Oh! My God.

[DB]

No.  I think you are missing my point.  Which is that there is something missing in the latest calculations.

 

Yes, I am focusing on penetration capability, that is primary reason for developing a new APFSDS.  Otherwise, we would still be producing the M829 & M829A1 - there would be no M829A2 or M829A3.

 

UK 120mm DU Charm-3 L-27 APFSDS (1998)

UK 120mm L-28 APFSDS (200x) [sorry, I was unable to find any specific info on this round other than it being mentioned in a few places]

 

Yes the DM63 was developed to improve the inconsistancy problems that were found with the DM53 but I am unaware of the M829A2 having similar problems & if it were, a replacement would have likely been fielded long ago (most likely prior to 2000).

225490[/snapback]

 

So, you claim that the main reason for developing a new APFSDS round is to provide better penetration capability (for your defined measure of performance - which appears to the homogeneous RHA perforation with an unspecified propbility of success, and an unspecified behind armour effect, and for undefined engagement geometries), then acknowledge that DM63, the most recently developed round of any discussed in this topic was designed for a reason other than that.

 

On the L28: see here for a cached copy of a tanknet discussion involving it.

 

http://66.102.9.104/search?q=cache:wctj1_U...lient=firefox-a

 

(Hope that works)

 

The key point is that it's apparently a tungsten version of the DU L27. I would suggest that it may not have been developed to provide greater performance, either - concerns over the post-combat effects of DU may be an alternative reason, as could the provision of an alternative to the somewhat difficult DU.

 

I do acknowledge your point that we don't have complete information. That is obvious, but does not require support from extrapolation of performance based solely on the duration of a development project.

 

It's worth bearing in mind that there is a concept called the law of diminishing returns.

 

David

 

Edit: Note, you need to look down as far as Dan Robertson's post, which differentiates between the 120mm L28 and the 105mm L28 - very different beasts.

Edited September 21, 2005 by DB

[Guest pfcem]

Hi Pfcem:

 

Again, these are just estimates.  They are based upon known trends in armor penetration by heavy alloy rod penetrators.  Only time will tell how accurate these estimates turn out to be.  Moreover as additional information on the M829 series becomes declassified than maybe we will be able to say definately “these were good estimates”, or “these were bad estimates”. 

 

But for the sake of discussion, what sort of penetration capabilities do you think would be reasonable for M829A1 through A3. I would be interested to see your take on either Perforation vs. Range or Perforation vs. Remaining Velocity for these three projectiles.

 

Best Regards

Jeff

225505[/snapback]

 

M829

540-560mm @ 2000m

Nearly every source I have seen indicates something within that range.

 

M829A1

600-650mm @ 2000m

I have seen estimates as low as 610mm @ 2000m & as high as 670mm @ 2000m.

Remember that M829A1 has a MV 100m/s lower than the M829 but with a penetrator with a significantly greater L/D ratio.

 

M829A2

700-750mm @ 2000m

I have seen estimates as low as 710mm @ 2000m & as high as 760mm @ 2000m.

I suspect the there is little difference between the M829A1 & M829A2 penetrator (I have seen no evidence to the contrary) but the M829A2 has a MV 100m/s greater.

 

M829A3

800-900mm @ 2000m

I have seen estimates as low as 800mm @ 2000m & as high as 960mm @ 2000m.

This does not include that latest calculations posted here which have the M829A3 as being in the same range as the M829A2. I suspect that the major improvement with the M829A3 over the M829A2 would be at ranges 3000m or more.

 

I think the relationship between the M829A3 & M829A2 is similar the that between the M829A & M829. The M829A3 & M829A1 have a lower MV but a heavier penetrator with a greater L/D ratio than the M829A2 & M829 respectively. Not neccessarily that much of an improvement at <2000m but with a more significant increase in penetration capabilities at 3000m or more.

