Accuracy Data for 88mm Flak

[Mr. Tittles]

Bell shaped curves are not all the same. I do not say I am anything beyond stats 101 but I know there are different shaped bell curves. The diagram above shows how it can vary.

[rexford]

Mr. Tittles,

I looked into your concerns regarding the impact of the 75L48 APCBC dispersion upon shot corrections at 1500m, and here is what I found:

1. The Germans specified that bracketing be used beyond 1200m

2. Using my hand calculator I calculated a series of first round range estimates using an average error of 16% and a bell shaped curve, and then applied random dispersion effects using one times the German table figures. 20 different series were run using bracketing after first shot misses:

A. 2 of 20 first round shots landed on a T34 M43 front aspect

B. 1 of 18 second shots hit the target (didn't fire at previous hits)

C. 9 of 17 third shots hit the target

D. 6 of 8 fourth attempt shots landed on the T34

So, after four shots with bracketing 18 of 20 targets were hit.

The German firing tests that are specified in the Panzertaktik book for later war crews requires that a target between 1200m and 2000m be hit with one of the first four shots when the initial range is not known.

If double dispersion were used, only 9 hits would be scored within the first four shots at each range.

My guess (speculation) is that the Germans would have made sure that the testing gun had close to the average dispersion, or was slightly better than average, for everyone who shot.

So, it appears that German gunners on the firing range were shooting with one times the table dispersion and not two times. British firing tests and calculations for hit % against a known range target, and targets where the range estimates are in error, use one times the dispersion.

Which brings into question the use of double dispersion. Here is what I think:

The British firing tests with 6 pdr Churchill IV's showed that some tanks have lousy guns. At 1000 yards the best three averaged 81% hits against a known range Panther turret, the worst two averaged 34% and all five averaged 62%.

If the British results are applied to the German dispersion figures one could speculate that:

A. the German figures represent the average of all guns

B. the average scores for the German worst guns have double (or more) times the average dispersion

C. the best guns have considerably less dispersion than the average, maybe as low as half the table figures

The above theory could explain, in part, why some Tigers did most of the killing. It is also possible that because of the limited edition status of Tigers compared to PzKpfw IVH, StuG IIIG and Panther, more care was given to Tiger weapon production and the variations from the average might have been less.

Would German guns have been as variable as British? Perhaps not.

When German dispersion figures are compared to British 17 pdr average, the German figures look reasonable.

For a 1500m target and a 16% average error, the individual range estimates for first shot attempts break down as follows:

1501-1600m, 2

1601-1700m, 1

1701-1800m, 2

1801-1900m, 1

1901-2000m, 2

2001-2100m, 1

2101-2200m, 1

1401-1500m, 2

1301-1400m, 4

1201-1300m, 1

1101-1200m, 1

1001-1100m, 1

0901-1000m, 1

20 total

[Mr. Tittles]

A. 2 of 20 first round shots landed on a T34 M43 front aspect

B. 1 of 18 second shots hit the target (didn't fire at previous hits)

C. 9 of 17 third shots hit the target

D. 6 of 8 fourth attempt shots landed on the T34

So, after four shots with bracketing 18 of 20 targets were hit.

But it took 63 rounds.

In Panzertruppen 2 on pg 41, theres a report about 75mmL43 Panzer IV.

Pzgr39 were fired at 1200m to 1600m. Every hit had a destructive effect. 2-3 rounds were expended per tank killed. Gr38HLB was seldom used. One to five rounds were required to set an enemy tank on fire. Note: 17 KV1, 26 T34, 1 T26, 1 MKII, 3 MKIII, 1 General Lee destroyed by 4 Panzer IVL43 during Feb to Mar 43

Note that many accounts state that AT fire would be used against a target till it caught fire. That is, 2-3 rounds may have been used to destroy a tank, but that could mean multiple hits also.

The 75mmL43 and 75mmL48 were the most produced KWK weapon in the German army. Many millions of rounds were produced for this weapon. It was also in use for years during the war. The schools would have had a solid understanding of this weapon and its capabilities. The APCBC round had a very small HE cavity and this lends itself to a more solid equally distributed rotational balance.

I think the second round shots above show a very low percentage (1 of 18). I would think it would be better than the first round shots by a factor of two (about 3 of 18 given good observation of first round shot). But I do think you are getting more in line with reality.

