I remember seeing a military related tv show on the Merkava tank. The young woman driver of the tank related that the #1 consideration in the design was crew survivability, since the IDF was so small. She particularly appreciated the fact that rounds hitting the front of the tank needed to penetrate not only the frontal armor, but also the front mounted power pack. She felt a lot safer having a larger mass in front of her.
I'd never thought about it before, but stalls and missed shifts probably happened constantly in ww2 battles. I've stalled my truck at intersections and been embarrassed. I can't imagine the stress of stalling a tank in the middle of a battle, or having a shift linkage break.
On the plus side I gather that unless you are in really nasty mud or on a hill, a tank is geared so low that you can start it in any gear. You don't even use first unless you are in some really heavy stuff. Some of the older tanks had complaints that you had to stop the vehicle before changing gears, which they thought was a inconvenience. The gears were basically just to chose thec speed range you wanted, and just how much torque you wanted at the tracks. Point is, it's like driving a truck with low range 4WD, it will start in any gear easily, and it's pretty hard to stall it with that much gearing. That happens in cars because the engines are pretty weak and the final drive gearing is relatively tall, and it's much worse in higher gears, since the effect multiplies. With a low geared tank or tractor, even if you get the wrong gear it's less likely to make you stall, unless the resistance is really high. I imagine it being something like driving a truck in 4LO with a very heavy load in the back. You will feel the difference but it will still start in any gear without a lot of trouble.
9:20 when he says "floatation issues"...... he isnt talking about crossing rivers, folks pretty much all farm equipment uses "floatation" tires..... big, fat, wide tires that spread out the weight in mud they preventing it from "sinking" into the mud..... and instead.... ride on the top ~1 inch of soil if all the weight was in the back on the m18...... the ass end would constantly get stuck 3 foot down in the mud BUT.... because the weight is spread out... the m18 might only sink 0.5 or 1 inch into the mud..... which is very easy for the tracks to overcome.... and speed away from that angry panther
@@hedgehog3180 and this is another reason battlemechs, and to an even greater extent, Warhammer 40k titans and other walker vehicles is a really bad idea that only works in Sci-fi, because IRL, they would be restricted to exposed bedrock. An AT-AT would never have worked on sand, soil or ice as it's ground preassure would make the ice start melting under it's feet, and the sand or soil would flow like quicksand. A 40k Dreadnaught, knight or titan or even a Baneblade/Fellblade sized super heavy tank would have even bigger problems. And that's from someone who's loved 40k and Battletech since I encountered the concepts at 13 and 10years old respectively. I'm going on my 36th year now, and the 40k collection has an entire room for itself, shared only with an R/C Leo2A6 and some Star Wars LEGO!
@@SonsOfLorgar but the stompas are litteraly powered by the believe thar they will work, so as long as the bois will believe the stompa won't sink, it won't sink
One of the interesting things about Merkava is that the hull makes a really good APC. The Namer is likely one of the best of the heavy APCs. The US Army trialed some Namers and they liked them but decided against purchasing some. And I always like how Chieftain reiterates that you can't judge a tank based on how many countries use it. Some designs may be so specialized, it's just not practical for another country to use it.
it have even more to do with politics and supplies. most countries prefer a locally built tank since it preserve jobs AND you don't require someone to produce them for you as they might become less of an ally in 15years and are now reluctant to give you spare parts or upgrade your tanks (addon armor packs and such)
The more and more I look into tanks the more I come back to this conclusion. They were all designed by engineers, to take advantage of existing infrastructure for creation, maintenance, and transport to implement a state's "tank doctrine". For example, Germany couldn't make many tanks AND had a manpower shortage compared to "All allies in WW2". Yeah, which is why they chose to make tanks that could kill 5+ tanks for every one lost, and be repaired and reused. The fact their metal industry collapsed, later using poorer materials, isn't the fault of the tank. The fact the train infrastucture collapsed forcing the tank to literally drive to the frontlines constantly playing a game of "hitlers firefighters" isn't the fault of the tank. Likewise, the Germans "fixed up" and re-used tons of captured tanks [as well as damaged German tanks] to supplement their small armor numbers. The Hetzer (not ever actually named that in real life) was a very successful tank destroyer in WW2... and based on a captured Czechoslovakian 38 tank. The German engineers were not stupid. They would take the guns off captured tanks because their infrastructure couldn't construct or supply another nations ammo, spend weeks chopping and replacing the vehicle with a gun they do produce and support, and boom. You've got a vehicle your troops can actually fire as much as necessary without running out of captured ammo. Likewise, the T-34 was unreliable and it didn't matter. They needed tanks. NOW. If any tank fell apart, they had 10 more to replace it. The Soviets knew they had a huge industral base that wasn't being bombed into oblivion. They needed a shell of metal around some guys manning an anti-tank/support gun. NOW. Here's one I'm actually going to do a video about. Everybody talks about how "gas is explosive and stupid for tanks." Tank fuels were chosen based on the fuels available by the industry of the country. When you crack heavy oils from the ground, you _always_ get multiple fuel types (plus oils). So many countries simply said "the navy gets the diesel, and everyone else gets the gas." [or variations thereof]. The "fuel" explodes? Who cares? You know what's even worse than fuel exploding on mostly outside fuel-tanks? The EXPLOSIVE AMMO INSIDE being hit by a round. Which is why the Shermans first got extra 1" of armor around ammo, then got wet racks, but never changed/protected their fuel tanks [AFAIK] during the war. Further, fuel explosions don't shoot turrets into the air and out of the tank. Ammo explosions do. So people say stupid things like "Americans were stupid because Shermans used gas making them explosive." 1) The ammo was the explosive part. 2) they fixed/improved that. 3) The Americans also made a diesel version of the Sherman, the M4A6, for export. The Americans didn't use Diesel because they _intentionally chose not to_. The countries that DID use diesel as a fuel backbone for tanks DID want to use diesel. Meanwhile, guess what Americans did use diesel for in WW2? Submarines and ships. So we knew about diesel engines, used them, and supplied them, and had gas left over for the tanks and planes. [Nobody ever complains that gas was for planes and made them "explode" either. Gas tended to be a better power-to-weight ratio.] Disclaimer: I'm not a historian. Another fun one is people who think the Merkeva is super safe because they put the engine facing the front / the enemy. As if the engine is going to somehow stop a modern tank round that can defeat multiple feet of composite armor. Say it with me: "Engines! aren't! armor!" They're made out of relatively thin sheets of metal and mostly empty space for rotating parts. An iron or aluminum block never has in the history of tanks, been used as an armor for anything above rifle rounds. You can easily RUclips videos of .50 caliber weapons perforating large truck engines. And those are TINY TINY TINY compared to a tank shell. People really don't appreciate how fast, or how much energy is in a modern (even a WW2) tank shell. It's not stopping at an engine. The Merkeva has a front engine so the tank can face the enemy, get hit, and the crew can run out the back. If they actually expected the engine to be "armor", the crew is already dead.
There was another point you said by yourself in some videos. The front mounted sprocket got a cleaner track to work with. On the way to the front the links loose dirt and thus are less likely to damage/wear down the teeth. That may not be the main reason but it is another addition.
Your point about transmission linkages is something I hadn't considered. I used to have a van with a column shifter that required a fair amount of finesse to shift smoothly between gears. Trying to force it when it didn't want to go into gear ran the risk of having the linkage separate leaving you stranded. Having that happen in a situation where people are shooting at you, yeah, I can see why they'd put the transmission in the front.
My family owned Econolines for years and that happened a few times. Once a cotter pin in the linkage broke and was replaced by a bobby pin as a permanent temporary fix.
@@edcrichton9457 Mine was close to 20 years old when I bought it, and the linkage was well worn. I learned pretty quickly how to shift it without causing a problem, but only after I had to push it out of traffic a few times.
My parents had a 79 Chevy van, witha three-on-the-tree. You learned quickly not to downshift straight from 3rd to 1st when coming to a stop. If you did, you'd bind up the linkage and have to coast to the shoulder, get out, and stick a screwdriver in the linkage to unbind it. I think I only did that once or twice. After that, I always shifted from 3rd to 2nd to 1st.
@@edcrichton9457 There's a well-abused '91 dodge shadow 5 speed out there somewhere that has a bent trim nail holding the cable end to the fore-aft linkage on the transmission side, and a rolled up piece of greased rubber hose as the bushing. Nothing like field-expedient repairs that not only work when needed (I yanked the thing apart on a 4-3 downshift in the middle of the night in downtown Atlanta), but also ended up working better than the factory parts (I hadn't realized just how much slop there was in the factory perforated bushing...)
