Inside the Chieftain's Hatch - AC I Sentinel Part 1

story of Sentinel begins to the pragmatic need when Australia answered the mother nation's call to arms in World War two it had exactly eight tanks in its inventory what kind of column tanks in actuality there are mark 6a lights so yeah technically tank but with a five oh and a time that even the 37 millimeter is starting to become a little bit underwhelming calling tank is a bit generous in any case operations overseas did confirm to the Australians the wisdom of having their own tanks instead of having to rely on attachments from other Commonwealth units such as the British Matilda's that we use in a very successful attack on Bardia which then resulted in the australians capturing italian m13 actually one around the corner here with big white kangaroos on the side which made an interesting photograph good models not very practical for a professional military however there is also the looming threat from Japan so pretty much tanks were needed where does Australia get them well this brings us to the next problem Australia was not a tank producing country in fact they had virtually no heavy industry whatsoever now it was manufacturing the LPS the local patterns were true a variant of the brand carrier the universal carrier but that was simply a matter of phenomenally available engines commercially available transmissions to an already extant design slightly modified for local needs a tank especially a cruiser was another kettle of fish entirely now it would take your typical tank producing country about two years to go from we need a tank to actually okay approved for service the US Army's head of research and development ordinance branch just before World War Two estimated about two years for a major end item to go from start to finish and everything about other countries more or less the same the famous tiger for example is a 1938 project didn't see service till 42 I possibly one of the fastest was t-34 but even that is most of two years at least if you start back in the age twenty days Australia starting from scratch even when it comes down to the industry to build the tanks in the first place problem now the other solution of course is just to buy tanks from somebody else well here's your next problem by the time the war cabinet Australia was given a request for 200 Cruiser tanks it was July 1940 and incidentally just make matters worse that number got exponentially bigger over time 1940 was not perhaps the best year for the British Army there was a small incident in France and all of a sudden the British are absolutely desperate for Tanks they are churning them out as fast as they can about one a day to replace the losses from France and also to meet the operational needs in North Africa so for the Australians they had none the Americans were the next best bet America can we buy some of your tech well God you got em two mediums never mind now that we're working on the m3 medium me m3 light but they were not yet ready for production so in the short term Australia was on her own this this brings us to Australian Cruiser Mark one commonly known as Sentinel now after much trial and tribulation the first prototype was accepted for testing around July August 1942 we have come to the Barrington tank museum in the UK they have the only remaining complete accessible mark 1 in the world now there is another complete mark one in Pokemon Niall there's runs but the Australian military won't let us film it now one of the nice things about doing the show is I get to show you features of Tanks that you know about but you maybe not know about the features and so the lesser-known details well you've got sort of a double whammy with this one this is a tank that almost nobody knows anything about anyway so hopefully you'll find it somewhat interesting as if you don't find the other ones interesting to begin with right anyway standard process exterior interior and then we coat let's get started so as we started toward the exterior Sentinel immediately you can see a philosophical divergence between the Australians and their mentors in the UK they were having a look at the a13 they decided that it was insufficiently armoured as a result of made two decisions firstly that this tank the Australian one have Armour worthy of the name Armour even if this came at the cost of some speed and mobility the other decision that they made was that the hole should be cast into something of a ballsy decision because at the time no tank had ever been built with a cast all as a result Sentinel is generally considered to be the first cast whole tank the other interesting feature is that due to shortages materials the Australians had to develop their own form of Steel they didn't have any nickel however their metallurgist had figured out by that point how to make weapons grade steel without nickel and they'd be building two pounder cannons without it for a while the armor itself has a cheap nicely sloped good two to two and a half inches thick which compares very favorably with anything else that anybody was driving around in at the time other features on the front so of course you have the headlights one on each side they feed in through the side here just behind there's a little plate engraved into the hull and it tells you three things it tells you the tank number which is 49 it tells you the whole number which is 56 and it tells you the turret number which is 18 8 by 18 a I have no idea about what it is this means is this one of sort of mid to later production tanks but in general terms is not much difference between them anyway you have armored visors for the driver and hole gunner you have the rather prominent armored housing for the machine gun which everybody keeps talking about it sounds the most famous thing about sentinel is the shape of the armored housing this is hardly good tag there's more to this tank than just the armored housing the axle housing at the front it's basically the transmission housing that you'd find on an American tank for example except instead of being bolted along the top it has actually voltage frontwards shall we say to the hull but for repair maintenance purposes under the bolts pull out the axle housing you're fine and as a point to note the numbers at the front of the axle housing the a h84 that means axle housing number 84 it's not the tank Hall number at all of course BK Bradford and kennel they were the guys that actually came up with casting for the tank similarly the 53 on