Paul Lakowski

Just a note about spaced plated armor[ from memory]. Research in the 70s showed that if the spacing between plate and main armor is large [ IE > 15 times the spaced plate thickness] The resistance Vs APFSDS and APDS AP is 10-20% more than the solid thickness figure, provided the striking velocity is > 1300m/s for APFSDS, > 1100m APDS & AP type shot . This research also suggest that the resistance of these two targets is identical at the following striking velocities APFSDS 700-1100m/s APDS 800-1000m/s AP 900-1000m/s When I get home I'll review the paper in question and update the above figures. Also what about Decapping plates. The spaced armor on the front of the Pz-III was designed to Decap APCBC ammo. I gather from test it was very good at this and even 'predetonated' the bursting charge in APHE ammo.

Composites are a smart choice for armor vehicle design due to there light weight and high strength [ as high as steel in some cases]. As far as armor goes the following generalities apply A range of composites tested against 12.7 AP shot showed a resistance of 17-20% of RHA regardless of if it was Sglass [ Fiberglas 2.6 g/cc] or Dyneema [ 0.9 g/cc] with even rubber offering 17% resistance. As you move to higher striking velocities the . Thickness effectiveness reaches 25-35% , while the HEAT resistance may well be 45-70%. Once you have a light weight structure , which BTW accounts for 1/4 the AFV weight, then you can add ceramics and steel plates or NERA appliqués etc. A resent test showed a Sglass- ceramic - poly type target offered about 1.5 times the resistance as the same mass of steel, so this stuff is not to be dismissed so lightly For the same level of protection these test beds have been shown to offer a 25-30% weight saving ,based on a heavier Sglass -aluminum - TiD frame/armor . If this was Dyneema with SiC based it might offer 40-50% saving. Heres some estimate figures I generated for Steel Beasts Upgrade modual , for the externally mounted gun thats on the LAV-III 105 mm which could just as easly be mounted on such a AFV as a plastic tank. The assualt gun version of the LAV-III features the Teledyne externally mounted 105mm gun in soft recoil mount turret carrying 30-45 rounds ROF 10-12 RPM ;firing M-900E2 round ?The front 'gun pod' armor cavity is 60cm thick and this does offer considerable potential The dimensions of the main gun mount are 0.5 x 0.6m and its length is about 3/4 of the LEO-1A3 turret [comparing silhouettes ]I make that about 0.75 m³ [volume], but theres also the 'trunk' that the 'gun pod' pivots on, thats about 0.5 x 1.5 x 0.6 = 0.46 m³ so combined thats about 1.2m³ [Volume] . The 1.2m³ turret volume compares to 4.2m³ for the LEO-1A3; means 0.287 of the volume or 1900kg /1.2m³ = 1583 Kg/m³ , compared to 2380kg/m³ for the LEO-1A3 or or 2/3 of the armor mass, thats.. <PRE> front side rear LEO-1A3 23.5cm 7cm 4cm Teledyne 15.6cm 4.7cm 2.7cm cavity 60cm 15cm 6cm density 2.04g/cm³ 2.46g/cm³ 3.55g/cm³ </PRE> Rear could be Aluminum and Alumina , but the rest looks like aluminum and some light weight material. A more likely possibility is that only the front and side of the actual 'gun pod' are armored heavily making the armor more like the following <PRE> Teledyne Front gun pod 23 cm steel in a 60cm cavity 3g/cm³ Front trunk 8.2 cm steel [ 3g/cm³ = 21cm cavity] Side gun pod 6.0 cm steel 15cm thickness = 3.14 g/cm³ Side trunk 3.4 cm steel [9cm thickness = 3 g/cm³] Rear gun pod 2.7cm steel [6cm thickness = 3.5g/cm³] Rear Trunk 2.7cm steel [6cm thickness = 3.5g/cm³] </PRE> So the armor looks like Aluminum Alumina combinations with Dyneema to boost the ceramic density .The armor could be 1 part Al-2024 [.5/0.8] + 1 part Dyneema [0.35/0.5] + 3 parts SiC [1.1/1.83]÷ 5 = 0.83 KE x 60cm= 50cm KE. The HEAT armor should be 0.8 + 0.5 + 3 x1.83 ÷5= 1.36 or 82cm HEAT. These figures might change as the free edge is hard to assess, It looks like there isn't any?? The layering of plates increases HEAT resistance 1.2 times bring this value up to ~100cm HEAT.Theres also the possibility of adding D-Tech type armor to the 'gun pod' and various vulnerable sections of the AGS turret as a whole. Going with this the Teledyne AGS armorcould look like .... "TURRET " [ 5cm Al-2024 45cm < Spectra & SiC > +7cm Al-2024] x 0.83/ 1.36 <PRE> FRONT SIDE REAR gun pod 50cmKE 98cm HEAT 12cm KE 24cm HEAT 5cm KE 10cm HEAT trunk 17cmKE 34cm HEAT 7cm KE 15cm HEAT 5cm KE 10cm HEAT </PRE> For a Assault gun version the front turret should be raised to 25mm @ 70° D-Tech armor and the whole armor reinforced with Kevlar or Dyneema /Spectra shield plus Ti bulging plates. 47mm KE & 200mm HEAT x angle or 70° 'front gun pod' and 60° 'side gune pod' with 45° 'front trunk', and the rest verical plates. This should add atleast 500 kg to the turret weight. "TURRET " <PRE> FRONT SIDE REAR gun pod 64cmKE 160cm HEAT 21cm KE 64cm HEAT 10cm KE 30cm HEAT trunk 23cmKE 62cm HEAT 11cm KE 35cm HEAT 10cm KE 30cm HEAT </PRE> [This message has been edited by Paul Lakowski (edited 01-30-2001).]