[ August 27, 2004, 04:32 PM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

I think any understanding of antitank fire should start by documentation of the guns precision. That is, the precision of the gun when all other variables are eliminated. So the crews ability to guage range, nerves, etc. are not to be part of the methodology.

In the case of the churchill 6 pdr, it would have been best if all the guns were fired by the same gunner (hopefully the most experienced) and that they were checked for alignment before the shoot. Hopefully they were all about the same in barrel life. In any case, the majority of the weapons showed some excellent precision against a very short target. To get that many hits against a 0.6 m x 1.5m target (less than 1 sq m!) at that range is remarkable.

[ August 27, 2004, 04:38 PM: Message edited by: Mr. Tittles ]

[rexford]

Here are the estimated hit % for 75L48 and 88L56 APCBC against the 2' x 5' Panther turret when the range is known, and a comparison to 6 pdr results:

500 yards

89% for 75L48

96% for 88L56

89% for best 3 6 pdr

52% for worst 2 pdr

800 yards

69% for 75L48

83% for 88L56

84% for best 3 6 pdr

52% for worst 2 pdr

1000 yards

57% for 75L48

72% for 88L56

81% for best 3 6 pdr

34% for worst 2 6 pdr

1500 yards

30% for 75L48

54% for 88L56

62% for best 3 6 pdr

12% for worst 2 6 pdr

Average for 88L56 is close to best 3 6 pdr guns when range is known.

[rexford]

Originally posted by Mr. Tittles:

A. 2 of 20 first round shots landed on a T34 M43 front aspect

B. 1 of 18 second shots hit the target (didn't fire at previous hits)

C. 9 of 17 third shots hit the target

D. 6 of 8 fourth attempt shots landed on the T34

So, after four shots with bracketing 18 of 20 targets were hit.

But it took 63 rounds.

In Panzertruppen 2 on pg 41, theres a report about 75mmL43 Panzer IV.

Pzgr39 were fired at 1200m to 1600m. Every hit had a destructive effect. 2-3 rounds were expended per tank killed. Gr38HLB was seldom used. One to five rounds were required to set an enemy tank on fire. Note: 17 KV1, 26 T34, 1 T26, 1 MKII, 3 MKIII, 1 General Lee destroyed by 4 Panzer IVL43 during Feb to Mar 43

Note that many accounts state that AT fire would be used against a target till it caught fire. That is, 2-3 rounds may have been used to destroy a tank, but that could mean multiple hits also.

The 75mmL43 and 75mmL48 were the most produced KWK weapon in the German army. Many millions of rounds were produced for this weapon. It was also in use for years during the war. The schools would have had a solid understanding of this weapon and its capabilities. The APCBC round had a very small HE cavity and this lends itself to a more solid equally distributed rotational balance.

I think the second round shots above show a very low percentage (1 of 18). I would think it would be better than the first round shots by a factor of two (about 3 of 18 given good observation of first round shot). But I do think you are getting more in line with reality.

In the German report it took 2-3 shots per tank, German crew firing tests required a hit by the fourth round at any range from 1200m to 2000m or so.

The Germans in the report were obviously better than my math model, so maybe they had the range measured beforehand. Or maybe they had someone with a TF 14 giving them range measurements. O they were better at range estimates than my model estimated (if they were always within 200m of actual with the estimate alot more hits would occur on the second and third try.

There is a reason why few hits occur on the second shot with bracketing, a fact that comes out when one goes through the math. Second shot corrections typically add or subtract 200m, which usually leads to a miss.

The first shot at a 1500m target will be short or long by several hundred meters, usually more than 200m. So adding 200m or subtracting 200m from the first range estimate doesn't come close enough to score a second round hit. I did the math, looked at the results and know why the misses occurred.

Only on the third shot was the range estimate very close to actual, usually after a long on the first shot and a short on the second, or vice versa.

Remember that we're looking at bracketing fire, not burst on target, so the second shot is not necessarily the best unless the first round range estimate is very close to actual (which it hardly ever is).

[rexford]

The average number of rounds fired at a T34 M43 to score a hit in the math simulation was:

1 round each for 2 tanks hit

2 rounds for 1 tank hit

3 rounds each for 9 tanks hit

4 rounds each for 6 tanks hit

55 rounds fired for 18 kills

Average is 3.06 rounds fired per tank kill (every round which hit had a destructive effect), not very much different from the German report you quoted (2-3 which averages about 2.5).

I don't think the math model results are very much different from the German battle report with 75L43. One difference could be a higher percentage of guns with better than average dispersion, and better range estimates to start with.

