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View Full Version : Why didnt the US build MkVIII or MXIV Spitfires instead of MkIX's?



Xiolablu3
01-23-2007, 10:35 AM
Just a quick question which I was pondering over today.

As the MkVIII Spitfires had much better range, and the MkXIV and MkVII had much better performace with their Griffon engines, why did the US decide to build MkIX's (as the MkXVI)?

I would have thought that beccause the US had such massive resources, that building the MkXIV in large numbers would not have been a problem, or at least MkVIII's which were a more advanced design than the MkIX.

So my question is, why the MkIX?

Thanks for your thoughts http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

berg417448
01-23-2007, 10:41 AM
I thought the US just built the engines.

JG53Frankyboy
01-23-2007, 10:41 AM
Originally posted by Xiolablu3:
Just a quick question which I was pondering over today.

As the MkVIII Spitfires had much better range, and the MkXIV and MkVII had much better performace with their Griffon engines, why did the US decide to build MkIX's (as the MkXVI)?

I would have thought that beccause the US had such massive resources, that building the MkXIV in large numbers would not have been a problem, or at least MkVIII's which were a more advanced design than the MkIX.

So my question is, why the MkIX?

Thanks for your thoughts http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

the Mk.XVI (Mk.IX airframe) was build in the UK.
only its engine, a Packard build Merlin 66, called Merlin 266, was build in the USA.............

the Mk.VII had Merlins too btw

Xiolablu3
01-23-2007, 10:47 AM
Sorry, was I thinking of the MkXII?

The earlyest Griffon engined Spitfire is hte one I meant.

BillyTheKid_22
01-23-2007, 10:56 AM
http://www.luchtoorlog.be/img/spit_v/prvii.jpg


http://forums.ubi.com/images/smilies/inlove.gif MkVIII Spitfires!!!

Xiolablu3
01-23-2007, 11:50 AM
Ahh, so the USA didnt build the whole plane, I thought they did.

I didnt realise all the airframes were built in Britain.

SO was it the Merlin 66 which was built as the Packard Merlin and put into the P51? DId Packard try and soup it up a bit? Or did they build a direct copy of the Rolls Royce engine?

JR_Greenhorn
01-23-2007, 01:37 PM
Originally posted by Xiolablu3:
So was it the Merlin 66 which was built as the Packard Merlin and put into the P51? Did Packard try and soup it up a bit? Or did they build a direct copy of the Rolls Royce engine? They didn't "copy" the engine, they built engines under license. There's a big difference. Building under license indicates that the firm that designed the engine (R-R), would've given both consent and cooperation to aid in Packard's production. It is also very likely that money changed hands somewhere, although the Lend Lease program may have been involved which wouldn't make things as cut and dried as they would be otherwise.

Packard wouldn't have "souped up" the engine very much, at least not at first, because their primary goal was to crank out engines to fill a need that R-R's own production couldn't keep up with. "Souping up" the engine would mean changes, which means more testing, engineering documentation (prints), retooling, and ultimately, delays in production. Once production had been ramped up, then it is possible that modifications were looked into or made to the Packard-produced Merlins. Likely such modifications would have involved both companies to some degree, depending on the terms of the license. Those with applicable history books at hand can tell you more.

Additionally, it didn't make nearly as much sense for an engine like the Griffon to be produced in the US, as no US production planes used that engine. Even though it may have had more potential than the Merlin, again, it would have involved redesigning, testing, and retooling to incorporate the Griffon into other airframes. Compared with Merlin engine production for P-51s and British Spits (and others?), Griffon engine production was insignificant in comparison, at least in terms of production numbers and demand for the engine type.

faustnik
01-23-2007, 01:46 PM
According to "Spitfire" by Stewart Wilson, Packard made the following improvements to the Merlin design; Bendix_Stromberg injection carburettors, automatic supercharger gear shifters, water-alcohol injection, ball-bearing main water pump, centrifugal air/oil seperator, and a high altitude magneto.

http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

SlickStick
01-23-2007, 02:08 PM
To quasi-quote Oleg:

Where did you read of Spitfires being made in USA?!?! Close this book forever and do not open anymore! http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Besides improvements, Packard also made the engines more easily serviceable without the need for many of the R-R custom-fit parts. The original R-R engines were hand-made and R-R did not believe that an American company could mass produce them. The original design drawings were changed to American format and tolerances opened a bit, which allowed a little more leeway in the manufacture of the engines on a production line.

