TomS said:
I saw this at a couple of trade shows circa mid to late 1990s. Not many more detail except that it had a two-man crew and was very preliminary. IIRC, the turret was plywood at this stage.
It's also frustratingly hard to google because at the time they were calling it the "Future Combat System" and google keeps kicking that to "Future Combat Systems" heh. And the "40 Ton Concept" moniker isn't much more distinctive.


Anyway, here's that video you probably remember:
https://www.youtube.com/watch?v=2AZe8jOuGpo
 
http://nationalinterest.org/blog/the-buzz/inside-the-us-armys-lethal-new-m1a2-sep-v3-abrams-main-16445

However, Kotchman did say that the M1A2 SEP v.3 is just one of the upgrades in the pipeline for the Abrams. However, he deferred comment to the U.S. Army about the nature of those potential additions. “The Army is considering additional engineering changes that would add capability to the Abrams tank,” Kotchman said.
 
I would like to know what is so wrong in the proposal that the M1 be fitted with a diesel engine and electric drive. Seriously and without the rancor or taking the question as an affront.
 
Foo Fighter said:
I would like to know what is so wrong in the proposal that the M1 be fitted with a diesel engine and electric drive. Seriously and without the rancor or taking the question as an affront.

What's wrong with the turbine it's got?
 
Well, Foo, Noise(frequency rather than volume), weight, complexity, and cost are often cited as issues with switching away from the turbine. It's not a terrible idea, hence the US Army and GF often revisiting it, it's no magic wand. The turbines are a known quantity, the costs are well in control, and there's other priorities that need the attention more urgently.
 
Fare enough, I was thinking of using the diesel in a generator capacity while using electric motors for drive. The interest was reducing fuel usage and costs. Not exactly a new idea as the German Army used this system in WW2 to good effect with a system generally popular with crews.
 
Foo Fighter said:
Fare enough, I was thinking of using the diesel in a generator capacity while using electric motors for drive. The interest was reducing fuel usage and costs. Not exactly a new idea as the German Army used this system in WW2 to good effect with a system generally popular with crews.

This is essentially how FCS was laid out. A diesel generator powered an electrical distributor that provided power to the drive motors that drove the sprocket. BAE did similar things with CV90 and M8 AGS. You're right it's not new, but most modern fighting vehicles in the West were also designed 40-50 years ago, and the electrical motors needed for that sort of application only appeared in the last 20 years.

Moose said:
Well, Foo, Noise(frequency rather than volume), weight, complexity, and cost are often cited as issues with switching away from the turbine. It's not a terrible idea, hence the US Army and GF often revisiting it, it's no magic wand. The turbines are a known quantity, the costs are well in control, and there's other priorities that need the attention more urgently.

Tactical mobility/acceleration is the most commonly cited benefit of turbines anecdotally, and they do have a higher torque at lower RPMs, but I suspect that the advantage is not terribly apparent. HIMAG did fine with a diesel. In general I suspect that this is an inflated benefit, as it might be real but it would be quite niche.

Audible signature only really matters when you're standing still. A diesel is pretty loud, they make my ears hurt. A turbine makes my ears hurt for different reasons, but it's also a lot quieter, by 10-15 db. Where a turbine may be 85 db at 1 meter, a diesel of similar size might be 95-100 db at the same distance. At speed though, the only thing you'd be hearing is the clanking of metal on rubber and machine gun fire. However, this is still important in close terrain, or really anything that isn't pretty flat and open like a desert, and probably relevant for cities and forests.

Diesels need to be heated before they can start in extreme cold (-40), which can take an hour or so, and isn't uncommon in Siberia or Alaska. It remains true in extreme hot weather, like deserts. Finally, most diesels are water cooled, which includes all the Euro Powerpacks and American diesels, which can be a problem since liquid cooling is vulnerable to damage. Anecdotally, they're also easier to maintain, due to being simpler, but I'm not sure this is a real benefit. There's also no real reliability advantage, modern diesels are extremely reliable, just ask Merkava IV or AVDS-1790.

So the biggest known, real advantages are probably the extreme weather performance, idle audible signature, and the lack of a cooling subsystem.

Fuel consumption is a tremendous disadvantage, but I haven't been restricted on how many liters of petrol I can buy yet, so I suspect that the fuel cost problem isn't quite as serious as it was when the M-1 tank was being designed.

