why do tanks absolutely need crazy bullshit V12 diesels or gas turbines, if even the heaviest agricultural tractors still rely on inline-6 designs? granted, most of them are turbocharged nowadays..i am very stupid. to me, an I6 would have far less tooling/production costs, and servicing it in the field would be far easier. giant xboxhueg tanks aren't really practical anymore either, given modern drone developments.
>>65258599well anon, how fast are tractors expected to move at? what about tanks?
>>65258614the engine block pictured (for a new holland 8870) can acheive a maximum field transport speed of around ~25-27 mph, depending on weights/tires/transmission. an M1 abrams, while certainly faster on paved ground (~40 mph), has a rated off-road speed of around 25-30 mph. but i'm talking out of my ass.
>>65258599the tank i drove can move its own 60 tons +10-15 tons of bullshit mounted on it and still reach 60 kph this can't do that
>>65258628And then if you factor in the Abrams weighing 65 tons, not 8 tons like the tractor?
>>65258599power to weight ratio, same reason why older cars consume more fuel that today's cars.engine power increase which mean it can send heavier weights at higher speed in a shorter time, if you take a modern car engine and put it in an old car, the old car will be able to have the same range or better range (depending on its weight) compared to the new modern car.your tractor engine is meant to drive a tractor, not a tank, if you want to use it in a tank you have to make sure your tank weight does not exceed the weight of the tractor your engine was meant for. simple as.
The advantages of diesel engines, such as torque and power at low RPMs, seem to be a thing of the past.
>>65259790>graphic shows diesel has an advantage at high RPMSo when you floor it and need to move or accelerate diesel is better?Great job Honeywell marketing.I sure hope MTU and Renk send you guys a fruit basket.
>>65259790You're not interpreting the purpose of this chart correctly. RPM is irrelevant, the peak is what matters. The rest is just there for context. Torque is also irrelevant, it's also just there for context. After all,the diesel can almost instantly reach whatever RPM you want. Meanwhile turbines take time to spool up/down, so in general they don't idle, they're either off or going full throttle no matter the circumstance. This is a big part of the reason why turbine-powered tanks are considered gas guzzlers. Either way, low RPMs are irrelevant.
>>65259940NTA, I'm an industrial electrician that has worked on gas turbine power plants. The reason turbines use so much fuel is efficently falls rapidly as load reduced, you want to run them as close to 100% rated power as possible. We ended up installing a couple of diesel generators to keep the turbines off until they would be near full load and only using them when the load was over 90% of their output.
>>65258599Because it has to be able to get your ass moving in a vehicle that weighs 50-60 tons? Why do you think?This isn't WW1 anymore, they're not welding some corrugated fence to an earthmover (short of maybe in Russia), an MBT is armored as all fuck and carrying a lot of ordnance, so if you want it to actually go fast (and to be able to take the thing across rough terrain), the engine has to be megastronk.
>>65258710>if you want to use it in a tank you have to make sure your tank weight does not exceed the weight of the tractor your engine was meant forit is no problem as long as you have a gearbox with an adapted gear ratio. Reduce the ration by a factor of eight and voila now you can easily move 64 tons instead of eight tonss. Only at 1/8th of the speed though.
i think there is no reason that a 13l scraper motor or a 9l turbo 6 couldn't shove a tank up to 50mph.
>>65260417I really hope you're just being a contrarian joker and not just retarded.
Isn't the powerplant needed to power all the other components the tank uses in general operation that a tractor doesn't?
>>65258599the KF-41 and the Skyranger have a souped up bulldozer engine innit
>>65258599Stealth thread to justify Russia using WW2 engines in their 'modern' tanks.
>>65258599To keep up the power to weight ratio that largely dictates the slope climbing and acceleration performance unless there is traction and gearing issue.Turret cost more than the hull. You aren't saving much from downsizing the engine, in fact it would seriously bottle neck the performance because the turret can't advance and evade quick enough or letting the engine have enough margin for error when things degrade.V8s are common on ifv, engineering/recovery and spg. I6 are seen on apcs that were actually cranked out in great numbers.
>>65260785Skyranger's a turret, not a whole vehicle. You can put it on a Piranha, you can put it on a Boxer, and you can probably put it on a Lynx.
>>65258599Tanks need huge reserves of power to be able to quickly accelerate and move fast. Modern big tractors produce something between 250 and 450 hp. Tanks need anything from 800 to 1500 and could use even more. Tank engines also must be compact and relatively lightweight - the bigger the engine, the more volume that needs to be armored it occupies, dramatically pushing the hull weight up. Engine itself shares a hard upper weight limit with other mechanicals, armor, electronics, weapons and ammo, fuel... So the lighter the better.Inline sixes in the 1000 hp range are locomotive territorry, they would be too big and heavy. Smaller engines from tractors don't meet the power requirements. Crazy tuned up smaller engines are not reliable and durable enough. So modern (or "modern") tank engines tend to be either turbocharged four stroke diesels in vee-configuration, inline opposed piston two strokes, or gas turbines.