 

The date of introduction for the M829, M829A1 & M829A2 were all about 5 years apart & they each had a 10-20% increase in penetration capabilities over the previous version. So, with 10+ years between the date of introduction between the M829A3 & the M829A2, there is no reason to believe that is would not have at least a 10-20% increase in penetration capabilities over the M829A2.

[Guest pfcem]

So, you claim that the main reason for developing a new APFSDS round is to provide better penetration capability (for your defined measure of performance - which appears to the homogeneous RHA perforation with an unspecified propbility of success, and an unspecified behind armour effect, and for undefined engagement geometries), then acknowledge that DM63, the most recently developed round of any discussed in this topic was designed for a reason other than that.

225514[/snapback]

 

I already did & stated that there was a reason for it.

 

 

 

On the L28: see here for a cached copy of a tanknet discussion involving it.

 

http://66.102.9.104/search?q=cache:wctj1_U...lient=firefox-a

 

(Hope that works)

 

The key point is that it's apparently a tungsten version of the DU L27. I would suggest that it may not have been developed to provide greater performance, either - concerns over the post-combat effects of DU  may be an alternative reason, as could the provision of an alternative to the somewhat difficult DU.

225514[/snapback]

 

The L28 being a Tungsten round, that makes sense given the current political climate surrounding DU. I hope for their sake that they are able to come closse to matching the L27 penetration capabilities.

 

 

 

I do acknowledge your point that we don't have complete information. That is obvious, but does not require support from extrapolation of performance based solely on the duration of a development project.

225514[/snapback]

 

Thank you.

Why not.

 

 

 

It's worth bearing in mind that there is a concept called the law of diminishing returns.

225514[/snapback]

 

Seems to me that it has been fairly linear so for. I see no reason to think that trend would not continue (if not increase given the accelerating rate of development - paticularly in materials for both the penetrator & the sabot).

Edited September 22, 2005 by pfcem

[Paul Lakowski]

M829

540-560mm @ 2000m

Nearly every source I have seen indicates something within that range.

 

 

 

 

M829A3

800-900mm @ 2000m

I have seen estimates as low as 800mm @ 2000m & as high as 960mm @ 2000m.

This does not include that latest calculations posted here which have the M829A3 as being in the same range as the M829A2. I suspect that the major improvement with the M829A3 over the M829A2 would be at ranges 3000m or more.

 

 

The date of introduction for the M829, M829A1 & M829A2 were all about 5 years apart & they each had a 10-20% increase in penetration capabilities over the previous version. So, with 10+ years between the date of introduction between the M829A3 & the M829A2, there is no reason to believe that is would not have at least a 10-20% increase in penetration capabilities over the M829A2.

225529[/snapback]

 

 

The problem is that those penetration figures were generated by us several years ago on tanknet. They were based on then information from Janes 'suggesting' the A3 sabot was 20% lighter. We summised an approximate 10% increase in MV over the M-829A2 and went from there. But if the basic yard stick [M-829A2] is off then the point of comparison maybe lost.

 

If the 20% reduction in sabot mass didn't go into higher charge to mass ratio and therefore higher MV, then where did it go?

 

It should be noted that ballistic researchers for years have been warning that the constant increase in penetration through higher L/d is governed by the 'law of diminishing returns' and this plateau is thought to be in the 35-40:1 L/d region...which current APFSDS are said to be approaching.

[jwduquette1]

Hi Pfcem

 

Our respective estimates are really not so different.

 

Perforation estimates – mm’s of RHA@0-degrees @ 2000meters

 

Projectile---------Your Estimate--------------My Estimate

---M829------------540 to 560 ---------------------537

---M829A1--------600 to 650 ----------------------651

---M829A2--------700 to 750----------------------710

---M829A3--------800 to 900----------------------770

 

I think an M829A3 estimate of 800mm is reasonable assuming a muzzle velocity of about 1.61Km/s. I’d guess that 900mm is also possible assuming the barrel can handle an operating pressure capable of developing an Mv of ~1.8Km/s. I thought I read some where that the muzzle velocity is being held down to 1.555Km/s to save on barrel ware.

