Jump to content

Gunnery on the M1A1


Toyguy

Recommended Posts

  • Moderators

My guess is that the "M1A3", whatever it is, won't be a radical change. It will just be a few more improvements and additions. Look at the M1A1 to M1A2 differences. Now think of a few more such differences to the M1A3. Computer components might get updated / upgraded, maybe different types of armor inserts and so on. For all we know, the "M1A3" will be the "M1A2 SEP" with a few more changes to it but otherwise might essentially be just that, an M1A2 with all its additional changes plus a few more. The Army generally (well, usually) dislikes it when its vehicles get all kinds of other acronyms tacked onto the end of the name and tries to keep things standardized as much as possible, so the M1A3 could just be a standardization of the M1A2 SEP++. Most likely it is a combination of all of that, with some standardized mounting brackets and such for specialized upgrade kits.

Anyway, the point is, I don't think it will be shield generators, rail guns and mini guns for coax just yet. ;) But that is all just useless speculation on my part...

Edited by Volcano
typo
Link to comment
Share on other sites

  • Replies 76
  • Created
  • Last Reply

Top Posters In This Topic

well, what the abrams really needs is a new powerpack. the LV100-5 gas turbine would have been a great replacement, with improvements to reliability, and reduction in fuel consumption and parts count. but it got cancelled. but i guess this is also the area that is most likely to get improved if things move forward with the M1A3 program, with all the alternate powerpack technologies the US army has been researching. they might even go from a mechanical to a fully electric transmission, and a hybrid engine.

currently, about 18% of the engine power and torque is lost through friction in the mechanical transmission.

Link to comment
Share on other sites

well, what the abrams really needs is a new powerpack. the LV100-5 gas turbine would have been a great replacement, with improvements to reliability, and reduction in fuel consumption and parts count. but it got cancelled. but i guess this is also the area that is most likely to get improved if things move forward with the M1A3 program, with all the alternate powerpack technologies the US army has been researching. they might even go from a mechanical to a fully electric transmission, and a hybrid engine.

currently, about 18% of the engine power and torque is lost through friction in the mechanical transmission.

Didn't the Wehrmacht try electric transmissions with the Tiger prototypes?

They didn't go with it because it used too much copper or something.

Link to comment
Share on other sites

Didn't the Wehrmacht try electric transmissions with the Tiger prototypes?

They didn't go with it because it used too much copper or something.

they didn't go with it because it occasionally caught fire, and got bogged down frequently.

but nowadays, you got diesel-electric trains, and diesel-electric boats running fine with no issues at all.

the principle is simple, connect an engine to an electric generator, and convert it back to mechanical power with an electric motor.

Liebherr_T282.jpg

this thing here is diesel electric.

it weights 203 tonnes, and has a top speed of 65kph,

with a power to weight ratio of 17hp/ton unloaded.

Link to comment
Share on other sites

The problem is fitting an entire generator system and then motors under-armor, especially under armor designed for a very small engine like a gas turbine. Size isn't a problem when you are working with a huge dumptruck or train, but a tank doesn't have a lot of room to play with. Remember that one of the primary considerations of using a gas turbine in the M1 originally was the engine's small physical size (and weight).

Link to comment
Share on other sites

  • Members

It can't be emphasized enough that for all armored vehicles, internal volume and gross weight come at a premium. There's MLC limits that dictate both operational mobility (what can roads and bridges support), external dimensions that must still allow for rail transport and/or fit into transport aircraft, and at the same time offer sufficient internal volume to insert the crew, their personal equipment, and the supplies needed to operate for the planned duration until the next resupply point. Some armies are now already calculating with nine liters of water per person, so a troop carrier with 11 crew and dismounts must already provide space for 100 liters/100kg instead of 11 canteens of half a liter as may have been the 1970s' specification. Add to that body armor and, on average, about 40kg of equipment (and more than one cubic meter per person to accommodate the gear) and one can easily understand that all this actually is a serious engineering challenge.

Link to comment
Share on other sites

The problem is fitting an entire generator system and then motors under-armor, especially under armor designed for a very small engine like a gas turbine. Size isn't a problem when you are working with a huge dumptruck or train, but a tank doesn't have a lot of room to play with. Remember that one of the primary considerations of using a gas turbine in the M1 originally was the engine's small physical size (and weight).

which is exactly why you'd want to go for a hybrid system.

http://defense-update.com/features/du-3-05/feature-HED-afv.htm

Link to comment
Share on other sites

which is exactly why you'd want to go for a hybrid system.

http://defense-update.com/features/du-3-05/feature-HED-afv.htm

Where exactly are all those batteries going to fit? They had a hard enough time trying to put 6 additional batteries in the SEP to extend silent watch to 24 hours, eventually having to cancel the under-armor APU just to get the batteries in.

