Aichi B7A Ryūsei

{{Short description|Japanese carrier-borne torpedo and dive bomber}} {{pp-semi-indef|small=yes}} {{Use dmy dates|date=May 2021}} {{Use American English|date=May 2021}}  {{Infobox aircraft |name= B7A ''Ryūsei'' |image= File:Aichi B7A Ryusei.jpg |caption= |type= Torpedo bomber and Dive bomber<ref name="chant-15">Chant 1999, p. 15.</ref> |national_origin= Japan |manufacturer= Aichi Kokuki <br/> 21st Naval Air Arsenal |designer= |first_flight= May 1942<ref name="chant-15"/> |introduction= |retired=September 1945 |status= |primary_user= Imperial Japanese Navy Air Service |more_users= |produced= 1942–1945 |number_built= 114 total |unit cost= |variants= }}

The '''Aichi B7A {{nihongo|''Ryūsei''|流星|"Shooting Star"}}''' (Allied reporting name "''Grace''"), was a large and powerful carrier-borne torpedo-dive bomber produced by Aichi Kokuki for the Imperial Japanese Navy Air Service during the Second World War. Built in only small numbers and deprived of the aircraft carriers it was intended to operate from, the type had little chance to distinguish itself in combat before the war ended in August 1945.

==Design and development== The B7A ''Ryūsei'' (originally designated AM-23 by Aichi)<ref name="Francillon1979p289">Francillon 1979, p. 289.</ref> was designed in response to a 1941 16-Shi requirement issued by the Imperial Japanese Navy Air Service for a carrier attack bomber that would replace both the Nakajima B6N ''Tenzan'' torpedo plane and the Yokosuka D4Y ''Suisei'' dive bomber in IJN service.<ref name="chant-15"/> It was intended for use aboard a new generation of ''Taihō''-class carriers, the first of which was laid down in July 1941. Because the deck elevators on the ''Taihō''s had a larger square area than those of older Japanese carriers, the longstanding maximum limit of {{convert|11|m|ft|abbr=on}} on carrier aircraft length could now be lifted.<ref name="Francillon1979p288">Francillon 1979, p. 288.</ref>

Chief Engineer Toshio Ozaki (name often seen as Norio Ozaki, but this is incorrect because the Kanji for both first names are the same and often confused) chose a mid-wing arrangement for the B7A to provide for an internal bomb-bay and to ensure enough clearance for the plane's {{convert|3.5|m|ft|abbr=on}} four-bladed propeller. This in turn necessitated the adoption of an inverted gull wing, similar to the F4U Corsair, in order to shorten the length of the main landing gear. The wing featured extendable ailerons with a ten-degree range of deflection, enabling them to act as auxiliary flaps. Dive brakes were fitted underneath just outboard of the fuselage. The B7A's outer wing panels were designed to fold upwards hydraulically for carrier stowage, reducing its overall span from {{convert|14.4|m|ft|abbr=on}} to approximately {{convert|7.9|m|ft|abbr=on}}.<ref name="Francillon1979p289"/>

Selection of a powerplant was dictated by the Japanese Navy, which requested that Aichi design the aircraft around the 1,360 kW (1,825 hp) Nakajima NK9C ''Homare'' 12 18-cylinder two-row air-cooled radial engine. This was expected to become the Navy's standard aircraft engine in the 1,340 kW (1,800 hp) to 1,641 kW (2,200 hp) range.<ref name="chant-15"/> One production model B7A2 was later fitted with a 1,491 kW (2,000 hp) Nakajima ''Homare'' 23 radial engine and plans were also made to fit the 1,641 kW (2,200 hp) Mitsubishi MK9 radial to an advanced version of the ''Ryūsei'' (designated B7A3 ''Ryūsei Kai'') but the latter effort never came to fruition.

The B7A had a weight-carrying capacity stemming from its requirements,<ref name="Francillon1979p288"/> resulting in a weapons load no greater than its predecessors. The presence of an internal bomb bay with two high-load-capability attachment points allowed the aircraft to carry two 250 kg (550 lb) or six 60 kg (132 lb) bombs. Alternatively, it could carry a single externally mounted Type 91 torpedo, weighing up to 848 kg (1,870 lb).<ref>NOT the famous "Long Lance", Type 93 torpedo, much too heavy and unfit to aerial drop from a plane; a derived "type 94" for plane use had been developed but not deployed</ref>

Defensive armament initially consisted of two 20 mm Type 99 Model 2 cannons in the wing roots and one flexible 7.92 mm Type 1 machine-gun mounted in the rear cockpit. Later production models of the B7A2 featured a 13 mm Type 2 machine-gun in place of the 7.92 mm gun.<ref name="Francillon1979p291">Francillon 1979, p. 291.</ref>