Foo Fighter said:
I would like to know what is so wrong in the proposal that the M1 be fitted with a diesel engine and electric drive. Seriously and without the rancor or taking the question as an affront.

It would require an entirely new hull. The US Army barely has enough money to pay for its soldiers and some new golf carts, let alone a new tank, and what new tanks it wanted to buy would have had diesels anyway because I was actually wrong about LV50-2 being used in FCS and it turns out that it was diesel powered like the M2/M8.

I suspect the US Army considers turbines only to be worth it for heavy armor, then. Part of the reason GCV died, besides managerial incompetence and the fiscal cliff, was because the diesel powerplant didn't provide sufficient power for a 70-ton fighting vehicle. At that point, you'd be looking at LV100 like FIFV was supposed to get.
 
Advertising by an involved company is less informative and more deflective. Fuel may also be more difficult to acquire when in a hot region. As for needing a new hull to fit a diesel engine, I can see no reason for that. The Chieftain hull with minor modifications went from a BL (hunk of junk) L-60 to the same powerplant fitted to the early Challenger. These were supplied to Iran mostly and some to Jordan. I believe the M1 hull is plenty big/roomy enough for the same re-engine process.
 
Foo Fighter said:
Advertising by an involved company is less informative and more deflective. Fuel may also be more difficult to acquire when in a hot region. As for needing a new hull to fit a diesel engine, I can see no reason for that. The Chieftain hull with minor modifications went from a BL (hunk of junk) L-60 to the same powerplant fitted to the early Challenger. These us were suppplied to Iran mostly and some to Jordan. I believe the M1 hull is plenty big/roomy enough for the same re-engine process.

If they wanted a diesel they'd have it. They don't so it doesn't.
 
Foo Fighter said:
Advertising by an involved company is less informative and more deflective. Fuel may also be more difficult to acquire when in a hot region. As for needing a new hull to fit a diesel engine, I can see no reason for that. The Chieftain hull with minor modifications went from a BL (hunk of junk) L-60 to the same powerplant fitted to the early Challenger. These were supplied to Iran mostly and some to Jordan. I believe the M1 hull is plenty big/roomy enough for the same re-engine process.

Yes it could be done. It would be at least as deep an upgrade as the SEP.

Similar was done [experimentally] with Leopard 2 with the MTU 883 and they found you'd have room left over with a modern powerpack. It might not be a bad idea to take XM2001/Crusader's turbine, which was supposed to power the eponymous M1 replacement, and fill the void space with a fuel tank [to regain the range lost with the under armour APU present in the SEP Abrams] but the US Army is still too infatuated with light tanks to consider a radical modification of its shrinking M1 fleet.

GDLS has an M1A2 with their GD883 powerpack (licence built EuroPowerpack) wandering around a parking lot, but the US Army isn't interested in it since it still pines for FCS.
 
From General Dynamics.

STERLING HEIGHTS, Mich. -- General Dynamics Land Systems successfully completed testing of its prototype diesel-powered M1A2 Abrams tank at Aberdeen Test Center, Maryland, March 31, 2000.

Testing included 300 miles of reliability, availability and maintainability evaluations on five test courses and firing 70 main gun rounds at stationary and moving targets by General Dynamics and Department of Defense engineers. The testing validated successful integration of the diesel-powered chassis with the tank's System Enhancement Package turret.

General Dynamics pursued diesel power propulsion to comply with Turkish requirements contained in the Request for Proposals for their Main Battle Tank competition.

The effort demonstrates the flexibility of General Dynamics' engineering staff and of the M1A2 Abrams tank to accept a variety of engines and transmissions. The tank moves as well as the standard turbine-powered tank with no difference in target detection, identification or main gun accuracy. The testing confirms that the tank's performance is not changed by the diesel engine and that it has a significantly lower operating cost.
 
The last time Diesel Abrams was seen in public was at AUSA 2013, minus the turret.
 

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Foo Fighter said:
Advertising by an involved company is less informative and more deflective.

Nope.

Foo Fighter said:
Fuel may also be more difficult to acquire when in a hot region.

It runs on kerosene aka jet fuel. Pretty common.

Foo Fighter said:
As for needing a new hull to fit a diesel engine, I can see no reason for that. The Chieftain hull with minor modifications went from a BL (hunk of junk) L-60 to the same powerplant fitted to the early Challenger. These were supplied to Iran mostly and some to Jordan. I believe the M1 hull is plenty big/roomy enough for the same re-engine process.

