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electromagnetic-suspension-system-20-638

To summarize, it appears the be similar to hydropuematic suspension, but is claimed to use one fourth of the power (take with a grain of salt). It is also said to have a longer lifespan than the average suspension.

In the case of power shortage or loss of power, the suspension acts as a normal suspension, although probably very poorly.

 

It can be used as a active suspension, and does not appear to take away internal volume. So does this mean that it is directly better than hydropuematic suspension? And as a last note, it can generate electricity through vibration and movement in the suspension. 

 

I like innovating new ideas but, there has the be a mayor drawback with this system.

 

 

Taking a second look at this.  I think what they mean is that an electromagnetic active suspension system would require less energy than an active hydropneumatic one.  That makes sense; electrical motors are more efficient than hydraulic ones.  They're also heavier, so I suspect that would be one of the trade-offs.

 

I don't know that there's been much research done in active suspensions lately though.

 

And yes, you could use the system to generate electricity, but this isn't necessarily a good idea.  The vibration is coming from the movement of the tank, so if you start generating too much electricity with the suspension you're essentially robbing the engine of power.  Regenerative use of vibration energy would be nifty

 

The system as drawn appears to have all the electromagnetic hardware in the suspension struts themselves.  That would raise the unsprung mass, which is not good for ride quality.  I'm sure you could design it differently and sidestep that problem; most other suspensions do.

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And yes, you could use the system to generate electricity, but this isn't necessarily a good idea.  The vibration is coming from the movement of the tank, so if you start generating too much electricity with the suspension you're essentially robbing the engine of power.  Regenerative use of vibration energy would be nifty

 

Are you saying that the suspension takes away energy from the engine, or are you talking about overcharging the system? 

 

The excess power from the suspension would turn into heat in the batteries and transformers.  This can simply be fixed with a heat sink. 

 

To avoid the suspension robbing power from the engine you simply have them at separate circuits. And in the case low battery power, you can simply prioritize the engine.   

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When a tank is moving over uneven ground it will tend to start oscillating, how much and what frequency being a function of the suspension's natural frequency and how high the tank's center of gravity is.  The energy for this oscillation comes from the forward speed of the tank.  If you damp out these oscillations, you're robbing energy from the tank.  So tank suspensions with higher damping coefficients have less pitching oscillation, but they have effectively higher rolling resistance.  Walter found an article from some time ago that mentions this effect.  Look on page 4.

 

So, you could damp out oscillations in the tank with an electrical suspension and turn them into electricity, but the energy is ultimately coming from the tank's engine.  So if you're feeding that energy back to the engine, you're just losing energy from conversion losses.  With a suspension that can be actively controlled, it makes more sense to prevent the oscillations from ever happening rather than trying to harvest them.

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  • 2 weeks later...
  • 1 month later...

With the introduction of unmanned turrets on MBTs I have been wondering:

 

 

What protection levels do a unmanned turret need?

 

Do we give  them them the same protection as ordinary turrets? Do we just make them Auto cannon proof from the front and from handheld AT weapons?

 

ops, quoted someone xD

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All this talk about fuel has got me thinking; If battery technology continues to improve and a purely electric-powered tank were to be designed, how might protection be affected when the tank has to contain numerous battery packs (which may or may not have a flammable electrolyte) rather than fuel tanks? 

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All this talk about fuel has got me thinking; If battery technology continues to improve and a purely electric-powered tank were to be designed, how might protection be affected when the tank has to contain numerous battery packs (which may or may not have a flammable electrolyte) rather than fuel tanks? 

Batteries would have to be divided into cells that are all parallel coupled. Right now, the only viable battery is lithium battery. They are highly volatile when damaged, and a chain reaction of these could cause mayor damage. They would have to be armored and isolated from the crew. When it comes to protection i highly doubt they would provide much, maybe except some because of the explosion caused by the lithium. 

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All this talk about fuel has got me thinking; If battery technology continues to improve and a purely electric-powered tank were to be designed, how might protection be affected when the tank has to contain numerous battery packs (which may or may not have a flammable electrolyte) rather than fuel tanks? 

 

The technology would have to improve rather a lot compared to the current state of things.  The very best lithium-ion batteries are still about 1/15 the volumetric energy density of diesel.  Electric motors are about two to three times more efficient than diesel motors, so the actual amount of energy carried on board for the motors could be less.  Electrical motors would also allow simpler transmissions, so that might save some space too.  But even accounting for those savings I would think you would need something like a fourfold increase in the energy density of batteries in order to have something workable for tanks.

