To modern eyes the D3A’s fixed, trousered undercarriage looks like a step backwards — by 1941 most front-line aircraft retracted their gear. But for a dedicated dive bomber the trade was deliberate. Retracting gear meant extra weight, hydraulics and structure, all for a modest speed gain the Navy was willing to forgo. Fixed gear was light, robust and could double as a rough dive reference, and the aircraft was never intended to outrun fighters.

Combined with large dive brakes and a very steady handling character, the fixed-gear layout helped make the D3A an exceptionally precise dive-bombing platform in the hands of well-trained crews. The same conservatism that made it look dated also made it simple to build and maintain, and forgiving to fly — qualities that mattered in the intense carrier operations of 1941–42. The penalty came later, when the type’s low speed left it desperately vulnerable to the improving Allied fighters of 1943 onward.

Early D3A1s used a Mitsubishi Kinsei radial of around 1,000 hp; the later D3A2 fitted the more powerful Kinsei 54 of roughly 1,300 hp, lifting top speed to about 430 km/h and extending range. Offensive load stayed modest by later standards — a single 250 kg bomb on a swing-out crutch that cleared the propeller in the dive, plus two 60 kg bombs on wing racks. Defence rested on two fixed forward-firing 7.7 mm machine guns and a single flexible 7.7 mm gun for the observer. It was never heavily armed; the D3A relied on accuracy, escort fighters and the skill of its crews rather than on firepower or protection.

The most cited demonstration of the D3A’s accuracy came in early April 1942, when carrier air groups struck British forces around Ceylon. On 5 April D3As overwhelmed the heavy cruisers HMS Cornwall and HMS Dorsetshire, sinking both within minutes; on 9 April they sank the carrier HMS Hermes and her escort. Accounts of the raid frequently quote an extraordinary hit rate — commonly given as around 80 per cent or higher against the cruisers — and the episode is often used to argue that the D3A sank more Allied warships than any other Axis aircraft. Both the precise percentage and the “most warships” claim are repeated widely but rest on wartime estimates and should be read as impressive-but-approximate rather than exact. What is not in doubt is that, against ships without air cover, the D3A and its trained crews were devastatingly effective in the spring of 1942.

The D3A was a wartime Japanese state product, built by Aichi for the Imperial Japanese Navy and never sold on an open market. No dependable flyaway unit price or cost-per-flight-hour figure survives in the public record, and wartime Japanese industrial accounting was disrupted by the collapse of 1945. What is well documented is the scale of production — roughly 1,495 airframes across the D3A1 and D3A2 variants. Any precise monetary figure attached to a D3A today should be read as an estimate, not a sourced fact.