http://en.wikipedia.org/wiki/Aichi_E16A

Artist's commentary:

日本海軍の水上偵察機……兼、急降下爆撃機。
『日本の兵器：「必要だったのは分かるが、どうしてそこまでするのかが分からない｣』と言うジョークを地で行くような機体です。
確かにアメリカの名機ドーントレスは「SB」つまり「Scout Bomber(偵察及び爆撃機)」とナンバリングされていたかも知れません。しかし、偵察機に急降下爆撃機能を付加するとか発想が斜め上過ぎる。米軍のドーントレスによる｢行きがけの駄賃爆撃」で痛い目見たのは事実ですし、偵察をしながら第一撃を加えられるに越した事はありません。それに空母が不足している中、飛行甲板を持たない艦艇から発進できる水上機に爆撃機能を持たせられるメリットは大きかったと思います。
しかし、さらに空戦フラップまで装備するとか非常識もいいところ。そもそも空戦フラップを急降下爆撃機に装備するという発想自体普通ありません。
「新技術はとりあえず何でも導入してみる」という技術者の悪い癖が大いに発揮された機体です。

そんな機体ですが、夜間爆撃などでなかなかの戦果を上げることが出来たようです。

Artist's commentary:

The Aichi E16A Zuiun was a Japanese naval reconnaissance seaplane.......as well as a dive-bomber.
The body of the Zuiun is one that really captures the essence of this ethnic joke, "Japanese weapons: 'We know that they're necessary, but we don't know why they had to go so far in doing it.'"
Certainly, it was a fact that the renowned American aircraft, the Dauntless was provided with an SB, or "Scout Bomber" designation number. Even so, the idea of adding dive-bomber capabilities to a reconnaissance aircraft was a rather foolish one.
It is known that due to the "gaining a reward on the way" attack by the US forces' Dauntless, the Japanese navy suffered significantly. And a preemptive capability during reconnaissance operations is a nice-to-have feature. Furthermore, the merit of a seaplane that possessed bombing capabilities and was deployable from warships without a flight deck was largely appreciated by the IJN that lost main aircraft carriers at the Battle of Midway.
However, it is safe to say that equipping the Zuiun with such functions as combat flaps also lacked common sense. From the offset, the idea of fitting combat flaps to a dive-bomber was unheard of.
The Zuiun's body largely demonstrates the engineers' terrible weakness for "trying to incorporate new technology at any cost."
Despite having possessed such a body, it appears that the Zuiun was able to make considerable military gains during night-time bombing operations.

The artist was a little off. The full version of the correct joke is below. This was spread on 2ch as an ethnic joke about each country's military.

French weapons: "We know what they wanted to do, but is that really all they wanted to do?"
Italian weapons: "We know why their weapons ended up like that, but did they really have to do that?"
English Weapons: "We know what they wanted to do, but we don't know why their weapons ended up like this"
Soviet weapons: "We know why their weapons ended up like this, but we don't know what they wanted to do."
German weapons: "We know they had to do it this way, but we don't know why they had to go so far in doing it."
Japanese weapons: "We know they had to do it this way, but we never really thought they'd actually use them."
American weapons: "We know that they're necessary, but we don't know why they had to make so many of them."

The original joke:

フランスの兵器「何がしたかったのかはわかるが、やりかったことというのはその程度なのか？」
イタリアの兵器「どうしてそうなるのかはわかるが、そうするしかないものなのだろうか？」
イギリスの兵器「何がしたかったのかはわかるが、どうしてこうなったのかはわからない」
ソ連の兵器「どうしてこうなったのかはわかるが、何がしたかったのかはわからない」
ドイツの兵器「こうするしかなかったのはわかるが、そこまでしてやる理由がわからない」
日本の兵器「こうするしかなかったのはわかるが、まさか本当にやるとは思わなかった」
アメリカの兵器「必要なのはわかるが、そこまで沢山作る理由がわからない」

American weapons: "We know that they're necessary, but we don't know why they had to make so many of them."

QFT!!!