How do you use 'LongBow Apache' if the radar can't lockon? There was talk of the same radar on M-1 at one point and I gather russian helos use radar to.

Right after Moscow 1941 they produced about 600 Marders with the 76L51 gun, but no such gun existed in the Russian inventory they had 76L41 [ 1.5 ton field gun] and 76L56 [3 ton AAA].Any one know for sure which gun was used . Lt Gen Heinz -Georglemm [ 12th Inf Div ,II corps ;Intial Period of War on the Eastern Front; D Glantz pp229 "When the lack of penetrating power of the small German AntiTank guns became clear,hundreds of captured 7.62cm guns were sucessfully employed as antitank guns following minor technical modifications." If this was so easy why didn't they convert the lot and just boost the 75mm ammo production at the expence of the 'increasingly usless 50L60 Pak 38? In addition theres a reference somewhere that another 600 76s were converted to Pak 36 or 39s. My estimates put the number of 76s in storage ware houses occupied within the first weeks of Barbarossa at 4000 guns plus some thing like 3 million rounds of ammo....I conclude the following from When Titans Clash.Heres some more estimates based on warehouse strenght. ~ 4000 x 76mm field guns with 2.5 to 3 million rounds of ammo [ ~4 months based on german 'fall 1941'arty consumption] ~1000 x 122mm Field Guns with 2 million rounds of ammo[ ~10months supply based on german 'fall 1941'arty consumption] ~1200x152mm Field Guns with ~1.7million rounds of ammo[~8 months supply based on german 'fall 1941'arty consumption] ~2000 x 82mm Mortors with ~ 4 million rounds of ammo [~8 months supply based on german 'fall 1941'arty consumption] ~ 500 x 120mm Mortors with ~ 2.3 million rounds of ammo[~18 months supply based on german 'fall 1941'arty consumption] ~ 600 x 76mm AAA with ~ 0.6 million rounds of ammo [~6 months supply based on german 'fall 1941'arty consumption] Given the appalling penetration of German AT guns until the PAK 40 came along in sufficent numbers in 43 and 44. Not exploiting such assets as these 76s and converting them all to to fire 75mm ammo is down right criminal.

WOW , can you tell us where on the T-72 you hit and at what range? BTW as to the hull down question , the externally mounted gun presents a 0.5m^2 target while hull down and the Bradley is probably at least 1.0 m^2 target. I gather that makes a big difference in hitting at range.