LOL. "Minor" modifications was a totally different rear hull. Sure you can build an M1 with a diesel, especially with the modern high power density units like the MTUs. But you need to rebuild the entire rear end of the vehicle and do "minor" things like adding an engine cooling system.
 
Cooling system is part of the power pack and proven to fit in the existing hull. A new rear hull section would have made the vehicle too expensive for the Turks who want to buy an M1 series with a diesel engine.
 
It probably had more to do with the German Army fobbing off all their Leopard 2s for fire sale prices until the late oughties.
 
Foo Fighter said:
Cooling system is part of the power pack and proven to fit in the existing hull. A new rear hull section would have made the vehicle too expensive for the Turks who want to buy an M1 series with a diesel engine.

The USMC and Australian Army all operate M1s powered by diesel. It is only a minor modification to customise the GT to run on diesel fuel rather than jet fuel. Just some changes in seals and the like for the different fuek properties. If you want to replace the engine type you need make some major changes to the tank. GTs have very low heat rejection so they don't need the same level of cooling as a diesel. So the M1 does not have the same kind of venting needed to run the radiators of a big Maybach or MTU or whatever they are called now. (MAN and MTU now owned by the same company... what is the world coming too?)
 
Abraham Gubler said:
(MAN and MTU now owned by the same company... what is the world coming too?)

MTU Aero Engines, formerly known as MTU München, has no tank engines in its product lineup.
MTU Friedrichshafen, a different company, is owned by Rolls-Royce Holdings. Volkswagen Group has a 75% share in MAN SE.
 
http://www.scout.com/military/warrior/story/1714621-abrams-tanks-to-control-robotic-attack-drones
 
http://www.scout.com/military/warrior/story/1728632-army-builds-new-abrams-tank-variant-for-2020s
 
Not intended to offend, for those who are keen to see the M1 retain a gas turbine, would it be possible to have a smaller turbine as a generator to provide power to an electric drive similar to the Ferdinand/Elephant? Just how much weight could be saved by removing the need for secondary drive via a gearbox?
 
Probably could given the 40 odd years that have passed since the Abrams/AGT1500 combination was designed. Be really interesting if one also factors in the developments that have taken place in the EV market in recent years.
 
Foo Fighter said:
Not intended to offend, for those who are keen to see the M1 retain a gas turbine, would it be possible to have a smaller turbine as a generator to provide power to an electric drive similar to the Ferdinand/Elephant? Just how much weight could be saved by removing the need for secondary drive via a gearbox?

You'd need to make room for the electric motors in the hull to drive the sprockets.

Assuming that can be, there wouldn't be an issue.

That said, internal volume would be your major concern since real estate is extremely limited in the Abrams hull. M1A2 has a weight issue, but that's being corrected with fiber optic cables sometime in the indeterminate future (~2021-22). A transverse mounting (imaginatively called Transverse Mounted Engine Propulsion System; TMEPS) of the AGT-1500 would spare 46 cu. ft. of volume for stuff in the rear engine bay (Hunnicutt, Abrams, p 250). This was the 80s though, so gas was cheap, and they (Chrysler) considered cramming a diesel APU and about 10 rounds of 120-mm in the space. You could probably have a ~100 gallon fuel tank in there, though. You'd reclaim the fuel lost by the -A2SEP's diesel APU and a little bit more, maybe.

A smaller turbine like LV100-5 you'd save even more space for more fuel, the mechanical transmission going you'd have more space, etc.

Hunnicutt's book has a diagram of the TMEPS so I could probably eyeball the amount of volume you'd save.

Also, CATTB actually had a transverse Cummins diesel (I forgot the name, it was the diesel AIPS, as I understand LV100-5 wasn't ready until the 1990s which is what the US Army ultimately picked as its future engine for the XM2001 howitzer) with a super lubricant/coolant that ran hotter so the cooling system was smaller. I don't know if the amount of space saved was identical to the TMEPS, or what it was used for, though (an APU and diesel engine cooling system, most likely). CATTB had a radically different hull than the production M1-series tanks, despite externally looking similar/identical, so it is likely more of an interesting tidbit than any useful information.

GTX said:
Probably could given the 40 odd years that have passed since the Abrams/AGT1500 combination was designed. Be really interesting if one also factors in the developments that have taken place in the EV market in recent years.

I suspect it would be new territory, even with the advances made since FCS. The MGVs were only the size of Bradleys (~25-30 tons) and there's a huge difference in sprocket power needed to drive a thirty ton AFV vice sixty plus.

