further details

Nil Illigitimi Carborundum

Norm


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## dairwin (Aug 17, 2017)

goldstar31 said:


> So the Battle of Britain Memorial Flight's Spits, Hurri's and Lanc have been grounded.
> 
> Engine problems but no further details
> 
> ...



Ha!  I hope grinding is not the problem.  Will be interesting to learn what it is though.

DAI


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