Where is this entire assembly going to fit? The M1 was designed with a turbine because it is smaller than a diesel engine. I don't think there is anyway you could fit a hybrid drive in the engine compartment and then expect similar performance to the turbine.

The answer for the M1 would be a new turbine that meets (or exceeds!) the requirements for specific fuel consumption as originally set out for the AGT-1500. It should be possible with the advancement in turbine technology since the 1970s.

Link to comment
Share on other sites

IRCC M1A2SEP v.2 will got it, there are also other interesting upgrades in M1A1SEP v.2, like HUD in TC vision block... well maybe not only in TC's vision blocks. :)

Last summer, Fort Knox got a shipment of brand new SEP v2 just off the assembly line (Manufacturing date was Feb 09), and they didn't have any of that. In fact the only difference I could tell between them and the SEP was the v2 has displays with green instead of tan text.

Link to comment
Share on other sites

Where exactly are all those batteries going to fit? They had a hard enough time trying to put 6 additional batteries in the SEP to extend silent watch to 24 hours, eventually having to cancel the under-armor APU just to get the batteries in.

Where is this entire assembly going to fit? The M1 was designed with a turbine because it is smaller than a diesel engine. I don't think there is anyway you could fit a hybrid drive in the engine compartment and then expect similar performance to the turbine.

The answer for the M1 would be a new turbine that meets (or exceeds!) the requirements for specific fuel consumption as originally set out for the AGT-1500. It should be possible with the advancement in turbine technology since the 1970s.

what do you mean the UAAPU was cancelled, they put it in. they removed part of the fuel tank on the left area of the engine compartment, and installed it there. a turbine might be small, but it needs large amounts of fuel, and an enormous cooling system, which is taking up a large portion of the engine compartment. the fuel needs of the gas turbine are so large infact, that part of the crew compartment is eaten up by huge fuel tanks in the front of the tank, and basically has twice the amount of fuel(505 vs 255 gallons), and it still doesn't have the range(442 vs 550 km) of a diesel powered leopard 2.

the pentagons insistence on a turbine engine is just baffling ludicrousness, if you stick the MB-873 in there(and it will fit), you get an engine just as capable as the abrams engine, but

now, suddenly you have more than doubled the on-road range to 1089km.

if you instead go with the MT-883 compact 1500hp powerpack, you all of a sudden have 1 meter of free space in the engine compartment.

then you have the new MTU MT-89x HPD series of diesel engines, with power density rivaling a turbine engine, and all of a sudden you have a ton of room for all sorts of fancy stuff.

Link to comment
Share on other sites

what do you mean the UAAPU was cancelled, they put it in. they removed part of the fuel tank on the left area of the engine compartment, and installed it there.

The SEP v2 comes with additional row of batteries on the left side to extend silent watch to 24+ hours. Those batteries were put there in place of the UAAPU.

turbine might be small, but it needs large amounts of fuel, and an enormous cooling system,

?

The cooling system is not particularly large. In fact, I would say that the precleaners and vee pack take up much more space than the oil and transmission coolers. The recuperator might even be a worse offender in terms of size.

the pentagons insistence on a turbine engine is just baffling ludicrousness

Hmmm....

Extreme low-end torque - Turbines generate max torque at minimum RPM. I wonder if that might be useful for a big, heavy vehicle.

much easier to start in cold weather - Anyone who has tried to start a diesel with ether in the middle of winter knows what I'm talking about.

much quieter - Diesels produce more of there noise in low frequencies, which travel farther.

Less moving parts in the engine - Self explanatory.

For the trade off of:

Worse fuel efficiency - In the Army with the best logistical support, it's not exactly a huge deal. Also, almost every Army ground vehicle has a range of ~500 miles. It's not exactly a great idea to spend a ton of money to recapitalize the entire tank fleet with diesels when the rest of the force won't be able to match the gains.

Higher thermal signature - If they can see a turbine exhaust, they can probably see the diesel's too.

Simply put, it's not ludicrous or baffling. It's an engineering choice with it's pros and cons.

Link to comment
Share on other sites

  • Members
How does the Leo 2 use the space freed up by having half the fuel capacity?

Well, the old MB-873 Ka-501 engine requires a lot more space than the turbine - or the Euro Powerpack (MTU 883) for that matter. 30 years of engineering efforts make a difference, of course.

The 873 model takes up a volume of about 1.64m³ (just the pure engine, not counting heat exchanger, gearbox, final drive, ...), or a power-to-volume ratio of 670kW/m³. The 881 model already offers 894kW/m³ (=1.23m³).

