A 1939 discussion of British, French, and German helicopter development leads into a counterfactual about the timing of naval adoption. The annual records coaxial and twin-rotor experiments, lift performance, hovering, backward flight, and the unresolved difficulty of directional control during autorotation. A later start to the war might have allowed useful shipborne helicopter capabilities to mature, especially for anti-submarine work involving dipping sonar. This remains a possibility because the passage does not claim that an operational solution was already available.
Notable Point · 23:45-25:37
Prewar helicopters and the anti-submarine question
Early helicopter reporting opens a counterfactual question: how might naval anti-submarine warfare have changed if rotary-wing aircraft had entered service before the war?