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本帖最后由 mathewwu 于 2012-7-19 11:59 编辑
导因于1920.3兵器总监(DNO)提交的一份备忘录，怀疑低速重弹的效果，而建议采用高速轻弹。其实他的看法是基于不完全的实验论证。以下引用 "British Battleships of World War Two" by Alan Raven and John Roberts 的说明：
The general requirement was for a gun capable of defeating a ship protected by a 15-inch belt and a 7-inch deck. The design for the 18-inch gun was regarded most favourably as the one least likely to be outclassed by foreign designs. . . .
All the heavy gun designs considered early in 1920 and listed above, followed the practice that had begun with the 13.5-inch gun of having a heavy shell/low velocity combination, but in March 1920, the DNO issued a memorandum in which he cast serious doubts upon the advisability of this system. His arguments were based on the results of the proof tests of the 13.5-inch, 1,250-pound and 1,400-pound projectiles, which demonstrated that it was by no means certain that, at oblique attack, the heavier shell was the more efficient armour piercer. Both the light and the heavy 13.5-inch shell had to pass the same proof tests at the same striking-velocities, and while there were no failures with the 1,250-pound projectile, there were many, at first, with the 1,400-pound projectile. The failed shells usually passed through the plate but not in a fit state to burst, probably - it was thought - because of the greater length of the heavy shell. When penetrating armour at oblique angles of attack, the projectile was deflected from its line of flight, which produced a whip in the base portion. The stresses set up by this whip were greater in the long-bodied shell than in the short one, and its chances of breaking up during penetration were, therefore, greater.
It was also pointed out by the DNO that the existing 15-inch armour-piercing capped shell was not, as was commonly believed, capable of penetrating whole, any armour then carried afloat. Under proof conditions, only two such shells had successfully penetrated, in an unbroken condition, a 12-inch plate at 20° to the normal. The first was fired with a striking-velocity of 1,690 feet per second, equal to a range of 12,300 yards, at a standard armour plate, and the second, with 1,347 feet per second, equal to 25,000-yards, at a Vickers trial plate.
Trials against turret roofs showed that 5-inch and 6-inch armour when struck at 60° to the normal, could keep out a 15-inch shell, though a hole was punched in the armour. From these results, it was deducted that a 7-inch armour deck would defeat a 15-inch armour-piercing capped shell at 60°, that is up to a range of 25,000 yards. Only one trial at a steeper angle had been held, in which a 15-inch APC shell penetrated a 7-inch plate, at 45°, with a striking-velocity of 1,465 feet per second. Again, the DNO intimated that a shorter-bodied 15-inch shell would probably have better powers of penetration, and for future designs, he proposed the adoption of a high-velocity gun, firing a light shell. The theoretical advantages of a gun of this type were, a high striking-velocity at short range, a steep angle of descent at long range and a greater danger-space up to certain ranges. The loss in striking-energy resulting from the lower weight of a short shell compared to a long one of the same calibre and type, were considered by the DNO to be far more important in small and medium calibre guns than in heavy guns. Calculations showed, that for an equal maximum chamber pressure, a 1,690-pound 15-inch shell would have a muzzle velocity of 2,650 feet per second compared to 2,450 feet per second in the existing 1,920-pound shell. This gave the lighter shell a greater danger-space up to 22,000 yards, or 25,000 yards with a modified ballistic cap (6 crh instead of 8 crh). In the opinion of the DNO, the greater striking-energy of the heavy projectile would have little effect on the ability of the shell to perforate in a fit state to burst. Calculations were also made for the 18-inch gun with 8 crh projectiles of 3,353 pounds and 2,837 pounds and muzzle velocities of 2,500 feet per second and 2,700 feet per second respectively. The remaining velocities were found to be the same at 23,000 yards and only differed by 25 feet per second at 30,000 yards.
To test these theories, experiments were conducted with short-bodied 15-inch armour-piercing capped shells. The detailed results of these trials are not known, but they must have vindicated the DNO's arguments, for the 16-inch Mk I gun mounted in Nelson and Rodney used the high-velocity/light shell combination; in the event it was to prove a mistake.
It was considered that the best distribution of the main armament was in four twin turrets, arranged as in the Queen Elizabeth class. This system was ideal for efficient fire-control, and twin mountings allowed for turret designs of maximum simplicity and reliability. It was realised, however, that it might be necessary to adopt triple turrets in order to keep the displacement of the new ships within reasonable limits. Designs for both twin and triple mountings were obtained from Vickers and the Elswick Ordnance Company, for inclusion in the sketch designs of the 1921 to 1922 capital ships. These turret designs were given a maximum gun-elevation of 40° or 45°, which, it was thought, was necessary in order to obtain the maximum possible range.
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发表于 2012-7-19 10:01
发表于 2012-7-19 11:43
楼主
发表于 2012-7-19 12:31
