200mm L/50 Type 29 naval gun
| 200 mm L/50 Type 29 naval gun | |
|---|---|
| Type | Naval gun |
| Place of origin | Greater Menghean Empire |
| Service history | |
| In service | 1933—1945 |
| Used by | Greater Menghean Empire |
| Wars | Pan-Septentrion War |
| Production history | |
| Designed | 1924—1929 |
| Produced | 1929—1944 |
| Specifications | |
| Weight | 19040 kg (gun only) |
| Barrel length | 10 meters (bore) |
| Caliber | 200mm |
| Breech | Welin breech block |
| Elevation | varies with mount |
| Traverse | varies with mount |
| Rate of fire | 2-4 rounds/min (depending on mounting) |
| Muzzle velocity | 840 m/s |
| Maximum firing range | 29,200 m at 46.7 degrees |
The 200mm L/50 Type 29 naval gun (Menghean: 200밀리 50구경장 29식 해군 대포, i-ryong-ryong milli o-ryong gugyŏngjang i-gu-sik haegun daepo) was a naval gun developed in the Greater Menghean Empire during the late 1920s. It formed the standard armament for Menghean heavy cruisers until the middle of the Pan-Septentrion War, when it was replaced in new construction by the 200mm L/55 Type 40 naval gun. A decent weapon for its time, it performed well in its "G-type" turret mounting, though the cramped "N-type" turret of the six-gun cruisers was found to have a lower rate of fire and higher dispersion.
Development
Under the Septentrion Nine-Power Naval Treaty, a capital ship was defined as any combat vessel with a standard displacement of over 12,000 long tons and carrying any gun with a caliber of over 8 inches (203 millimeters). This set the latter as the effective upper limit on caliber for "treaty cruisers" designed to make maximum use of the non-limited displacement category. An amendment to the treaty in 1930 further cemented this restriction, distinguishing between heavy cruisers with guns 6 to 8 inches in caliber and light cruisers with guns under 6 inches in caliber.
By the time of the treaty's signing, the Menghean Navy already operated a few armored cruisers with 8-inch guns, but these were 1900s-vintage weapons which the Navy deemed obsolete for newly built warships. As such, in 1924 ordered research into a new type of 200-millimeter gun which could be mounted on a prospective treaty cruiser design. This would eventually develop into the Madaesan-class. The requirements called for greater accuracy and range than early designs, as well as a new armor-piercing shell.
The completed naval gun was accepted for service in 1928, the 29th year of Menghe's unification, and was accordingly given the Type 29 designation. The cause of its long development is unknown, and surviving documents are scarce; some historians suggest it was due to limited funding from the Federal Assembly, which had also delayed the construction of the Madaesan-class cruisers, while others interpret it as a sign that the Navy waited until the Madaesan had been laid down before officially issuing the weapon a Type-year designation.
Description
The 200mm L/55 Type 29 was a built-up gun with a Welin breech block. Each round consisted of a single shell and two separate bag-type powder charges. On all naval mounts, the shell and charges were lined up behind the breech and rammed in automatically at a fixed angle of 5 degrees. As a result of the fixed loading angle, the exact rate of fire depended on the range of the engagement, as at long ranges the gun would have to transition to and from a higher elevation between each salvo.
Performance
Note: figures below are for the 126-kilogram Type 29 armor-piercing shell. High-explosive and illumination shells were also available; they had the same mass as the AP shell. Note that while the maximum range is listed for 46.7 degrees, the "G-type" turrets could only elevate to +45 degrees.
| Elevation | Range | Striking velocity | Angle of fall | Penetration (side) | Penetration (deck) |
|---|---|---|---|---|---|
| 2.4 degrees | 5,000 m | 650 m/s | 3.0 degrees | 268mm | N/A |
| 5.3 degrees | 10,000 m | 498 m/s | 7.5 degrees | 190mm | N/A |
| 10.5 degrees | 15,000 m | 396 m/s | 15.8 degrees | 139mm | 30mm |
| 18.0 degrees | 20,000 m | 364 m/s | 29.0 degrees | 96mm | 46mm |
| 31.0 degrees | 25,000 m | 380 m/s | 47.0 degrees | 72mm | 67mm |
| 46.7 degrees | 29,200 m | 394 m/s | 52.0 degrees | 60mm | 93mm |
Mountings
Two main mountings were designed for the 200mm L/50 Type 29 naval gun. The "G-type" was the original version intended for the Madaesan-class cruisers. It featured heavy armor comparable to the cruiser's main citadel, and offered good interior space for loading and fire control. The "N-type" turret, by contrast, was intended as a more compact version for use on the Taean and Jinan-class cruisers, which had a lighter displacement and a narrower beam. In an effort to save weight and space, the guns were mounted close together and were not individually sleeved; some internal equipment was also not duplicated. The armor was also thinner, though still comparable to the belt and deck armor of the Taean cruiser family. Because the gunhouse was more cramped and the hoists less efficient, the firing cycle was 28 seconds at +5 degrees, compared to 16 seconds at the same elevation on the "G-type" turret.
The narrow spacing between barrels on the "N-type" turrets was found to result in above-normal shell dispersion, because the muzzle blast from each gun impacted the trajectory of the shell from the gun next to it. An electronic timing system intended to slightly stagger the firing of the two guns was only slightly successful. There were no reports of disappointing accuracy on the "G-type" turrets, suggesting that the problem stemmed from the mounting rather than the gun itself.
While some heavy cruiser turrets in this period had the ability to elevate past 60 degrees and fire timed-fuse HE shells at formations of aircraft, this feature was not included on either turret type. Even if it had been, the slow traverse and elevation rates, as well as the need to return the gun to +5 degrees for reloading, would have rendered the anti-air capability ineffective for the most part, a problem which Dayashinese and Tyrannian cruiser captains encountered during the Pan-Septentrion War.
| Turret designation | G-type | N-type |
|---|---|---|
| Used on | Madaesan-class cruiser Taegisan-class cruiser |
Taean-class cruiser (1938 refit) Jinan-class cruiser |
| Elevation | -5 to +45 degrees | -5 to +50 degrees |
| Elevation rate | 8 degrees/sec | 8 degrees/sec |
| Train | -120 to +120 degrees | -135 to +135 degrees (?) |
| Train rate | 3 degrees/sec | 5 degrees/sec |
| Loading angle | +5 degrees | +5 degrees |
| Rate of fire | 3-4 rounds per minute | 2 rounds per minute |
| Independently sleeved? | Yes | No |
| Armor | Front: 200mm Sides:150mm Top:125-75mm Rear:20mm |
Front: 100mm Cheeks: 75mm Sides and rear: 20mm Top:50-30mm |
| Crew | Gunhouse: 20 Shell room: 9 Powder room: 10 |
Gunhouse: 17 Shell room: 9 Powder room: 10 |
See also