[rexford]

Originally posted by Mr. Tittles:

Bell shaped curves are not all the same. I do not say I am anything beyond stats 101 but I know there are different shaped bell curves. The diagram above shows how it can vary.

The normal distribution curve, which is what the Germans and British used for dispersion results, can be defined by a mid-point and a standard deviation.

The standard deviation for German dispersion data equals the 50% zone length divided by two and multiplied by 1.48. So, the German data for 50% zones is all one needs to define the exact shape of the normal distribution curve (bell shaped), cause the mid-point is in the middle.

The different size of the 50% zones sets the shape.

[rexford]

The British firing tests which defined the 9.6 kg Pzgr APCBC round as the standard ammo for the 88mm L56 Flak gun were performed during February 1944, prior to D-Day. The report was dated November 1944.

They could not have been from Home Guard units, and probably were obtained in Italy during 1943 (my guess). To the best of the British folks knowledge, 88mm L56 Flak guns were firing 9.6 kg Pzgr APCBC through early 1944.

[Mr. Tittles]

The average number of rounds fired at a T34 M43 to score a hit in the math simulation was:

1 round each for 2 tanks hit

2 rounds for 1 tank hit

3 rounds each for 9 tanks hit

4 rounds each for 6 tanks hit

55 rounds fired for 18 kills

You forgot the rounds fired at the two non-hit tanks! You need to add 2 tanks not hit with 4 shots gives you 8+55=63. You should have run simulation till all tanks were hit. The other two tanks would probably require another round? So 65 rounds and 20 hits? So 3.25 rounds per hit?

Also, the hit=kill may not be reality given the armor protection and the performance of the gun at these ranges. The report said they would have destructive effect but not an absolute kill/burn.

Panzertruppen 2 also states that Panthers could open up at 2000+ meters. They state that every 4-5 rounds was a hit at 1500-2000m (battlefield conditions, its precision was probably better). Even the Panther HE had this performance against guns and buildings at these ranges. Didnt the French test the Panther gun after the war and find similar results? I recall that they fired HE at target tanks at some great range and could get repeatable hits.

I would guess that at ranges under 1500m, the panther would need about 2 rounds and it would not need to use bracketing till 1500m+ or so.

[ August 27, 2004, 06:00 PM: Message edited by: Mr. Tittles ]

[rexford]

For bracketing by 75L48 APCBC vs T34 M43 at 1200m, following results were obtained (avg error of 16% in first round range estimate, single dispersion, firing by 20 guns vs 20 targets on first try):

4 of 20 first rounds hit target

8 of 16 second shot rounds hit target

3 of 8 third round shots hit target

3 of 5 fourth round shots hit target

18 of 20 targets hit by fourth round or less, as per German training requirements that a target be hit by fourth round from 1200 to 2000m.

Average number of shots per target, 41 shots to kill 18 T34, for 2.3 shots per kill on average.

For 1200m and 1500m bracketing exercises the results were 3.06 shots per kill at 1500m and 2.3 shots per kill at 1200m, darn close to the 1942 report for 75L43 against T34.

[rexford]

"I would guess that at ranges under 1500m, the panther would need about 2 rounds and it would not need to use bracketing till 1500m+ or so."

Sir, it is okay to guess but please recognize that initial guesses may not be correct.

As I mentioned in an earlier post on another thread (did you read my discussion on BoT, which corrects some misconceptions about the method's effectiveness), burst on target doesn't work with high misses, which is half the misses. And it won't work with rounds that are short by quite a bit, which is a good share of the short misses.

BoT will not lead to great second shot corrections on a good share of the shots were it might be used.

The Germans also instructed gunners to use BoT type corrections to 1200m, and bracketing thereafter.

Panthers would have to use bracketing quite a bit on shots beyond 1200m (2m high T34 M43):

average range estimate for 1300m target is 1550m for 20% error. Set gun to 1650m for bottom aim.

First shot is 3.5m over target bottom, a random dispersion for this case brings shot down -.2m for 3.3m over target bottom.

Panther uses bracketing to decrease range setting by 200m, for 1450m shot. Trajectory is 1.5m over target bottom, dispersion brings round down -.4m so it lands near target center (1.1m over bottom).

A hit.

This is for one case out of a million or billion possible for the target range and target height.

If the initial range estimate is 30% in error, which it could be, the 1300m target is estimated to be at 1700m and the gun is set for 1800m.

