cherry blossom
Senior Airman
- 504
- Apr 23, 2007
There is a respectable origin of the idea that RR's tolerances were looser than ideal for mass production in Hooker's autobiography Not Much of an Engineer.
Greatest aviation myth this site “de-bunked”.
- Thread starter SaparotRob
- Start date
Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
fastmongrel
1st Sergeant
I don't doubt Hooker was a superb mathematician and engineer but he didn't have anything to do with the production side of things in 1940, he was working on superchargers. I don't think a 23 year old would have been anywhere near a senior management discussion.
It's a good story but I wouldn't be surprised if he heard it 2nd or 3rd hand.
Kevin J
Banned
The only thing better than spam fritters is Czech salad. It's made with tomatoes, peppers, hard boiled eggs, cheese and spam, all chopped up into small cubes then mixed with half a jar of mayo. Lush. Eat with French stick. Almost as good as corned beef hash.
It was said by Lovesey to someone from Ford, in the very early days of production expansion. Lovesey wasn't a production engineer and up to then his main involvement in engines were the racing engines for the Schneider Trophy. He was quite probably just being polite.
buffnut453
Captain
There is also credible production specification data from Rolls Royce archives, to include production specifications and design drawings, which show that tolerances were well defined and were anything but loose.
Again, I would ask people to think about the logic of the idea. The Merlin had been in production in the UK since 1936. The first Packard-built engine ran in August 1941. Britain produced 168,000 Merlins across 4 different sites. Licence production in the US was about 55,000. I'd really like to know how the Brits managed to produce so many engines, especially those prior to August 1941 (bearing in mind every Spitfire and Hurricane had a Merlin) if tolerances were "looser than ideal for mass production."
The evidence all points to a large degree of interchangeability between RR and Packard Merlins, to include RR-designed modifications being implemented in the Packard production line first. You simply can't do that if tolerances are so different. The only other scenario is that UK tolerances were looser in the period 1936-1941 but were tightened up based on Packard recommendations. There is ZERO evidence that anything like that happened, plus it would require all 4 UK-based factories to alter their production methods to align with the Packard tolerances. Again, those 4 UK factories more than twice the number of Merlins than did the US factories.
Sorry, but the whole idea is laughable.
I think it is a myth that will never be busted, despite all the evidence so many people like it, it supports all their ideas and preconceptions.
fastmongrel
1st Sergeant
Quoted from wiki
At first, the factory had difficulty in attracting suitable labour, and large numbers of women, youths and untrained men had to be taken on.
Doesn't sound like craftsman style production. Roughly half the new wartime workers were women who would have had no opportunity to train in a trade prewar.
At first, the factory had difficulty in attracting suitable labour, and large numbers of women, youths and untrained men had to be taken on.
Doesn't sound like craftsman style production. Roughly half the new wartime workers were women who would have had no opportunity to train in a trade prewar.
cherry blossom
Senior Airman
- 504
- Apr 23, 2007
I am exposing my deep ignorance but might the issue have been that RR used first-angle projection and Ford and later Packard used third-angle projection. Is it possible that Hooker misreported the issue whilst correctly reporting that Ford had to redraw everything?
wuzak
Captain
Ford UK likely used the UK standard, which was first angle.
Packard definitely had to redraw to US standard 3rd angle.
If the tolerances had to be tightened, it would have been at the behest of Ford UK, and happened before Packard got the contract to build the Merlin.
There were "disputes" in the shadow factories because (for example) Capstan lathe operators were paid less. But the capstan lathe operators in the main RR factory could machine anything, the ones in the shadow factories made one item on one machine. While the main demand was for the two stage Merlin, RR were also making all sorts of other Merlins (like the ones for the Hornet) Griffons and in the early part of the war Peregrins and Vultures.
Luftwaffe ace Heinz Knocke describing his first encounter with P-38s said "It flies like the very devil himself" - close
This myth gets even better, did Packard decide the direction of rotation too? Surely Rolls Royce were a bit to dim to have sorted the bore and stroke on their own?
- Thread starter
- #94
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
Could this be the birth of that myth?
- Thread starter
- #95
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
RE: post #85. Rolls Royce has a certain reputation among ALL my friends. We would all agree with buffnut453. The idea that Rolls Royce doesn't know how to build engines is ridiculous. We would have thought the reverse would have been the myth.
swampyankee
Chief Master Sergeant
- 3,954
- Jun 25, 2013
There tends to be a great deal of information in corporate drawing standards that doesn't get listed on drawings. Maybe somebody didn't connect these to the drawings.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
Only if Knocke encountered the P-38 in '41 and used that description while BS'ing with American pilots.
- Thread starter
- #98
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
Don't bother me with facts.
There has been all sorts of things posted including actual drawings and tolerances by Snowygrouch from archives. People are happy to believe that a company like Packard undertook license production of an engine and made up their own tolerances, so I fear the myth will never be de bunked.
Doubt it. The myth was started somewhere between Caiden and the Stars & Stripes Newspaper.
