"Ed Huntress" wrote in message
news
On Mon, 9 Oct 2017 10:34:08 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
. ..
On Sun, 8 Oct 2017 16:09:44 -0700 (PDT), Christopher Tidy
wrote:

Interesting. How about these holes and weld tails (see below)?
These
must be for additional strength and fatigue resistance, right?

Must be.


https://www.flickr.com/photos/138493...posted-public/
https://www.flickr.com/photos/138493...posted-public/

Fascinating that the part has 3 weld tails and no (visible)
welding
on
the bottom left side. Those tabs are under extremely high
pressure
as
pivot points. Historical failure surely led to this practice.
I'll
bet Caterpillar, Kubota, Case, Hitachi, Komatsu, Volvo, etc.
engineers
have some stories to tell about them. If you write to them and
they
respond, please share it with us. I always got Gibbs-slapped as a
kid
because I constantly asked for more details about everything.


Before computers the practice was to design as carefully as existing
theory and manual calculation permitted and then test to
destruction.
WW2 aircraft engines that had to be as light (=weak) as possible are
a
good example.
http://spitfiresite.com/2010/04/the-...in-engine.html
"Only 175 had been built and these were considered to be rather
unreliable. As a result, Rolls-Royce introduced an ambitious
reliability-improvement programme to fix the problems. This
consisted
of taking random engines from the end of assembly line and running
them continuously at full power until they failed. Each was then
dismantled to find out which part had failed, and that part was
redesigned to be stronger. After two years of this programme the
Merlin had matured into one of the most reliable aero engines in the
world, and could sustain eight-hour combat missions with no
problems."

In the early decades of the last century, that's how Rolls-Royce
developed their automobile engines, too.

Royce took measurements from the best engines of the day and then
averaged them. That's how he arrived at, for example, the odd
bore/stroke dimensions of their early engines.

The 1904 Grey Ghost was developed that way. To this day, many
historical automobile experts consider it to be the best engine for
its day, of all time.

The bar was rather low in 1904, however. d8-)

--
Ed Huntress

https://www.wired.com/2010/03/boeing...ing-flex-test/

-jsw