"Maneuverability of fire
Aiming the cannon and coaxial machinegun is done with the turning mechanism, elevation mechanism, and hydraulic turning mechanism which works only when the engine is running. The hydraulic mechanism has two gears and is controlled by a foot pedal.
The horizontal aiming speed of the gun depends on the rate at which the engine is running. Data on the aiming mechanisms is given in the following table.
Mechanism
|
Range (degrees)
|
Number of turns in range
|
Angle for one turn
|
Turning mechanism (manual)
|
360
|
673
|
30 minutes
|
Elevation mechanism
|
22
|
36
|
36 minutes
|
The hand crank and hydraulic rotation mechanism are independent. The effectiveness of the hydraulic turning mechanism is given as follows:
Gear
|
Engine RPM
|
Turret traverse
|
Time
|
1
|
500
|
360
|
1 min. 20 sec.
|
2
|
500
|
360
|
1 min. 15 sec.
|
1
|
1000
|
360
|
1 min. 26 sec.
|
2
|
1000
|
360
|
43 sec.
|
1
|
1500
|
360
|
54 sec.
|
2
|
1500
|
360
|
27 sec.
|
1
|
2000
|
360
|
40 sec.
|
2
|
2000
|
360
|
20 sec.
|
The effort required to elevate the gun when the tank is horizontal is as follows.
Gun position
|
Effort in kilograms
| |
Elevation
|
Depression
| |
-5 degrees
|
6
|
1.5
|
0 degrees
|
7
|
1.2
|
+5 degrees
|
9
|
2
|
+10 degrees
|
8
|
1
|
+15 degrees
|
10
|
2
|
The effort needed to turn the turret with the tank flat on the ground is 2-3 kg.
Turret and gun looseness:
The looseness of the gun is 3 thousandths vertically. The looseness of the turret is 4 thousandths horizontally.
Gunnery trials
Muzzle velocity and maximum pressure:
The stock round from the 88 mm KwK 43 tank gun was used. The results attained were averages from armour piercing and high explosive rounds, six of each.
Type of shell
|
Number of shots
|
Muzzle velocity
|
Maximum pressure
|
Armour piercing
|
6
|
1018
|
3006
|
High explosive
|
6
|
759
|
-
|
Examination of precision and accuracy of the 88 mm KwK 43 gun in place:
To determine the accuracy and precision of the gun with armour piercing tracer shells, the gun was fired at vertical targets from a range of 1000-2000 meters. Aiming was done with the telescopic monocular sight with variable magnification. The visibility was good. The angle of the tank was 0 degrees. Time to fire was unlimited. Correction to aim was made after every shot.
Conditions
|
Range
|
# of shots
|
# of hits
|
100% radius
|
50% radius
|
1st group, 4x4 meter target
|
1000
|
10
|
10
|
48 cm
|
36 cm
|
2nd group, 4x4 meter target
|
1000
|
10
|
10
|
67 cm
|
43 cm
|
3rd group, 6x6 meter target
|
2000
|
10
|
10
|
93 cm
|
62 cm
|
Precision and accuracy of the 88 mm tank gun KwK 43 at ranges of 1000 and 2000 meters are good.
Determining rate of fire and accuracy when shooting in place:
The rate of fire of the gun was checked against one, two, three, and four targets with HE shells, in groups of 5 shots, with the following conditions:
- The shells are in the ready rack.
- The time is counted from the "load" command to the last shot.
- Change of range is performed when shifting fire.
- Correction of fire is performed after every shot.
The results were as follows:
Conditions and targets
|
Range to target
|
# of shots
|
# of hits
|
# of close misses (within 30 meters)
|
Time to fire (seconds)
|
Rate of fire (RPM)
|
Manual turning mechanism
|
||||||
PzIII
|
800
|
5
|
3
|
2
|
54
|
5.6
|
PzII
|
800
|
2
|
2
|
-
|
58
|
5.2
|
PzIII 15 degrees away
|
900
|
3
|
3
|
-
|
||
PzII
|
800
|
2
|
2
|
-
|
57
|
5.2
|
PzIII 15 degrees away
|
900
|
3
|
3
|
-
|
||
PzII
|
900
|
1
|
1
|
-
|
70
|
4.3
|
PzIII
|
800
|
2
|
2
|
-
|
||
T-40 35 degrees away
|
1400
|
2
|
2
|
-
|
||
Hydraulic turning mechanism
|
||||||
PzIII
|
800
|
5
|
4
|
1
|
53
|
5.6
|
PzII
|
800
|
2
|
2
|
-
|
52
|
5.7
|
PzIII 15 degrees away
|
900
|
2
|
2
|
-
|
||
PzII
|
500
|
1
|
1
|
-
|
59
|
5.4
|
PzIII
|
800
|
2
|
2
|
-
|
||
T-40 35 degrees away
|
1400
|
2
|
1
|
1
|
||
PzII
|
500
|
1
|
1
|
-
|
58
|
5.2
|
PzIV
|
650
|
1
|
1
|
-
|
||
PzIII
|
800
|
1
|
1
|
-
|
||
T-40 35 degrees away
|
1400
|
2
|
1
|
1
|
||
Effectiveness of firing from the move
An AP-tracer shell was fired at a 4x6 meter target at a range of 900-1100 meters under off-road conditions while moving at 10-12 kph. There were three attempts at 4 shots each. The tank was aiming at 0 degrees, aiming was done through the optical sight at the 2.5x setting while using the hydraulic turning mechanism.