Buick designed the M18 so naturally used two of their V-8's to hustle it around. The engines were mounted to a frame which could be slid out like a drawer to make servicing or replacing the two engines easier and faster. The US Army thought that was slick but told Buick to use the radial engine instead because they had plenty of mechanics and parts for those.
@@billwilson3609 Making a engine easily accessible is not quite the same as making it easily exchangeable. With the Leopard 2's power pack, they can just swap out the whole thing within 15 minutes. The recovery tank can just carry a spare power pack on its back to the damaged tank and switch it out and in a real pickle it can even put its own power pack into the MBT and then wait for another recovery vehicle or a truck to bring it a new one.
@@TrangleC The US Army made a shortened version of their Christie Combat Car by replacing the V12 Liberty engine with a Wright radial. The compact radial allowed them to remove it with the transmission and rear drive attached as one assembly by using a truck with a winch crane. Their M6 heavy tank had a similar arrangement using a fluid drive (kerosene was the fluid) that might have been removable as an assembly. I think the radial and multibank engines in the M3 and M4 could be removed and reset in less than one hour. Chrysler's engineers made sure that could be done so Ordnance would approve using the multibank engines.
Glad he addressed the mechanical advantage of pulling the track forward (think block and tackle) and that it's way down on the scale of considerations for a tank design .. always love your talks
There is no mechanical advantage of pulling the track forward. Why? Because the axis of the sprocket and the axis of the idler are fixed relative to one another.
You will never see a conveyor belt in any different configuration and basically a tank tread is a conveyor belt. You cannot push the tread around the axels because you don't get the same torque because of a number of physical restrictions.
@@markkarnes5597 Tail drive conveyors are a thing. It's just typically not done because of the tension effects. Tail drive feeders are fairly common. We have both on the current project I'm working on.
I got to drive an M113A3 around Grafenwoehr and Hohenfels Germany as a 12B, and since it was the platoon commander's vehicle it was really like having a tracked vehicle to joyride around the mountains of Germany with. They were definitely balanced well considering all the very steep grades I'd have to drive down and up. Checking the oil in the two front final drives was just as important as the engine oil, stressed in the manual and by my NCO's. (One of them called the 113 a 'tracked grenade'.) The up front engine served another purpose very well-at night I'd lay my 3 layer sleeping bag over the engine intake grate on top and get nice residual engine heat for nearly the entire night.
@@TheChieftainsHatch I hate to be one of those people that replies to one of your comments, but need to get an answer before they go off sale. Is the shirt you're wearing in this video the normal green T-shirt from the store, or is it a custom version? The shade of green in the video looks a lot different (and a lot better) than the vomit-color that it looks like on the website.
I've been watching RUclips videos for a very ling time. It's becoming clear that many channels are becoming very fine operations. This is a perfect example of the more professional work as opposed to amateur videos. Keep up the good work.
The argentine TAM also has the engine on the front, with a small hatch on the back for loading ammo and stuff. It's a german design, the chasis is a marder derivative and the turret was to be the upgraded leopard 1 turret, but leopard 2 make that useless, so german engineers use ir for the TAM project instead
The TAM is so full of potential with some modern upgrades to it, and it has awesome operational range...srsly, the U.S. should really look to front engine designs or perhaps all electric systems to replace the aging Bradleys and M1s and make a universal modular vehicle which can be adapted to any role. 20 years from now, maybe we'll just have drone tanks and robot infantry though.
@@pex_the_unalivedrunk6785 They tried. Twice. The Future Combat Systems tried just that, but was a victim of being too advanced for its time, and short-term priorities. The Ground Combat Vehicle was... the less said about it, the better.
@@pex_the_unalivedrunk6785 the issue with that is you end up wit flawed vehicles for their roles. now sharing a certain degree of component parts (ie as much as possible) but haveing separate purpose-built chassis is the way to go. of course light-medium tanks and IFVs have a lot more uncommon than MBTs and regular IFVs, so those could potentially share a chassis.
Strv 103 (the S-tank) also had the engines up front (and served as a role model for Merkava). The reason for putting the engines in fron was to have them function as additional front armor, protecting the crew. With the gun arrangement of strv 103 it would also be more difficult to replenish the ammo if there was an engine in the way.
Hopefully this comment doesn't get buried, but I have a question for the monthly Q/A. The Chieftain MBT is often described as the most well-armoured vehicle of its time, but wouldn't the appearance of HEAT shells make the armour relatively useless? Why did nations continue to build heavily armoured vehicles when HEAT rounds were a thing and composite armour had yet to be developed? Were HEAT shells uncommon compared to traditional anti-tank shells, thus the need to protect against conventional kinetic projectiles have more importance and thus the need for heavy armour? Pretty long-winded question but I'd love to get an answer for this!
my two cents, you dont stop making planes just because the other guys make anti air rockets. Tanks are still useful even if their best defences are nullified, because its still a mobile weapons platform thats resistant to most threats.
I'll add my opinion as well. HEAT still needs to go through armour so adding more does help, albeit not as much as composite does but this combined with spaced or skirts would help.
HEAT was a major headache but was not magic. The 105mm L7s HEAT round could chew through about 400mm as i recall. When France and Germany started work on what would split into the Leopard 1 and AMX-30, they emphasized sniping and outmanuvering oponents, while the Cheiftan and to a lesser extent the Pattons were expected to be able to slug it out. As such France and Germany considered sufficient armor impractical and settled for resistance to 20mm autocannon while the Americans and British had 2,3,4 times the effective armor in some places to be able to shrug off known main gun rounds at the cost of speeds that could best be described as leisurely. Of course warheads kept improving and what was ok armor was eventually rendered as underwhelming as Leo 1's.
Most well armored at its time cheiftan is not. You forget T-64 exist? It comes down to AP can hit stuff at first shot much more reliable over a long distance. People probably will sling AP at your direction first.
The weight distribution is a very significant factor - if you have the turret in the middle of the tank (which is much easier with the front transmission) you can upgrade/downgrade the turret and don't bother with the balance, but if you have the front placed turret you will have problems as with soviet T-34-85 which was particularly nose heavy despite the fact they'd played with the turret armor thickness to reduce the weight as much as possible. Also, the middle position is most comfortable when you driving through the bumpy terrain. And what soviet engineers had done immediately when they were making the new medium - they'd placed the turret in the middle on T-44 (but managed to keep the engine/trans in the back by mounting all the machinery transversely).
It is also the great flaw of the Merkava. Having the engine and the transmission at the front puts harsh restraints on how voluminous and how heavy the frontal hull armor can be. The hype about the Merkava being the most safe tank for the crew is strong, but most people don't know that it has one of the weakest frontal hull armor protections of all modern MBTs and it still is incredibly front heavy, which is why there are a bunch of pictures of Merkavas which nose-dived into ditches and couldn't get out again or even somersaulted down slopes and even one famous picture of a Merkava doing something like a headstand on its nose and gun barrel.
It's pretty much a tossup; rear-drive tanks have the tensioner at the bow, and front-drive tanks have the tensioner at the stern. Either way, you need to have some arrangement that results in the actual tensioning mechanism not being obscured by either the idler wheel or the hull of the tank, and there have been any number of solutions to the problem over the decades.
@@ABrit-bt6ce oh, I didn't know that you just have to press a button to regulate the tension the track on the the Challenger, really cool! A dumb question: the button I presume is pressed by the driver inside but how he knows if the tension is correct, is there a gauge?
It’s easier to tension at the front as the back is covered in mud and crap that’s been dragged and thrown up :). It’s all muddy, so we’re talking quantity.
@@lkchild it is correct! Back in 1976 I was driving in Italy the Leopard 1A2 and to tension the track I had a big open key to be inserted on the front idler but we had to be two of us to work on it but it was relatively easy to wash off the mud...
Thank you, I have been watching your videos for a number of years now. I am interested in WW2 armour/tanks, particularly the Sherman. I find your videos informative, entertaining, and extremely useful for my own talks that I give from time to time. Just thought I'd encourage you.
