8.8 cm KwK 36

The 8.8 cm KwK 36 (German: 8,8 cm Kampfwagenkanone 36) was an 88-millimetre (3.5 in) tank gun used by the German Army during World War II. This was the primary armament of the PzKpfw VI Tiger I tank. It was developed and built by Krupp.

This article is about the Tiger I tank gun. For the renowned German "88", see 8.8 cm Flak 18/36/37/41.
8.8 cm KwK 36
A captured Tiger I tank fitted with the 8.8 cm KwK 36
TypeKampfwagenkanone
Place of originGermany
Service history
Used byNazi Germany
WarsWorld War II
Production history
DesignerKrupp
Unit cost18,000 ℛ︁ℳ︁
Specifications
Barrel length492.8 cm (194.0 in) bore (56 calibres)
ShellFixed QF 88 × 571mmR
Shell weight10.2 kg (22 lb) Pzgr 39 Armor-piercing, capped, ballistic capped shell
7.3 kg (16 lb) Pzgr 40 Armor-piercing composite rigid (APCR)
Calibre88 mm (3.46 in)
Elevation-8° to +15°
Rate of fire10 round per minute
Muzzle velocity780 m/s (2,600 ft/s) APCBC
930 m/s (3,100 ft/s) APCR
Maximum firing range10,500 m (34,449 ft)

Design

The KwK 36 was derived from the 8.8 cm FlaK 36 anti-aircraft gun by adapting/modifying it to the limited space available in tank turrets. Parts of the KwK 36 were built to practically the same design as the 75-millimetre (3.0 in) and 50-millimetre (2.0 in) guns already used in German tanks. The breech ring was square in section and 320 millimetres (13 in) on a side. The breech block was of vertical falling wedge type and operated semi-automatically, meaning that after firing the empty cartridge case was automatically ejected, while the breech cocked itself and remained open, ready to receive the next round.

The "L/56" in the designation is descriptor of barrel length; the ratio of the length of the barrel in proportion to the width of the bore. The designation "L/56" means the barrel is 56 times 88 mm - about 4.9 m (16 ft 1 in). The longer the tube is in relation to its bore, the higher the muzzle velocity it can generate on fixed charge. A longer gun barrel allows the expanding gas from the shell's charge to act on the projectile longer than a short barrel, imparting it more velocity and force. For the Tiger II's 8.8 cm KwK 43 L/71, barrel length is 6.25 m (20 ft 6 in) generating a higher velocity.

Performance
8.8 cm KwK 36 at Base Borden Military Museum

The KwK 36 was very accurate and high-powered, and its high muzzle velocity produced a very flat trajectory. This allowed its gunners a higher margin of error in estimating range.

In British firing trials during the war, a British gunner scored five successive hits from 1,200 yards (1,100 m) at a 16-by-18-inch (41 by 46 cm) target. Another five rounds were fired at targets moving at 15 miles per hour (24 km/h), and, although smoke obscured the gunners' observation, three hits were scored after directions given by the commander. The sighting system resulted in excellent firing accuracy for the 8.8 cm KwK 36 gun on the Tiger I.[1]

Capability

The gun's performance was highly dependent on distance to target and type of ammunition loaded. For kinetic penetration, the speed of the projectile upon impact is crucial, and the cumulative effect of air resistance decreases the velocity of the shell as the distance to the target increases. The accuracy achieved during controlled test firing to determine the pattern of dispersion gives a greater accuracy than the variation expected during practice firing on a range due to differences between guns, ammunition and gunners; both at precisely known distances.[2] Due to errors in estimating the range and many other factors, the probability of a first shot hit under battlefield conditions was much lower than at the firing range. Observing the tracer from the first round in battle, the average, calm gunner might achieve the firing range accuracy shown in the second column with the second round fired at the same target.[2]

This gun used the same size 88 x 571R mm cartridge, with the exception of being electrically primed compared to the percussion primed cases employed by the Flak 18/36/37.