>>65258599>if even the heaviest agricultural tractors still rely on inline-6 designs?The tractor goes maybe 20mph amd weighs only 3-12 tons. The tank goes 60-70mph and weighs 60-70 tons.
>dude why do heavy things we expect to move quickly require big engines????
>>65258599>>65258628The New Holland 8870 weighs about 5 tons. The Abrams Sep V4 weighs about 80 tons. The Abrams is too heavy, but it also requires battlefield mobility and acceleration.
>>65258599Do not underestimate the agricultural tractor. Modern machines go up to 40 mph, put out more than 900hp and can weigh in excess of 30 tons. Add to that the loads tractors pull which go well over 200kN.The use case is wholly different from a tank, though. A tractor needs to put out constant power under load and behave elastically (i.e. high torque rise). Acceleration is secondary. This is why you see low revving (1.700-2.200 rpm) 6 cylinder engines with long strokes.Tank engines typically rev higher (2.200-2.600 rpm). So they have shorter strokes and more cylinders to prevent excessive piston speed. This also gives them a more responsive characteristic, being "rev happier".
>>65259895>>65259940First of all. Acceleration is determined by the area under the HP curve. Peak power roughly tells you top speed. Second of all the leopard uses 100-150 of that hp just to run its radiators whilst the agt1500 cools itself with its own intake gasses recycled through it. So the peak power advantage doesn’t even matter
>>65262462bodied that loser, get fucked dieselcels
>>65262462AGT1500 net power is nearly 300hp below 1500hp as well. Most modern MBTs lose roughly 20%, even Leopard. 10% is rare. Furthermore the max torque is roughly 4000 ft-lsbI recall that Honeywell's fine graph was mainly a marketing trick and in practice even acceleration RPM was too high to have much of that stated advantage or something like that.
>>65262794Where are you getting these numbers? Are you quoting drive train losses? The leopard is losing 150hp to what’s essentially its accessory drive before that power even makes it to the transmission. Buddy if you’re trying to argue in favor of diesels use their actual strengths such as fuel efficiency. Gas turbines are unironically ridiculous
>>65258599Size and shape is unironically a constraint for tank engines. A tractor can be designed around pretty much any sort of engine, but an engine that needs to go into a tank needs to be compact and have a low profile.
>>65258628>>65258599Have you considered that you're a fucking retard that can't comprehend vehicle weight and load demand?
>>65258599because they weigh nearly 150,000 lbs or about as much as two loaded 18 wheelers. its not a tractor hauling a hay bale.
More cylinders = more redundancy (v12 losing a cylinder has 2x more remaining cylinders than an i6 to keep running in combat)More displacement = more power with less stress vs boostTurbines can burn basically any fuel and are incredibly power dense
>>65263899>More cylinders = more redundancyNo, there are very few ways to lose a 2-stoke diesel cylinder that doesn't end the rest of the engine within minutes.The only way I can think of is a head gasket leak reducing compression enough to stop ignition.
>>65263984Typically if your head gasket has failed that badly, it will either pump oil into the coolant system until the engine runs dry, or fill the coolant system with combustion pressure and start blowing out coolant hoses and fittings. Either way it's not the kind of thing you can just ignore.
>>65258628Neat, apparently a Baneblade or Leman Russ does move at the speed of an Abrams.
>>65264033Good point, in that case I can't think of a single way to lose a 2-stoke diesel cylinder that doesn't kill the engine.Maybe a blocked injector but if that's happeing your fuel is contaminated and the rest are getting blocked soon enough.
>>65264040Damn. I read Baneblade and it was pretty good. I expected them to be moving really slowly.
>>65263351M1 numbers are from manual. I can't recall where to find precise net power values of Leopard 2 anymore. Surely some of it's many operators has released them? Soviet MBTs are out there for certain.Only exception in tank diesels I've seen is the Type 10. It isn't just as powerful, but loses far less for cooling and it's transmission is very effective as well.>if you’re trying to argueHonestly I don't see enough difference to argue. Just pointing out Honeywell was trying to sell things. Besides I like generally less effective things like 2-strokes and air-cooling.
>>65258599>why do tanks absolutely need crazy bullshit V12 diesels or gas turbines, if even the heaviest agricultural tractors still rely on inline-6 designs? granted, most of them are turbocharged nowadays..They are very heavy compared to tractors.You need that power to get them moving at speed.
