Editing Mitsubishi A6M Zero (section)

===A6M5 Type 0 Model 52===
[[File:A6M5 scrapped.jpg|thumb|Mitsubishi A6M5 Model 52s among other aircraft types abandoned by the Japanese at the end of the war ([[Naval Air Facility Atsugi|Atsugi Naval Air Base]]) and captured by US forces.]]
<!-- [[File:Cockpit of an A6M5 Zero.jpg|thumb|Cockpit of a Mitsubishi A6M5 Model 52 Type Zero fighter at the [[Imperial War Museum]].]] -->
[[File:A6M5 52c Kyushu.jpg|thumb|A6M5c Zeros preparing to take part in a kamikaze attack in early 1945]]

Sometimes considered as the most effective variant,<ref>Mikesh 1994, p. 53.</ref> the Model 52 was developed to again shorten the wings to increase speed and dispense with the folding wing mechanism. In addition, ailerons, aileron trim tab and flaps were revised.<ref>Nohara 1993, p. 80.</ref><ref>''Sekai no Kessaku Ki'' Vol. 9, pp. 57–59.</ref> Produced first by Mitsubishi, most Model 52s were made by Nakajima. The prototype was made in June 1943 by modifying an A6M3 and was first flown in August 1943.<ref>''Sekai no Kessaku Ki'' Vol. 9, Bunrindou, 1993, p. 21.</ref> The first Model 52 is said in the handling manual<ref>''Summary of Provisional Handling Instructions'', February 1944, English translation.</ref> to have production number 3904,<ref>Mikesh 1994, p. 115.</ref> which apparently refers to the prototype.

Research by Mr. Bunzo Komine published by Mr. Kenji Miyazaki states that aircraft 3904 through 4103 had the same exhaust system and cowl flaps as on the Model 22.<ref>"Reisen Mushimegane", Fumetsu no Reisen, Maru, 2007.</ref> This is partially corroborated by two wrecks researched by Mr. Stan Gajda and Mr. L. G. Halls, production number 4007 and 4043, respectively.<ref>Gajda, Stan. [http://www.j-aircraft.org/smf/index.php?topic=9730.0 "The transitional Zero: New evidence that supports the theory."] ''j-aircraft'', 28 July 2010. Retrieved: 30 November 2015.</ref>{{vs|date=December 2015}}<ref>Halls, L.G. [http://www.j-aircraft.org/smf/index.php?topic=9974.0 "	 The "Hybrid" Zero: More Evidence."] ''j-aircraft'', 9 September 2010. Retrieved: 30 November 2015.</ref>{{vs|date=December 2015}}<ref>Lansdale, Jim. [http://www.j-aircraft.org/smf/index.php?topic=9048.0 "Transitional model of the Mitsubishi ReiSen 52 (A6M5): Part II."] ''j-aircraft'', 21 March 2010. Retrieved: 30 November 2015.</ref>{{vs|date=December 2015}} (The upper cowling was slightly redesigned from that of the Model 22.<ref name="Nohara 1993, p. 51"/>)
An early production A6M5 Zero with non-separated exhaust, with an A6M3 Model 22 in the background.
A new exhaust system provided an increment of thrust by aiming the stacks aft and distributing them around the forward fuselage. The new exhaust system required "notched" cowl flaps and heat shields just aft of the stacks. (Note, however, that the handling manual translation states that the new style of exhaust commenced with number 3904. Whether this is correct, indicates retrofitting intentions, refers to the prototype but not to all subsequent planes, or is in error, is unclear.) From production number 4274, the wing fuel tanks received [[Fire extinguisher#Halons, Halon-replacement clean agents and carbon dioxide|carbon dioxide fire extinguishers]].<ref>''Sekai no Kessaku Ki'', Vol. 9. pp. 57–59.</ref><ref>A6M5 Summary of Provisional Handling Instructions, February 1944 (translated) at 4-4.</ref> From number 4354, the radio became the Model 3, aerial Mark 1, and at that point it is said the antenna mast was shortened slightly.<ref>''A6M5 Summary of Provisional Handling Instructions'', February 1944 (translated). p. 4-4.</ref> Through production number 4550, the lowest exhaust stacks were approximately the same length as those immediately above them. This caused hot exhaust to burn the forward edge of the landing gear doors and heat the tires. Therefore, from number 4551 Mitsubishi began to install shorter bottom stacks.<ref>Nohara 1993, p. 79.</ref> Nakajima manufactured the Model 52 at its Koizumi plant in [[Gunma Prefecture]].<ref>''Sekai no Kessaku Ki'', Vol. 9 Bunrindou 1993, p. 23.</ref> The A6M5 had a maximum speed of {{convert|565|km/h|mph|abbr=on}} at {{convert|6000|m|ft|abbr=on}}, reaching that altitude in 7:01 minutes.<ref>''Sekai no Kessaku Ki'', Vol. 9, Bunrindou, 1993, p. 24.</ref>