Panzergranate 39 (PzGr. 39)
Finnish training chart for KwK 36, shows an 88 mm PzGr. 39 (APCBC round).
  • Type: Armour-piercing, capped, ballistic cap (APCBC) projectile with explosive filler and tracer.
  • Projectile weight: 10.2 kg (22 lb)[3]
  • Muzzle velocity: 773 m/s (2,540 ft/s)
  • Explosive filler: 0.059 kg (0.13 lb)
  • Propellant weight: 2.5 kg (5.5 lb)[3]
Penetration figures given for an armoured plate 30 degrees from vertical
Hit probability versus
2.5 x 2 m target[2]
RangePenetrationTest bedFiring range
100 m132 mm100%100%
500 m110 mm100%100%
1000 m99 mm100%93%
1500 m91 mm98%74%
2000 m83 mm87%50%
2500 mn/a71%31%
3000 mn/a53%19%

PzGr. 40 (APCR)
Penetration figures given for an armoured plate 30 degrees from vertical
Hit probability versus
2.5 x 2 m target[2]
RangePenetrationTestbedFiring range
100 m171 mm100%100%
500 m156 mm100%100%
1000 m138 mm99%80%
1500 m123 mm89%52%
2000 m110 mm71%31%
2500 mn/a55%19%

Hl.39 (HEAT)
  • Type: high explosive anti-tank (HEAT) round with a shaped charge.
  • Projectile weight: 7.65 kg (16.9 lb)
  • Muzzle velocity: 600 m/s (2,000 ft/s)
Penetration figures given for an armoured plate 30 degrees from vertical
Hit probability versus
2.5 x 2m target[2]
RangePenetrationTestbedFiring range
100 m90 mm100%100%
500 m90 mm100%98%
1000 m90 mm94%62%
1500 m90 mm72%34%
2000 m90 mm52%20%

Sprgr. L/45 (HE)
  • Type: high explosive (HE) round
  • Projectile weight: 9 kg (20 lb)[2][3]
  • Explosive filler: 0.9 kg of amatol (3765 Kilojoules)[4][3]
  • Propellant weight: 2.55 kg (5.6 lb)–2.95 kg (6.5 lb)[2][3]

Penetration comparison
Penetration figures (90 degrees) uses American and British 50% success criteria,
and allowing direct comparison to foreign gun performance.[5]
Ammunition typeMuzzle velocity
(m/s)		Penetration (mm)
100 m 250 m 500 m 750 m 1000 m 1250 m 1500 m 2000 m 2500 m 3000 m
PzGr. 39 (APCBC) 780 m/s (2,600 ft/s) 162 158 151 144 138 132 126 116 106 97
PzGr. 40 (APCR) 930 m/s (3,100 ft/s) 219 212 200 190 179 170 160 143 128 115
Hl.39 (HEAT) 600 m/s (2,000 ft/s) 110 110 110 110 110 110 110 110 110 110

See also

Weapons of comparable role, performance, and era

References
  1. Green, 2005, p. 121
  2. Jentz, 1996, p. 9
  3. H.Dv. 481/60, p. 24
  4. German Explosive Ordnance (Projectiles and Projectile Fuzes) - Department of the Army Technical Manual TM-9-1985-3. 1953. p. 445 https://archive.org/details/TM9-1985-3.
  5. Bird, Lorrin Rexford; Livingston, Robert D. (2001). WWII Ballistics: Armor and Gunnery. Overmatch Press. p. 61.

Bibliography
  • Green Michael, Panzers at War. London: Zenith Press, 2005. ISBN 0-7603-2152-3
  • Thomas L. Jentz, Germany's Tiger Tanks: Tiger I and Tiger II - Combat Tactics. London: Schiffer Publishing, 1996. ISBN 0-7643-0225-6
  • H.Dv. 481/60 Merkblatt für die Munition der 8,8 cm Kampfwagenkanone 36
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