Front/Back sprocket also makes a difference in track tension distribution over the length while moving . Practically speaking - With front sprocket, chances of throwing the track while forward travel is higher than with a rear sprocket. The opposite in reverse (naturally) and for breaking. Though with adequate track tensioning, the difference is not so large to make a gigantic difference / worth paying too much attention to over the main reasons chieftain talked about (Front Sprocket worked out well enough for WW2 tanks with pretty low tension after all). Its just an important side aspect to keep in mind from the engineering side, esp. if the vehicle has a narrow track and high suspension travel.
I enjoy your lessons on the amazing history of armor. I'm a native Texan who's family came from Ireland in the late 1800's and I hear that the Hurley name is quite common in Dublin. I thank you for your help in keeping me engaged in this time of homebound occupancy.
If you aren't full of yourself, you should call a corpsman. "You" is typically supposed to be filled with "yourself", if bits of yourself aren't the filling inside you, it means you need urgent surgey to stop your organs falling out.
Thanks. The Tank Museuem's David Willey had a couple of additional points regarding sprocket wheels worth clicking over to as well. Mr. Willey's examples were not so modern and of a more general sense. But good stuff. His graphics department even had some drawings.
Another issue was the gun projecting past the front of the tank, which was thought to be a bad thing. A central turret allows a longer gun with out an overhang. Designers worried about this until guns got so long it was unavoidable. It makes the tank less cumbersome and its easier to traverse the gun, no worries about obstacle in the front quadrant. Your point about having the driver next to the transmission is well taken. One of the pluses of a torque converter is the elimination of a clutch. Slipping the clutch in a heavy high torque vehicle is a big nuisance and many WW II tanks have two steering clutches. The final point is that minimizing the internal volume of the tank in order to maximize armor doesn’t seen to be on the designers list. Compare any modern tank with a WW II design. Even in a cramped older design the internal volume is greater, the modern stuff is much more efficient. Thanks for the heads up on “Engineers of Victory” Paul Kennedy. The concept is good, to focus on the creators of the weapons systems that won WWII everyone from Sgt Cullen to Wilfred Freeman. Great read. As an “apprentice rivet counter” the niggling technical mistakes e.g. calling the torpedos the Swordfish intended to launch at Bismarck acoustic rather than magnetic, are annoying but really who cares. See you on the next one!
@@coreys2686 there are plenty of interviews with ww2 veterans who claim that combat is like a drug, you start to crave it. while others out right said they enjoyed combat.
Front final drives get hammerd and abused more than a rear final drive. Just from personal experience as a maintenance officer. All your point are valid and informative. Thank you.
Uploaded just when i was scouring around for answer for this exact question. If only i found this yesterday i would've saved myself 5 hours of nap time.
Thank you for making this video I’ve never looked into it but I’ve always thought the same way industrial mechanic think driving the track at the back is way less strain on the track mounting system and less strain on the track but I never thought about the other things
There is a reason barely ANY front offloading APC exist. In fact, I know of none. Rear offloading is far safer. Right off the bat, you have the full length of the APC as instant cover. Second, see Saving Private Ryan, landing sequence, to see how horrific front offloading can be. With Landing craft you really didn't have much choice, water was inevitably shallower in the front than the back but with APC that is not the case. I appreciate your opinion, but kindly admit, it was offered with little forethought and analysis. Some design features are there for a reason.
On the wilson gear box, to expand, the linkages are both pushing and pulling alone. The gear pre-selecting is pushing or pulling to rotate a selector drum by way of a bell crank. On the Gear Change function, it's just pushing or pulling a bell crank to lift the bus bar. Compare to a conventional gear box selector that needs to twist as well as push/pull.
One other (very slight) advantage to a front drive sprocket is that the returning track gets more time to shake loose the mud/dirt/dust before it engages the high-pressure mating faces on the drive sprocket, reducing wear and meaning track tension can last a little longer between adjustments. It's not a big advantage, and certainly doesn't rate compared to those issues raised in the video, but it is a factor. Can't think why the Chieftain didn't bring it up ... ;)
The Merkava engine placement supports keeping up to 6 troops inside the tank (plus the normal tank crew). A secondary reason for the front engine design is crew protection; there are significantly fewer Israelis than there are hostile Arabs in the region, with the subset of trained Israeli tank crews being scarcer still, so keeping the crews alive is important.
Correct and mind you that that the engine is a big block capable to stop almost any incoming shots! In plain English the Merkava is one of the most survivable tank ever...
Turned out there was a bit of a gap in the published history on the subject. Yeide's book covers the operational history of the TDs, but for the technical development, there's only sub-chapters in Hunnicutt. As I was digging in the Archives, I found a lot of unpublished stuff, so I ran with it.
To address your point around 11:00 WRT engine arrangement for APCs - don't forget the entire 8x8 BTR series, which are notoriously rear-engined despite being roled as APCs, with the troopaloops simply disembarking from twinned hatches on either side of the vehicle. On the other hand, one can argue the relative merits of a single larger ramp-style hatch vs. multiple smaller hatches, or even the merits of the BTR with regards to its doctrinal use as an APC in general, until they're blue in the face. I don't particularly feel like doing that.
Hey Chieftan, great video, as ever; love the content. The Israeli design impetus for engine forward is primarily crew safety and ease of evacuation. True, the door in the back makes it MUCH easier to ingress and egress ammo and other supplies, but the real ease is in evacuating (from the tank, or from the battlefield by loading into the tank) injured soldiers. The forward engine also means that there is that much more heavy metal between the tankers inside the tank, and the enemy outside. This is important, especially since Israel's enemies have, since the 1980's, grown very fond of using the KORNET missiles. Israel may lose a tank, and that is a huge economic loss, but it increases the survivability of the soldiers. I just wanted to add that information, having served in the IDF (not in an armored unit, but I operated in tandem with armored units).
Chieftain remember fuel and hydraulic lines are specially designed quick disconnect couplings and generally different sized or color codes to prevent them getting crossed up. Another point is how they also will have full up packs ready to issue at the SSA or Support to eliminate time consuming component replacements. The unserviceable full up then can be sent where time and generally better facilities or equipment can make that task a lot easier. A good example of a front drive sprocket with everything forward is the US M113 FOV.
I am sure they also used the front transmissions as additional armor to add to crew survivability. The other thing I wonder about is, how the track behaves when pulled from the top and around the rear idler, vs being pulled from under the vehicle. As for the driveshaft, why didn't they just run it along the side bottom corner with a transfer case? I know the answer mainly is simplicity, but for making a great tank, it's not that much more complicated. The Russians are not an example of efficiency or user friendly design. They just slapped together pieces of metal and put things inside that made the contraption turn into a tank. Surprising how well things are designed, nonetheless.
We see split systems sometimes in drive lines for weight distribution and spacing. Even the Porsche 928 is an example of engine in the front, long driveshaft, transmission/differential in the rear.
A sprocket pulls the slack out of the track not push the track. Thus if you have a front sprocket , the slack is pulled out of the top of the track leaving slack in the bottom to help the track flex more on the bottom to follow the boggies on the suspension better and allow the boggles to remain in better contact with the track. This works better on most types of track suspension types and not just on tanks but most track systems Inc construction equipment, snowmobiles etc.
Thanks a lot for the answer, I was wondering about that for along time. Now, my next question would be, why weren't tripple differentials and Wilson-style preselector gearbox more widely adopted?
Does not a front drive wheel incur less wear as dirt has more opportunity to fall off the track before encountering the wheel whereas a rear drive pulls the dirty track right from the ground increasing wear? Thank you for another great video!
Supposedly. But I don't think it's enough of a difference to matter. If it's the case of replacing the sprocket and track at 2,000 miles vs 2,500 miles, we'll just replace the sprocket a couple weeks sooner.
Honestly - I just watched random video, where some guys doing restoration of sherman tank. I recognized it specifically by sprocket wheels. Watching how the tank was designed (tank was basically stripped apart for restoration works) inside - I asked myself a question: why the don't put the gearbox and drive sprockets with the engine? Is it a balance of the mass? Tension of tracks? And I am about to find out! Thanks Chieftain :)
Merkava engine at the front is extra armour for crew. Even if penetrated and engine knocked out the tank can act as a pill box / strong point and still be useful. Handy when your country is only about 60 miles wide and 200 miles long.
1. Accessing the transmission easily from all angles for maintenance 2. Short linkages for shifting gears, easier gear shifts, aiding with fatigue 3. Weight balance (front and back) What is different today: 1. More reliable power packs, easy to disconnect take out and for work 2. Automatic gearboxes, controlling thing by wires not linkages 3. Power pack balances the thick heavy armor at the front
Thank you for the well thought out answers and explanations. On another video, can you please go over your personal library? I was able to identify many of the books in the background (for once, perfect angle to do so here), but not all books. Can you go over some of those books?