As for my thoughts on part of the original question and I'm no expert, just speaking of what I've read. The bulk of Mk. IXs were made up of previous Mark's airframes. Mk. Vs with Merlin 61 was the first in Production in 1942 I believe and this stop gap model was sorely needed to immediately counter the FWs that were overwhelming the current Mk. Vs.

As the Mk. VII and Mk. VIII were not ready for production at that time, the Mk. IXs closed the gap significantly and were the most-produced variant. Even more so once they went to Merlin 66s and added clipped-wings to the IXs. Although, they started clipping Mk. Vs in 1942 as well, IIRC.

The Mk. VIIIs and Mk. XIIs didn't go into Production until mid to late 1943, again, IIRC.

Viper2005_
01-23-2007, 02:46 PM
AFAIK tolerances were actually tightened. This was certainly the case when automotive contractors were told to make engines in the UK - they were set up for very high volume mass production using expensive machines and cheap labour, and ran much tighter tolerances than the aerospace industry as a result.

They made great engines but tended to have much more difficulty incorporating modifications to the production line as a result of their tighter tolerances and relatively unskilled labour.

AFAIK the changes incorporated by Packard may be split into two categories:

1) Improvements. Several manufacturing changes were made by Packard at the suggestion of Rolls-Royce, who were unable to incorporate them themselves due to the pressure to maintain production.

2) Changes to utilise local suppliers and equipment.

- Slightly different ratios were used in the reduction gear and supercharger step up gears simply because locally available machinery was better able to make gears with different numbers of teeth.

- When fitted to US aircraft manifold pressure gauges calibrated in "Hg were used instead of boost gauges calibrated in psi gauge. Since everybody likes round numbers, this meant that many of the Packard engines had slightly different ratings than their Rolls-Royce counterparts. For example, 67" Hg is actually slightly over +18. This had a small but noticable impact upon full throttle heights and low altitude power output.

- Various accessory items were replaced with locally manufactured items (carbs, throttles, mags etc). AFAIK this was simply an attempt to remove bottlenecks in the supply chain - there would have been no point in shipping parts from England in order to fit them to engines which would then be sent back to England... Doubtless some of the American kit thus fitted represented an improvement, but the primary goal was simply to ramp up to maximum production as quickly as possible in order to hold the Nazis at bay.

It is worth remembering in this context that the Spitfire V came about because the Merlin XX series engines were not available in sufficient numbers to supply both the Hurricane and Spitfire, so the 45 was created by using the old single speed production line to produce a Merlin XX less its MS gear drive; it was considered that the Hurricane vitally needed the superior engine in order to remain competitive.

The Spitfire III was far superior, but production was more important than performance. It ended up serving as the prototype for the Spitfire IX (to which it was superior in speed, even towards the end of its life when in very poor condition).

The intended follow-on, the Spitfire IV was the first Spitfire fitted with a Griffon. AFAIK it was also intended to have 6 cannon. But it was also overtaken by events...

Lack of spare engine and airframe production capacity had a very damaging effect upon the British Aerospace Industry throughout the War. Old types often remained in production somewhat past their sell-by date simply because stopping production to change over to a new type would have resulted in a fatal gap in supply.

SlickStick
01-23-2007, 03:09 PM
Originally posted by Viper2005_:
AFAIK tolerances were actually tightened.

As opposed to R-R's hand-built tolerances, which were not detailed on the original design drawings, I should have said Packard's were "applied" as opposed to using the word "lessened", to allow for mass production.

"When the first of the Packard-built Merlins arrived in Britain, the engineers at Rolls-Royce stripped it down and were amazed to find that the production-line built Packard engine, far from being as bad as they expected it to be for component tolerances, was actually better. Up until then, R-R Merlins were hand built, every face being finished off by hand, and this time-consuming process placed great strain on the production capability of the skilled workforce involved in the manufacture of these engines. The Packard engine changed many minds, although there were still some at R-R who remained unconvinced of the quality of the American engine, produced as it was by a largely unskilled and semi-skilled female workforce. In the end, the engine's performance removed any doubts about its quality and workmanship.

Although it is not commonly known, Packard greatly improved the maintainability of the engine (by allowing easier use of interchangeable parts, rather than custom finished ones), and their changes were also incorporated in subsequent British production."

Packard's Legacy (http://en.wikipedia.org/wiki/Rolls-Royce_Merlin)

Rattler68
01-23-2007, 03:17 PM
The colonial troops had it bad too, Xiola, and we're pretty pissed about it!! http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

We didn't get later mark Spits until very late '44 or '45, or not at all!

Probably the 600 series squadrons as well.

smokincrater
01-23-2007, 04:58 PM
A little known fact is that Rolls Royce offered a license to Ford but Henry made the mistake of his life when he turned it down. Thinking that Britain would not last the distance against Germany.