 

Best Regards

Jeff

[Guest pfcem]

The problem is that those penetration figures were generated by us several years ago on tanknet. They were based on then information from Janes 'suggesting' the A3 sabot was 20% lighter. We summised an approximate 10% increase in MV over the M-829A2 and went from there. But if the basic yard stick [M-829A2] is off then the point of comparison maybe lost.

 

If the 20% reduction in sabot mass didn't go into higher charge to mass ratio and therefore higher MV, then where did it go?

 

It should be noted that ballistic researchers for years have been warning that the constant increase in penetration through higher L/d is governed by the 'law of diminishing returns' and this plateau is thought to be in the 35-40:1 L/d region...which current APFSDS are said to be approaching.

225556[/snapback]

 

I wonder if the "suggestion" of a 20% lighter sabot may have actually meant a 20% lighter sabot which would then result in a heavier penetrator if the combination of sabot & penetrator were of of similar weight.

 

The lower MV would indicate an even heavier penetrator.

 

The M829A1 projectile (sabot & penetrator) is quoted as being 9kg [again, I am assuming the M829A2 projectile (sabot & penetrator) is similar to the M829A1] while the M829A3 projectile (sabot & penetrator) is quoted as being 10kg.

 

Like I have already said, the M829A1 achived a roughly 10-20% increase in penetration capability over the M829 by firing a longer/heavier penetrator at a 100m/s lower MV. It is not inconceivable that the M829A3 to M829A2 relationship were not similar.

 

I would not be supprised to discover that the L/d ratio of the M829A3 penetrator was actually quite similar to the M829A2 penetrator but being both longer & greater in diameter.

[Paul Lakowski]

http://www.atk.com/ProductsSolutions/conve...argecaliber.asp

 

According to this site the M-829A3 inflight projectile is 924mm long. Looking at the cutaway the tracer cavity/section looks to be about 1/2 the sabot diameter or around 6cm. Looking at previous sectioned pictures of the M-829A2 shows the distance between the penetrator nose and the tip of the windscreen at about 1.5 times the forward rod diameter or ~ 3cm. If that holds true for the M-829A3 as well that suggest the penetrator length is in the region of 83cm?

[DKTanker]

The data supporting these papers is based upon ¼ and ½ scale rods ballistic trials combined with finite element modeling and a wee-schmattering of full scale ballistic trials.  Personally I find some of this material hard to believe, but there it is.  Academia types have to continuously generate new papers and new research to justify their existence.  I figured if there were some practical examples of this sort of thing happening – ala yours or others observations on the battlefield – then it might be easier to swallow.  Any thoughts or opinions on the subject?

225048[/snapback]

 

One small, but critical error. You are assuming that the gunner of a tank will use the front slope as the aim point even if at an oblique angle. Nope, not going to happen. All gunners of all nations are trained to aim at center mass (usually that is amended to the turret ring). Given that, you have to move the aim point ever more away from the front slope towards the middle of the hull with every increase in obliquiety. So, while the probability of a richochet off the front slope increases with obliquiety, the probability of that being the aim point, and thus struck, decreases.

[Guest pfcem]

Lets assume that the M829A3 penetrator is:

 

800mm long

25mm in diameter

+20% for DU-V

1555m/s MV with a 50m/s/km velocity drop

 

What do you calculate its armor penetration to be?

[jwduquette1]

One small, but critical error.  You are assuming that the gunner of a tank will use the front slope as the aim point even if at an oblique angle.  Nope, not going to happen.  All gunners of all nations are trained to aim at center mass (usually that is amended to the turret ring).  Given that, you have to move the aim point ever more away from the front slope towards the middle of the hull with every increase in obliquiety.  So, while the probability of a richochet off the front slope increases with obliquiety, the probability of that being the aim point, and thus struck, decreases.