No thats not what I'm after, I have an erosion based penetration formula thats needs info like projectile lenght and diameter not things like basting charge size. Are there any other sectioned diagrams for 75L48 , 75L 70 and 88L71 ammo with some measurement figure?

Markus you know full well the 120mm L55 is to face future threats expected to come from front line Russian 152mm externally mounted gun tank which may well have 90-100cm of frontal KE protection.

My understanding was that the rational for choosing LAV was to get an 'off the shelve' model in wide spread use to keep costs down so that the money could be spent on the FCS . I've heard of the 'tupperware tank' in the British Press, is this the same FCS you refer to?

Actually the reduced density probably won't make that much difference. In the change from BR-350A to BR-350B the filler charge goes from 0.06 Kg to 0.15kg and this only results in a 5mm increase in penetration . However the projectile is 234mm long [bR-350B] compared to 221mm for the BR-350A. This increase in length is the primary reason for increased penetration. Lewis show me a drawing cause thats all that matters right now!

Don't play games with me! What are the REAL differences. A small difference in the blasting charge probably won't change any thing the real issue is .... the size and shape of the penetrator as this is what does the penetrating.Blasting charges are for after penetration effect. Does any one have cut away drawings of the 75L24 Pz rot round?

The Bradleys are alread accounted for in the Heavy brigades. It would make more sence to recondition them for some role in the heavy brigades . Perhaps in there dreams but not in the real world. Which ones? where? About 1 to 1.2 meters is about the best penetration your going to get out of a heavy 6 inch warhead today and 0.8 meters out of a 4 inch warhead. That will probably end being as well protected as the Bradleys but not 15 years old. You should understand this much by now, the purchase of weapons only accounts for 10% of defence budgets, while maintinance is easly 1/3 of the cost...and wages account for something like 50%[ I think R& D is the rest]

I've seen pics of these rounds and the penetrators look the same. I always assume the K Gr rot Pz was APC , as opposed to the PzGr 39 , which is APCBC. I don't see the difference other than a bursting charge comp.

One of the on going problems on tring to predicte armor penetration is to asses the impact of hard plates as armor. Its clear that harder armor produces less penetration but its also clear that there are other issues at work. For one fracture toughness is important as is steel yield strenght. In fact from the 70s on the reference to the relation of the projectile hardness and the target hardness has been replace by the relation of the Yield strenghts of the projectiles and plates. Does any one know what the yield strength of Face hardened armor was? In addition modern armor calcutations assume layers of armor with differing qualities [ IE hardness etc], can be assess from a linar approach. So if Face hardened thickness is universally 5mm in depth and offers 1.8 times the resistance of RHA then a plate 20mm thick should offer..... 1 x 1.8 + 3 x 1.0÷ 4 = 1.2 times the resistance compared to RHA. If the plate were 80mm thick, the approximation should be; 1.8 + 15 ÷16= 1.05 times the RHA resistance.

I'll look more into guns and ammo later, Can any one tell me the survival rate of AT guns on the eastern front in 1941/1942? Also how many Russian artillery pieces did the Germans capture in 1941?

Maintenance is a biggy and I've heard that LAV maintenance is a fraction of that of a similar tracked AFV, maybe even 1/10th the cost. In these cost concise times this is important.

Stoffel; It keeps sending me to a perilpoint home page. Whats the route to the discussion group?

Firstly the original Bradley weight 22.5 tons but the A2/3 version with all the add on armor is ~ 30 tons. The Bradley A0 armor is poor offering all kinds of weak spots where HMG ammo can penetrate at ~ 1km LAV III is vunerable ~ 1km or more to HMG, however the addon 'Mexas expandable armor' package features NERA plates over most of the vehicle that should offer immunity to 12.5 API & most 14.5 API hits , while the HEAT protection may well be at the RPG-7V level [ especially if this is an angled hit]. Its possible some RPG-7V side hits might get through. In the future this kind of armor will get better. As to 105mm APFSDS penetration it would have great difficulty getting through K-5 equipped late model T-72Bs etc but since this armor only covers about 1/2 the target profile penetration is still possible at range. Finally ICB is to replace light infantry DIv not M-1/M-2 Div. Personally when I saw the French 6th Light armor divison in the late 80s I just figured every one would have one by the end of the century,just made sence ....Guess I was wrong about that one too [This message has been edited by Paul Lakowski (edited 01-26-2001).]

