The D3A's successful engine raises a counterfactual about why comparable power was not offered to the Zero and B5N. Separate army and navy funding supported a wider choice of companies and research paths, while industrial depth remained limited. Standardizing the carrier aircraft around a stronger radial could increase the B5N's power by an estimated 200-300 horsepower and the Zero's by about 100 horsepower. Those estimates belong to the proposed comparison, rather than a tested conversion. A carrier could support its air group with one pool of spare engines and parts, and technicians could work with the same engine across its aircraft. That commonality would reduce the number of separate maintenance arrangements aboard ship.
Notable Point · 1:30:48-1:33:34
A common radial engine could simplify carrier-aircraft support
Standardizing the Zero, B5N and D3A around one stronger radial could simplify spares and maintenance and raise fighter and torpedo-bomber power.