About the remark on APCs disembarking crew(infantry) ergonomics and narrow ramps, putting engine, or engines, to the front, or more specifically front right pushes driver and commander into this narrow space on the front left, reducing crew efficiency and in particular commanders ability to have a good view over right side of the vehicle. I am talking about BVP M80 since I haven't had much experience with other tracked IFVs and APCs. Mind you, permanent crew of our IFVs are not tank core guys, we are also infantryman, chosen out of the ranks of mechanized infantry, so we are rarely narrow guys, this is why I usually chose to disembark with my infantry to get a better view of the surroundings and be able to command the vehicle better. This in turn introduced a lot of different problems and some unsafe practices that would get me reprimanded or even punished if any of my COs decided to report me for them instead of just warning me. My opinion is that engine in the front is a bad idea for tracked vehicles.
I built it. It was supposed to be presented to another office, but we couldn't figure out how to get it across the Atlantic, so I kept it after finishing it.
Very interesting video! Of course there was disadvantage and advantage with the front drive versus the rear drive but we must go back 70 years to see in the correct perspective the situation, namely the the ease of production! In fact all the German tanks had the front drive together with gearbox because of the front transmission and the final drive and the Germans wanted to avoid complicated links to the rear and to be easily connected for shifting, clutching, steering and braking. Apparently it was also easier to produce, install and maintain and it is good to remember that there was only the Hellcat that was fitted with the power-pack (as far I remember) for quick extraction and maintenance but the transmission was at the front! That said the real improvement as nowadays is having the power-pack both at the front or at the rear but the real advantage where is it?
@AKUJIRULE it really did made sense having the power pack for quick extraction of the engine for repair or maintenance as it it did had a slide to pull it out from the rear by lowering the rear panel. But as I mentioned before the transmission and the gearbox was at the front and it was a slow job quite similar to the Sherman...
Chieftain, a friend of mine once asked me this and I answered as best as I could but I wasn't sure of the answer. Could you answer for me? How do you go to the bathroom in a tank?
Now there's a question. As the British always have a way to boil water, tea and hot rations et cetera, you have to get rid of the byproduct somehow. Imagine being in there for several days locked down simulating NBC conditions. And they called USN submarines pig boats.
@@TheChieftainsHatch while rolling or do you still stop to filler er up? And what to do with the bottle after? Kinda hard to see tankers with bottles of urine about.
Front sprocket, track can shed soil before being ground into the sprocket = less wear, and pulling on the looser track on top of the wheels = softer engagement.
Something you could, in general, cover. Throwing tracks. I trained at Ft. Irwin circa 1972-1974, as armored cav. We used M113 APC always referred to as "apes". The problem was that if you went sideways, rather than up and down a hill, past 15 degrees would throw a track. Not problem for the M48a8 until about 45 degrees / [I seem to remember the designation M48a8 but memory is hazy- they were the last version of the M48, up gunned to the same 105 as the M60]. We were told to limit the sideways slope to 30 degrees /. Don't know if it was a maintenance issue. So I have been wondering about this side of a slope limit for ALL the other tracked vehicles you cover??? This also has tactical implications.
The IAF uses front engined tanks for the same reason the US Army puts the fuel tanks in the front for the Abrams. It helps absorb the sort of expected rounds that military expects to encounter, early Cold War solid shot for the IAF and swarms of ATGMs for the US-A.
Crew safety. One of the stated reasons for the S-Tank having a front engine was to provide additional mass that incoming rounds would need to penetrate to get to the crew.
There is a video by either Chieftain or Jingles from a couple of years back, where they talk about the super pershing receiving some new tungsten core ammo, which went through a jagdpanzer4 like hot knife through butter. The going hit the front, hit the engine and went through the back armor as well. Based on this, it might help with lower calibre rounds, but a full sized mbt tank round would be probably impervious to the fact, that there is an engine in the way.
@@V4zz33 What year Jagd P.IV? The latter half of the war the Germans were forced to use softer and softer grades of "armor" steel because they lacked the alloying elements required. (Such as Molybdenum)
@@alexhohl8530 ah but it also adds a giant armour space between a heat round and the fighting compartment which is why i understood the Merkava was laid out like that, to maximise crew protection. Of course if its hull down in a position for weeks on the golan heights the crews would also like the back door for ease of putting the cat out at night.
I always thought front sprocket causes excessive track slack as the sprocket "pushes" the forward tracks rearward but "pulls" the returning tracks forward when the tank is moving forward, whereas the rear drive "pulls" on the forward tracks rearward and "pushes" return tracks forward therefore keeping the track tension when the tank is in the forward motion. I can see that on my 1/16 RC Stug III. When I reverse the tank (essentiallymaking it a rear drive tank), the slack disappears.
"Inches are everything." - The Chieftain 2020
Thats what she said...
@@atfyoutubedivision955 not that funny but i accept.
That's what she said!
@@jameslee1376 Just not too you.
@@nocturnal0072 Ouch. =(
I remember seeing a military related tv show on the Merkava tank. The young woman driver of the tank related that the #1 consideration in the design was crew survivability, since the IDF was so small. She particularly appreciated the fact that rounds hitting the front of the tank needed to penetrate not only the frontal armor, but also the front mounted power pack. She felt a lot safer having a larger mass in front of her.
I'm going to use your last sentence when I try to convince my wife to get implants.
@@AmbuBadger ahahahaha
I'd imagine a frontal engine is a really good spall protection system or spaced armour to defeat HEAT too.
Every little bit can help
@@settratheimperishable4093
Definitely, unless it explodes.
I'd never thought about it before, but stalls and missed shifts probably happened constantly in ww2 battles. I've stalled my truck at intersections and been embarrassed. I can't imagine the stress of stalling a tank in the middle of a battle, or having a shift linkage break.
Having broken a shift linkage in a car I can only imagine if it had been a tank in a war zone or combat. Talk about stress.
On the plus side I gather that unless you are in really nasty mud or on a hill, a tank is geared so low that you can start it in any gear. You don't even use first unless you are in some really heavy stuff. Some of the older tanks had complaints that you had to stop the vehicle before changing gears, which they thought was a inconvenience. The gears were basically just to chose thec speed range you wanted, and just how much torque you wanted at the tracks. Point is, it's like driving a truck with low range 4WD, it will start in any gear easily, and it's pretty hard to stall it with that much gearing. That happens in cars because the engines are pretty weak and the final drive gearing is relatively tall, and it's much worse in higher gears, since the effect multiplies. With a low geared tank or tractor, even if you get the wrong gear it's less likely to make you stall, unless the resistance is really high. I imagine it being something like driving a truck in 4LO with a very heavy load in the back. You will feel the difference but it will still start in any gear without a lot of trouble.
9:20 when he says "floatation issues"...... he isnt talking about crossing rivers, folks
pretty much all farm equipment uses "floatation" tires..... big, fat, wide tires that spread out the weight in mud
they preventing it from "sinking" into the mud..... and instead.... ride on the top ~1 inch of soil
if all the weight was in the back on the m18...... the ass end would constantly get stuck 3 foot down in the mud
BUT.... because the weight is spread out...
the m18 might only sink 0.5 or 1 inch into the mud..... which is very easy for the tracks to overcome....
and speed away from that angry panther
Thank you.
If something is heavy enough it can make things that are normally fairly solid act like a liquid.
@@hedgehog3180 and this is another reason battlemechs, and to an even greater extent, Warhammer 40k titans and other walker vehicles is a really bad idea that only works in Sci-fi, because IRL, they would be restricted to exposed bedrock.
An AT-AT would never have worked on sand, soil or ice as it's ground preassure would make the ice start melting under it's feet, and the sand or soil would flow like quicksand.
A 40k Dreadnaught, knight or titan or even a Baneblade/Fellblade sized super heavy tank would have even bigger problems.
And that's from someone who's loved 40k and Battletech since I encountered the concepts at 13 and 10years old respectively. I'm going on my 36th year now, and the 40k collection has an entire room for itself, shared only with an R/C Leo2A6 and some Star Wars LEGO!
And that is why the Australian M113s have grown another idler sprocket...
@@SonsOfLorgar but the stompas are litteraly powered by the believe thar they will work, so as long as the bois will believe the stompa won't sink, it won't sink
One of the interesting things about Merkava is that the hull makes a really good APC. The Namer is likely one of the best of the heavy APCs. The US Army trialed some Namers and they liked them but decided against purchasing some.