the turret front there on the mountain lift that's the mounted casting number it's not the the turret casting number far side more visors another headlight and then you get to decide of the tank as you come around to the right-hand side towards the front you can see the viewport and the only marking on the tank now most viewports will have a little slit so even when it's closed you can still see something out not so in this case if you want to look to the right and you don't want to turn your complete periscope at the front there to the right does rotate then you have to actually open up the viewport on the side now I mentioned that the number was the only marking on the tank this was true because it was never really a fielded tank unlike a lot of other vehicles which would have a unit marking on the front that's how you would tell an Australian tanks he looked at the Univ arcing and he had to know what girls raylene unit markings were the other thing is that most of the Australian vehicles were painted in the Australian standard camouflage scheme which was a two-tone of olive green and light tan now looking at this one comparing it with other Australian vehicles I've seen around the world the brown appears to be wrong it's a little bit too brown not enough light tan however when these guys were repainting this vehicle I can only assume that since they were across the world from paint chips and only have black or white photographs work from that they can probably be excused for making one or two small errors it wouldn't be the first time the other famous example is the blue on the Matilda's that you see on various museu the contour scheme no it wasn't really blue but hey you didn't know that at the time and nobody's around to tell you you were wrong so that's it for the upper side here we're gonna come back to it but now my favorite part attracts coming down to the running gear two types of track were available they were not interchangeable the steel track was single pin had 129 links per side had a four inch pitch and required a sprocket wheel of 20 teeth now the alternative and the more common one was this rubber track 13 to 3 if you change tracks you have to change a wheel a 6 inch pitch and a t6 links per side now the track may look so much familiar in fact it's basically bm3 mediums track and that by reputation Bazaar Sentinel was based on the m3 medium and so really the only thing that they kept was the track and wanted to of the suspension components so the track itself rubber both sides the end connectors are exactly the same as you'd find on an m3 or not a m4 they also worked in Systema guides you could get browsers that you would attach to the tracks as well for additional traction the suspension units bogies three per side like your typical bogie unit it is bolted to the hull with the advantage that it takes no space inside the tank you have lots of room for all your equipment demo whatever else you want to put inside and also course is very easy to replace a damaged suspension uni just on Bolton's downside mobility probably not as good as a proper independence system the bolts are big but there's only for them now if you compare it with a say the m3 medium it's got 16 bolts holding on a single bogey which seems reasonable this is just for but the bogie does kind of angle underneath the hull so the weight of the hole rests partially on the bogie as well as the four bolts still I can only imagine if you see if you slide let's say into an obstacle going down a hill the lateral force on the bogie if there's only four bolts holding it in place that's probably asking for trouble the bogies themselves they come in two types most of them have the central return roller some later vehicles had a return low-level woods offset more to the rear you saw this again with the American thanks the suspension is a horizontal volume suspension system it realize it doesn't look like it but it is I think what throws people off is that there is the coil spring of the back it's a dampener spring and people think that makes it a horseman as you go further back along the whole side we started sees a couple of the cool features of Sentinel and then one is intended because of course Australia is not a cold place so it's in Cairns a couple of weeks ago 47 degrees in gardeny humidity and I can only imagine it gets worse if we go to places like Papua New Guinea or the deserts of North Africa tanks of course they're basically Overton's if it's hot outside is hotter inside accuracy if it's cold outside is colder inside no don't know why but what they've done is from here all the way to the back of the hole this is sort of an umbrella housing for vents that go all the way to the rear you can also see - they may be shoots here because they're not on the far side of this turret but these are also slots to go all the way up inside they could be for the 303 ammunition shell casings coming out and the canvas belt we'll find out when we get inside but there are cooling vents in the turd as well there's some towards the rear and there appears to be one up at the top right corner as well which I initially thought was a periscope mounting until I realized it was on basically every scent hole I saw then they get to the sponson box is nothing really remarkable about these sake they're a nice size for all your various pioneer tools or tank repair equipment they're held in place by simple latches you know latch forward loosen lifted up I can't open these up though because somebody has placed a screw and boat so I need a cup of pliers to undo it you could of course if you were completely paranoid use padlocks to secure your equipment if you were afraid that your buddy might take it from your Hank but then again is it really paranoia if they are out to get you it's not commonly known but the word steal is actually an army acronym goes back many many years it stands for supplies taken in excess of authorized this sector and being an official army acronym it is thus fair game so here you are if you should become a tanker word of advice keep an eye on your foot just go back to the idler wheel quick point to note somebody is going to ask what is this oval thing for in the whole site I know they will ask because I have asked myself what is this powerful thing for and all sides and the answer is I haven't the faintest clue initially wood thing was some sort of an access board or an escape at it's not it's welded in place so hopefully we'll find out when we go inside in a voyage