Similar to how band tracks seem to be the future for medium armor (as soon as you can put them on a Bradley without needing to lift the thing off the ground, anyway), but their utility for tanks and tank-like objects in the plus 40 ton range is dubious at best.

One of Future Combat System's (a TACOM study from the mid-1990s, unrelated to Shinseki's trainwreck) design goals was that it was supposed to be 40 tons or less (somehow) so it could fit band tracks and electric drives, as I understand. Not to say that it's impossible, but an electric drive to move a 60-ton tank is just going to be big and heavy.
 
Kat Tsun said:
Foo Fighter said:
Not intended to offend, for those who are keen to see the M1 retain a gas turbine, would it be possible to have a smaller turbine as a generator to provide power to an electric drive similar to the Ferdinand/Elephant? Just how much weight could be saved by removing the need for secondary drive via a gearbox?

You'd need to make room for the electric motors in the hull to drive the sprockets.

Assuming that can be, there wouldn't be an issue.

The issue has been cooling electric motors in the MBT sprocket HP/torque range for speeds above 20 MPH.
Which has in turn motivated hybrid powertrains.
 
marauder2048 said:
Kat Tsun said:
Foo Fighter said:
Not intended to offend, for those who are keen to see the M1 retain a gas turbine, would it be possible to have a smaller turbine as a generator to provide power to an electric drive similar to the Ferdinand/Elephant? Just how much weight could be saved by removing the need for secondary drive via a gearbox?

You'd need to make room for the electric motors in the hull to drive the sprockets.

Assuming that can be, there wouldn't be an issue.

The issue has been cooling electric motors in the MBT sprocket HP/torque range for speeds above 20 MPH.
Which has in turn motivated hybrid powertrains.

Yet the Germans solved this issue with the Ferdinand/Eliphant, how heavy were those? 65 tonnes (143,000 lb).
 
Foo Fighter said:
marauder2048 said:
Kat Tsun said:
Foo Fighter said:
Not intended to offend, for those who are keen to see the M1 retain a gas turbine, would it be possible to have a smaller turbine as a generator to provide power to an electric drive similar to the Ferdinand/Elephant? Just how much weight could be saved by removing the need for secondary drive via a gearbox?

You'd need to make room for the electric motors in the hull to drive the sprockets.

Assuming that can be, there wouldn't be an issue.

The issue has been cooling electric motors in the MBT sprocket HP/torque range for speeds above 20 MPH.
Which has in turn motivated hybrid powertrains.

Yet the Germans solved this issue with the Ferdinand/Eliphant, how heavy were those? 65 tonnes (143,000 lb).

The Ferdinand/Elefant was extremely susceptible to engine/powertrain failures and fire due to overheating.
And that was at a *maximum* road speed less of less than 20 MPH.
 
Actually the Ferdinand/Eliphant matured into a half decent TD, the overheating and fires were earlier on. The Maus was powered in the same way but with a different installation and while slow, these vehicles were developed over seventy years ago. Modern units would be much more efficient.
 
Foo Fighter said:
Actually the Ferdinand/Eliphant matured into a half decent TD, the overheating and fires were earlier on. The Maus was powered in the same way but with a different installation and while slow, these vehicles were developed over seventy years ago. Modern units would be much more efficient.

Modern MBTs have far greater and ever increasing thermal loads to manage and that trend shows no signs of abating.
 
Thermal load of a turbine or diesel is much greater than that of an electric motor, yet those are handled routinely. This seems to be a non-issue to me.
 
Hobbes said:
Thermal load of a turbine or diesel is much greater than that of an electric motor, yet those are handled routinely. This seems to be a non-issue to me.

The notional configuration being discussed is a smaller gas turbine generator powering electric motors in the hull which in turn drive the sprockets.
The power density of the electric motors that fit in the alloted hull volume and can generate the HP/torque in the mid-to-upper performance
band for an MBT necessitates liquid cooling of the stator windings. And of course the gas turbine generator needs cooling.

That total thermal load is greater than the thermal load of the larger, original gas turbine at the mid-to-upper MBT performance band.
 
I would like to see some facts to back up statements like these.
 
Clarification and curiosity, basically I never stopped asking "Why" when I got to ten years old. Not looking to offend anyone. I am 58 years old last month and reckon I will go on asking "Why" for as long as I am around to get up the nostrils of our dear bleeders in government.