The LV 100 turbine offers 1050kW power output for a weight of 1000kg, the MB-873 produces 1100kW with 1915kg weight (dry).

Dimensions (including turbo loader, turbine in parentheses):

Length: 1.615m (1.140m)

Width: 1.025m (1.000m)

Height: 1.095m (1.300m)

Link to comment
Share on other sites

i think the dimensions for the systems required to run a gas turbine should be taken into consideration in calculation of reduced internal volume. and the fact is, the abrams is unable to have an ammunition bunker in the hull, because that would reduce the range of the tank from 442 to.. well under 200km. it doesn't matter how small the engine is, it can be the size of a snowflake, if it requires double the fuel to run, you still need to allocate space for that fuel.

and then its better to go for the bigger engine, with lower fuel consumption, because the size of the complete propulsion system will be smaller.

Link to comment
Share on other sites

the abrams is unable to have an ammunition bunker in the hull

You make it sound as if that's a good thing.... It is in my opinion the biggest flaw with the Leopard 2.

But that's no different than stating the Abrams is flawed because of its fuel consumption. There is a reason why these things are the way they are. And its not because the designers couldn't see past their own foreheads. Look back at their development, you will see why.

These tanks were designed to fight the Russians, in eastern Europe. The fact that the Leopard stores half of its ammo in the Hull, right beside the guts and eyeballs of the crew is not a huge deal when your tactics state you fight from prepared positions. And reverse to another, ambush, and repeat. The hull would only be exposed for short periods. But fast forward to today, and ask yourself which one you would rather ride in over an Anti-tank mine or IED. I'll take my chances in the M1.

This was one of the driving forces behind the selection of the turbine for the M1. It was the tactics they planned to use, and road marching thousands of miles was less important to the designers. Understanding that they would be lucky to even survive the horde, let alone advance into russia.

The positives far out weighted the cons for the situation in which it was designed to fight. The weight, and engine performance across the board where ideal for that fight. Show me a diesel that will make the same power at -32 degrees and +120 F. The turbine is also less complex, has fewer moving parts. I don't know the exact numbers, but the ability to go extend periods between rebuilds was also a factor. Its ability (as stated already) to start quickly, and not require time to "Warm up" before making power was a rather large factor as well.

Today things are different, and its no wonder these vehicles don't exactly fit the roll of today's and tomorrow's wars. And its why these vehicles will continue to evolve.

There... you made me type all of that. Knowing full well that you knew every bit of it. This place has become synonymous with short memory's, and your no exception to the rule noob.

Link to comment
Share on other sites

You make it sound as if that's a good thing.... It is in my opinion the biggest flaw with the Leopard 2.

but it is a good thing, if you put it behind blast doors with blowoff panels on the roof, like the 6 emergency rounds already stuffed into the abrams hull, you'd have more rounds for an extended skirmish with the ruskies.

if you put the MB-873 engine into the abrams, you could reduce the amount of fuel, and stuff

more rounds into the hull. i'd say about 12 extra rounds, on the left and right of the driver.

also, jp-8 is pretty weighty, about 0.8kg per liter. and the abrams has 1907 liters of

it. or about 1.5 tonnes of fuel.

the amount of fuel needed on the MB-873 is half that of the abrams, so the tank would be 750kg lighter, this is weight which can be used for stuff like blast doors for rounds stored in the hull. or extra armour.

These tanks were designed to fight the Russians, in eastern Europe. The fact that the Leopard stores half of its ammo in the Hull, right beside the guts and eyeballs of the crew is not a huge deal when your tactics state you fight from prepared positions. And reverse to another, ambush, and repeat. The hull would only be exposed for short periods. But fast forward to today, and ask yourself which one you would rather ride in over an Anti-tank mine or IED. I'll take my chances in the M1.

the bushmaster. or any other vehicle with a V-shaped bottom.

There is a reason why these things are the way they are. And its not because the designers couldn't see past their own foreheads. Look back at their development, you will see why.

yes, its because the geniuses at pentagon was in love with turbines, and selected whichever prototype had one. GM was offering a prototype with a diesel, and it was turned down.