The first shot is 4.8m over target bottom with a random dispersion.

Second shot uses range setting of 1600m, is 2.6m high at target and overflies by 0.6m.

Third shot uses 1400m range setting, shot is 1.0m over target bottom for middle area hit.

[rexford]

If a Panther targets a 1300m T34 M43 with an initial range estimate of 1050m (20% error on low side), the range setting would be 1150m for the navel area.

The shot would land 128m short of the target on level ground and the BoT correction would bring the second round closer to the target but still short on the great majority of tries.

Bracketing after the first miss would bring the second try to a point where 90% would hit.

In this case the Panther might use bracketing or burst on target for the second shot, with significantly different results.

[Mr. Tittles]

In Tankerschool (end 1943) the crews had to fulfill the following:

1st Exercise:

Using HE on a target at unknown range but less than 1200 meters. Own tank stationary target stationary (size of AT-Gun)

Criterion to pass: 1 Hit out of 4 rounds

2nd Exercise:

HE on a target at range greater 1200m, six HE rounds authorized (target the same as in 1)

Criterion to pass: 1 Hit

3rd Exercise:

AT round on a (stationary, frontal) tank target at greater than 1200m. 4 rounds authorized

Criterion to pass: 1 Hit

4th Exercise:

AT round on a moving (ca. 20km/h) tank target across the field of vision at 800 - 1200m. 3 (!!!) rounds authorized

Time: 30 sec. Firing time, target moves 150 m

Criterion to pass: 1 Hit

Notice: No Examination on tanktarget stationary below 1200 m !!

[Mr. Tittles]

For bracketing by 75L48 APCBC vs T34 M43 at 1200m, following results were obtained (avg error of 16% in first round range estimate, single dispersion, firing by 20 guns vs 20 targets on first try):

4 of 20 first rounds hit target

8 of 16 second shot rounds hit target

3 of 8 third round shots hit target

3 of 5 fourth round shots hit target

18 of 20 targets hit by fourth round or less, as per German training requirements that a target be hit by fourth round from 1200 to 2000m.

Average number of shots per target, 41 shots to kill 18 T34, for 2.3 shots per kill on average.

Since you have a 10% failure to pass the class (2 out of 20 need 5+ rounds), then these gunners in your test are barely average (well, there were quite a few A's and B's so maybe 10% washout is not that bad?). You are also at the minimum range stated in the test. The test calls for 1200m+. I realize this is just one run, but like dispersion itself, how do you know where this one run lies on a graph of runs? Interesting how single dispersion is seeming to fall in line with both combat reports and tank school testing.

Note the additional requirement to hit a moving target in the final test. It is somewhat easier because the range is 800-1200m. It differs in that it is not an unknown range and the crew could set the gun for 1000m initially. This probably models a defensive action where general range data is known and the enemy is advancing into a kill zone. If 3 rounds are needed for a moving target; Could a stationary target under similar circumstances be a 2 round sure thing? Less than two rounds?

[ August 28, 2004, 10:08 AM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

Guaging range is probably not a linear function and more a function of the range itself. Guaging out to 1000m might be linear but it might go sevrely non-linear beyond that. It might start out at 100m as a 5% error and ramp up t0 10% at 1000m. Beyond 1000m it might ramp faster depending on the optics involved. If its just a human eye then its probably the worst case. Eyes using binoculars would be better and enhanced stereoscopic devices better still. Theres a chance that a coincidence type range finder may be used and the error would go down dramically.

The case of when to use bracketing or BOT is largely a function of being able to percieve the fall of shot. The ability to guage the depth perception being critical. If firing from a slight height advantage and the TC has a very good stereoscopic binos, he would be able to percieve long and short shots and guage the amount of error to correct the fall of shot on target. If firing at a tank on the back edge of a hill, long shots can not be seen to fall on terrain in relation to the target. They just fly over. Since flying over and the height difference between flying over is extremely difficult to judge, the best course of action would be to bracket a round to fall short and 'walk' a round up to the target.

Tall tanks, like the Panther TC position, gives a built in height advantage albeit a small one.

[ August 28, 2004, 10:05 AM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

I am beginning to think that this double dispersion business only applies to doubling the 50% data and applying it to first round shots. I do not think that doubling any other area, like the first sigma area, means anything.

And having range data like pre-measured ranges (either through firing shots/MGs into those area as tests or at previous targets, measured ranges from dedicated rangefinding equipment, surveying, etc) throws this double dispersion ballpark figure out of the window.