225583[/snapback]

 

Hello DkTanker:

 

Interesting observations. Thanks. I think I see what you mean about the shrinking target aspect presented by the glacis as the shot line moves further away from the front of the T72 and more toward the side of the tank.

 

I guess what I was looking at was more mechanical – i.e. interaction between rod and glacis, and weather or not it would seem realistic for M829 or M829A1 to ricochet given the right circumstances of impact velocity and compounded angle. Course the other unknown is the glacis hardness. The harder the plate the greater the likely hood for rebound. If there was the potential for ricochet, then I suppose the next step would have to be looking at potential target aspect presented for a given shot line + probable projectile dispersion for a given range.

 

Regards

JD

[DB]

Why not.

225540[/snapback]

Because extrapolation of historical data into the future without a good theory to support it is an uncertain process at best - if it were easy anyone would be asuccessful investor

 

I am very wary when "forward looking statements" are made, and your looked very like one.

 

Now, can anyone explain what perceived threat was not countered by the M829A2 that is by the M829A3?

 

Your earlier comment about improved long range performance would be a good candidate - desert engagements appear to be relatively long ranged.

 

David

[Paul Lakowski]

Because extrapolation of historical data into the future without a good theory to support it is an uncertain process at best - if it were easy anyone would be  asuccessful investor

 

I am very wary when "forward looking statements" are made, and your looked very like one.

 

Now, can anyone explain what perceived threat was not countered by the M829A2 that is by the M829A3?

 

Your earlier comment about improved long range performance would be a good candidate - desert engagements appear to be relatively long ranged.

 

David

226111[/snapback]

 

 

I wonder if maybe the original idea was indeed for a longer penetrator at 1800m/s MV, but the barrel pressure problems have truncated this rounds potential by limiting MV to 1555m/s [for safty reasons?]. It would not be the first time a projectile had not lived up to its potential, and it won't be the last either .

[jwduquette1]

I wonder if maybe the original idea was indeed for a longer penetrator at 1800m/s MV, but the barrel pressure problems have truncated this rounds potential by limiting MV to 1555m/s [for safty reasons?]. It would not be the first time a projectile had not lived up to its potential, and it won't be the last either .

226156[/snapback]

 

Coincidentally -- or not so coincidentally -- the operating pressures for both M829A1 & M829A2, M829A3 are basically the same. M829A1 is reported as 5698-Bars, and M829A3 is reported as 5660-Bars. Apparently the A2 operates at a slightly lower pressure than A1, but I dont know the exact value.

[jwduquette1]

Hi Paul:

 

Out of curiosity, what is the basis for your use of a 1.13 multiplier for DU in the Anderson L/D effect Equation? I typically see a somewhat lower level of contrast in side by side tests of DU and WHA rods of the same density. I know Anderson’s EQ is based primarily off of WHA rod with densities of between 17.1 to 17.6. Can I assume that your use of 1.13 for DU reflects both a rod density effect multiplier combined with the adiabatic shear banding advantage of DU rods? Moreover the simplified Anderson Equation for L/D effects has no direct input for rod density (or target density and target strength for that matter). Does your 1.13 represent both density and shear band effects rolled into one comprehensive multiplier?

 

Best Regards

Jeff

Edited September 23, 2005 by jwduquette1

[Guest pfcem]

Because extrapolation of historical data into the future without a good theory to support it is an uncertain process at best - if it were easy anyone would be  asuccessful investor

 

I am very wary when "forward looking statements" are made, and your looked very like one.

 

Now, can anyone explain what perceived threat was not countered by the M829A2 that is by the M829A3?

 

Your earlier comment about improved long range performance would be a good candidate - desert engagements appear to be relatively long ranged.

 

David

226111[/snapback]

 

But I am not extrapotating historical data into the future. I am saying that with all the advancements that have been made in both materials & propellants over the last 10 years, that the M829A3 should be notably superior to the M829A2. The latest calculations posted here do not show that. Each new version of the M829 series has had an estimated 10-20% increase in penetration capabilities over the previous. There is no reason to believe that the M829A3 would not continue that tread (possibly even increase it given the greater time variation).

