History question

[exftrplt]

When did exhaust valve rotators first turn up on aircraft engines? WWII or earlier? What engine was first? Radial or opposed first? Questions questions questions.

[WLIU]

Google tells me that

In 1918 Continental Engineering Corp filed a patent on the provision of means for rotating lift valves, e.g. to diminish wear

In 1954 a General Motors engineer applied for the patent for another mechanism.

In 1961 a Briggs & Stratton engineer filed for a patent describing a better mechanism.

In 1979 TRW filed for a patent of a better mechanism.

Best of luck,

Wes

[exftrplt]

Thanks WLIU