I know that much of the penetration model in the game is based on rexfords work, is the hit model based on double dispersion?

[Mr. Tittles]

Until the beginning of 1942 British anti-tank gunnery used a 'false range', they aimed low and added a few hundred yards depending on the actual range. From the beginning of 1942 they adopted zeroing of anti-tank guns, usually using a tank sized target at 500 yard with the aim point being centre of mass. This meant the actual range could be set on the range drum, part of the drill for coming into action was to prepare a range card for recognisable objects in the zone of fire. They also issued simple tables for lead depending on range and speed and whether the target was a 'direct crosser' (45- 90 degree approach angle) or 'diagonal crosser' (15 - 45 degrees). This was related the lead graticules ('lead units') in the anti-tank telescopes. Of course the time of flight of the shot from high velocity anti-tank guns at normal battle ranges was under 1 second, and a tank moving at about 15 mph covered about 7 yards in this time. A 'direct crosser' at 15 mph required a lead of 1 and a 'diagonal crosser' a half, the smallest lead order was a quarter.

Anti-tank engagements were conducted by the No 1 giving initial orders to identify the target relative to the centre of arc, describing it, ordering the range and lead, and ordering fire. He then ordered corrections using 'Add' or 'Drop' for range (these were cumulative) and a new lead (not cumulative). These corrections were judged by observing the tracer to see where the shot went relative to its target. By 1943 ranges and correction were always ordered to the nearest 200 yards unless the target was hull down in which case 100 yards was used.

The following table, based on firing table probable errors, shows the inherent direct fire accuracy of anti-tank guns when their MPI was on the target centre (ie no human errors). In operations worn guns and other mis-alignments could reduce the chance by up to half at shorter ranges and to a quarter at longer ranges. In the first years of the war training material was issued detailing the most vulnerable areas of enemy tanks. This may have had some use for very short range engagements with infantry anti-tank weapons. It was unrealistic at longer ranges and the 1942 doctrine of 'centre of mass' ended it as far as anti-tank artillery was concerned. Trials also established that a 2 or 6-pdr at the end of its barrel wear life would hit only 18 inches low at 1000 yards.

Table 2 - Chance of Hitting a Vertical 6ft × 6 ft Target

Gun

1000 yds

2000 yds

5000 yds

2-pdr

90%

40%

1%

6-pdr

96%

55%

3%

17-pdr

98%

80%

15%

25-pdr (Chg super)

80%

45%

7%

http://members.tripod.com/~nigelef/anti-tank.htm

[rexford]

Originally posted by Jeff Duquette:

Lorrin Said: “British evidence shows that the Tiger 88mm L56 and the Flak 88mm L56 fired different APCBC rounds at least through late 1944. Tiger used small capacity round, 88mm Flak used large capacity round.”

The heavier and more accurate 8,8cm Pzgr.39 FES was employed by both the FLAK18 & 36 as well as the 8,8cm KwK36. The Flak18 & 36 were employing the more accurate round as early as 1942.

The less accurate APCBC round employed by the 8,8cm Flak18 & 36 is the 8,8cm Pzgr.Patr.mBd.Z. This round was not employed by the KwK36. The 8,8cm Pzgr.Patr.mBd.Z round has a higher level of shot scatter, or a larger dispersion pattern than the FES round.

Flak 18 & 36 firing pzgr 39 FES had a 50% dispersion zone at 1000m of 0,2m (horizontal) and 0,4m (vertical).

Flak 18 & 36 firing Pzgr.Patr.mBd.Z had a 50% dispersion zone at 1000m of 0,4m (horizontal) and 0,7m (vertical).

KwK 36 Firing pzgr 39 FES had a 50% dispersion zone at 1000m of 0,2m (horizontal) and 0,4m (vertical).

The greater accuracy issue appears to be associated with ammunition type rather than the Tiger-1’s main gun being more accurate than the Flak-36.

Source information:

1) H.Dv.481/541 “Merkblatt fur die Munition der 8,8 cm Flugabwehrkanone 18, und der 8,8 cm Flugabwehrkanone 36” dated May 20, 1942.

2) H.Dv.481/60 “Merkblatt fur die Munition der 8,8 cm Kampfwagenkanone 36”, dated Jan 1, 1943.

Penetration data for 88mm Flak 18 & 36 firing Pzgr shows two different figures at 30 degrees from vertical, suggesting an improved round at some point (9.6 kg weight).

