Joined: November 13th, 2008, 10:19 pm

September 14th, 2018, 9:59 am #21

We have but I'm interested here.  It's nothing like likely but Collins might be a relative by marriage.  Ironic that the big problem in tracing that would be the loss of those records.
"Be harmonious, enrich the soldiers, and scorn all other men"

"Whoever fights monsters should see to it that in the process he does not become a monster himself."

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Joined: December 25th, 2004, 12:37 pm

September 15th, 2018, 5:07 am #22

So many inches: From 1898 to 1957  the inch in the USA  was what is now called the US Survey Inch: 1" = 2.54000508 cm. The International Inch was adopted by all Inch using countries in 1957: 1" = 2.54 cm (exact). This was originated as the Engineering Inch adopted by the Brits in the early 1930s. The Imperial Inch had a different length at that time. To make matters worse the original standard was lost when the houses of Parliament in London burned down in the early 1800s. 
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Joined: December 11th, 2004, 1:10 pm

September 17th, 2018, 2:43 am #23

And IIRC that inch was really a derived measurement as the standard in Parliament was a foot. Not forgetting the intermediate standard in the foot of Nelson's Column.    
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Joined: December 25th, 2004, 12:37 pm

September 19th, 2018, 1:17 am #24

The actual standard is the US Survey Foot. Its the
  • Mendenhal Order of 1893.           1 yard = 36003937 meter    or    1 meter = 39.37 inches.
  • The International inch standard    1 inch = 25.4 mm (exact).
  • Order in Council 411 (1898)         1 imperial yard = 36/39.370113 meter or 1 meter = 39.370113 inches
  • Industrial Inch (1927)                  1 inch = 25.4 mm (exact)  (UK 1930) (USA 1933) 
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Joined: November 13th, 2008, 10:19 pm

September 19th, 2018, 1:30 am #25

Three barleycorns, round and dry, placed end to end.  Said Edward I iirc.  I like the use of "round" and "end to end" for the same items.
"Be harmonious, enrich the soldiers, and scorn all other men"

"Whoever fights monsters should see to it that in the process he does not become a monster himself."

"We take pride in the terminatory service we provide"
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Joined: April 11th, 2006, 12:54 pm

September 21st, 2018, 8:30 am #26

seasick.warships1discussionboards wrote:
The actual standard is the US Survey Foot. Its the

  • Mendenhal Order of 1893.           1 yard = 36003937 meter    or    1 meter = 39.37 inches.
  • The International inch standard    1 inch = 25.4 mm (exact).
  • Order in Council 411 (1898)         1 imperial yard = 36/39.370113 meter or 1 meter = 39.370113 inches
  • Industrial Inch (1927)                  1 inch = 25.4 mm (exact)  (UK 1930) (USA 1933) 
.

Sort of, but the internationally defined term is "metre", not the USA's weirdness of "meter".

.
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Joined: April 10th, 2006, 7:48 pm

September 21st, 2018, 9:37 am #27

TZoli wrote: Friedman's both RN book (British Cruisers, and British Destroyers and Frigates) mentions this 0,661inch - 16,7894 or 17mm machine gun a new light AA for ships under development in 1935 or after 1935.
My friend provided me a low quality sketch drawing of a side view showing a sextuple mount (two rows, 3 gun each) in a mount very similar to the 40mm/39 Pom-pom quad. But due to copyright reasons I cannot share it. 
He provided these info: 

Also some data . 6 barrels in two rows of three, belt fed, Weight of mount around 3 tons (Vickers, no ammo) or 4tons 15 with 1200 rounds weighing 7.5 cwt and 10,000 rounds on the mount (L class Cover)

Generally based on 2pdr pompom (quad?) firing 85gm bullets at 300rpm. MV 3300 ft/sec. Official calibre 0.661in 
(=  16.7894mm to be exact. I wish modern authors wouldn't convert exact inches to approximate but anachronistic metric. 17mm looks like a designed size, and 0.661 its conversion.  The bullet weight would determine the calibre.)
To return to the beginning, there are reasons to be cautious about quoted calibres: are they referring to bore or projectile diameter?

For instance, the .5 inch (12.7 mm) Vickers MGs had actual bullet diameters of .514 inches or 13.056 mm (by comparison, the .50 Browning, also nominally 12.7 mm, uses .510 inch bullets or 12.95 mm).


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Joined: April 11th, 2006, 12:54 pm

September 21st, 2018, 9:53 am #28

ONCE the RN had examined the Vickers initial ideas, the design requested for testing was based on 3300 f.s./25 tons/at 80 deg F, rising to 27.5 tons at 120 deg F charge temperature.  Initially they were very flexible over cartridge size/barrel length as they were trying to find the best cartridge size and cordite type for fast automatic loading.

It seems that most of the test firing of 0.661" ammunition was conducted using "pressure barrels" of various lengths to simulate the s.v. (striking velocity) at various ranges as the Ordnance Board were trying to see what effect the 0.661" bullet would have on aircraft structures, and the engine block/cylinders in particular.  They wanted the final equipment to fire solid bullets, high explosive bullets and incendiary bullets, but the main trials were with solid bullets only.

The main design and trials work SEEMS to have been in the choice of cartridge/cordite (or equivalent) to enable fast reliable firing.

There are two or three gun design reference numbers in the TNA:PRO archives, but I couldn't find any drawings.

--------------------

The detailed Ordnance Board and Naval Ordnance Department files from WW2 have (officially) been lost, seemingly having been disposed of in the 1960's.   Likewise most of the Vickers technical gun files seem to have been lost at about the same time.  The Vickers files that remain ALLEGEDLY mainly consist of commercial and shipbuilding files (I cannot confirm).

.
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Joined: November 13th, 2008, 10:19 pm

September 21st, 2018, 2:08 pm #29

"1967, minister?  Oh, no it was a very good year.  We lost no end of embarrassing files".
"Be harmonious, enrich the soldiers, and scorn all other men"

"Whoever fights monsters should see to it that in the process he does not become a monster himself."

"We take pride in the terminatory service we provide"
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Joined: December 25th, 2004, 12:37 pm

September 23rd, 2018, 2:21 am #30

I have a hard time putting an "r" before an "e". Must be an American thing.

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