Subtle Sabotage

AFAIK, only Rolls-Royce (Derby, Glasgow, Crewe), Ford UK and Packard USA built Merlins but I’m always ready to be proved wrong.
It would make sense for Casa to set up an overhaul facility for 111’s and Buchons but production would seem over the top.

Somebody (JDK?) posted a pic a year or so back of a Merlin component with Buick cast into it.

Edit
Henry Ford said no when the British Government asked him to build Merlins, before Pearl Harbour. I think Packard volunteered but I’m not certain.

I’ve seen the Ford logo on a few Merlins 🙂

Did Casa also build some? or were they just overhauling them?

Ford built Merlins in Manchester.

Bruce

30,000 plus of them IIRC.

In Sir Stanley Hooker’s words (from memory but pretty close) “they came out like shelling peas, and very good engines they were.”

Ford built Merlins in Manchester.

Bruce

I was not aware that Ford was involved in the manufacture of Merlin engines, I thought Packard were the only firm interested in the project. As for engine tolerances why were engines made by Studebaker notorious for guzzling gas? not sure if it was Wright Cyclones or Pratt and whitneys, Perhaps Jules can make a comment on this.

Interesting thread. I will make one or two points:

Engineering tolerances are just that – if they are made to a minimum tolerance, then they will work – the tolerance is built in to the ‘fit’ of the part. If the drawing is wrong, then there might be a problem, but a part is either serviceable or it is scrap.

Sabotage certainly happened; I am aware of a German aircraft that following an engine change, was forced down on its final flight when the engine stopped. Investigation when the remains of the aircraft were recovered many years later found rags stuffed into the oilways of the engine, something that could only have ben done at the overhaul workshops.

Most German aircraft I have seen have little or no paint on internal surfaces, and are usually painted only in the cockpit area. In fact, the Spitfires had more paint protection in the inside of the fuselage than their counterparts. The Germans did however have a very effective anodising process that was used on some aircraft, primarily the Junkers designs. If you look at the wrecks of the Ju88’s recovered in Norway and elsewhere, you will be sruck by the good confition of the yellow anodised stringers and other parts.

Ta Ta for now

Bruce

Anyway, all in all, a great story. These guys were the unsung heros of the war, bearing in mind what could have happened to them if this was found out by the Germans….. 🙁

TNZ

It might be said that German engineering, and production in general, was to a very high standard. Far too high, in fact.

iirc, one of the findings of the late 1944 emergancy fighter programme was that German aircraft had five times as much paint on the inside than the outside. Fine for a peace-time service life of some years but by 1944, the average operation service life of a German single seat aircraft was six hours…

As to the poor s*ds working in forced labour conditions, how can we even begin to comprehend what they lived, and mostly died, through?

Harald,
if the generosity regarding design tollerance and fit in what are classed as high performace engines, was that great then i can only agree and happy to stand corrected sir.

Dave

I agree that manufacturing technology and practices have improved over the ensuing years but also bear in mind that Ford completely re-drew the Merlin to motor industry standards before they started production. They said what seems obvious to us now, “any part must be interchangeable in any engine”. Apparently despite their reputation for engineering excellence, that wasn’t the case with Rolls-Royce components.

funhouse –

Bear in mind that these engine designs predate the development of modern concepts of dimensional control, to say nothing of the part-to-part uniformity achievable by modern manufacturing methods. At the time these engines were designed there would have been an implicit assumption that, while some of the parts might end up at the high side of the tolerance range and others would end up at the low side, other parts would fall in the middle, and it would all even out in the end – the machine would go together and perform as designed. It is when you force the tolerances all in one direction that you end up with problems. If we were talking about linear dimensions, an accumulation of tolerances might make some feature at the end of a group of axially connected parts end up improperly located relative to some other part of the machine. In the case of cylindrical fits, I can imagine that slightly loose pistons connected to slightly loose wrist pins riding in slightly loose connecting rods with slightly loose end journals connected to crankshafts which themselves are not as rigidly constrained as intended might result in an engine which is already “tired” the day it leaves the assembly line.

Harald

The thing that stands out for me in all this, is the courage shown by the guys who performed these ‘acts of sabotage’. They were most certainly working within a regime which was entirely intolerant of disobedience, and so every day faced discovery and therefore execution.

Sidetracking slightly, a book which I read a couple of years ago, “The Fall of Fortresses” by Elmer Bendiner, tells of anti aircraft shells which hit B17’s, failed to detonate, and when the aircraft returned to England the shells were opened up to reveal small notes from anonymous slave labourers who had sabotaged the detonators, saying “this is all we can do…”. Undoubtedly, they had risked their lives, to save those of Allied aircrews. Such courage beggars belief in this day and age…

this would surely have affected oil consumptions and operating temperature, and surely the general tolerance of the parts. At least they surely had a very low TBO, and if u consider the rough use and mantainance on engines during ww2…

Alex

Interesting story,
But I think that is all it is. While I have no doubts that some form of sabotage went on within the forced labour workshops, I doubt that machining mating parts to the drawing tolerances either upper limits or lower limits, would affect the performance to that extent. The component tolerance limits would have been worked out at the design stage.

Just my thoughts.

uhm, actually the BD performances were fairly superior to the ones of the Merlin. It was the upsaid sabotage that caused problems to the next generation of DB engines, like the 603. They had the first operational jets in war, made a huge experimentation (often succesfull!) in aviation and other fields, produced impressive and effective tanks.. I always thought that if they lasted until 1945 it was because of the superior engineering.

Alex

27 litres of Merlin more or less kept on equal terms with much larger DB (44+ litres?) engines for most of the war. That’s not too bad for inferior engines is it?

Advanced research, certainly. I’m not convinced about engineering in general.

..as long as they had sabotage… the german early war machines and industry production was superior under every aspect to their opponents, and the increasing of the production numbers until 1945 was impressive for a nation under siege and bombings.. in the aviation field german instruments are considered to be of a too high standard for application in warfare, same goes with the engineering of engines and weapons.
I think the only thing in which the allies were superior was battleships(but i’m not a navy buff so i cant really say..) and probably the M1 Garand (who anyway had a german counterpart..).

Alex

…to be honest their engineering was really superior under all aspects…

Alex

Advanced research, certainly. I’m not convinced about engineering in general.

…to be honest their engineering was really superior under all aspects…

Alex

Hi Harald.

Welcome to the Forum and thanks for the anecdote. It brings a smile to my face just thinking of the Germans scratching their heads wondering why their ‘Superior’ engineering wasn’t doing the job. 🙂