Despite the plane's weight and size, it displayed fighter-like handling and performance, beating the version of the A6M Zero in service at the time. It was fast and highly maneuverable.<ref name="Gunston1985p26">Gunston 1985, p. 26.</ref>

Given the codename "'''Grace'''" by the Allies, the B7A first flew as a prototype in May 1942, but teething problems with the experimental NK9C ''Homare'' engine and necessary modifications to the airframe meant that the type did not enter into production until two years later in May 1944.<ref name="chant-15"/> Nine prototype B7A1s were built and 80 production version B7A2s completed by Aichi before a severe earthquake in May 1945 destroyed the factory at Funakata where they were being assembled. A further 25 examples were produced at the 21st Naval Air Arsenal at Omura.<ref name="Mondey1984p8">Mondey 1984, p. 8.</ref>

==Operational history== In June 1944, the ''Taihō'' was the only Imperial Japanese Navy aircraft carrier then modern enough to operate the B7A ''Ryūsei'' in its intended role. Other Japanese carriers lacked the modern arresting gear necessary to assist the recovery of aircraft weighing over 4000 kg. However, ''Taiho'' was sunk during the Battle of the Philippine Sea before enough B7As were even available to embark. Afterward, the B7A was relegated to operating from land bases, primarily with the Yokosuka and 752nd Air Groups.<ref name="chant-15"/> The Japanese completed only one other carrier capable of operating the B7A, the ''Shinano'', which was sunk by ''Balao''-class submarine ''Archerfish'' in November 1944, just ten days after being commissioned.

==Variants== ;B7A1: One prototype and eight supplementary prototypes. ;B7A2: Two-seat torpedo-dive bomber aircraft for the Imperial Japanese Navy; 105 built.<ref name="combinedfleet">Matsuura 1997 [http://www.combinedfleet.com/ijna/b7a.htm Aichi B7A Ryusei (Shooting Star)] retrieved: 16 September 2010.</ref> ;B7A2 Experimental: One aircraft fitted with a 1,491 kW (2,000 hp) Nakajima ''Homare'' 23 radial engine. ;B7A3: Proposed version with a 1641 kW (2,200 hp) Mitsubishi MK9A (Ha-43). Not built.

===Number built=== According to Model Art (2000), p. 72. *Funakata Factory, Aichi Kokuki, Nagoya, work number 3201-3289. {| class="wikitable" | || January || February || March || April || May || June || July || August || September || October || November || December || Sub total |- | 1942 || colspan="11"| || 1 || 1 |- | 1943 || 0 || 0 || 0 || 1 || 0 || 1 || 1 || 1 || 1 || 0 || 1 || 0 || 6 |- | 1944 || 1 || 1 || 0 || 0 || 1 || 0 || 1 || 1 || 2 || 5 || 5 || 9 || 26 |- | 1945 || 7 || 12 || 11 || 13 || 8 || 3 || 2 || 0 || colspan="4"| || 56 |} *21st Naval Air Arsenal, Imperial Japanese Navy, Ōmura, work number 1-25. {| class="wikitable" | || January || February || March || April || May || June || July || August || September || October || November || December || Sub total |- | 1944 || colspan="3"| || 1 || 0 || 1 || 0 || 1 || 4 || 1 || 0 || 0 || 8 |- | 1945 || 2 || 1 || 3 || 2 || 4 || 0 || 4 || 1 || colspan="4"| || 17 |}

==Operators== ;{{JPN}} *Imperial Japanese Navy Air Service **Yokosuka Naval Air Group **131st Naval Air Group **752nd Naval Air Group **1001st Naval Air Group **5th Attack Squadron, a part of 131st/752nd Naval Air Group

==Specifications (B7A2)== [[File:B7A-Ryusei-1.jpg|thumb|Aichi B7A ''Ryūsei'', prototype #7. Naval Air Technical Arsenal ''Ko-B7-7''.]] [[File:B7A-Ryusei torpedo.jpg|thumb|Aichi B7A carrying a torpedo. Yokosuka Naval Air Group ''Yo-231''.]] thumb|Captured Aichi B7A "Grace". {{Aircraft specs |ref=''Aircraft of World War II - 300 of the World's Greatest aircraft 1939–45,''<ref name="chant-15"/> ''Aichi B7A Ryusei (Shooting Star),''<ref name="combinedfleet"/> ''and Japanese Aircraft of the Pacific War'' <ref name="Francillon1979p291"/> |prime units?=met  |crew=2 |length m=11.49 |length note= |span m=14.4 |span note= |width m= |width note= |height m=4.075 |height note= |wing area sqm=35.4 |wing area note= |aspect ratio= |airfoil= |empty weight kg=3810 |empty weight note= |gross weight kg=5625 |gross weight note= |max takeoff weight kg=6500 |max takeoff weight note= |fuel capacity= |lift kg= |lift note= |more general=  |eng1 number=1 |eng1 name=Nakajima NK9C Homare 12 |eng1 type=18-cylinder air-cooled radial piston engine |eng1 hp=1825 |eng1 note=for take-off ::::{{cvt|1670|hp|order=flip}} at {{cvt|2400|m}} ::::{{cvt|1560|hp|order=flip}} at {{cvt|6550|m}}