Subsequent variants included:
* A6M5a, Model {{nihongo2|52甲}} (''Kō'', 52a) – Starting at Mitsubishi number 4651, an armament change substituted the belt-fed Type 99-2 Mark 4 cannon, with 125 rounds per gun, in place of the drum-fed Type 99-2 Mark 3 cannon that carried 100 rounds per gun. Hence, the bulge in the underside of the wing for each cannon's ammunition drum was deleted and the ejection port for spent cartridge cases was moved. Thicker wing skinning was installed to permit higher diving speeds.<ref name="Kessaku Ki 1993, p. 22">''Sekai no Kessaku Ki'', Vol. 9, Bunrindou, 1993, p. 22.</ref>
* A6M5b, Model {{nihongo2|52乙}} (''Otsu'', 52b) – Armament change: The 7.7&nbsp;mm (.303&nbsp;in) Type 97 gun ({{cvt|750|m/s|ft/s|abbr=on}} muzzle velocity and {{cvt|600|m|ft|abbr=on}} range) in the right forward fuselage was replaced by a 13.2&nbsp;mm [[Type 3 aircraft machine gun|Type 3 Browning-derived gun]] ({{cvt|790|m/s|ft/s|abbr=on}} muzzle velocity and {{cvt|900|m|ft|abbr=on}} range, with a rate of fire of 800 rounds per minute) with 240 rounds. The larger weapon required an enlarged opening, creating a distinctive asymmetric appearance to the top of the cowling, and a revised gas outlet near the windscreen. In addition, each wing cannon received a fairing at the wing leading edge. A plate of armored glass {{cvt|45|mm|abbr=on}} thick was fitted to the windscreen. A larger propeller spinner was fitted, suggesting a change to the propeller.<ref>''Sekai no Kessaku Ki'', Vol. 9, Bunrindou. p. 77.</ref> The type of ventral drop tank was changed, it now had fins and was suspended on a slanted pipe. The first of this variant was completed in April 1944 and it was produced until October 1944.<ref>Nohara 1993, p. 82.</ref>
* A6M5c, Model {{nihongo2|52丙}} (''Hei'', 52c) – Armament change: One 13.2&nbsp;mm (.51&nbsp;in) Type 3 machine gun was added in each wing outboard of the cannon, and the 7.7&nbsp;mm gun on the left side of the cowl was deleted. Four racks for rockets or small bombs were installed outboard of the 13&nbsp;mm gun in each wing. Engine change: Some sources state that the hei had a Sakae 31 engine<ref>''Mechanic of World Aircraft'', Vol.5, Koujinsha, p. 220-221.</ref> In addition, a {{cvt|55|mm|abbr=on}} thick piece of armored glass was installed at the headrest and an {{cvt|8|mm|abbr=on}} thick plate of armor was installed behind the seat. The mounting of the central {{cvt|300|L|USgal|abbr=on}} drop tank changed to a four-post design.<ref>''Sekai no Kessaku Ki'', Vol. 9, Bunrindou, pp. 46–49.</ref> Wing skin was thickened further. The first of this variant was completed in September 1944.<ref name="Kessaku Ki 1993, p. 22"/> Because of the gain in weight, this variant was used mainly for intercepting [[Boeing B-29 Superfortress|B-29s]] and special attack.<ref>Sekai no Kessaku Ki, Vol. 9 Bunrindou 1993 at 22.</ref>
* A6M5-S (A6M5 Yakan Sentōki) – Armament change: To intercept B-29s and other night-flying aircraft, an air arsenal converted some Model 52s to [[Night fighter|night fighters]].<ref>''Sekai no Kessaku Ki'', Vol. 9, Bunrindou, 1993, p. 23.</ref> They were armed with one 20&nbsp;mm Type 99 cannon behind the pilot, aimed upward, similar in intent to the Luftwaffe's [[Schräge Musik]] installation.<ref>Graham, Rob. [http://www.j-aircraft.com/a6mresearch/zeronf.htm "FAQ: Zero Night Fighter."] ''j-aircraft.com''. Retrieved: 30 November 2015.</ref> However, lack of radar prevented them from being very effective.

Some Model 21 and 52 aircraft were converted to "bakusen" ([[Fighter-bomber|fighter-bombers]]) by mounting a bomb rack and {{cvt|250|kg}} bomb in place of the centerline drop tank.

Up to seven Model 52 planes were ostensibly converted into A6M5-K two-seat trainers.<ref name="Francillon,1979, p. 399"/> Mass production was contemplated by Hitachi, but not undertaken.<ref>Nohara 1993, p. 84.</ref>