And I always like how Chieftain reiterates that you can't judge a tank based on how many countries use it. Some designs may be so specialized, it's just not practical for another country to use it.
Suitability and specialisation do not really influence proliferation.
If you don't make it yourself, you'll take what you can a) get and b) afford.
Cold war germany had quite a few of those designs. Tanks, vehicles, helicopters
it have even more to do with politics and supplies.
most countries prefer a locally built tank since it preserve jobs AND you don't require someone to produce them for you as they might become less of an ally in 15years and are now reluctant to give you spare parts or upgrade your tanks (addon armor packs and such)
@@daszieher well, first you shod check if there is someone kind enough to give you 200 MBTs for free. Even if you actually do have local production...
@@mancubwwa whoever gives you 200MBT is someone who expects you to use this gift in their intentions.
there is always a catch.
short answer: "these people weren't fools, there are reasons why people do things"
Too often we look back and see faults in designs but neglect the actual amount of thought and limitations.
@@reubensandwich9249 and C O N T E X T
@@steyn1775 Where's Matt Easton when you need him?
as well as reasons why they shouldn't
The more and more I look into tanks the more I come back to this conclusion. They were all designed by engineers, to take advantage of existing infrastructure for creation, maintenance, and transport to implement a state's "tank doctrine". For example, Germany couldn't make many tanks AND had a manpower shortage compared to "All allies in WW2". Yeah, which is why they chose to make tanks that could kill 5+ tanks for every one lost, and be repaired and reused. The fact their metal industry collapsed, later using poorer materials, isn't the fault of the tank. The fact the train infrastucture collapsed forcing the tank to literally drive to the frontlines constantly playing a game of "hitlers firefighters" isn't the fault of the tank. Likewise, the Germans "fixed up" and re-used tons of captured tanks [as well as damaged German tanks] to supplement their small armor numbers. The Hetzer (not ever actually named that in real life) was a very successful tank destroyer in WW2... and based on a captured Czechoslovakian 38 tank. The German engineers were not stupid. They would take the guns off captured tanks because their infrastructure couldn't construct or supply another nations ammo, spend weeks chopping and replacing the vehicle with a gun they do produce and support, and boom. You've got a vehicle your troops can actually fire as much as necessary without running out of captured ammo.
Likewise, the T-34 was unreliable and it didn't matter. They needed tanks. NOW. If any tank fell apart, they had 10 more to replace it. The Soviets knew they had a huge industral base that wasn't being bombed into oblivion. They needed a shell of metal around some guys manning an anti-tank/support gun. NOW.
Here's one I'm actually going to do a video about. Everybody talks about how "gas is explosive and stupid for tanks." Tank fuels were chosen based on the fuels available by the industry of the country. When you crack heavy oils from the ground, you _always_ get multiple fuel types (plus oils). So many countries simply said "the navy gets the diesel, and everyone else gets the gas." [or variations thereof]. The "fuel" explodes? Who cares? You know what's even worse than fuel exploding on mostly outside fuel-tanks? The EXPLOSIVE AMMO INSIDE being hit by a round. Which is why the Shermans first got extra 1" of armor around ammo, then got wet racks, but never changed/protected their fuel tanks [AFAIK] during the war. Further, fuel explosions don't shoot turrets into the air and out of the tank. Ammo explosions do.
So people say stupid things like "Americans were stupid because Shermans used gas making them explosive." 1) The ammo was the explosive part. 2) they fixed/improved that. 3) The Americans also made a diesel version of the Sherman, the M4A6, for export. The Americans didn't use Diesel because they _intentionally chose not to_. The countries that DID use diesel as a fuel backbone for tanks DID want to use diesel. Meanwhile, guess what Americans did use diesel for in WW2? Submarines and ships. So we knew about diesel engines, used them, and supplied them, and had gas left over for the tanks and planes. [Nobody ever complains that gas was for planes and made them "explode" either. Gas tended to be a better power-to-weight ratio.]
Disclaimer: I'm not a historian.
Another fun one is people who think the Merkeva is super safe because they put the engine facing the front / the enemy. As if the engine is going to somehow stop a modern tank round that can defeat multiple feet of composite armor. Say it with me: "Engines! aren't! armor!" They're made out of relatively thin sheets of metal and mostly empty space for rotating parts. An iron or aluminum block never has in the history of tanks, been used as an armor for anything above rifle rounds. You can easily RUclips videos of .50 caliber weapons perforating large truck engines. And those are TINY TINY TINY compared to a tank shell.
People really don't appreciate how fast, or how much energy is in a modern (even a WW2) tank shell. It's not stopping at an engine. The Merkeva has a front engine so the tank can face the enemy, get hit, and the crew can run out the back. If they actually expected the engine to be "armor", the crew is already dead.
"Inches are everything"
-Chieftain 2020
An Inch is legal defined in America by 1 inch is 25.4mm
@@reubenjackson7829 did you mean 1/3 football field?
That's what she said. Sorry, somebody had to say it.
There was another point you said by yourself in some videos. The front mounted sprocket got a cleaner track to work with. On the way to the front the links loose dirt and thus are less likely to damage/wear down the teeth. That may not be the main reason but it is another addition.
Your point about transmission linkages is something I hadn't considered. I used to have a van with a column shifter that required a fair amount of finesse to shift smoothly between gears. Trying to force it when it didn't want to go into gear ran the risk of having the linkage separate leaving you stranded. Having that happen in a situation where people are shooting at you, yeah, I can see why they'd put the transmission in the front.
My family owned Econolines for years and that happened a few times. Once a cotter pin in the linkage broke and was replaced by a bobby pin as a permanent temporary fix.
@@edcrichton9457 Mine was close to 20 years old when I bought it, and the linkage was well worn. I learned pretty quickly how to shift it without causing a problem, but only after I had to push it out of traffic a few times.
My parents had a 79 Chevy van, witha three-on-the-tree. You learned quickly not to downshift straight from 3rd to 1st when coming to a stop. If you did, you'd bind up the linkage and have to coast to the shoulder, get out, and stick a screwdriver in the linkage to unbind it. I think I only did that once or twice. After that, I always shifted from 3rd to 2nd to 1st.
@@edcrichton9457 There's a well-abused '91 dodge shadow 5 speed out there somewhere that has a bent trim nail holding the cable end to the fore-aft linkage on the transmission side, and a rolled up piece of greased rubber hose as the bushing. Nothing like field-expedient repairs that not only work when needed (I yanked the thing apart on a 4-3 downshift in the middle of the night in downtown Atlanta), but also ended up working better than the factory parts (I hadn't realized just how much slop there was in the factory perforated bushing...)
Another T-shirt quote "Inches are everything!'
O.o
#ChieftainOutOfContext
Whoever designed the first modern power pack where you can just yank the whole thing out in 10 minutes was brilliant.
Buick designed the M18 so naturally used two of their V-8's to hustle it around. The engines were mounted to a frame which could be slid out like a drawer to make servicing or replacing the two engines easier and faster. The US Army thought that was slick but told Buick to use the radial engine instead because they had plenty of mechanics and parts for those.
@@billwilson3609 Making a engine easily accessible is not quite the same as making it easily exchangeable.
With the Leopard 2's power pack, they can just swap out the whole thing within 15 minutes. The recovery tank can just carry a spare power pack on its back to the damaged tank and switch it out and in a real pickle it can even put its own power pack into the MBT and then wait for another recovery vehicle or a truck to bring it a new one.
@@TrangleC The US Army made a shortened version of their Christie Combat Car by replacing the V12 Liberty engine with a Wright radial. The compact radial allowed them to remove it with the transmission and rear drive attached as one assembly by using a truck with a winch crane. Their M6 heavy tank had a similar arrangement using a fluid drive (kerosene was the fluid) that might have been removable as an assembly. I think the radial and multibank engines in the M3 and M4 could be removed and reset in less than one hour. Chrysler's engineers made sure that could be done so Ordnance would approve using the multibank engines.
Glad he addressed the mechanical advantage of pulling the track forward (think block and tackle) and that it's way down on the scale of considerations for a tank design .. always love your talks
There is no mechanical advantage of pulling the track forward.
Why? Because the axis of the sprocket and the axis of the idler are fixed relative to one another.
You will never see a conveyor belt in any different configuration and basically a tank tread is a conveyor belt. You cannot push the tread around the axels because you don't get the same torque because of a number of physical restrictions.