Results: 12 shots were made, one of which was to range in and 11 were counted. 8 shots hit, or 72%. Effectiveness of firing on the move was as follows, from the center of the target:
- x: -185 y: -80
- x: -170 y: -55
- x: -150 y: -20
- x: -145 y: -15
- x: +125 y: -10
- x: +150 y: +150
- x: +155 y: +185
- x: +205 y: +305
Horizontal aiming with the hydraulic traverse allows precise aiming at the target, and the semiautomatic braking elevation mechanism allows precise aiming vertically. These two factors increase effectiveness when firing on the move.
As the tank broke down, it was not possible to fully examine the semiautomatic braking elevation mechanism over a large amount of shots fired on the move.
...
Reliability of the gun and its mechanisms
During trials, 152 shots were fired, of which 60 were AP-T and 92 were HE-fragmentation grenades. The recoil length was normal and fell within the range of 510-525 mm.
After 58 shots, the semiautomatic guide failed. (See photo #11)
Photo #11. Destroyed semiautomatic guide.
After 90 shots, the roller arm failed. (See photo #12)
Photo #12. Destroyed roller arm.
After a new roller was installed, 62 shots were made, and the gun functioned normally."
CAMD RF 38-11355-2860
Very interesting stuff. Tank you for keeping up the best blog there is on the internet! :)
ReplyDeleteSeriously, an exermination of the gun without penetration tests?
ReplyDeletePenetration data for the KwK 43 was already available, it was tested on the Ferdinand. There wasn't exactly an ample supply of captured ammunition, so things that haven't been tested yet naturally take priority.
DeleteAre the testresults here on the blog? I didnt see then yet then
DeleteThere a couple spots. They all appear to have been from tests of the very earliest 88mm AP designs used at Kursk.
Deletehttp://tankarchives.blogspot.com/2013/03/penetration.html
There's a table that I have saved that has the 88-MM o?p.43 penetrates 121 at 60° 1000m but I don't have the link. Also, has three other guns.
-m
This is calculated Data. I am looking for real test of foreign guns under soviet criteria.
ReplyDeleteWill this do? Table 2
Deletehttp://4.bp.blogspot.com/--CjPc8EhNyY/UDSprEolkuI/AAAAAAAABBM/-UmqWTcd9yk/s1600/pen2.jpg
Comparing the accuracy of 8,8 cm L/71 with D-25T.
ReplyDelete1000 meters:
8,8 L/71
R100=48 cm R50=36 cm
R100=67 cm R50=43 cm
Avg =58 cm Avg=40 cm
D-25T
R100=80 cm R50=24 cm
2000 meters:
8,8 L/71
R100=93 cm R50= 62 cm
D-25T(at 1900 meters)
R100=120 cm R50=45 cm
links:
http://tankarchives.blogspot.ca/2013/02/accuracy.html
http://tankarchives.blogspot.ca/2013/05/accuracy-revisited.html
http://tankarchives.blogspot.com.br/2013/07/ballistic-tables-of
I believe this proof that German and Soviet accuracy system are not equivalent, and the German system have larger values for the same gun that in Soviet system.
Why do you say that? Theoretically (according to ballistics tables), the KwK 43 is less precise than the D-25 for the best 50%. This is demonstrated in practical trials as well: 40 cm vs 24 cm, 62 cm vs 45 cm. Theory matches practice.
DeletePrecision and accuracy are two different things.
DeleteR50 say about precision, R100 about accuracy.
If you have a circle with 100 cm radius and inside it another with 50 cm radius ,at 2000 meters.