 

And at that point I'm not convinced that the chemistry of the cells would be particularly similar to what exists now, so it's hard to make predictions.

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   Isn't higher efficiency of electric motors and energy density of diesel a main reason why AFV designers are still trying to put diesel engines/electric motors combo in their vehicles insiead of just going full electrical battaries? For me such system is viable future design/tech.

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   Isn't higher efficiency of electric motors and energy density of diesel a main reason why AFV designers are still trying to put diesel engines/electric motors combo in their vehicles insiead of just going full electrical battaries? For me such system is viable future design/tech.

 

It may be the reason now.  But in the past, the conversion losses from running a diesel engine to turn a generator to make electricity to run an electrical motor that went to the final drives was less efficient than running a diesel engine to a mechanical transmission to the final drives.  It's only been in recent years that generator and electrical motor efficiency has improved enough that using them both in series is comparable to, or maybe even a little better than mechanical and hydromechanical transmissions.

 

Biggest advantage of the electrical transmission is probably the elimination of the mechanical transmission, which as we know has a nasty habit of breaking down in the middle of Ukraine in 1944 during a full-scale retreat.  Electrical transmissions also make more complex steering systems to implement in tracked vehicles.  Purely mechanical systems that deliver constant power to the tracks, have regenerative, multi-radius steering, and neutral steering are... a little complicated:

 

chieftaingearbox_zps0c25340d.jpg

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It may be the reason now.  But in the past, the conversion losses from running a diesel engine to turn a generator to make electricity to run an electrical motor that went to the final drives was less efficient than running a diesel engine to a mechanical transmission to the final drives.  It's only been in recent years that generator and electrical motor efficiency has improved enough that using them both in series is comparable to, or maybe even a little better than mechanical and hydromechanical transmissions.

 

Biggest advantage of the electrical transmission is probably the elimination of the mechanical transmission, which as we know has a nasty habit of breaking down in the middle of Ukraine in 1944 during a full-scale retreat.  Electrical transmissions also make more complex steering systems to implement in tracked vehicles.  Purely mechanical systems that deliver constant power to the tracks, have regenerative, multi-radius steering, and neutral steering are... a little complicated:

 

chieftaingearbox_zps0c25340d.jpg

Electrical drive systems also make a lot of sense in wheeled death traps, as the inevitable shafts running all over the shop to drive the wheels tend to take up a lot of internal room on the hull.

 

Going wheeled and electric also allows you to potentially run wheels in reverse and thus eliminate some of the complexity of the suspension units by removing the steering system.

 

The major problem with electric drives is, was and ever shall be that they gobble up strategic resources (copper and, lately, rare earth elements), while a conventional drive system just needs steel. So they represent something of a luxury good in a total war situation.

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With the introduction of unmanned turrets on MBTs I have been wondering:

 

 

What protection levels do a unmanned turret need?

 

Do we give  them them the same protection as ordinary turrets? Do we just make them Auto cannon proof from the front and from handheld AT weapons?

 

ops, quoted someone xD

 

The unmanned turret on the T-14 for example, features light and thin armor capable of withstanding autocannon fire at best, but it does come equipped with an APS.

I can't say the APS design is ideal. It lacks in many cases, but it will provide the necessary protection against a few KEPs. 

 

On the other hand, an unmanned turret in which every component is tightly placed and with thin armor, is more likely to suffer a catastrophic kill than a "normal" tank unless the ammo rack can be completely sealed after reloading. 

And the damage will be more extensive, always resulting in a mission kill. 

 

Overall it's a more survivable and lighter design, but it is vulnerable to counter-APS solutions. Personally I think the T-14 should have had more armor on the turret. After all, an unmanned turret has a lot less surface to protect.

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Electrical drive systems also make a lot of sense in wheeled death traps, as the inevitable shafts running all over the shop to drive the wheels tend to take up a lot of internal room on the hull.

 

Going wheeled and electric also allows you to potentially run wheels in reverse and thus eliminate some of the complexity of the suspension units by removing the steering system.

 

The major problem with electric drives is, was and ever shall be that they gobble up strategic resources (copper and, lately, rare earth elements), while a conventional drive system just needs steel. So they represent something of a luxury good in a total war situation.