Hi guys , I was wondering if any one had info on the consumption and production of WW-II german AT gun ammo? I have info on arty that suggests that in mid 1941 they had ~ 3500-3600 rounds per gun [ FH-105] and the consuption was ~ 18O rounds per gun per month. While production was about 1/3 to 1/4 of this figure. I'm looking for similar info on AT guns or any snips.

I haven't belly laughed like this in ages, thanks guys

One principle reason American ammo did so poorly in WW-II had nothing to do with metalurgy but every thing to do with buraucracy. They never actually tested against slanted armor . Instead they fired at vertical plates and just assumed the geometrical LOS would tell them how much it would be @ 60°. Thats to say if it penetrated 100mm @ 0° it should penetrate 50mm @ 60°, right? Well had they tested they'd have found out that for there sharply pointed rounds vertical penetration of 100mm @ 0° would translate into 40mm @ 60°[ 80mm LOS] or even worse 53mm @ 45°[76mm] ...looks like the german idea of leaving sloped glacis at 45-55° made a lot more sence than the Russian idea of 60°! And if you think thats bad you should see the HVAP figures!

Just got a great package in the mail from Jeff 'TM9-1907' covering amoungst other things air & ground burst patterns for various Allied [ USA] shells. I had no idea they were that varied. Some are star shaped but most are a long thing side lob type pattern. Only airburst have anything approaching a ellipical pattern. These mostly come in a low angles 10-30°. If any one has seen this type of data , was it compareable for Germans Russian and British HE ammo?

1951 WO 291/1143, "Effectiveness of British and Russian tanks." Penetration in millimetres, ranges in yards: <PRE> Weapon Range 0º 30º 0.866 60º 0.5 77mm APCBC 600 145 115 ^ 1.6 52 ^ 1.47 1000 136 108 ^ 1.5 48 ^ 1.5 1500 124 100 ^ 1.5 45 ^ 1.48 17 pdr APCBC 600 172 136 ^ 1.6 62 ^ 1.46 1000 162 128 ^ 1.6 58 ^ 1.45 1500 150 119 ^ 1.6 55 ^ 1.45 17 pdr APDS 600 248 200 ^ 1.5 70 ^ 1.8 1000 232 188 ^ 1.4 65 ^ 1.8 1500 213 172 ^ 1.4 60 ^ 1.8 85mm APCBC 600 137 110 ^ 1.5 49 ^ 1.5 1000 128 103 ^ 1.5 46 ^ 1.48 1500 118 95 ^ 1.5 43 ^ 1.46 {from Russian 600 110 88 ^ 1.55 39 ^ 1.5 range tables) 1500 96 76 ^ 1.6 35 ^ 1.48 Weapon Range 0º 30º 0.866 60º 0.5 20 pdr APDS Mk 1 600 300 240 ^ 1.55 80 ^ 1.9 1000 280 225 ^ 1.5 75 ^ 1.9 1500 260 210 ^ 1.5 67 ^ 1.95 122mm APCBC 600 203 162 ^ 1.55 74 ^ 1.5 1000 193 153 ^ 1.6 70 ^ 1.47 1500 182 145 ^ 1.47 66 ^ 1.47 (from Russian 600 149 118 ^ 1.6 53 ^ 1.5 range tables) 1500 130 104 ^ 1.55 47 ^ 1.47 @ 30° @ 45° @ 60° 90mm APC 700- 750m/s 0.866 ^1.45 0.707 ^ 1.75 0.5 ^ 1.34 90mm HVAP 1000m/s 0.866 ^ 1.7 0.707 ^ 2.2 0.5 ^ 2.4 By comparison modern 90mm & 105mm ammo is ...... Angle & COS 10° 0.98 30° 0.866 45° 0.707 60° 0.5 AP 0.95 ^ 2 0.77 ^ 1.8 0.56 ^ 1.6 0.4 ^ 1.3 HVAP 0.97 ^ 1.5 0.8 ^ 1.5 0.54 ^ 1.75 0.37 ^ 1.43 APDS 0.98 ^ 1.0 0.806 ^ 1.5 0.61 ^ 1.4 0.47 ^ 1.1 HEAT 0.98 ^ 1.0 0.877 ^ 0.9 0.73 ^ 0.9 0.51 ^ 0.95 </PRE> [This message has been edited by Paul Lakowski (edited 01-23-2001).]

