I think i have this correct. When the D-Model was produced, the number of 50 Cal went from 4 to 6 They obviously thought the added weight was worth it, but was it for sure.? i do not know, i am just asking. I would think you could carry more ammo if there are just 4 guns, but maybe i am wrong. Not even sure how the guns worked.......... be it 4 or 6, did they all fire at once until ammo was exhausted.? My main question is was it really better to have 6 over 4.? I am sure in certain scenarios it was. Was there any kind of general consensus from Pilots Did they want 6 guns.? Thank You
I don't know the exact background, but there are good reasons in principle: The basic indicator of firepower is kg/s, (For the simple lead thrower - from 20mm upwards, other nasties regarding "kaboom" come into play), which in the case described would mean an increase in destructive potential of 50%. This would have to be offset by very considerable disadvantages in order to dispense with it There are also factors that you want to compensate for: wing-mounted guns are less accurate than those mounted in the fuselage. (because the wings twist) They therefore tend to work according to the watering can principle. In addition, there is the peculiarity that jamming can occur at high G-forces. Mostly because the belt feed causes problems. So the rule of thumb applies here: The more, the better
Also to be borne in mind is how the armament of the P-51/Mustang REDUCED before getting to the P-51B. In order of production:- NA-73X prototype used by North American and Mustang I (from British order and including the 2 XP-51 given to the USAAF as prototypes as per contractual requirements) - 2x0.5" in lower fuselage & 2x0.3" (outboard) and 1x0.5" (inboard) in each wing. Mustang IA/F-6A/P-51 - first Lend Lease aircraft - 4x20mm. 55 of 150 retained by USAAF post Pearl Harbor. A-36A - First model ordered for the USAAF. 2x0.5" in lower fuselage & 4x0.5" in wings. Former often removed in service. P-51A/Mustang II - 4x0.5" in the wings. 350rpg in board & 280rpg outboard. P-51B/C/Mustang III - retained the armament of the P-51. Each version was building on what went before in a period of rapid development and taking account of combat lessons on other types. First flight of the NA-73X was 26 Oct 1940. The first RAF Mustang squadron became operational in Jan/Feb 1942. First flight of the prototype P-51B 30 Nov 1942. First flight of the P-51D as on 17 Nov 1943, a fortnight before the first P-51B flew their first mission on 1 Dec 1943. When it came to the P-51D/K/Mustang IV/IVa it was not just a case of adding 2 more guns to increase its "limited" firepower. Substantial revisions were made to the wing which included a new design for the armament. The guns were mounted upright instead of being tilted at an angle which had been identified as a source of jamming in the feed belts. 400rpg for the innermost guns and 270rpg for the outer two pairs. It was possible to fit just 4x0.5" with 400rpg for all guns, and some pilots preferred that option. I've seen it claimed that for those pilots who excelled in air to air combat, 4x0.5" was plenty. For the average pilot, who were the majority, the more guns the better. A similar debate existed with the P-40. It went from a mixed 0.3"/0.5" armament in P-40B/C to 4x0.5" in the P-40D (only 22 built) to 6x0.5" in the P-40E. Later, to lighten the aircraft, most of the P-40L and very early P-40N reverted to 4x0.5"