 

 

Another advantage, implied in one of the articles Walter posted a while back, is that electrical and hydraulic transmissions have a lower moment of inertia, which means that they take less time to spin up.  This should give an advantage during initial acceleration.  This would help reduce exposure time while moving to the next bit of cover, and might even be useful in dodging older ATGMs.

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  • 2 weeks later...

I have been recently reading about IFV and APC designs and one thing has always confused me:

Why do so many APCs and IFVs have such tall benches for the crew to sit on?

M113_Interior.jpg

P4114672.jpg

Marder_Mannschaftsabteil.JPG

US_Army_53413_Range_Training_in_India_fi

 

While IFVs like the CV90 does not, which saves a ton of space and makes the vehicle much smaller. (Excluding the newer models which have a 140mm raised troop compartment for seats that protect against landmines and IEDs).

 

While it is true that the the CV90 crew compartment is very small, it still can hold 8 soldiers without any problems for long rides. As for crew ergonomics, I spoke with a CV9030NO gunner. He told me the tank was very spacious and they could easily store their belongings and food. He loved it.

 

And another thing i find weird is the large rear ramp. Swedish testing found a double door to be the best option for a quick dismount. Of course with a very thick rear door, a rear ramp would be the best.

 

Personally I have sat in a M113. It was very spacious, but a little short, my head hit the ceiling which made me sit in very uncomfortable pose, I am of average height so this goes for everyone. There was a lot of space behind the seats to store belongings and such on the right side, on the left side there appeared to be a fuel tank, which i found weird.  I did not like the benches at all, simply because they were too tall, if the benches had been shorter or removed I could sit straight with my legs stretched.  As for width, I can't imagine it being more spacious than any other APC. Shoulder to shoulder as always. 

 

And for comparison, here is the CV90 troop compartment: 

1200038149.jpg

IMG_5399.jpgft-editorial-cv90-lease-purchase-2-.jpgHere is a small one with only one person. And yes, I am aware of the bench like seats, but I am unsure if I would qualify them as benches.

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I'm not terribly sure I understand you completely, but I think I get the gist of it. Anyway, I think the CV90 benches are spring loaded to dampen any sudden movement (due to explosions). This means that the passengers will suffer less from a sudden acceleration, but that also mean they need less room to decelerate. In vehicles with static benches the passenger upward velocity is the same as the vehicle hull upward velocity. Ergo, you need more space to slow down the passengers, since they're not wearing seatbelts or anything.

 

As you might know, this is important because the dangerous bit about IEDs isn't a hull breach or something, but rather the sudden acceleration/deceleration of the crew/passengers.

 

I know for certain that the driver position is dampened, fairly sure about the other two crew positions and I think the passenger comparment has something similar, but I didn't take photos of that when I was inside one.

 

Here's a photo from the driver seat:

2FR5LOQ.jpg

 

The driver's 'seat' (more like hammock) is suspended by those two red bands (there are two at the rear as well). The things the bands connect to should allow for a bit of slip in case of a sudden upwards acceleration.

 

And yes, the CV90 crew positions are fairly spacious, plenty of room to store bottles and boxes. Especially the driver has a fair amount of room behind him.

Here are some more photos of CV90 crew positions: http://sturgeonshouse.ipbhost.com/index.php?/topic/11-stug-iii-thread-and-also-other-german-vehicles-i-guess/?p=72613

(Yes, they're in the German thread, no I don't have the power to move those three posts.)

 

Also note how the commander and gunner have almost the exact same controls. I seriously had to look for clues on what the commander position was. Found it because the network selector for the commander has a few extra buttons and switches compared to the gunner.

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Also note how the commander and gunner have almost the exact same controls. I seriously had to look for clues on what the commander position was. Found it because the network selector for the commander has a few extra buttons and switches compared to the gunner.

 

 

There's been a move towards redundant controls at all crew positions in the turret.  In the Merkava IV, IIRC, the loader can locate and service targets if necessary.

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Not when you find that by the time battle started, roughly half of the ammunition has been discarded and replaced with beer.

 

It would impair the efficiency of that particular tank, sure, but from a combined arms standpoint it would be a major force multiplier.  Especially when you consider how much beer you could cram in an Abrams' bustle.

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It would impair the efficiency of that particular tank, sure, but from a combined arms standpoint it would be a major force multiplier.  Especially when you consider how much beer you could cram in an Abrams' bustle.

Need a positioned captured?  Drive the beer Abrams into a key position, then let the crunchies know that there is beer to be had if they just go protect that tank...

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