@@markkarnes5597 Tail drive conveyors are a thing. It's just typically not done because of the tension effects. Tail drive feeders are fairly common. We have both on the current project I'm working on.
@@GIwillo
Your last sentence is correct.
I got to drive an M113A3 around Grafenwoehr and Hohenfels Germany as a 12B, and since it was the platoon commander's vehicle it was really like having a tracked vehicle to joyride around the mountains of Germany with. They were definitely balanced well considering all the very steep grades I'd have to drive down and up. Checking the oil in the two front final drives was just as important as the engine oil, stressed in the manual and by my NCO's. (One of them called the 113 a 'tracked grenade'.) The up front engine served another purpose very well-at night I'd lay my 3 layer sleeping bag over the engine intake grate on top and get nice residual engine heat for nearly the entire night.
I happen to be wearing my significant emotional event t-shirt right now. Nicely timed Chieftain.
Glad to know they're actually getting used!
@@TheChieftainsHatch Hey you're keeping me entertained while I wait on a plumber for my busted toilet. Thanks!
@@TheChieftainsHatch can i please ask, where are these tshirts from? where can i get one? greetings from slovenija
@@TheChieftainsHatch I hate to be one of those people that replies to one of your comments, but need to get an answer before they go off sale. Is the shirt you're wearing in this video the normal green T-shirt from the store, or is it a custom version? The shade of green in the video looks a lot different (and a lot better) than the vomit-color that it looks like on the website.
I've been watching RUclips videos for a very ling time. It's becoming clear that many channels are becoming very fine operations. This is a perfect example of the more professional work as opposed to amateur videos. Keep up the good work.
Maybe one day even germany will receive its justice.
The argentine TAM also has the engine on the front, with a small hatch on the back for loading ammo and stuff. It's a german design, the chasis is a marder derivative and the turret was to be the upgraded leopard 1 turret, but leopard 2 make that useless, so german engineers use ir for the TAM project instead
The TAM is so full of potential with some modern upgrades to it, and it has awesome operational range...srsly, the U.S. should really look to front engine designs or perhaps all electric systems to replace the aging Bradleys and M1s and make a universal modular vehicle which can be adapted to any role. 20 years from now, maybe we'll just have drone tanks and robot infantry though.
@@pex_the_unalivedrunk6785 They tried.
Twice.
The Future Combat Systems tried just that, but was a victim of being too advanced for its time, and short-term priorities.
The Ground Combat Vehicle was... the less said about it, the better.
@@pex_the_unalivedrunk6785 the issue with that is you end up wit flawed vehicles for their roles. now sharing a certain degree of component parts (ie as much as possible) but haveing separate purpose-built chassis is the way to go.
of course light-medium tanks and IFVs have a lot more uncommon than MBTs and regular IFVs, so those could potentially share a chassis.
German and Argentine collaboration.....where have I heard of that before?
Strv 103 (the S-tank) also had the engines up front (and served as a role model for Merkava). The reason for putting the engines in fron was to have them function as additional front armor, protecting the crew.
With the gun arrangement of strv 103 it would also be more difficult to replenish the ammo if there was an engine in the way.
Hopefully this comment doesn't get buried, but I have a question for the monthly Q/A.
The Chieftain MBT is often described as the most well-armoured vehicle of its time, but wouldn't the appearance of HEAT shells make the armour relatively useless? Why did nations continue to build heavily armoured vehicles when HEAT rounds were a thing and composite armour had yet to be developed? Were HEAT shells uncommon compared to traditional anti-tank shells, thus the need to protect against conventional kinetic projectiles have more importance and thus the need for heavy armour?
Pretty long-winded question but I'd love to get an answer for this!
my two cents, you dont stop making planes just because the other guys make anti air rockets. Tanks are still useful even if their best defences are nullified, because its still a mobile weapons platform thats resistant to most threats.
I'll add my opinion as well. HEAT still needs to go through armour so adding more does help, albeit not as much as composite does but this combined with spaced or skirts would help.
The M60A1 and the Chieftain had the same LOS frontal armor. Try again
HEAT was a major headache but was not magic. The 105mm L7s HEAT round could chew through about 400mm as i recall. When France and Germany started work on what would split into the Leopard 1 and AMX-30, they emphasized sniping and outmanuvering oponents, while the Cheiftan and to a lesser extent the Pattons were expected to be able to slug it out. As such France and Germany considered sufficient armor impractical and settled for resistance to 20mm autocannon while the Americans and British had 2,3,4 times the effective armor in some places to be able to shrug off known main gun rounds at the cost of speeds that could best be described as leisurely. Of course warheads kept improving and what was ok armor was eventually rendered as underwhelming as Leo 1's.
Most well armored at its time cheiftan is not. You forget T-64 exist?
It comes down to AP can hit stuff at first shot much more reliable over a long distance. People probably will sling AP at your direction first.
The weight distribution is a very significant factor - if you have the turret in the middle of the tank (which is much easier with the front transmission) you can upgrade/downgrade the turret and don't bother with the balance, but if you have the front placed turret you will have problems as with soviet T-34-85 which was particularly nose heavy despite the fact they'd played with the turret armor thickness to reduce the weight as much as possible. Also, the middle position is most comfortable when you driving through the bumpy terrain. And what soviet engineers had done immediately when they were making the new medium - they'd placed the turret in the middle on T-44 (but managed to keep the engine/trans in the back by mounting all the machinery transversely).
It is also the great flaw of the Merkava.
Having the engine and the transmission at the front puts harsh restraints on how voluminous and how heavy the frontal hull armor can be.
The hype about the Merkava being the most safe tank for the crew is strong, but most people don't know that it has one of the weakest frontal hull armor protections of all modern MBTs and it still is incredibly front heavy, which is why there are a bunch of pictures of Merkavas which nose-dived into ditches and couldn't get out again or even somersaulted down slopes and even one famous picture of a Merkava doing something like a headstand on its nose and gun barrel.
I love his level of chill.
David Willey of The Tank Museum also talked about this in one of his latest videos. So which one is easiest to tension the track?
It's pretty much a tossup; rear-drive tanks have the tensioner at the bow, and front-drive tanks have the tensioner at the stern. Either way, you need to have some arrangement that results in the actual tensioning mechanism not being obscured by either the idler wheel or the hull of the tank, and there have been any number of solutions to the problem over the decades.
Or if you have a Challenger you just press the button. ;)
@@ABrit-bt6ce oh, I didn't know that you just have to press a button to regulate the tension the track on the the Challenger, really cool! A dumb question: the button I presume is pressed by the driver inside but how he knows if the tension is correct, is there a gauge?
It’s easier to tension at the front as the back is covered in mud and crap that’s been dragged and thrown up :). It’s all muddy, so we’re talking quantity.
@@lkchild it is correct! Back in 1976 I was driving in Italy the Leopard 1A2 and to tension the track I had a big open key to be inserted on the front idler but we had to be two of us to work on it but it was relatively easy to wash off the mud...
That moment when u Realize that the RUclips small screen button is a iron cross.
Well actually it's a Balkenkreuz. Not entirely the same.
Thats correct and its nice to know some people know that there is a difference between bars and cross
Thanks Chieftain, I've been wondering about this for ages and you have finally answered my questions
Outstanding video and presentation.
Interesting. I never really thought about transmissions, front and rear drive... and why. Thanks for the great bit O history! Cheers!
Thank you, I have been watching your videos for a number of years now. I am interested in WW2 armour/tanks, particularly the Sherman. I find your videos informative, entertaining, and extremely useful for my own talks that I give from time to time.
Just thought I'd encourage you.
Front/Back sprocket also makes a difference in track tension distribution over the length while moving . Practically speaking - With front sprocket, chances of throwing the track while forward travel is higher than with a rear sprocket. The opposite in reverse (naturally) and for breaking. Though with adequate track tensioning, the difference is not so large to make a gigantic difference / worth paying too much attention to over the main reasons chieftain talked about (Front Sprocket worked out well enough for WW2 tanks with pretty low tension after all).
Its just an important side aspect to keep in mind from the engineering side, esp. if the vehicle has a narrow track and high suspension travel.
I enjoy your lessons on the amazing history of armor. I'm a native Texan who's family came from Ireland in the late 1800's and I hear that the Hurley name is quite common in Dublin. I thank you for your help in keeping me engaged in this time of homebound occupancy.