Also asking around the Packards have a little more supercharger whine than RR units. Otherwise I am told they are just the same, performance wise.

ImpStarDuece
01-23-2007, 06:28 PM
There were actually proposals tossed around in the US to build the Spitfire Mk V and Mosquito B Mk IV/FB Mk VI with US Merlins fitted.

Neither was considered seriously though, mostly as a cast of 'Not Inveneted Here' syndrome.

Packard made some significant improvements to the Merlin during the war, and there was a continual two way street of information and ideas passing between the development teams in the US and UK.

One of the less favoured innovations was the two piece crank case, which initally had a tendency to leak & spit oil. There are lots of pictures of P-51B/Cs throwing oil, something that was rare on a Spitfire. The two piece crank was improved in the 266/V-1650-7 and was eventually as reliable as the Rolls Royce built engines, and far easier to maintain.

The initial V-1650-1s (analogous to the Merlin 20 and 30 series, starting with the Merlin 28) were a little out of favour with Lancaster III and Mossie XX crews because their maximum engine limits were lower, offering less horsepower than the Merlin 21/22/24/25s which they often replaced. I never found out why they weren't rated to the same boost levels as the earlier RR either, as the engines were notionally the same.

HellToupee
01-23-2007, 06:48 PM
Originally posted by SlickStick:
The Mk. VIIIs and Mk. XIIs didn't go into Production until mid to late 1943, again, IIRC.

Mk XII went into production in mid 42 and service early 43. It was only useful at low altitude chasing 190 raiders so they built few of them.

SlickStick
01-23-2007, 09:16 PM
Originally posted by HellToupee:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by SlickStick:
The Mk. VIIIs and Mk. XIIs didn't go into Production until mid to late 1943, again, IIRC.

Mk XII went into production in mid 42 and service early 43. It was only useful at low altitude chasing 190 raiders so they built few of them. </div></BLOCKQUOTE>

Ah that early, eh? I read further and found that they only made 100 Mk. XIIs.

HellToupee
01-24-2007, 03:20 AM
Originally posted by SlickStick:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HellToupee:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by SlickStick:
The Mk. VIIIs and Mk. XIIs didn't go into Production until mid to late 1943, again, IIRC.

Mk XII went into production in mid 42 and service early 43. It was only useful at low altitude chasing 190 raiders so they built few of them. </div></BLOCKQUOTE>

Ah that early, eh? I read further and found that they only made 100 Mk. XIIs. </div></BLOCKQUOTE>

yes the fighting was at high altitude where the mkIX was alot better so they only had a sepecialised role mainly in the tip and run raids.

Had the 2 stage giffon been ready it would have probly been the next major variant.

Sergio_101
01-24-2007, 03:42 AM
No Spitfires not components thereof were manufactured in the US.
Except for engines.

The Packard Merlin myth continues on.

No lisence fees were collected during the war.
Perhaps because so many Packard Merlins were
provided under lend lease.

There were few changes in the Packard Merlins.
Most changes reflected the change to a mass
production enviorment.

Detachable heads were implimented before RR
did, this was a vast improvment
but the heads were a RR design. RR was under too much pressure
to make the change at that time.

Crankcase in two pieces? Sorry, I have seen a half dozen
Packard V-1650-7 and -9s in various stages
of disassembly, no two piece crank cases.

for the most part, as previously noted, the Packards
were superior in servicability and overall reliability.
Before some ultranationalist Brit jumps in,
the reasons were stated previously.
The detachable heads of the Packard eliminated
the cylinder liner leaks that plauged early Merlins.
<span class="ev_code_RED">Closer manufacturing tolerances allowed by "Statistical Quality Control"
eliminated hand fitting. Demming's SQC method was key in
maintaining quality in the massive industrial output by the US during WWII."</span>
This allowed for easy replacement of parts in the field.

The power section of the Packard and RR Merlin had 100%
parts interchangability.
To keep the parts interchangability packard used
the dismal Witworth thread system.
Yes, even the fasteners interchange.
Superchargers and reduction drives for US applications
were different. US SAE#50 prop spline for US Merlins.

Sergio

PS: I never heard of oil leaks being more common in P-51s than Spits.
That's news to me. P-51s were notable as not being leakers.

ImpStarDuece
01-24-2007, 05:15 AM
Originally posted by Sergio_101:


Crankcase in two pieces? Sorry, I have seen a half dozen
Packard V-1650-7 and -9s in various stages
of disassembly, no two piece crank cases.


