Inside the Chieftain's Hatch: M3 Grant. Part 1

when world war ii kicked off the epitome of US tank design was medium tank m2 this is basically a self-propelled machine-gun nest which happened to have a 37 millimeter up top to deal with anti-tank work however in 1939 ordnance branch did some experimentation to see if maybe a 75 millimeter cannon might not be a little bit better at the anti-infantry roll and the answer was well actually yes it is come 1939 also shortly thereafter a slight altercation kicked off in Europe and the Americans watching the goings-on over in places like France Poland started to come to the conclusion that perhaps the 37 millimeter wasn't going to cut it in the anti-tank role and you needed something a bit bigger well that something bigger was the 75 millimeter the ordnance had done experimentation as I said previously you look at the t 5e - it's basically in the m2 medium that had a 75 millimeter pack howitzer m1 mounted on the right sponsor this / - be somewhat successful as a result orders for the m2a1 were curtailed and the m3 medium went into production as it was going to be an interim vehicle while they figured out the problems with the t6 which was what would soon become the m4 Sherman which had a 75 millimeter of course in a fully rotating turret no ordnance branch were originally quite happy to simply make a turretless tank with a 75 in the hole pretty much like you'd say sturmgeschütz however infantry branch still had a lot of sway in tank development at the time and they were insistent upon maintaining the 37 millimeter now I'm not actually seeing any reasons as to why just that they did according to General Barnes the only thing that comes to mind perhaps is the ability for close-in protection against the infantry with canister rounds for basically big shotgun shells which are not available for the 75 by doing all this however they've reduced the amount of machineguns on the vehicle and they really did want to have this thing turn into the anti-infantry death blossom machine-gun vehicle of doom as a result they decided to put another cupola on top of the turret with another 30 Cal this maiden already all tank even taller when did the production in March 1941 and was known in British service as the medium tank m3 Lee British however were not incredibly enthralled by either the height of the turret or the fact that the commander didn't have access to the radio they requested that a new turret be designed mounted on the same turret ring it's a little bit lower a little bit longer and deeper and had a bulge for the radio mount better service of course this is known as medium tank m3 grant not General Grant British were the official documentation from Churchill was very clear not used were general but in practice it turned out that people started calling about anyway and reproduction both in the factory of the Pullman standard car company which was famous for making luxurious passenger cars through our roads and also the pressed steel car company famous for making slightly less luxurious rolling stock so we are at the Museum of Australian armor and artillery in Cairns Queensland and they be nice enough let us wander around their m3 ground it's gonna go neat traditional manner we're gonna wander around the outside and part one talk about the running gear of the engine and so on and then in part two we're gonna hop inside and see how much fun that six or seven lives inside hat also starting off with the whole we can see of course this is one of the ones of riveted construction about 300 cast whole vehicles were built by Alko and another 350 welded by Baldwin but the vast majority of m3s were of course rivets this was the heaviest the most time-consuming form of construction and you also had the minor hazard that rivets could pop off and become projectiles inside the tank however it was a level of technology in so many tanks of the era were riveted as it was the armor itself is pretty reasonable for the time you've got about two inches up on the upper slope one and a half down here sloped at 53 and the three-piece final drive housing is about two inches we also of course have the large bulges here for the final drive now the great thing about the final drive housing and transmission housing for the m3 which was kept on to the m4 but it's how easy it was to access the transmission you simply unbolt the housing pull it off two guys could do it with a crane and if you compare that to a lot of other vehicles at the time this was an amazing piece of user interface shall we say made life so much easier as the other features you have on the front that would be behind the brush guards Forest Service lights and siren plugging in here and a point of amusement shall we say is the twin machine gun ports now of course remember the Americans loved machine guns on their tanks they really did and having the cupola on top just wasn't enough so they put the two here these were fixed in Traverse they were aimed by moving the entire hull they were adjustable in elevation however there are some immediate problems can you imagine being the gunner on the 75 or the 37 trying to service a target and the tank is doing this because the drivers having a whale of a time trying to spray things from machine guns but this proved to be pretty much a complete