Its also evident from the data that the amount the projectile turns changes with range , probably due to the arc of the projectile. I'm currently looking at a paper that shows different results for sloped impact from shot to shot suggesting that the spinning of the projectile plays a role but in some cases the projectile shattered at 45° in other cases it didn't and these are Tungsten Alloy Vs aluminum [ classic 'elastic plastic' projectile plate interaction]. My believe is that nose shape plays a role in this slanted impact/shatter situation. Heres some data for steel AP with tungsten carbide core vs slant RHA. 3.6:1 L/d steel 590BHN ogive 4.6 CRH with a Tungsten core @ 600-1500m/s Vs 255-295BHN plate @increasing angle , results = P/L value..... Int.J.Impact Engng Vol-22,pp 100-381 ;[pp172] <PRE> 0° 20° 30° 1.36 1500m/s 1.0 0-.95 0.91 1400m/s 1.54 1.1 0.91 0.82 1.66 1300m/s 1.45 1.11 0.77 0.73 1.64 1200m/s 1.27 1.06 0.73 0.64 1.55 1100m/s 1.18 1.07 0.91 0.54 1.58 1000m/s 1.04 1.04 0.79 0.5 1.52 900m/s 0.95 1.05 0.73 0.59 1.53 800m/s 0.82 1.03 0.59 0.41 1.52 700m/s 0.68 0. 97 0.45 0.32 1.43 600m/s 0.54 0.9 0.36 0.18 1.32 </PRE> The peak values [ highlighted] are the shatter zone or transitional velocity.The 24.4 caliber HVAP shot is ~ 6.2 mm diameter and.22mm long. Result is in P/L values.At vertical the P/L of WC-St = 1.21 xV - In of L/d x 0.15 x sharpness = [This message has been edited by Paul Lakowski (edited 01-22-2001).]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Iron Duke: Damn California and its power crisis!!! I haven't been able to use my PC all weekend (and part of last week) and look how much I miss out! <HR></BLOCKQUOTE> Yes well if you just pay us the money that you owe it wouldn't be cut off all the time Some one asked about BELL CURVE. It means a distribution of results around a statistical average. So theres no such thing as a single penetration Vs plate X at a given range. If you take 10 shots you'll get 10 different results , if you take the average of these results thats the 'ballistic limit'. If you graphed those results you'd find that [ if its a normal distribution as in penetration] 2/3 of all results should fall within +/- 7% of the 'average figure' calculated above. Further 90% of results should fall within 2x 7%, while all results should fall within 2.6 times 7%[called the 'standard deviation']. This appears to apply to accuracy and range estimation as well as has been mentioned by Rexford above. In Ogorkiewcz Tech Of Tanks he reports Standard deviations for ranging system as follows [ off the top of my brain] 25-30% [of range] Visual estimation 15-20% stadimetric 5-10% Ranging MG 10-20 x Sqrt of range in km.Steroscopic Range finder 10-20% @ 1km. 14-28% @ 2km. 17-35% @ 3km. These turn out to be Standard Deviations. [This message has been edited by Paul Lakowski (edited 01-22-2001).]

As I understood it the 75L24 was developed from the 75mm IG which is known for its accuracy. As to APDS , one of the big problems is seperation of the sabot pelts or pot sabot after it leaves the barrel. If theres even the slightest contact with the subcalibre projectile it will 'kick in' a large amount of error or dispersion.