PS: I never heard of oil leaks being more common in P-51s than Spits.
That's news to me. P-51s were notable as not being leakers.

Description of V-1650-9 from http://www.unlimitedexcitement.com/Pride%20of%20Pay%20n...0V-1650%20Engine.htm (http://www.unlimitedexcitement.com/Pride%20of%20Pay%20n%20Pak/Rolls-Royce%20Merlin%20V-1650%20Engine.htm)

Crankcase:

Two aluminum castings split on horizontal centerline. The upper crankcase has two engine mounting feet and carries the crankshaft and mean bearings, cylinder blocks, accessories, wheelcase, supercharger, and reduction gear. The lower ends of the cylinder liners fit into openings in the upper crankcase and the cylinder blocks seat on inclined face. The cylinder blocks are bolted to the upper crankcase with 14 high-expansion steel studs each. The crankshaft is retained by forged aluminum main bearing caps which are seated in milled cutaways in the upper crankcase. Each main caps is retained by two large studs (one of which serves as a locating dowel) extending from the main bearing web in the crankcase and are also transversally cross-bolted through the sides of the crankcase. The upper crankcase also has an oil pressure relief valve located on the "A" bank and a generator-drive and support on the "B" side.

The lower crankcase serves as an oil sump, and also carries an oil pressure pump and three scavenge pumps, with provisions for an optional hydraulic pump. Baffles in he lower crankcase help reduce oil surge and improve oil control, particularly at unusual attitudes which can occur in flight. Each of the two primary scavenge pumps is equipped with removable oil screens; one scavenge pump collects oil via an extension pipe to a pickup at the propeller end of the engine, the other scavenges oil from the sump at the supercharger end of the engine. The third scavenge pump is the auxiliary scavenge pump used to collect oil from the supercharger impeller bearings -- it is located directly below the pressure pump.

Large studs on the face of the upper half pass through main bearing webs on lower-half to clamp the two halves over the bearing shells. Center main bearing provided with faced flanges which bear upon the center crank cheeks to provide axial location (and absorb thrust loads) for the crankshaft. Cast magnesium-alloy oil pan bolts to the bottom of the crankcase lower half. Oil is scavenged from front and rear or the oil pan."


I'll dig up some pictures of P-51s throwing oil as well.

luftluuver
01-24-2007, 05:20 AM
Originally posted by smokincrater:
A little known fact is that Rolls Royce offered a license to Ford but Henry made the mistake of his life when he turned it down. Thinking that Britain would not last the distance against Germany. Ford Of England built some 30,400 engines, of the 20 series, at Trafford Park between June 1941 and March 1946.

After the Henry Ford/RR deal fell through, Henry spent $2 million dollars trying to build his own V-12 engine. Ford gave up but produced a V-8 version that went into tanks (mostly Shermans). Some 25,741 being produced.

Ratsack
01-24-2007, 08:00 AM
Originally posted by Sergio_101:
...

There were few changes in the Packard Merlins.
Most changes reflected the change to a mass
production enviorment.
....

This business of tightening tolerances for mass production has been mentioned a couple of times in this thread. The Brit automotive industry was already mass-producing Merlins in the UK. I think Stanley ****** mentions in his biography, Not Much of an Engineer, that when RR took the original drawings to one of the British motor companies for mass production (it may have been Morris: I can't remember), they were told they couldn't start mass production on the basis of the Rolls drawings because the tolerances weren't tight enough. The drawings of the engine had to be completely re-drafted. I think Viper may have been referring to this in his post above.

The tolerances may have been narrowed further in the US. I don't know, and I'm not saying it didn't happen. However, the tightening of tolerances for mass production had already begun with the automotive industry in the UK.

Cheers,
Ratsack

PS For the record, I'm not a pom, ultranationalist or otherwise.
PPS I don't recall ever meeting an ultranationalist pom.

stathem
01-24-2007, 08:05 AM
Hmm, don't know if this helps, but from memory of P1ngu's postings of the Power to Fly;

Napier wanted to get clearance to use paper gaskets on the Sabre, but the Air Ministry wouldn't have it (what did they use otherwise, copper?)

They were peeved because the AM were quite happy to take Packard Merlins with paper gaskets. Could this have something to do with the tolerance issue?

smokincrater
01-24-2007, 04:37 PM
Just as a comment,(do not take this personally) I have found that North American tolerances to be the worst in the world(particulary General Motors products). The Germans and Japanese are diffenenlty among the best at build quality. I believe it was RR that found concerns over the Americans abillity to come to their tolerances. And by the way the Merlin was a great British Engine(therefore it leaked oil like no tomorrow, no matter what it was in).