waste very quickly one machine gun was deleted and they installed a plug there to fill up the hole however pretty soon thereafter they decided to get rid of the second one as well as a complete waste of space and although pretty much every m3 you see will have the kourt's so the Machine does in actuality see that the welded over and it's pretty rare to actually find a picture of one in service with the machine guns they did come with tripods that were stowed in the back of the tank and you could dismount them and use some as a regular tripod mounted 30 Cal if you so desired oddly the machine guns were kept some of the earliest m4 mediums also had the twin machine guns were very quickly that said this is a really stupid idea and they saw the light and got rid of it as you keep on moving around to the left obviously have the large drivers hatch I had the periscope inside of course we'll have a look on the inside 75 millimeter gun m2 you will note that it stops short of the tracks this was a thing in tank design at the time they really didn't want to have the gun go further than the track well suffice to say about turned out to be a rather silly idea so later production vehicles had a 75 millimeter gun m3 which was longer had a higher muzzle velocity better for anti-tank work you will see on some photographs of m2 equipped cannons that there is a large counterweight on the end of the muzzle this is used for the stabilization system the longer m3 cannon just didn't need it because the gun was heavier you then continue around to the side now the running gear is basically held over from the m2 medium this was a factor in quickly ramping up production the old-fashioned vertical valued bogies two wheels per bogie bolted simply onto the hull now the advantage of course with the bolts is that was very easy to make replacements you had damage to the bogie system Edith unbolt it and put new one back in another advantage of this was it took up no space inside the hole unlike a lot of other suspension systems such as Christie downsides however and you had a lack of mobility relatively speaking because you just didn't have the range of motion for the wheels that you would have on on other vehicles send a roller on the top of the bow gate this is a effectively they call it now a light duty bogie the heavy duty bogies would have a return ramp for the track and also the return roller was located a little bit further to the rear the tracks are another mobility reducer there are only 16 inches wide now the thinking at the time was if you made wider tracks then the the entire track system would be heavier as well as the tank and you had a slower tank and they decided that speed was more important than flotation in hindsight this could be argued to not have being the best decision and of course later on you had dumbbell end connectors or of course later on you have the horizontal body suspension which was much wider had twin turbo gear wheel the track 279 links per side these particular ones are a rather worn example of T 40 ones and they were simple rubber pads that if you are random balled on one side you can flip them over and then run the rubber on the other side or it's just incredibly inconvenient Mia can only imagine taking off each and every one of these end connectors and flipping them over later the kief when t1 is replaced by the T 51 which had a double thickness of rubber on one side so he still had the same service life at the track but you didn't have to go through all the hassle of flipping it over other patterns you had Roberto blue eyes and he had Chevron's both steel and rubber primary access into the Holocaust was through these large doors inside each door and you also see scattering one of the two parts of the hall in turn are these pistol ports this is again another concession to the fact that he no longer had machine guns in sponsons so the idea was he could take your thumb 7:45 and just shoot out this if there was any empty that got to close the door was of course a bit of a liability to the armored integrity of the vehicles that's a result by late production vehicles say it deleted this and the only access into the hall would have been here down through the turret basket or through the hatch which was retained it's on the whole roof just behind the main gun I was coming back from the door you can see one of the unit markings you haven't figured that British had a system of shapes and colors what to tell you the squadron and troop that the vehicle was in another thing that the British usually use the Americans you don't see so much are the sand shields of course British were operating a lot in North Africa in the desert and these are simple sheets of metal which covered the return run of the track and was supposed to keep the dust and in actuality of course of things fell off very quickly and we're discarded nobody bothered replacing and to come back to the back we see again the traditional idler wheel setup of the time just like we saw on the m10 so you would have these locking bolts here you undo these you then screw in the spreader bolt this will loosen the clamp around the idler arm pull off this retaining plate so it's under this tip you just hammer it off this way you have now released the serrations the teeth here you then take Little Joe that big