 

If the estimates I have seen are to be believed, then the M829A2 would have a very hard time defeating the T-72BM/T-90/T-84 beyong 2000m.

 

Plus the M829A3 was probably developed to counter the Black Eagle &/or T-95 which should be expected to have increased armor protection over current Russian tanks.

[jwduquette1]

But I am not extrapotating historical data into the future.  I am saying that with all the advancements that have been made in both materials & propellants  over the last 10 years, that the M829A3 should be notably superior to the M829A2.  The latest calculations posted here do not show that.  Each new version of the M829 series has had an estimated 10-20% increase in penetration capabilities over the previous.  There is no reason to believe that the M829A3 would not continue that tread (possibly even increase it given the greater time variation).

226204[/snapback]

 

Hi pfcem:

 

On the other hand, we may very well be seeing a plateau being approached in rod penetration capability. This isn’t really unprecedented. Larger bore AP penetration capability peaked, as did APC. As did HVAP. As did APDS. Why shouldn't we expect to see the same trend in APFSDS? Why should we continue to see these 10 to 20% penetration increases in succeeding generations of long rod penetrators for forever?

 

As you push aspect ratio ever higher you get progressively less efficient penetrators. As you push velocity ever higher and higher you also reach a peak at which gains in rod penetration are minimal.

 

Regards

JD

[Paul Lakowski]

Hi Paul:

 

Out of curiosity, what is the basis for your use of a 1.13 multiplier for DU in the Anderson L/D effect Equation?  I typically see a somewhat lower level of contrast in side by side tests of DU and WHA rods of the same density.  I know Anderson’s EQ is based primarily off of WHA rod with densities of between 17.1 to 17.6.  Can I assume that your use of 1.13 for DU reflects both a rod density effect multiplier combined with the adiabatic shear banding advantage of DU rods?  Moreover the simplified Anderson Equation for L/D effects has no direct input for rod density (or target density and target strength for that matter).  Does your 1.13 represent both density and shear band effects rolled into one comprehensive multiplier?

 

Best Regards

Jeff

226185[/snapback]

 

Hi Jeff.

It came from a Int.J.imapct Engng paper that Ray Woodward wrote back in the 1990s where he compared 1/4 scale and full scale WHA & DU penetrators.I will see if I can find a pdf file on it.

[Guest pfcem]

On the other hand, we may very well be seeing a plateau being approached in rod penetration capability.  This isn’t really unprecedented.  Larger bore AP penetration capability peaked, as did APC.  As did HVAP.  As did APDS.  Why shouldn't we expect to see the same trend in APFSDS?  Why should we continue to see these 10 to 20% penetration increases in succeeding generations of long rod penetrators for forever? 

226343[/snapback]

I agree that we may be approaching a plateau in penetrator performance but I do not believe that it was reached with the M829A2 (the M829A3 may be getting pretty close though).

 

I believe there are three areas where APFSDS can be improved.

 

1) the material makup of the penetrator

2) the material makup of the sabot (a lighter sabot would allow for a heavier & stronger penetrator without changing the overall weight of the total projectile)

3) propellant

 

The M829A3 obviously has made improvements in all three.

 

 

 

As you push aspect ratio ever higher you get progressively less efficient penetrators. 

226343[/snapback]

Since the M829A3 penetrator appears to be of greater diameter than the M829A2 penetrator as well as longer, its L/D ratio may not be that significantly different.

 

We are obviously not going to likely see penetrators get much longer than the M829A3 but they may start to get larger in diameter.

 

I am thinking it would be nice to see penetrator that was 20mm in diameter at the front & rear (maybe 25mm at the rear) tapering to 30mm for half its length in the middle with a 25mm lightweight "windscreen".

