F-35's Costs Climb Along With Concerns

"Jack Love" wrote in message
...
On Fri, 28 Apr 2006 15:04:23 -0700, (Harry
Andreas) wrote:

In article ,
wrote:

Note that this is sort of the same approach that lost Germany the war.
Everything was hand-finished to very high standards, while us sloppy
folks cranked out ten times as many tanks as they could because we let
the tolerances be looser and eliminated a lot of the skilled
'touch-labor' in the finishing stages.


And we kept a good handle on when 'good enough' was in fact good
enough.

One of the extreme examples of this was the engine cooling fan on
tigers(?) - it was machined out of a single piece of aluminum. - Took lots
of precision machining.

US tanks had a standard car fan - stamped steel blades riveted to the
pulley. - Took 5 stamps, 10 rivets, and mumble mumble machining on the
pulley assembly. MUCH cheaper and easier.

wrote:
In article ,
(Ricardo) wrote:


Incidentally, a few sources have claimed that the Packard
built Merlin, whilst a superb engine, lacked the power levels
of the Rolls Royce version. This, it is claimed, was because
the British kept secret the composition of the phosphor-bronze
bearings that they used in the engine.


The Packard Merlin did differ as far as I know but also as far
as I know it was not because of secrets. The British versions
were to closer tolerances requiring much more skill in assembly.
In "Sigh for a Merlin" a fault called skew gear failure was
traced to a difference in assembly order from Rolls Royce in one
of the (British) shadow factories.

In fact the Rolls Royce tolerances were rather looser than those
used by either the British Ford Motor Company or Packard. Rolls
Royce used hand fitting to match up parts, whereas Ford and Packard
were mass production companies which relied on close tolerances so
that parts were interchangeable without the laborious fitting and
adjusting that Rolls Royce used. The Rolls Royce system did require
a higher skill in assembly due to these fitting requirements.

Mike

Paul J. Adam wrote:
Packard cleaned up the castings, milled the mating faces approximately
flat (at least, compared to a metal-metal seal) and put a gasket between
them. I don't recall hearing tales of P-51s routinely or regularly falling
from the skies when their engines failed, nor of the Packard Spitfires
being execrated for unreliability (or, for that matter, lack of
horsepower).

A family friend, now departed, was a wrench-turner on (American)
Merlins during the war. He always said the Packard was easier to
work on, but did not take damage as well as, the RR version. His
reasoning was that, where RR might use (arbitrarily, as I can't recall
his exact words) 30 bolts spaced closely to attach an exhaust manifold,
Packard would use 20 spaced farther apart. He said that he saw
cases where Packard and Rolls-Royce engines would come back
with near-identical damage and the genuine article could still produce
power.


Jeff

My father-in-law had a similiar experience here in Canada. In circa
1942 he was an apprentice machinist for a new factory tasked with
manufacturing a British 4.5" naval gun design. IIRC, the original
British procedure for any shaft/bushing was to machine the shaft with
0.020 in interference and the hand file the shaft to fit. As he said,
there wasn't one in a hundred in their labour pool that could do this.
Part of his job was developing new dimensions and tolerances to allow
parts to be manufactured independently, inspected for dimensions, and
then assembled without further machining.

"Paul J. Adam" wrote in message
...
In message , Ricardo
writes
Incidentally, a few sources have claimed that the Packard built Merlin,
whilst a superb engine, lacked the power levels of the Rolls Royce
version. This, it is claimed, was because the British kept secret the
composition of the phosphor-bronze bearings that they used in the engine.
No, I can't quote a source/s.

On the other hand, I heard - from "old factory hands" lecturing on
manufacturing technique at Highbury College in 1988 - that a big
difference between Packard and Rolls-Royce was in fitting the cylinder
head.