As a retired US Army Senior NCO, glad you're an Officer that isn't full of himself.
You obviously don't know me well enough yet... :)
If you aren't full of yourself, you should call a corpsman. "You" is typically supposed to be filled with "yourself", if bits of yourself aren't the filling inside you, it means you need urgent surgey to stop your organs falling out.
He's ex-enlisted
Thanks for this topic.
Thanks. The Tank Museuem's David Willey had a couple of additional points regarding sprocket wheels worth clicking over to as well. Mr. Willey's examples were not so modern and of a more general sense. But good stuff. His graphics department even had some drawings.
Strv 103 also has the engine/gear at the front :)
But the Swedish door wedge is kinda special :D
Another issue was the gun projecting past the front of the tank, which was thought to be a bad thing. A central turret allows a longer gun with out an overhang. Designers worried about this until guns got so long it was unavoidable. It makes the tank less cumbersome and its easier to traverse the gun, no worries about obstacle in the front quadrant. Your point about having the driver next to the transmission is well taken. One of the pluses of a torque converter is the elimination of a clutch. Slipping the clutch in a heavy high torque vehicle is a big nuisance and many WW II tanks have two steering clutches. The final point is that minimizing the internal volume of the tank in order to maximize armor doesn’t seen to be on the designers list. Compare any modern tank with a WW II design. Even in a cramped older design the internal volume is greater, the modern stuff is much more efficient.
Thanks for the heads up on “Engineers of Victory” Paul Kennedy. The concept is good, to focus on the creators of the weapons systems that won WWII everyone from Sgt Cullen to Wilfred Freeman. Great read. As an “apprentice rivet counter” the niggling technical mistakes e.g. calling the torpedos the Swordfish intended to launch at Bismarck acoustic rather than magnetic, are annoying but really who cares. See you on the next one!
I was wondering this for quite a while, and I really didn’t actually except people to make such dedicated videos.
Thank you!
great take
We should get a tour of your book collection! It looks like an invaluable set of resources for these types of videos ^-^
Hey Chieftain, i hope you can answer this. When you were in service, did your tank ever get shot? Did you ever fought another tank?
Not shot by anything bigger than a rifle. Never shot at a tank.
Check out his video on the M1 Abrams, he goes into detail about his experience there.
@CommandoDude Nobody with any sense ever wishes they were in combat.
@Charles Yuditsky I don't think anyone who's actually been in combat wants to be again.
@@coreys2686 there are plenty of interviews with ww2 veterans who claim that combat is like a drug, you start to crave it. while others out right said they enjoyed combat.
Very good, sir!
was just thinking about that a few minutes ago
perfect recommendation timing
Front final drives get hammerd and abused more than a rear final drive. Just from personal experience as a maintenance officer. All your point are valid and informative. Thank you.
Uploaded just when i was scouring around for answer for this exact question. If only i found this yesterday i would've saved myself 5 hours of nap time.
Thank you for making this video I’ve never looked into it but I’ve always thought the same way industrial mechanic think driving the track at the back is way less strain on the track mounting system and less strain on the track but I never thought about the other things
Another shirt quote: “Track Tension is Life”
I was thinking "Inches are everything"
You throw a track in somebody's kill zone and you might find that to be truer than you want
Short and informative. Nicely done 😁👍🏼
Very good explanation. As always.
Very informative video thank you. Your best ever video was your review of the Jeep :)
I found it interesting and informative. APPROVED
10:50 what? A true APC has the ramp at the front so that Assault Terminators or Veteran Squads can charge the enemy immediately
There is a reason barely ANY front offloading APC exist. In fact, I know of none. Rear offloading is far safer. Right off the bat, you have the full length of the APC as instant cover. Second, see Saving Private Ryan, landing sequence, to see how horrific front offloading can be. With Landing craft you really didn't have much choice, water was inevitably shallower in the front than the back but with APC that is not the case. I appreciate your opinion, but kindly admit, it was offered with little forethought and analysis. Some design features are there for a reason.
@@TheHomelessDreamer it was a Warhammer reference...
@@TheHomelessDreamer I know this was six months ago but...wow lmao.
It also have the ramp at rear.
On the wilson gear box, to expand, the linkages are both pushing and pulling alone. The gear pre-selecting is pushing or pulling to rotate a selector drum by way of a bell crank. On the Gear Change function, it's just pushing or pulling a bell crank to lift the bus bar.
Compare to a conventional gear box selector that needs to twist as well as push/pull.
Thanks for a great video! This had always confused me, and I didn’t understand it until now, so thanks! :)
Thanks, you just answered a question I've always wondered about. Not a large question but a question nonetheless.
From tanks to how goose walks, to metabolism of a hummingbird. Quarantine makes me learn things i didn't know i want to learn
Excellent video! Thank you for sharing your knowledge with us.
wow, off the cuff. You are good sir.
Another good one, thanks.
Big fan of the channel, loving the Father Ted haircut
One other (very slight) advantage to a front drive sprocket is that the returning track gets more time to shake loose the mud/dirt/dust before it engages the high-pressure mating faces on the drive sprocket, reducing wear and meaning track tension can last a little longer between adjustments. It's not a big advantage, and certainly doesn't rate compared to those issues raised in the video, but it is a factor. Can't think why the Chieftain didn't bring it up ... ;)
The Merkava engine placement supports keeping up to 6 troops inside the tank (plus the normal tank crew). A secondary reason for the front engine design is crew protection; there are significantly fewer Israelis than there are hostile Arabs in the region, with the subset of trained Israeli tank crews being scarcer still, so keeping the crews alive is important.
Correct and mind you that that the engine is a big block capable to stop almost any incoming shots! In plain English the Merkava is one of the most survivable tank ever...
Thanx for answering a question I hadn't asked yet, but was about to:-)
Was a perfect meal time video.
Sounds like you have been a tank crewman or mechanic. My experience is farm machinery and I’m impressed.
Crewman.
Just found this channel, great video! But I'm curious why you have an entire book dedicated to can openers?
Turned out there was a bit of a gap in the published history on the subject. Yeide's book covers the operational history of the TDs, but for the technical development, there's only sub-chapters in Hunnicutt. As I was digging in the Archives, I found a lot of unpublished stuff, so I ran with it.
Been wondering that for a while. Thanks for the insight.
Both interesting and informative.
To address your point around 11:00 WRT engine arrangement for APCs - don't forget the entire 8x8 BTR series, which are notoriously rear-engined despite being roled as APCs, with the troopaloops simply disembarking from twinned hatches on either side of the vehicle.
On the other hand, one can argue the relative merits of a single larger ramp-style hatch vs. multiple smaller hatches, or even the merits of the BTR with regards to its doctrinal use as an APC in general, until they're blue in the face. I don't particularly feel like doing that.
Wow look at those guns!! The chieftains been liften!!!
Hey Chieftan, great video, as ever; love the content. The Israeli design impetus for engine forward is primarily crew safety and ease of evacuation. True, the door in the back makes it MUCH easier to ingress and egress ammo and other supplies, but the real ease is in evacuating (from the tank, or from the battlefield by loading into the tank) injured soldiers. The forward engine also means that there is that much more heavy metal between the tankers inside the tank, and the enemy outside. This is important, especially since Israel's enemies have, since the 1980's, grown very fond of using the KORNET missiles. Israel may lose a tank, and that is a huge economic loss, but it increases the survivability of the soldiers. I just wanted to add that information, having served in the IDF (not in an armored unit, but I operated in tandem with armored units).
Definitely did this video after seeing DW's video on the Tank Museum channel haha
very useful information
Is that a Bird-of-Prey and a Vor'cha I spy on the shelf there... Miranda and Excelsior as well. :D Good tastes in the classics!
The algorithm finally synchronized with my interest
I did find this interesting and informative. Thank you, sir
Made it so even an Air Force guy could understand. Thank You for the clarification.
Chieftain remember fuel and hydraulic lines are specially designed quick disconnect couplings and generally different sized or color codes to prevent them getting crossed up. Another point is how they also will have full up packs ready to issue at the SSA or Support to eliminate time consuming component replacements. The unserviceable full up then can be sent where time and generally better facilities or equipment can make that task a lot easier. A good example of a front drive sprocket with everything forward is the US M113 FOV.
I am sure they also used the front transmissions as additional armor to add to crew survivability. The other thing I wonder about is, how the track behaves when pulled from the top and around the rear idler, vs being pulled from under the vehicle.