|prop blade number=4 |prop name=constant-speed propeller |prop dia m=3.5 |prop dia note=  |max speed kmh=567 |max speed note=at {{cvt|6550|m}} |max speed mach= |cruise speed kmh= |cruise speed note= |stall speed kmh= |stall speed note= |never exceed speed kmh= |never exceed speed note= |minimum control speed kmh= |minimum control speed note= |range km=3038<ref name="chant-15"/> |range note= |combat range km= |combat range note= |ferry range km= |ferry range note= |endurance= |ceiling m=11250 |ceiling ft=36900 |ceiling note= |g limits= |roll rate= |climb rate ms=9.6 |climb rate note= |time to altitude={{cvt|4000|m}} in 6 minutes 55 seconds |wing loading kg/m2=158.9 |wing loading note= |fuel consumption kg/km= |power/mass={{cvt|0.147|hp/lb|kW/kg|order=flip}} |thrust/weight=

|more performance=  |guns=<br> ** 2× {{cvt|20|mm|3}} Type 99 Model 2 cannon in the wings ** 1× {{cvt|7.92|mm|3}} Type 1 machine gun or {{cvt|13|mm|3}} Type 2 machine gun in the rear cockpit |bombs=<br> ** {{cvt|800|kg|0}} of general ordnance ''or'' ** 1× {{cvt|800|kg|0}} torpedo }}

==See also== {{aircontent |related= |similar aircraft= * Douglas BTD Destroyer * Douglas A-1 Skyraider * Fairey Spearfish * Blackburn Firebrand |lists= * List of aircraft of World War II * List of bomber aircraft * List of military aircraft of Japan }}

==Notes== {{Reflist|2}}

==Bibliography== * Chant, Chris. ''Aircraft of World War II - 300 of the World's Greatest aircraft 1939-45''. Amber Books Ltd., 1999. {{ISBN|0-7607-1261-1}}. * Francillon, Ph.D., René J. ''Japanese Aircraft of the Pacific War''. London: Putnam & Company Ltd., 1979. {{ISBN|0-370-30251-6}}. * Gunston, Bill. ''Military Aviation Library World War II: Japanese & Italian Aircraft''. Salamander Books Ltd., 1985. {{ISBN|0-89009-899-9}}. * {{cite journal |last1=Millot|first1=Bernard|title=Aichi B7A "Ryusei" (Grace)|journal=Le Fana de l'Aviation: Le Fanatique de l'Aviation |date=October 1976 |issue=83 |pages=26–29 |issn=0757-4169 |language=fr|trans-title=}} * Mondey, David. ''Concise Guide to Axis Aircraft of World War II''. Temple Press, 1984. {{ISBN|0-600-35027-4}}. * Model Art Special Issue ''Carrier Attack Bombers of the Imperial Japanese Navy''. Model Art Co., Ltd., 2000.

==External links== {{commons category}}

* {{cite web |author=Joao Paulo Julião Matsuura |url=http://www.combinedfleet.com/ijna/b7a.htm|title=Aichi B7A Ryusei (Shooting Star)|access-date=16 September 2010|work=combinedfleet.com |series=WWII Imperial Japanese Naval Aviation Page|year=1997}} * [http://www.nasm.si.edu/collections/artifact.cfm?id=A19630360000 Aichi B7A2 Ryusei (Shooting Star) GRACE] {{Webarchive|url=https://web.archive.org/web/20100408191012/http://nasm.si.edu/collections/artifact.cfm?id=A19630360000 |date=2010-04-08 }} - National Air and Space Museum * [http://www.ijnafphotos.com/jbwb7a1.htm IJN Pics]

{{Aichi Aircraft}} {{Japanese Navy short aircraft designations}} {{Imperial Japanese Navy official aircraft names}} {{Allied reporting names}}

{{DEFAULTSORT:Aichi B7A Ryūsei}} B7A Ryūsei B7A Ryūsei, Aichi Category:Single-engined tractor aircraft Category:Low-wing aircraft Category:Inverted gull-wing aircraft Category:Carrier-based aircraft Category:Aircraft first flown in 1942 Category:Aircraft with retractable conventional landing gear Category:Single-engined piston aircraft