Using D-25-T, trials above say that 50% of shots is going to the 50 cm circle radius, 30% hit the 100 cm and 20% is going to miss, 80% of hit probability.
Using KwK 43 less than 50% of shots is going to hit the small circle but all others shots is going to hit the bigger circle, 100% of hit probability.
The reason for this is that shot dispersion from KwK 43 is a ellipse (0.3,0.5(German standard)) from D-25 is a circle(0.3,0.3(Soviet standard).
To explain:
The area from a circle with radius=15 is
π *15*15=706
The area from a ellipse with radius=10,20 is
π *10*20=628
This mean that even with the bigger radius(20) the area from ellipse is smaller than from a circle(so less dispersion)
If German standard are equal to soviet standard than the R100 from KwK 43 NEVER is going to be small tha R100 from D-25.
The Russians reported their guns dispersion in terms of average mean deviation while the Germans reported their guns dispersion in terms of 50% deviation zone . To compute the 50% dispersion zone from the mean dispersion values multiply by 1.69.
ReplyDeleteThe Rheinmetall Weapons Handbook shows the difference. It used to be online pdf but it is gone now, sorry.
https://www.pinterest.com/pin/414331234441992228/
-m
If you apply that multiplier, then the D-25T becomes much less precise than the KwK 43 (contrary to practical trials). Furthermore, if you take the figure from D-25T tables (30 cm) and multiply it by that multiplier, you get 50 cm, a radius that covers 90% of the shots in practical trials.
DeleteFurthermore, I highly doubt that a Rheinmetall handbook is going to have any kind of coefficients for the D-25. I've seen many people cite this mystical coefficient, but I have yet to see a scan or even a direct quote from that page.
The Rheinmetall handbook has a statistical conversion table showing average mean deviation to the 50% zone deviation.
DeleteThis is found on post #3 here: http://www.tank-net.com/forums/index.php?showtopic=37561
-M
I don't see 1.69 anywhere in the third post. You still haven't explained why practical trials reveal the opposite effect compared to what that conversion factor would result in.
DeleteYou have to follow the math.
ReplyDelete50% Zone ρ = (2γ) = 1.3490 σ .
σ= 1.25331 x mean deviation.
So 1.25331 x 1.3490 = 1.69 x mean deviation = 50% Zone
This is from DDR 122mm firing table.
http://www.matrixgames.com/forums/upfiles/21308/A1605F6CE6754C30ABA67D2808B392A2.jpg
There is a Russian firing table out there somewhere for the 122mm D-25.
Essentially both say the average mean deviation at 1000m is .3m vertical and .3m horizontal.
The DDR table has 0.3 and 0.4. By your math if they were converting from Soviet tables it would be 0.5 and 0.5, no?
DeleteAlso you still haven't addressed the issue that these claims clash with practically obtained results.
Peter, that is only one test of one gun. It may not representative of the gun system on the whole.
DeleteIn addition armies may have figured dispersion differently.
US and UK seem only considered round to round dispersion and found how far they spread from a central point. Like these examples of 17-pdr tests.
It doesn't look like they cared if this was not the target center.
http://worldoftanks.com/en/news/21/The_Chieftains_Hatch_Firefly/
http://worldoftanks.com/dcont/fb/imagesforarticles/chieftains_hatch/usfirefly/17prdisp1000.jpg?MEDIA_PREFIX=/dcont/fb/
See all factors that can cause dispersion on US Table I, page 12.
http://www.dtic.mil/dtic/tr/fulltext/u2/316221.pdf
The Russians may have included all gun inaccuracies like round to round shell dispersion along with systematic inaccuracies like gun jump and barrel whip. That is why their number is higher.
I have no idea of what the German's included in their dispersion number.
-M
This DDR table is using Soviet standard the 0.3 and 0.4 value are from HE rounds 0.3 and 0.3 from AP rounds.
DeleteThe link to the handbbok:
http://pt.scribd.com/doc/241360314/R-Germershausen-Ed-Handbook-on-Weaponry-BookZZ-org#scribd
Accuracy and precision are different things, technically speaking. Precision is what artillery tables tell you, accuracy is how far your sights are off the center of where your shells hit. Artillery tables do not mention accuracy, because accuracy changes depending on how well your sights are calibrated. Tables don't include it since you can change it, but you can't sand down the shells you get and re-measure propellant loads to get the same amounts, which is why the table contains deviation figures from those factors.
DeleteUh, no, again, you have made a technically incorrect statement. Do you have any education or training in regards to the things you go on about?
ReplyDelete