of discovery but until then I haven't the faintest I still have a buddy's favorite question how do you attention the track I'm a sentinel it's actually a little bit different on this tank than most most times the idler wheel itself is forward or backwards maybe an offset idler arm in this case the entire idler mounting will slide forwards and backwards you can see that there are four slots which run on bolts they're basically guide bolts and that's the size of that slot shows you just how far forwards or backwards the item mounting will go it's actually conduct the tensioning is pretty simple you just pull out the cotter pin remove the locking plate use your really big wrench to screw backwards and forwards put the locking plate back on put your caught up it back on and you're done another characteristic feature Sentinel is the long sloping engine deck it doesn't have very much on it just access ports this was required by the power plant which was a marvel of mechanical complexity rivaled only by the a57 multi banks you found on a couple of American mediums now this again goes back to the problem of Australian manufacturing capability remember that Australia was not known for its heavy industry they figured that in order to get a tank like this to move at a reasonable clip they needed about 400 horsepower to do it and nothing like that had ever been built in Australia the solution therefore was to find engines from abroad the first choice of engine was going to be the Guba some radial diesel diesel engine you'd find it maybe in the m3 light tank however production capacity was not available Gilbertson were willing to give the dies and jigs but they didn't have any tooling so that kind of fell by the wayside the second choice was a twin GM 671 as you would eventually find on the m4 a 2 on the m10 got a motor carriage and on Valentine's however again production capacity was not available the next choice is said well how about the Pratt & Whitney single wasp it's an aircraft engine really powerful and you by the way we have the license to build these things here in Australia for aircraft manufacturing great idea the problem was that the War Department decided that producing aircraft was more important than producing tanks at least when it came to the engines so all Pratt Whitney wasp production went to Australia aircraft manufacturing so yet again the Australian tank manufacturing says well what the devil do we do now at this point they're starting to scrape the bottom the barrel their solution is the Cadillac it is a v8 346 cubic engine plant cranks at a whopping 110 horsepower not very powerful but it was available so how do you get a 25-ton tank to move at any reasonable clip with 110 horsepower engine easy you get three of them and so there are three engines in the tank one at the rear to further forward all meeting together the three outputs match in a transfer box very transfer box and that is why you have such a long engine neck other feature on the engine deck you do see the external fuel stowage it is quite simply external fuel storage it's not connected to the fuel system in any way shape or form you can also see that the ventilation system does continue underneath the whole side couple of spare track blocks and some towing eyes not much else on the rear of the tank all right so to come up onto the back of the year the engine deck and the first point to note is getting these access panels off was an activity fraught with peril because the thing is sloped like this is a somewhat glossy paint and you just have this tendency is sliding off so imagine doing this in the rain for example my cameraman is completely kitted out with all this mountaineering safety you you can imagine I of course am NOT in health and safety over there going oh my god so there are three engines in a cloverleaf configuration to Ford and one to the back all three of them have their own propeller shafts they meet in a single transfer case which is located under the turret about this far forward from there it is a single propeller shaft forward to the transmission as you can imagine with three engines which are all water-cooled is a lot of cool it required 23 gallons filled in two different positions surrounding the three engines of the fuel tanks they tally 140 imperial gallons there are five individual tanks but only one place to actually fill it which is the Capitals going now and to tell just how much fuel you have left is a good old-fashioned dipstick which actually reads up 146 so I guess it gave you a couple spare the manual is not specific as to how far you can actually get on 140 gallons of fuel of course being three engines you have three times the maintenance requirements so there are three dip sticks there are three oil filler so case in point if you look at the rear engine here this is the the oil filler and the dipstick is located further forward it's we kind of pulled it half out so I can actually get at it it's way over there so push it down a little bit here if you won't do any serious maintenance undo all the bolts that are all the way around the engine deck lift off and move the engine back deck set it aside now the three engines the transfer box the cooling system the fuel tanks are all mounted together on a slip so you would then take your train and lift the entire set the entire pack comes out it's one of the first examples of a of a contained pack shall we say obviously you doesn't have the transmission that's further forward but it does allow relatively quick access to everything once you've you know cleared everything out of the way that is it for the engine deck and next we're gonna go forward onto the turret and then inside for a part two all right so take three because I screwed up first two dad didn't Australia was not a tank producing company company like all bogeys they are bolted to the hull this means that you have or not like all bullies because I bet you somewhere welded cuz somebody somewhere is gonna say there is a welded bogie system I don't know of any off the top of my head but somebody's gonna tell me three wake up we of course must keep the blooper reels they tend to be the most popular part of the show it's kind of depressing you

Channel: The_Chieftain

Views: 120,896

Rating: 4.9745307 out of 5

Keywords: Inside the Chieftain's Hatch, Sentinel, AC1, Australian Cruiser, World of Tanks

Id: uPFHr18pt3Q

Length: 22min 39sec (1359 seconds)

Published: Sun Mar 27 2016

Reddit Comments

[u/KelloPudgerro]

No penis joke/10