Aaron_GT
01-25-2007, 02:34 AM
Neither was considered seriously though, mostly as a cast of 'Not Inveneted Here' syndrome.

The proposal to build Mosquito B.IV (or equivalents) in the USA was seriously considered. The problem wasn't so much 'NIH' but the fact that De Havilland simply didn't have the available senior and skilled staff to spare to keep production in the UK, Canada and Australia going AND extend it to the USA. In actuality Canadian subsidiaries of US firms (e.g. of Boeing) did build parts for Mosquitos, and some US firms in the USA built some subassemblies for Canadian production Mosquitoes, in addition to engines. Some raw materials came from the USA (the temperate softwoods used in the Mosquito were in surprisingly short supply at times, let alone the balsa) The USA was also instrumental in sourcing some much needed production equipment to be taken to Cananda to get them produced there. Starting up more production lines was just too much of a stretch for De Havilland. But as noted the USA was more involved in Mosquito production than some realise.

Ratsack
01-25-2007, 05:17 AM
Very good point, Aaron. There's a great deal more to the logistics of mass manufacture than just turning out examples of the finished product.

cheers,
Ratsack

Aaron_GT
01-25-2007, 10:55 AM
At times the UK, USA and Canada worked really well on a team effort basis to produce stuff. At times there was bickering too, but then there was bickering and working at cross purposes between the USAAF and USN, RAF and RN too... so that probably comes down to some extent to different agendas and personalities.

I was quite surprised, though, when I found out how much the USA (or at least Hap Arnold) wanted the Mosquito, and that the USA did contribute a fair bit to it. Full US production is one of the what-ifs, but then the P-38L, A-26 and P-61 were decent planes too, and with local production the issue of personnel stretch wasn't the same (problems getting the P-61 up to speed notwithstanding).

Sergio_101
01-25-2007, 04:37 PM
Originally posted by ImpStarDuece:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Sergio_101:


Crankcase in two pieces? Sorry, I have seen a half dozen
Packard V-1650-7 and -9s in various stages
of disassembly, no two piece crank cases.


PS: I never heard of oil leaks being more common in P-51s than Spits.
That's news to me. P-51s were notable as not being leakers.

Description of V-1650-9 from http://www.unlimitedexcitement.com/Pride%20of%20Pay%20n...0V-1650%20Engine.htm (http://www.unlimitedexcitement.com/Pride%20of%20Pay%20n%20Pak/Rolls-Royce%20Merlin%20V-1650%20Engine.htm)

Crankcase:

Two aluminum castings split on horizontal centerline. The upper crankcase has two engine mounting feet and carries the crankshaft and mean bearings, cylinder blocks, accessories, wheelcase, supercharger, and reduction gear. The lower ends of the cylinder liners fit into openings in the upper crankcase and the cylinder blocks seat on inclined face. The cylinder blocks are bolted to the upper crankcase with 14 high-expansion steel studs each. The crankshaft is retained by forged aluminum main bearing caps which are seated in milled cutaways in the upper crankcase. Each main caps is retained by two large studs (one of which serves as a locating dowel) extending from the main bearing web in the crankcase and are also transversally cross-bolted through the sides of the crankcase. The upper crankcase also has an oil pressure relief valve located on the "A" bank and a generator-drive and support on the "B" side.

The lower crankcase serves as an oil sump, and also carries an oil pressure pump and three scavenge pumps, with provisions for an optional hydraulic pump. Baffles in he lower crankcase help reduce oil surge and improve oil control, particularly at unusual attitudes which can occur in flight. Each of the two primary scavenge pumps is equipped with removable oil screens; one scavenge pump collects oil via an extension pipe to a pickup at the propeller end of the engine, the other scavenges oil from the sump at the supercharger end of the engine. The third scavenge pump is the auxiliary scavenge pump used to collect oil from the supercharger impeller bearings -- it is located directly below the pressure pump.

Large studs on the face of the upper half pass through main bearing webs on lower-half to clamp the two halves over the bearing shells. Center main bearing provided with faced flanges which bear upon the center crank cheeks to provide axial location (and absorb thrust loads) for the crankshaft. Cast magnesium-alloy oil pan bolts to the bottom of the crankcase lower half. Oil is scavenged from front and rear or the oil pan."


I'll dig up some pictures of P-51s throwing oil as well. </div></BLOCKQUOTE>

Ok, I stand corrected, sort of, the lower crankcase is
more of an oil pan.
There is also a detachable oil pan, but it's more like a cover.

All major structure is in the "upper crankcase"
I would call the "lower crankcase" a two piece oil pan.

Sergio