John Diehl's analysis of German ammunition in AFV-G2 magazine showed the 88mm Flak 18 & 36 firing Pzgr and Pzgr 39 APCBC.

[Rausch]

Perhaps I can help.

The 8.8 cm Pzgr. 39 was interchangeable between the 8.8 cm Flak 18/36/37 and the 8.8 cm Kw.K. 36, when the primer was changed.

The projectile and shell were the same. Dimensions, explosive weight and type, propellant weight and type, base fuze type and all other attributes were the same. The only difference was that the Flak round used the C/12 n.A. or C/12 n.A. St. primer (ignited by percussion) and the Kw.K. used the primer C/22 or C/22 St. primer (eletrically ignited).

The weight for the 8.8 cm Pzgr. was 9.5 kg and the muzzle velocity when fired out of a 8.8 cm Flak 810 m/s.

The weight for the 8.8 cm Pzgr. 39 was 10.2 kg and it had the muzzle velocity of 800 m/s when fired from the 8.8 cm Flak or 8.8 cm Kw.K. 36.

780 m/s was not the muzzle velocity of the 8.8 cm Pzgr. 39 but the 8.8 cm Pzgr. 39-1 when fired out of the 8.8 cm Kw.K. 36.

Here are the values for a 50% dispersion zone. Format is distance - width x height (all in m).

8.8 cm Pzgr. fired from 8.8 cm Flak:

100 - ? x ?

500 - 0,3 x 0,2

1000 - 0,7 x 0,4

1500 - 1,1 x 0,6

2000 - 1,6 x 0,8

8.8 cm Pzgr. 39 fired from 8.8 cm Flak:

100 - 0,1 x 0,1

500 - 0,3 x 0,2

1000 - 0,5 x 0,7

1500 - 0,8 x 1,1

2000 - 1,0 x 1,6

8.8 cm Pzgr. 39 fired from 8.8 cm Kw.K. 36:

100 - 0,1 x 0,1

500 - 0,2 x 0,2

1000 - 0,2 x 0,4

1500 - 0,3 x 0,6

2000 - 0,5 x 0,9

The production numbers told in this thread were exlusively for tank guns, the ammo used by Flak guns were taken from the Luftwaffe production.

Regards,

Michael

Sources are:

1) Geschoßblätter von Wa.Prüf. Amt 1, no date, but regarding the ammo described late 1943 or 1944.

2) H.Dv. 119/328 – Schußtafel für die 8,8 cm Kampfwagenkanone 36 (L/56) (8,8 cm Kw.K. 36), Februar 1944.

3) H.Dv. 119/763, L.Dv. 500/763 – Erdschußtafel für die 8,8 cm Flak 18 mit 8,8 cm Sprgr. L/4,5 (Kz) mit Zt.Z. S/30 oder A.Z. 23/28 und 8,8 cm Pzgr. mit Bd.Z. der 8,8 cm Pzgr, September 1938, Nachdruck von April 1940.

4) H.Dv. 481/60 – Merkblatt für die Munition der 8,8 cm Kampfwagenkanone 36, 8.1.1943.

5) H.Dv. 481/541 – Merkblatt für die Munition der 8,8 cm Flugabwehrkanone 18 (8,8 cm Flak 18) und der der 8,8 cm Flugabwehrkanone 36 (8,8 cm Flak 36), 20.5.1942.

6) L.Dv. 4402/5 – Die Munition der Flakartillerie, Beschreibung, Teil 5, Munition der 8,8 cm Flak 18, 36 und 37, Juli 1942.

[ September 09, 2004, 10:04 AM: Message edited by: Rausch ]

[Mr. Tittles]

Thanks.

So the Tiger I KWK was more accurate than the 88mm FLAK even when both fired the Pzgr. 39? Thats interesting. The FLAK gun is a huge firing mount. It certainly has enough mass.

But the Tiger I gun is actually mounted very differently. The gun is trunioned by the very thick mantlet to the very heavy tank. The Tiger I gun also has a heavy muzzle break that may act as a vibration attenuator (or barrel stabilizer).

I looked back at the ammo production and thought that it was actually not that much given training, loss through shipment/interdiction, etc. I read once that ammo supplied in front line situations usually does not exceed a 10% ratio of actually being fired at the enemy to that supplied.

