Aiči B7A Rjúsei [Grace]

Aichi B7A - an overview of the versions

艦上攻撃機"流星"- Kandžó kógekiki Rjúsei - on-Board attack aircraft Rjúsei

Allied code name: Grace
Japanese name: 流星 - Ryusei -a Comet - shooting star






sources:
Tadeusz Januszewski and Kryzysztof Zalewski, Japońskie samoloty marynarski 1912-1945, volume 1., Lampart, year 2000, ISBN: 83-86776-50-1
http://www.combinedfleet.com/ijna/b7a.htm
author archive.

Aichi B7A Ryusei[/heading]

the Creation and production:

Approximately in the middle of 1941, issued by command of the imperial navy (海軍航空本部 Kaigun Kōkū Hombu), the specifications for the 16-Shi (16-Shi), in these specifications, and are among other things also the technical requirements for the new on-board attack aircraft. The requirements for this aircraft issued by the navy made a considerable advance, we must remember that at that time in the company of 中島飛行機株式会社 - Nakajima Hikōki Kabushiki Kaisha (hereinafter referred to as Nakajima) has launched the construction of the first two prototypes of on-board torpedo bombers B6N Tenzan, later in the my ally code known as Jill. The newly required aircraft so had to supplement, or replace the currently developed aircraft B6N and dive bombers D4Y Suisei (Judy). Yes, the new attack aircraft was to perform the role of both categories of aircraft should be capable of torpedo attack, but also hit the target bombs from dive bombing.

The technical department of the naval air force had deployed the imaginary bar performances really high, the required maximum speed of 570 km/h, a range of 1 850 km with a load of 800 kg of bombs in bomb bay or podvěšeným torpedo. Without the bomb load was required in the range 3 to 300 km. For the attack was, next to bombs or torpedoes, required there the armament and for their own defense had a second crew member to operate the machine gun. A great emphasis was placed on maneuverability, this should be at the level of the legendary A6M2 Zero. Kaigun Kōkū Hombu requested that it was possible to hang up all my gear into the bomb bay, it turned out in the case of air version of the torpedo type 91 Kai 2 as impossible, and so the request was modified - torpedo zavěšovalo under the torso slightly to the left. The bomb bay accommodate e.g. two dvousetpadesátikilové bombs, or one piercing weighing 800 kg bombs of smaller caliber, of course zavěšovaly to the bomb bay. The design team had one advantage on his side - he didn't have to in their plans to restrict the small size of the cabin elevators of existing aircraft carriers, these elevators were the planes transported on the flight or hangar deck, so far, there were limitations for the length of the on-board aeroplane eleven meters, this limitation has now been made and the designers could go with a length of up to thirteen metres. The navy planned that these new attack drones, will operate from the decks of large aircraft carriers of the class Taihō (Taihó), the keel of this ship was founded in the shipyards in the Kobe in July this year. The truth is, that of the five planned ships were completed, only one – Taihō (大鳳) and she was sunk just three months after the completion of the american submarine the USS Albacore.

Specifications 16-Shi, i.e., the actual requirements for on-board attack bomber were awarded directly to the company 愛知航空機株式会社 - Aichi Kōkūki Kabushiki Kaisha based in Eitoku (hereinafter referred to as Aichi), the company's management has instructed the start of work on the project factory's designated as AM-23 engineer engineer Norio Ozaku, who assisted Yasusiro Odzava and Morisige Mori. Meet all the requirements of naval aviation it was a really daunting task and to meet the many and sometimes conflicting requirements was a really challenging design problem.