massive wrench and lever the wheel forwards backwards attention to track step on your retaining plate under the clip release spreader bolt tighten the clamps and you're done we have the exhausts the radiator air comes out of the hole above the rear hole the exhaust of course are on each side behind the doors we can see radial engine it's angled a little bit forwards and down to allow the powertrain the propeller shaft to clear underneath the hole as much as possible little hole up here it's for your hand crank it's not really user starting the engine but what you want to do and this would come for any radial engine tank it's before you get going you want to turn the engine a couple of revolutions because all the oil is probably pool at the bottom of some of the cylinders you can end up with hydrostatic lock so yeah cycle the engine a couple of times and then you'll be able to start it the engine has mentioned it is a nine cylinder radial pumps at about 400 horsepower first speed is about 24 miles per hour sustained speed closer to 21 as a 185 gallons of 92 octane petrol get it maybe a 120 miles there are four fuel tanks to each of thirty two and a half gallons are mounted vertically at the front corners of the engine compartment and the other to each of sixty are located a little bit more to the rear over the sponsons you although you can access the engine for general maintenance purposes back here if you really want to do some heavy work or pull the pack I'm afraid what you got to do it you're going to unbolt the engine compartment deck lift that off with a crane and then it can lift up and out the radial event you figure that a better way doing if you look at nem 18 the engine will actually slide out backwards so that's it for the engine compartment really so let's hop up onto the back deck when you come up to the engine deck itself where which actually wasn't all that hard because it's got all the handheld's to climb on to the side door just make a right instead of going into the vehicle and para mind this isn't air-cooled vehicles is owns if you need any ports for the cooling system as a result the only hatches here there's five of them and therefore the five fuel tanks for the main engine and one for the axillary motor confusingly this is also sometimes known as Little Joe the grill here is the air intake for the radiator so the air gets sucked in here blown directly over the radial inch and then out that gap above the rear whole engine air intake for the actual combustion comes in through the hole through the engine fighting compartment we can also see back here another one of the pistol ports aiming to the rear we can see another pistol port on the side of the turret and this is all for the forty five and we have the distinctive bulge here for the radio on the grant turret and of course I am sitting on one of the sponson boxes for stowage of tool to one out of course a lot of them would also be mounted into the fixtures and fittings that are on the back of the engine deck well I must know where the outside here just going to point out a couple of things towards the front of the rear I so now come to the whole roof and if it wasn't for the fact that there are so many people on this tank there should be a lot of room for sleeping on the right-hand side again I'm directly over 275 we've got the main hatch door here on some of the cast Hall versions the hatch that should be sloped downwards you can see here also the mechanism for the primary side for the 75 moment gun of course it's a case-mate so as the gun traverses left to right the entire site itself has to have room to just swing around this pivot point as well the 37 millimeter gun of course was also stabilized and much as you wanted the counterweight on the m2 here it's also a counterweight which would be fixed here and it looks like a recoil cylinder when it's mounted it's not just a lump of metal designed to balance the system for the stabilizer to take effect again a lot of photographs you'll see that it has been removed they're just not using the stabilizer now the whether or not the stabilizer was a good thing is another matter um it is frequently known that a lot of units didn't use of this they said it didn't work looking into armored Board's investigations into no matter however they realized that there were two or three problems firstly the early stabilizers yeah they didn't work very well they eventually fixed those relatively quickly the second problem was that they were so classified that nobody taught the crews how to use them and how to maintain them as a result they didn't work when they tried to use them and this led to a loss of confidence there were a couple of units that actually did do their digging and figure out how to use and maintain the stabilizers they swore by them they actually had better performance in the field that even armored board said that the stabilizer was capable of but it's just another example of it's not just the equipment you gotta know how to use it so anyway that brings us to a conclusion of the exterior of the vehicle part 2 will be back and we hop inside and you see the six positions you

Channel: The Chieftain

Views: 314,009

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Id: RIjLtAt1zII

Length: 17min 7sec (1027 seconds)

Published: Tue May 17 2016