The positives far out weighted the cons for the situation in which it was designed to fight. The weight, and engine performance across the board where ideal for that fight. Show me a diesel that will make the same power at -32 degrees and +120 F. The turbine is also less complex, has fewer moving parts. I don't know the exact numbers, but the ability to go extend periods between rebuilds was also a factor. Its ability (as stated already) to start quickly, and not require time to "Warm up" before making power was a rather large factor as well.

i think you're overestimating the impact this has on the fighting ability of the tank.

plus diesels can run idle consecutively for hours on end, while the abrams turbine drinks greedily even at a standstill.

batteries have a bad habit of not working that well in the cold. forcing you to keep the engine running, to stop the batteries from running flat.

well, i guess you could wait for battery power to be reduced, then have the engine running for a while to charge the batteries back up, and then turn off the engine again.

as for hot conditions, well, the turbine gets so hot in those conditions that its exhaust can autoignite fuel.

There... you made me type all of that. Knowing full well that you knew every bit of it.

its always interesting to see old knowledge in a new context :P

Link to comment
Share on other sites

yes, its because the geniuses at pentagon was in love with turbines, and selected whichever prototype had one. GM was offering a prototype with a diesel, and it was turned down.

The entire subject of turbines is detailed thoroughly in The Technology of Tanks. The AGT-1500 was supposed to provide a specific fuel consumption of 225 g/kWh, which was similar to contemporary diesels, but this later dropped to 274 g/kWh, and eventually 290 g/kWh. Fuel consumption per net sprocket power shows a similar difference between diesels and turbines.

It also points out that turbines enjoy several other advantages such as, "easier starting at low temperatures, insensitivity to the cetane or octane rating of the fuel, much lower consumption of lubricating oil, virtually no smoke emissions and quieter operations." The book points out that the M1 needs more intake airflow (18 kg/kWh as compared to 6 kg/kWh) but also needs less cooling air flow (30 kg/kWh as compared to 45 kg/kWh). It also points out the the operational readiness of the M1-series was higher than M60, based on operational experience.

As I've said, the M1 was engineered for a specific mission, and it was every bit as good as contemporary tanks. The problem now isn't that the M1 uses a turbine, the problem is that the M1 uses a forty year old engine.

Link to comment
Share on other sites

The entire subject of turbines is detailed thoroughly in The Technology of Tanks. The AGT-1500 was supposed to provide a specific fuel consumption of 225 g/kWh, which was similar to contemporary diesels, but this later dropped to 274 g/kWh, and eventually 290 g/kWh. Fuel consumption per net sprocket power shows a similar difference between diesels and turbines.

It also points out that turbines enjoy several other advantages such as, "easier starting at low temperatures, insensitivity to the cetane or octane rating of the fuel, much lower consumption of lubricating oil, virtually no smoke emissions and quieter operations." The book points out that the M1 needs more intake airflow (18 kg/kWh as compared to 6 kg/kWh) but also needs less cooling air flow (30 kg/kWh as compared to 45 kg/kWh). It also points out the the operational readiness of the M1-series was higher than M60, based on operational experience.

As I've said, the M1 was engineered for a specific mission, and it was every bit as good as contemporary tanks. The problem now isn't that the M1 uses a turbine, the problem is that the M1 uses a forty year old engine.

so you agree that the fuel consumption is too high then. good.

i just read this blurb on the new LV-100 turbine engine:

http://www.defenseindustrydaily.com/sustaining-the-m1-abrams-us-army-puts-a-tiger-in-its-tanks-01790/

some of the improvements stated here:

reduced parts count by 43%

reliability improvement of 400%

50% reduction in fuel consumption at idle.

112km longer range with the current fuel tanks.

well, thats great. fantastic. in 40 years, the fuel consumption of the turbine has increased

by 21%.

maybe in 160 years, the abrams will have a turbine capable of the same fuel consumption

as a diesel.

Link to comment
Share on other sites

so you agree that the fuel consumption is too high then. good.

Because the engine is 40 years old, not because turbines themselves inherently flawed. A 40 year old diesel engine would be just as bad and I would be just as eager to have it replaced. Diesels have their own faults too. As I've said from the beginning, the choice between turbines and diesels is an engineering one.

well, thats great. fantastic. in 40 years, the fuel consumption of the turbine has increased by 21%.

Let's stop pretending like the LV-100 is new technology. It has been under development from a contract awarded by AIPS program since 1984. Do I really need to point out the advancements made by turbines in the last 25 years?

maybe in 160 years, the abrams will have a turbine capable of the same fuel consumption as a diesel.

Is this the game you really want to play?

Link to comment
Share on other sites

yes.

Single crystal blades made cheaply (relatively) and reliably! <- HUGE

Computer simulations allow design of radically shaped blades not previously possible.

Improved metallurgy which supports higher N1 temperatures, which increases efficiency.

Reduction in size of centrifugal compressors, which offer higher performance than axial flow compressors.

Just a few off the top of my head. I don't feel like going back through my old college textbooks again.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...