Why did the US Navy prefer radial engines?

Short answer

The US Navy knew radial engines were much simpler to maintain and that their rugged design could absorb combat damage and keep flying. An inline engine was far more vulnerable to a hit on its cooling system that could seize the engine. That cooling also added complexity and maintenance.

Published: October 31, 2026 · Updated: October 31, 2026 · Edited by Above Ten Thousand · Editorial policy

Why did the US Navy prefer radial engines?

F4U at 2023 Oshkosh

The US Navy's preference for radial engines stemmed from a simple idea: they were much easier to maintain.

Fewer systems to look after

The cooling systems that came with inline designs added complexity and required more maintenance. The radial was also a trusted engine. The US Navy assumed a radial was far simpler to maintain.

Withstanding hits

The radial's design was rugged: it could absorb combat damage and keep flying. An inline engine, by contrast, was far more vulnerable to hits on its cooling system, risking the engine seizing up. That combination of ruggedness and the ability to keep flying after taking damage was part of the Navy's reasoning.

The F4U Corsair as an example

The F4U incorporated the largest engine available at the time: the 18-cylinder Pratt & Whitney R-2800 Double Wasp radial, producing 2,000 hp (1,500 kW). The propeller clearance problem was solved by placing the main landing gear at the lowest point of the V formed by each wing, allowing for a short, sturdy landing gear leg.