 

As you push velocity ever higher and higher you also reach a peak at which gains in rod penetration are minimal.

226343[/snapback]

The M829A3 is slower than the M829A2 & that seems bo be a problem for many but I point out again that the M829A1 is 100m/s slower than the M829 & everyone agrees that it has a 10-20% increase in penetration capability. So why not the M829A3?

[TRYTRY]

How about M829A3 vs DM53? Which is the best one?

Edited October 16, 2005 by TRYTRY

[Guest pfcem]

How about M829A3 vs DM53? Which is the best one?

235560[/snapback]

What do you mean by "best"?

 

The esitmated penetration performance of the DM53 (when fired from a L44 gun) is slightly lower than that of the M829A2. Germany has developed the DM63 which is not believed to improve the penetration performance of the DM53 but was developed because of some inconstancys in the performance of the DM53.

 

I have noticed that the esitmated penetration performance of the DM53 (when fired from a L44 gun) has increased from 650mm@2000m to 730mm@200m during the last 6 months or so. Anyone know where the increase comes form & why the L55 performance was not increases as well? The new figures indicate that the L55 does not really add much to the penetration performance of the DM53 (only ~80mm@2000m).

 

The estimated penetration performance of the DM53 (when fired from a L55 gun) is lower than what has been theorized for the M829A3 (when fired from a L44 gun).

 

More recent calculations made in this thread tend to indicate that there is very little (if any) increase in penetration performance from the M829A2 to the M829A3. Although I think it is fair to say that we do not yet know enough about the M829A3 to say that these calculation are indeed correct. All we do have is an "official" MV of 1555m/s & a cut-away photo (that may or may not be accurate) that shows the M829A3 penetrator to be notably longer than the M829A2 penetrator & possibly of slightly larger diameter. That & that the M829A3 should benefit from ~10 years of technilogical advancement in several areas that could be applied to APFSDS.

 

Of coarse since the US rounds use DU, they may not even be an option for many.

Edited October 16, 2005 by pfcem

[Paul Lakowski]

There was a time when 80mm increase was consider good.

 

What we have been trying to point out resently is that most ballistics studies show that as L/D and V increase the relative increase in penetration falls of as the values move asymetoicaly [sp] towards some limit ...usually hydrodynamic limit. Alot of the significant increases of the last 20 years have been when these inceases are coupled with improved materials like DU ; high strength alloys etc . As far as I can see from the research they are running out of options . This may explain the increased pressure to produce ET guns and even EM guns in the future.

[DKTanker]

Of coarse since the US rounds use DU, they may not even be an option for many.

235658[/snapback]

 

Point of order. That the rounds use DU hasn't reduced options for any. There may be those that refuse to use DU, but the option remains.

[Guest pfcem]

Point of order.  That the rounds use DU hasn't reduced options for any.  There may be those that refuse to use DU, but the option remains.

236128[/snapback]

Picky Picky Picky

 

I will try again.

 

The US rounds use DU & there are a number on nations (for whatever reasons) refuse to use DU at this point so they would not consider the US rounds as a viable option. Their opinion of DU may change at some point (like in wartime for example) & could then conceiveble use the US rounds.

[jwduquette1]

How about M829A3 vs DM53? Which is the best one?

235560[/snapback]

 

Hi TRYTRY

 

I'd estimate that @ 2000m @ 0-degrees the M829A3 will out penetrate DM53 LKEII by about 20% to 25%.

 

Regards

JD

[Guest pfcem]

Hi TRYTRY

 

I'd estimate that @ 2000m @ 0-degrees the M829A3 will out penetrate DM53 LKEII by about 20% to 25%.

 

Regards

JD

236157[/snapback]

So with the latest estimate for the DM53 being 730mm@2000m, that would put you estimate for the M829A3 at 876-913mm@2000m. Or is your 20-25% based on the previous 650mm@2000m for the DM53, making your estimate for the M829A3 at 780-813mm@2000m.