Rolls-Royce used a precision hand-scraped metal-to-metal fit. Very
effective, though extremely demanding in scarce skilled labour.
(Attempting to 'file flat' is a useful exercise for a trainee mechanical
engineer; it teaches a certain humility in demanding surface finishes)


When I started work as an engineering apprentice at ICI they still
sealed the main steam joints on the turbines in the power station
this way. It isnt the file flat that's so time consuming as the
scraping of the surface until its flat according to the reference
surface plate.

They now use a lapping machine and gasket and its no less
reliable and a LOT quicker, plus I doubt there are many
fitters around with the skills to scrape joints flat any more.

Keith





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wrote in message
...
In article ,
(DeepSea) wrote:

That is interesting - I had no idea that British interest is
what gave the P-51 its start.

At the time Britain was buying every fighter they could get
their hands on, including the Brewster Buffalo. British and
French purchasing gave a major boost to the US aircraft industry.
The first production orders for the Airacobra were from France.

Ken Young


The first use of the Grumman Wildcat in combat was by
the Fleet Air Arm of the RN

Keith



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"Harry Andreas" wrote in message
...
In article ,
wrote:

Note that this is sort of the same approach that lost Germany the war.
Everything was hand-finished to very high standards, while us sloppy
folks cranked out ten times as many tanks as they could because we let
the tolerances be looser and eliminated a lot of the skilled
'touch-labor' in the finishing stages.

Hmmm. I wouldn't ride that horse too far.

Ever see a 1944 built Walther P-38, or Waffenfabrik Mauser?
They didn't spend nearly any time finishing them as compared to
the early war versions.


The German record was very mixed

They certainly become very efficient at manufacturing light weapons,
the MG-42 was a classic design that was simple , reliable and
excellent. Trouble is they also made plenty of monstrously complex
weapons systems. The Panther and Tiger tanks were examples of
technically advanced weapons that simply couldnt be cranked out in
the numbers needed due to the complexity of their manufacture.

"US folk" cranked out so much hardware because there were more of
us, we had more natural resources at hand, and we weren't being bombed.


Trouble is even Britain outproduced Germany for much of the war
with fewer natural resources and we WERE being bombed.
Bombing didnt seriously disrupt the German manufacture of weapons
until mid 1943 by which time the tide of war had turned. The allies
decided in many cases to accept technically inferior weapons
if they could be more easily mass produced

Compare Battle tank production in 1943

Germany 3,000 Mk 4, 3,800 Panthers, 650 Tigers
USA 21,000 M4 Sherman

Keith





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In article , "Keith W"
wrote:

"Harry Andreas" wrote in message
...
In article ,
wrote:

Note that this is sort of the same approach that lost Germany the war.
Everything was hand-finished to very high standards, while us sloppy
folks cranked out ten times as many tanks as they could because we let
the tolerances be looser and eliminated a lot of the skilled
'touch-labor' in the finishing stages.

Hmmm. I wouldn't ride that horse too far.

Ever see a 1944 built Walther P-38, or Waffenfabrik Mauser?
They didn't spend nearly any time finishing them as compared to
the early war versions.


The German record was very mixed

Keith, I hear ya, and the other posters who have said similar things,
but I still object to Mr McCall's statement that, in Germany,
"Everything was hand-finished to very high standards".
That's just not true. As you point out, it was very selective, and as
I pointed out, there are definite examples of German industry
reducing their quality standards to meet production demands.

cheers

PS: now that the Hobbit's (Rooney) out, what will England do?

--
Harry Andreas
Engineering raconteur

Harry Andreas wrote:


PS: now that the Hobbit's (Rooney) out, what will England do?

Try and win some football without a spoilt brat throwing tantrums on the
pitch and verbally abusing the match officials when, rightly, he is
called to task.

In article , Ricardo
wrote:

Harry Andreas wrote:


PS: now that the Hobbit's (Rooney) out, what will England do?

Try and win some football without a spoilt brat throwing tantrums on the
pitch and verbally abusing the match officials when, rightly, he is
called to task.

LOL!

Well, Ashley Cole looked all right today anyway.

--
Harry Andreas
Engineering raconteur