[ September 09, 2004, 03:42 PM: Message edited by: Mr. Tittles ]

[rexford]

Originally posted by Rausch:

Perhaps I can help.

The 8.8 cm Pzgr. 39 was interchangeable between the 8.8 cm Flak 18/36/37 and the 8.8 cm Kw.K. 36, when the primer was changed.

The projectile and shell were the same. Dimensions, explosive weight and type, propellant weight and type, base fuze type and all other attributes were the same. The only difference was that the Flak round used the C/12 n.A. or C/12 n.A. St. primer (ignited by percussion) and the Kw.K. used the primer C/22 or C/22 St. primer (eletrically ignited).

The weight for the 8.8 cm Pzgr. was 9.5 kg and the muzzle velocity when fired out of a 8.8 cm Flak 810 m/s.

The weight for the 8.8 cm Pzgr. 39 was 10.2 kg and it had the muzzle velocity of 800 m/s when fired from the 8.8 cm Flak or 8.8 cm Kw.K. 36.

780 m/s was not the muzzle velocity of the 8.8 cm Pzgr. 39 but the 8.8 cm Pzgr. 39-1 when fired out of the 8.8 cm Kw.K. 36.

Here are the values for a 50% dispersion zone. Format is distance - width x height (all in m).

8.8 cm Pzgr. fired from 8.8 cm Flak:

100 - ? x ?

500 - 0,3 x 0,2

1000 - 0,7 x 0,4

1500 - 1,1 x 0,6

2000 - 1,6 x 0,8

8.8 cm Pzgr. 39 fired from 8.8 cm Flak:

100 - 0,1 x 0,1

500 - 0,3 x 0,2

1000 - 0,5 x 0,7

1500 - 0,8 x 1,1

2000 - 1,0 x 1,6

8.8 cm Pzgr. 39 fired from 8.8 cm Kw.K. 36:

100 - 0,1 x 0,1

500 - 0,2 x 0,2

1000 - 0,2 x 0,4

1500 - 0,3 x 0,6

2000 - 0,5 x 0,9

The production numbers told in this thread were exlusively for tank guns, the ammo used by Flak guns were taken from the Luftwaffe production.

Regards,

Michael

Sources are:

1) Geschoßblätter von Wa.Prüf. Amt 1, no date, but regarding the ammo described late 1943 or 1944.

2) H.Dv. 119/328 – Schußtafel für die 8,8 cm Kampfwagenkanone 36 (L/56) (8,8 cm Kw.K. 36), Februar 1944.

3) H.Dv. 119/763, L.Dv. 500/763 – Erdschußtafel für die 8,8 cm Flak 18 mit 8,8 cm Sprgr. L/4,5 (Kz) mit Zt.Z. S/30 oder A.Z. 23/28 und 8,8 cm Pzgr. mit Bd.Z. der 8,8 cm Pzgr, September 1938, Nachdruck von April 1940.

4) H.Dv. 481/60 – Merkblatt für die Munition der 8,8 cm Kampfwagenkanone 36, 8.1.1943.

5) H.Dv. 481/541 – Merkblatt für die Munition der 8,8 cm Flugabwehrkanone 18 (8,8 cm Flak 18) und der der 8,8 cm Flugabwehrkanone 36 (8,8 cm Flak 36), 20.5.1942.

6) L.Dv. 4402/5 – Die Munition der Flakartillerie, Beschreibung, Teil 5, Munition der 8,8 cm Flak 18, 36 und 37, Juli 1942.

Good info and glad you joined the discussion.

Do you know the breakdown of 88mm Pzgr 39 rounds used by the Tiger in terms of Pzgr 39 vs Pzgr 39-1 and Pzgr 39 A1, and when the various rounds would have been used.

The ballistic table I have is for the 88mm PZgr 39-1 and 39 A1, with a 10 kg round fired at 780 m/s. It is good news to hear that the 800 m/s muzzle velocity and 10.2 kg weight are appropriate for 88mm Pzgr 39 but how common was Pzgr 39 relative to the other two projectiles (39-1 and 39 A1).

With an 800 m/s muzzle velocity and a 10.2 kg round, the Tiger trajectory to 1000m would attain a maximum height of about 2.14m as opposed to 2.25m for a 780 m/s muzzle velocity. A little better.

Do you know if the German Tiger crews actively used a sort of battlesight aim (aim gun at target bottom, set gun for 800m to 1000m range and then hit all 2m tall targets between gun and range setting?