As for the driveshaft, why didn't they just run it along the side bottom corner with a transfer case?
I know the answer mainly is simplicity, but for making a great tank, it's not that much more complicated. The Russians are not an example of efficiency or user friendly design. They just slapped together pieces of metal and put things inside that made the contraption turn into a tank. Surprising how well things are designed, nonetheless.
We see split systems sometimes in drive lines for weight distribution and spacing. Even the Porsche 928 is an example of engine in the front, long driveshaft, transmission/differential in the rear.
A sprocket pulls the slack out of the track not push the track. Thus if you have a front sprocket , the slack is pulled out of the top of the track leaving slack in the bottom to help the track flex more on the bottom to follow the boggies on the suspension better and allow the boggles to remain in better contact with the track. This works better on most types of track suspension types and not just on tanks but most track systems Inc construction equipment, snowmobiles etc.
Correct.
Thanks a lot for the answer, I was wondering about that for along time. Now, my next question would be, why weren't tripple differentials and Wilson-style preselector gearbox more widely adopted?
Love the shirt!!
Does not a front drive wheel incur less wear as dirt has more opportunity to fall off the track before encountering the wheel whereas a rear drive pulls the dirty track right from the ground increasing wear? Thank you for another great video!
Supposedly. But I don't think it's enough of a difference to matter. If it's the case of replacing the sprocket and track at 2,000 miles vs 2,500 miles, we'll just replace the sprocket a couple weeks sooner.
@@TheChieftainsHatch Thanks!
Honestly - I just watched random video, where some guys doing restoration of sherman tank. I recognized it specifically by sprocket wheels. Watching how the tank was designed (tank was basically stripped apart for restoration works) inside - I asked myself a question: why the don't put the gearbox and drive sprockets with the engine? Is it a balance of the mass? Tension of tracks? And I am about to find out! Thanks Chieftain :)
Merkava engine at the front is extra armour for crew. Even if penetrated and engine knocked out the tank can act as a pill box / strong point and still be useful. Handy when your country is only about 60 miles wide and 200 miles long.
1. Accessing the transmission easily from all angles for maintenance
2. Short linkages for shifting gears, easier gear shifts, aiding with fatigue
3. Weight balance (front and back)
What is different today:
1. More reliable power packs, easy to disconnect take out and for work
2. Automatic gearboxes, controlling thing by wires not linkages
3. Power pack balances the thick heavy armor at the front
I love how the ending indirectly ties back to why a bulldozer has the design it does, because it is the most efficient for that layout and task.
Thank you for the well thought out answers and explanations.
On another video, can you please go over your personal library? I was able to identify many of the books in the background (for once, perfect angle to do so here), but not all books. Can you go over some of those books?
@The_Chieftain Love your T-shirt, especially for Austin, TX, (Prius) versus Houston, TX (Sherman in River Oaks)! 😉
The River Oaks Sherman (If that's the one from the HOA story) is now in College Station.
Neat. Thanks for sharing.
This video make Hanzs happy and a Ivan angry XD. Joke aside really good information about this topic thanks Chieftain.
About the remark on APCs disembarking crew(infantry) ergonomics and narrow ramps, putting engine, or engines, to the front, or more specifically front right pushes driver and commander into this narrow space on the front left, reducing crew efficiency and in particular commanders ability to have a good view over right side of the vehicle. I am talking about BVP M80 since I haven't had much experience with other tracked IFVs and APCs. Mind you, permanent crew of our IFVs are not tank core guys, we are also infantryman, chosen out of the ranks of mechanized infantry, so we are rarely narrow guys, this is why I usually chose to disembark with my infantry to get a better view of the surroundings and be able to command the vehicle better. This in turn introduced a lot of different problems and some unsafe practices that would get me reprimanded or even punished if any of my COs decided to report me for them instead of just warning me. My opinion is that engine in the front is a bad idea for tracked vehicles.
That's a nice 15th Anniversary model!
Except a tanker shouldn't get a floaty thing from Wargaming, they should have sent him a proper tank. How could they make such a mistake?
I built it. It was supposed to be presented to another office, but we couldn't figure out how to get it across the Atlantic, so I kept it after finishing it.
@@TheChieftainsHatch Now that makes more sense.
after Googling this subject I'm glad to see a video , also some tracks are supposed to be slack ?
Very interesting video! Of course there was disadvantage and advantage with the front drive versus the rear drive but we must go back 70 years to see in the correct perspective the situation, namely the the ease of production! In fact all the German tanks had the front drive together with gearbox because of the front transmission and the final drive and the Germans wanted to avoid complicated links to the rear and to be easily connected for shifting, clutching, steering and braking. Apparently it was also easier to produce, install and maintain and it is good to remember that there was only the Hellcat that was fitted with the power-pack (as far I remember) for quick extraction and maintenance but the transmission was at the front! That said the real improvement as nowadays is having the power-pack both at the front or at the rear but the real advantage where is it?
@AKUJIRULE it really did made sense having the power pack for quick extraction of the engine for repair or maintenance as it it did had a slide to pull it out from the rear by lowering the rear panel. But as I mentioned before the transmission and the gearbox was at the front and it was a slow job quite similar to the Sherman...
Love that shirt
fortunately you immediatly demonstrate your insight in the world with your fantastic T shirt, goodbye
Chieftain, a friend of mine once asked me this and I answered as best as I could but I wasn't sure of the answer. Could you answer for me?
How do you go to the bathroom in a tank?
Mourtzouphlos a spent casing is useful for that
Normally, stop the tank and get out, find a bush. If you have to take a leak, a plastic bottle.
Now there's a question. As the British always have a way to boil water, tea and hot rations et cetera, you have to get rid of the byproduct somehow. Imagine being in there for several days locked down simulating NBC conditions. And they called USN submarines pig boats.
@@TheChieftainsHatch while rolling or do you still stop to filler er up? And what to do with the bottle after? Kinda hard to see tankers with bottles of urine about.
While rolling. The bottle is kept aside until it can be disposed of later.
Front sprocket, track can shed soil before being ground into the sprocket = less wear, and pulling on the looser track on top of the wheels = softer engagement.
Something you could, in general, cover. Throwing tracks. I trained at Ft. Irwin circa 1972-1974, as armored cav. We used M113 APC always referred to as "apes". The problem was that if you went sideways, rather than up and down a hill, past 15 degrees would throw a track. Not problem for the M48a8 until about 45 degrees / [I seem to remember the designation M48a8 but memory is hazy- they were the last version of the M48, up gunned to the same 105 as the M60]. We were told to limit the sideways slope to 30 degrees /. Don't know if it was a maintenance issue. So I have been wondering about this side of a slope limit for ALL the other tracked vehicles you cover??? This also has tactical implications.
The IAF uses front engined tanks for the same reason the US Army puts the fuel tanks in the front for the Abrams. It helps absorb the sort of expected rounds that military expects to encounter, early Cold War solid shot for the IAF and swarms of ATGMs for the US-A.
Crew safety. One of the stated reasons for the S-Tank having a front engine was to provide additional mass that incoming rounds would need to penetrate to get to the crew.
There is a video by either Chieftain or Jingles from a couple of years back, where they talk about the super pershing receiving some new tungsten core ammo, which went through a jagdpanzer4 like hot knife through butter. The going hit the front, hit the engine and went through the back armor as well.
Based on this, it might help with lower calibre rounds, but a full sized mbt tank round would be probably impervious to the fact, that there is an engine in the way.
Same with the merkava
@@V4zz33 What year Jagd P.IV? The latter half of the war the Germans were forced to use softer and softer grades of "armor" steel because they lacked the alloying elements required. (Such as Molybdenum)
@@alexhohl8530 ah but it also adds a giant armour space between a heat round and the fighting compartment which is why i understood the Merkava was laid out like that, to maximise crew protection. Of course if its hull down in a position for weeks on the golan heights the crews would also like the back door for ease of putting the cat out at night.
@@TornadoADV I'm guessing this was on a test range.
clickbait in the tank world: put a tiger as thumbnail :D. very informative video!
I always thought front sprocket causes excessive track slack as the sprocket "pushes" the forward tracks rearward but "pulls" the returning tracks forward when the tank is moving forward, whereas the rear drive "pulls" on the forward tracks rearward and "pushes" return tracks forward therefore keeping the track tension when the tank is in the forward motion. I can see that on my 1/16 RC Stug III. When I reverse the tank (essentiallymaking it a rear drive tank), the slack disappears.