Ozakův the design team is put to work without delay and after less than a year he was already in may 1942, completed the first prototype. The resulting piece was very graceful all-metal středoplošník with wings conspicuously bent to the shape of the letter "W". With regard to the dimensions of the bomb bay were the overall dimensions, on-board the aircraft, quite impressive. The outer part of the wings can be folded up and the margin of the folded wings was only seven and a half feet, and the aircraft worked in the hangar much less valuable space. The prototype was powered by yet neodladěným and therefore not very reliable engine NK9B Homar 11 capacity of 1 800 hp. The prototype engine was tested not long before the release specification 16-Shi, however, did not prevent the marine technicians, so its use was not part of the requirements. The engine in this early version suffered from very poor properties – completely unexpectedly decreased filling pressure of the compressor and reciprocally dramatically decreased the performance of the engine, to eliminate this defect worked the japanese technicians-motoráři until 1944, the defect was completely removed except for the version NK9H-WITH Homar 23. Engine spinning a four-blade propeller with a constant speed about an average of 3 450 mm. Thanks to the "prolomeným" wings, didn't have to be the chassis, with regard to the středoplošnou concept too high. The wing was equipped with slot flaps and their effectiveness increased the ailerons, which vysouvala together with the flaps. On the bottom side of the centerplane were still braking flaps, which are necessary to maintain the speed at an optimum level during the dive bombing. In the wings were installed two cannons the type 99 model 2 the caliber of 20 mm and an observer / radio-operator / gunner in one person could have space for aircraft to defend the machine gun type 1 the caliber of 7.92 mm. Soon after the completion of the prototype have been launched flight tests. If it wasn't for unreliable engine operation, it would be a very good aircraft, the required maximum speed has been exceeded, the prototype reached, if the engine allowed a speed of 590 km/h, unfortunately, the engine's too often allow it. Pilots are highly expressed on the flight characteristics, perhaps even leaking hydraulics chassis worked some problems. The test, however, thanks to the nevyzrálému engine protahovaly, although involve a total of nine prototypes marked B7A1. The navy is adopted under the comprehensive designation of "on-Board torpedo bomber Ryusei". These prototypes to combat units received were used solely for testing.

In April 1944 they were available more reliable engines NK9C Homar 12, then in a factory in the city Funataka, belonging to the group Aichi launched a serial production of the new version of the attack bomber, identified B7A2 Ryusei. Engine Homar 12 was already debugged, compared to the previous version has been changed the gear ratio of the compressor and, if necessary, higher performance, it was possible to the compressor to inject a mixture of water and methanol (similar to the German device MW-50). Changes to see also defensive armament, in the back of the cabin was installed more efficient velkorážný machine gun type 3 the caliber 13.2 mm. Production is therefore easy pace run, helped by the fact the fact that the production of this sophisticated aircraft was about something less demanding than the production of a smaller dive bomber Yokosuka (Yokosuka) D4Y2 Suisei (Judy). In Funatace was to may 1945 produced a total of eighty bombers B7A2, in may this area of Japan suffered a devastating earthquake, which was the production in this factory ceased completely. Twenty-five aircraft of this type made in parallel 21. Naval arsenal in the Sasebu (大村の第二一海軍航空廠 - Omura Well Dai Ni Ichi Kaigun Kokusho, Sasebo), with the approaching end of the war the production was accompanied by the constant problems with the quality and quantity of material required for the construction of these aircraft. The japanese navy was meanwhile forced to reassess the need for such on-board aircraft. From the construction of affiliated carriers class Taihō gathered, the only other aircraft carrier, from which they could make aircraft Ryusei operate was a giant 信濃 - Shinano (Šinano), but she was sunk before inclusion into the service during one of the recent test cruises. The imperial japanese navy, therefore, had no suitable aircraft carrier, in fact this was also one of the reasons why even in 1945 Kaigun Kōkū Hombu zformulovalo directive 20-Shi, which after suppliers of aviation equipment requiring a smaller attack bomber that could operate from the decks of the other carriers. The answers to these specifications, the project was marked B8A1 Mokusei, but this aircraft did not exceed the stage of the project.

Let's go back to the type of B7A Ruysei, one aircraft was modified for the installation of the engine NK9H-S Homar 23 about the performance of the 2 000 hp, this engine already had low-pressure fuel injection and finally to the designers got rid of the vices of previous versions – a sudden loss of power. Aircraft with this engine was only tested. On paper no longer remained version B7A3 with the engine Mitsubishi (Mitsubishi) MK9A with take-off power of 2,200 horsepower.