Did they actively use the gun sight triangles for range estimation?

I figured all along that the 88mm L56 Flak would not have the same dispersion as the Tiger tank gun based on the stability of the mount.

Thanks for the great info, it's appreciated.

Lorrin

[rexford]

Michael,

A few questions on the terrific data you posted:

The last two dispersion results have the lateral first and then the vertical:

8.8 cm Pzgr. fired from 8.8 cm Flak:

100 - ? x ?

500 - 0,3 x 0,2 (should this be 0,2 x 0,3?)

1000 - 0,7 x 0,4 (lat and vert seem reversed)

1500 - 1,1 x 0,6 (ditto)

2000 - 1,6 x 0,8 (ditto)

The vertical and lateral dispersion appear to be reversed for the above ammo and gun, should it be:

1000 - 0,4 x 0,7

1500 - 0,6 x 1,1

2000 - 0,8 x 1,6

8.8 cm Pzgr. 39 fired from 8.8 cm Flak:

100 - 0,1 x 0,1

500 - 0,3 x 0,2 (lat and vert reversed?)

1000 - 0,5 x 0,7

1500 - 0,8 x 1,1

2000 - 1,0 x 1,6

8.8 cm Pzgr. 39 fired from 8.8 cm Kw.K. 36:

100 - 0,1 x 0,1

500 - 0,2 x 0,2

1000 - 0,2 x 0,4

1500 - 0,3 x 0,6

2000 - 0,5 x 0,9

The dispersion figures for 88mm Kwk 36 firing Pzgr 39 are the same as the table listings for Pzgr 39-1 and 39 A1. Dou you know what major differences existed between Pzgr 39 and 39-1 and 39 A1? I see a FES tag on the 39-1 and 39 A1 ballistic table.

Interesting that the 88mm Flak firing Pzgr has the same vertical dispersion as the 88mm Flak firing Pzgr 39 but less lateral dispersion. So the earlier 88mm Pzgr was more accurate than the later Pzgr 39 when fired from the 88mm Flak with a constant aim.

Thanks.

Lorrin

[Rausch]

I took a look on the gun descriptions as they were presented in the ballistic manuals and I could identify two differences between the 8.8 cm Flak and the 8.8 cm Kw.K.

1. The recoil of the Kw.K. variant was about half of the Flak variant.

2. The loading chamber was longer and had more volume in the Kw.K. variant.

Rifling, barrel length and the other attributes were listed with same values.

Regarding amo production I have not seen till now a detailed breakdown of the 8.8 Pzgr. 39 rounds in the subvariants.

When I look on the anual ammo production summaries (which break the production numbers down to single months) I notice that the headers changed from "8,8 cm Pzgr." at the beginning, in 1942 to "8,8 cm Pzgr. u. 39" and again in 1943 to "8,8 cm Pzgr. 39 u. 39-1".

This is true for the Kw.K. and the Flak production numbers, so the Flak could and did

also fire the 39-1 variant. It looks to me that the 39-1 variant was introduced in 1943 while the 8.8 cm Pzgr production ceased in 1942, but the percentage of whole production was not pointed out.

And the production numbers tell of course nothing about the percentages in storage.

We should not forget that the 39-1 variant was the intermediate solution to give the new introduced 8.8 cm Kw.K. 43 (also -1/2/3 variants) till the 39/43 design was finalized for mass production.

I have about 40 microfilm reels about German equipment production and equipment data, but I will need years to scan them all and look what deta they contain in detail. So perhaps one day I can tell more.

Till now I have not read anything about the use of a sort of battlesight aim, but I also never looked much for crew reports (the mass of papers to look through is too huge). A look in the war diaries of Tiger equipped units could be of help, but at the moment I cannot do more than to point where you can find them in the BAMA Freiburg.

Looking in the ballistic table a range of 900 m had been more appropriated, since with a selection of 1000 m distance a 2 m high target would have been only hit in the range 650-1000 m.

The Tiger Fibel indicates that the range triangles were actively used. For range eastimation the commander, driver (if possible) and the gunner gave all a range eastimation with the gunner having the most weight, since he had the best chance to get the distance right.

In the few battle reports I could read the driver made never an eastimation and for experienced crews the commander made only the target selection and let the range eastimation full in the hands of the gunner.

Regards,

Michael

[ September 09, 2004, 03:55 PM: Message edited by: Rausch ]

[Mr. Tittles]

Do you have any dispersion data that relates 95% areas also?