Sorry if offence has been inferred.
 
Foo Fighter said:
Clarification and curiosity, basically I never stopped asking "Why" when I got to ten years old. Not looking to offend anyone. I am 58 years old last month and reckon I will go on asking "Why" for as long as I am around to get up the nostrils of our dear bleeders in government.

Sorry if offence has been inferred.

No offense taken or inferred. It just helps to know what specifically you are asking about.
For example, virtually all of the electric motors that I know of that deliver even a
third of the peak torque delivered by the Abrams sprockets require liquid cooling and those are
in environments where they also have access to under-body airflow.
 
marauder2048 said:
Hobbes said:
Thermal load of a turbine or diesel is much greater than that of an electric motor, yet those are handled routinely. This seems to be a non-issue to me.

The notional configuration being discussed is a smaller gas turbine generator powering electric motors in the hull which in turn drive the sprockets.
The power density of the electric motors that fit in the alloted hull volume and can generate the HP/torque in the mid-to-upper performance
band for an MBT necessitates liquid cooling of the stator windings. And of course the gas turbine generator needs cooling.

That total thermal load is greater than the thermal load of the larger, original gas turbine at the mid-to-upper MBT performance band.

Perhaps. I was thinking along these lines:
A Leo II has a 1500 shp/1100 kW diesel. The heat load from this is on the order of 1100 kW at full power. An 1100 kW electric motor dissipates about 50 kW as heat, add another 50 kW for the generator (95% efficiency) and the heat load is still only 10% of the engine heat output.

I suspect a tank gearbox dissipates a similar amount of heat. So replacing the gearbox with an electric drive should be close to a wash, from a cooling perspective.
 
Hobbes said:
marauder2048 said:
Hobbes said:
Thermal load of a turbine or diesel is much greater than that of an electric motor, yet those are handled routinely. This seems to be a non-issue to me.

The notional configuration being discussed is a smaller gas turbine generator powering electric motors in the hull which in turn drive the sprockets.
The power density of the electric motors that fit in the alloted hull volume and can generate the HP/torque in the mid-to-upper performance
band for an MBT necessitates liquid cooling of the stator windings. And of course the gas turbine generator needs cooling.

That total thermal load is greater than the thermal load of the larger, original gas turbine at the mid-to-upper MBT performance band.

Perhaps. I was thinking along these lines:
A Leo II has a 1500 shp/1100 kW diesel. The heat load from this is on the order of 1100 kW at full power. An 1100 kW electric motor dissipates about 50 kW as heat, add another 50 kW for the generator (95% efficiency) and the heat load is still only 10% of the engine heat output.

I suspect a tank gearbox dissipates a similar amount of heat. So replacing the gearbox with an electric drive should be close to a wash, from a cooling perspective.

It's a power density argument more than aggregate heat load argument.
I don't know of many electric motors in that MBT HP/torque range that have 95%
efficiency at peak torque but as you point out you have to dissipate 50 kW but from a very small volume.

And that electric motor is likely in close communication with an inverter in the 800+ Vdc range which needs
a high power density cooling mechanism as well.

AFAIK, proposals of this kind have used PAO loops or cryogenic coolers but there are more efficient
ways of cooling electric motors in development.

But it's unclear, to me at least, if any of the above solutions can meet the shock loading requirements
that the existing powertrains have to meet.
 
Actually, changing the subject slightly from the Ferdinand/Eliphant to another piece Germanic of air cooled machinery. I am trying to find a way to fix up a ceramic electric heater for my 45 year old VW type 3. Anyone got any suggestions? I am about fed up with a non heat in the winter situation and would appreciate a suggestion or two. The stuff in the internet shops is less effective than me blowing on the windscreen while driving, it only encourages the icicles. Go on, it is, oh hang on give me a minute, I'll get it soon..........
 
The problem is to get enough heat, you need a large amount of power. Electric heaters for home use draw 1 kW or more. A 12V system will have a hard time supplying that much power (you'll draw 85A, which is more than your standard alternator can supply, so you'd have to replace the alternator).
Internet shops generally sell heaters that can be fed from a 12V outlet, so limited to 120W or so, which is not enough.

One thing you could look into: modern VW diesels use a supplementary heater (because it takes a while for the diesel engine to warm up).
This is called a PTC heater, see this DIY installation. Still draws up to 70A so again needs an alternator upgrade.
 
Thanks, gives me something to read into during the Yule season. I hope you guys all have a good one.
 

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