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Author Topic: Sentinel ACIV  (Read 31136 times)

Offline GTX

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Re: Sentinel ACIV
« Reply #75 on: January 20, 2018, 11:14:08 am »
The results were great and I thought to share a samplerer for you all in the ASAP. More to come as well as CA-15 and CA-23 for the zoom zooms.

Looking forward to more mate.

Offline Abraham Gubler

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Re: Sentinel ACIV
« Reply #76 on: January 24, 2018, 02:40:00 am »
Here a handful of AC1 pictures from the archive. The caption (actually a hand typed, half sized, tissue paper sheet inserted before the photo) of the AC1 bogged in the dried up river bed assures the reader that the tank was able to recover from this position under its own power.

In my previous post hawkeyes may have noticed the photo of nine cast hulls of Australian Cruiser Tanks stacked three up? Eight of these are AC3 hulls with a single AC1 in mid right. These hulls have been cast, heat treated and machined were needed and are ready for transport to the production line. 200 AC3s were ordered and there is an extensive folio in the National Archives of all the purchase orders that went out for all the sub-components. Then attached to each one is a 1943 dated stop work order.
"There is a tendency in our planning to confuse the unfamiliar with the improbable." Thomas Schelling

Offline Basilisk

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Re: Sentinel ACIV
« Reply #77 on: January 24, 2018, 07:26:48 am »
That's quite neat, I haven't seen some of these before. Thanks for sharing.

In my previous post hawkeyes may have noticed the photo of nine cast hulls of Australian Cruiser Tanks stacked three up? Eight of these are AC3 hulls with a single AC1 in mid right.
Looks like 8 AC3 hulls, 2 AC1 Hulls, at least 1 and probably 3 AC3 axle housings, and right at the bottom of the photo what looks to me like the top of an AC1 turret.

Offline Abraham Gubler

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Re: Sentinel ACIV
« Reply #78 on: January 25, 2018, 07:37:25 pm »
The photos are from a great ‘book’ called “The Production of Armoured Fighting Vehicles in Australia” put together by the AFVs Directorate in early 1943 as a record of what they had done to date with the AC Tank program. It’s a huge leather bound thing held together by three bolts full of photo plates and information about the design and production of the tanks.
"There is a tendency in our planning to confuse the unfamiliar with the improbable." Thomas Schelling

Offline Abraham Gubler

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Re: Sentinel ACIV
« Reply #79 on: January 28, 2018, 02:30:06 am »
Some more imagery.
"There is a tendency in our planning to confuse the unfamiliar with the improbable." Thomas Schelling

Offline Basilisk

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Re: Sentinel ACIV
« Reply #80 on: January 28, 2018, 05:28:47 am »
The photos are from a great ‘book’ called “The Production of Armoured Fighting Vehicles in Australia” put together by the AFVs Directorate in early 1943 as a record of what they had done to date with the AC Tank program. It’s a huge leather bound thing held together by three bolts full of photo plates and information about the design and production of the tanks.

Ah, that makes sense, David Fletcher wrote an article in Classic Military Vehicles I think that used that book as a source, so I guess a copy went along with the Sentinel that went to Bovington.

Offline Abraham Gubler

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Re: Sentinel ACIV
« Reply #81 on: January 30, 2018, 02:10:58 am »
Some more pics.

Top to Bottom: AC3 wooden mockup, previously published AC3 prototype using AC1 hull, AC3 cast hull ready for assembly, AC3 vs Panzer IV, AC3 vs Panzer III
"There is a tendency in our planning to confuse the unfamiliar with the improbable." Thomas Schelling

Offline ninjrk

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Offline GTX

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Offline rdmr

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Re: Sentinel ACIV
« Reply #84 on: November 25, 2018, 05:09:11 pm »
Fantastic ninjrk!

Offline Basilisk

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Re: Sentinel ACIV
« Reply #85 on: November 25, 2018, 09:08:20 pm »
100+ pages of plans for the AC3 here: https://recordsearch.naa.gov.au/SearchNRetrieve/Gallery151/dist/JGalleryViewer.aspx?B=382893&S=15&N=103&R=0#/SearchNRetrieve/NAAMedia/ShowImage.aspx?B=382893&T=P&S=1

From memory, if you have a look somewhere around half way through that is a couple of drawings of an AC4 hull. It only has a 64" turret ring so must be an early draft before the design was enlarged to 70".

I've never figured out why certain files get digitised before others that one was scanned something like 18 months ago, they don't seem to be going by age, or by series, or anything else obvious. Tangentially related to this thread since the AC4 could also carry a 25 pounder, these are from a couple of months back, the first experiment towards a 25 pdr tank gun, tested June 1942:

Barcode: 33033164


Barcode: 33033162


The rest are AC1 but you can find them under series MP891/30.

Offline ninjrk

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Re: Sentinel ACIV
« Reply #86 on: December 03, 2018, 06:09:08 am »
I confess I'm a little surprised that there was no mention of trying to fit the QEF 75mm main gun in the Sentinel instead of the 25 pdr.  I'd assume its because the 25 pdr was in production in Australia and ammunition was plentiful?

Offline Basilisk

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Re: Sentinel ACIV
« Reply #87 on: December 03, 2018, 06:57:23 am »
Pretty much. The intent was to only to use imported components where there was no local alternative. Sometimes you see comments online suggesting the Vickers was a bit old fashioned or too bulky, and they should have used the BESA, well neither the BESA nor its ammunition were being made in Australia. I think there is a fairly short list somewhere of foreign components required for the tanks, the major ones were the engines and roller element bearings, and bunch of little things like light bulbs.

Having said that, as designs were drawn up to fit a 6 pdr to the Sentinel, and as I understand it the OQF 75mm is essentially a rebarreled 6 pdr, I don't imagine it would have been out of the realm of possibility to make a 75mm Sentinel.

Offline rdmr

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Re: Sentinel ACIV
« Reply #88 on: December 06, 2018, 02:48:52 pm »
And I think the engines, although technically made overseas, were chosen as there was a large stock in country ( I do not know where it was, or who owned it ) and presented no or very little issue with supply.

Offline Basilisk

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Re: Sentinel ACIV
« Reply #89 on: December 07, 2018, 12:59:12 am »
And I think the engines, although technically made overseas, were chosen as there was a large stock in country ( I do not know where it was, or who owned it ) and presented no or very little issue with supply.

No, the Cadillac V8s came direct from the US. As they weren't anybody's first choice as a tank engine, the Americans and even the manufacturer didn't think a multiple engine power plant would work, there was no competing demand and they could be had in almost any quantity desired. Until the US started putting multiple Cadillac V8s into their tanks.

There was I believe a stock of Ford V8s in Australia, they were used in the LP Carriers. A triple Ford V8 using those was one of the fall backs if the Cadillacs couldn't be had.