Use:

The aircraft should operate on board aircraft carriers Taihō, she had to bear the 24 on-board fighters A7M2 Reppu (Sam), a 24 attack bomber B7A2 Ruisei (Grace) and 4 reconnaissance aircraft C6N1 Saiun (Myrt), at the time of the sinking had on board 22 fighter A6M5 Reisen (Zero), 18 torpedo bombers B6N2 Tenzan (Jill), 22 dive bombers D4Y2 Suisei (Judy) and 3 of the older dive bombers D3A2 (Val). The giant aircraft carrier Shinano was to carry, among other types of 20 aircraft Ryusei.

A real combat deployment of these powerful and resourceful aircraft was very deplorable, most of these aircraft had in its state 752. Kokutai, it was in February 1945, when this unit operated from a base in Katori, Chiba prefecture (Chiba), probably were her aircraft Ryusei deployed in battles over Okinawa. Suggests that the fact that after the cessation of the fighting was completed and the unit was held in reserve at the base of the Kisarazu for the case of the allied landings. Another unit that had these aircraft in its arsenal, was 131. Kokutai and 1001. Kokutai. With the approaching end of the war through the japanese forces frequent reorganisations and merging, it is therefore difficult to track down which unit the aircraft Ryusei should in your condition, you need only to make them again to take the next step. American fighter pilots and, above all protiletadloví gunners shot down his "Japa" and the intelligence officer, according to the description of the assigned type of the downed machine. On the basis of a detailed research, however, historians will get to an interesting report. Eg. 19. 3. 1945 was in the battles of Okinawa very badly damaged aircraft carrier class Essex the USS Franklin, operate in the Task Force TF-58.4. On that day, first it was attacked by a suicide air raid twin-engine bomber G4M2 Betty, that will, however, ride along the deck and jumped into the sea. Subsequently he approached the dive bomber D4Y3 Judy, and now watch out, flinging two dvousetpadesátikilové bombs, one on the bow and the other at the stern of the boat, inside the boat broke out a large fire, which was extinguished until the following day... As we know, bomber Judy two cougars this mass never has been and it wasn't even possible for him to hang up. Ryusei (Grace) however, in its bomb bay two such bombs could carry, in addition, it was a completely new type of aircraft, whose silhouette was not known, and then we get to this: single-engine dive bomber = Judy. The second kind of case is that of a torpedo attack four operations of single engine aeroplanes by day 12. 8. 1945 to the union of the anchored battleships of admiral Oldendorfa. One dropped a torpedo punched into the stern of the BB-38 USS Pennsylvania devítimetrový hole. In the report of captain William M. Moses is mentioned that the attacking aircraft was a single-engine with a strong break of the wings. This once again clearly shows the deployment of Ryusei. On the other hand, however, there are also reports, where these planes are identified as the Betty (G4M).

The allied intelligence service, this aircraft has assigned a code naming Grace.

One specimen has been preserved to the present day, is stored in the depository of the Smithsonian National Air and Space Museum in the unfolded state.

sources:
René J. Francillon Ph. d., Japanese Aircraft of the Pacific War, Naval Institute Press, Annapolis Maryland, Reprinted 1990, ISBN 0-87021-313-X.
Tadeusz Januszewski and Kryzysztof Zalewski, Japońskie samoloty marynarski 1912-1945, tiel 2, Lampart, 2000, ISBN 83-86776-00-05.
Of aeronautics and astronautics no. 8/ 1988, publishing Our troops, str. 29/ 309, Václav Němeček, Aircraft 39-45, Aichi B7A Ryusei, ISSN 0024-1156.
http://www.combinedfleet.com/ijna/b7a.htm
http://www.airtoaircombat.com/detail.asp?id=268
http://www.aviastar.org/air/japan/aichi_b7a.php
http://www.airwar.ru/enc/bww2/b7a.html
http://ja.wikipedia.org/wiki
www.aviation-history.com
airandspace.si.edu
author archive

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