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Sturgeon's House

Aerospace Pictures and Art Thread


LostCosmonaut

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DdjlPQi.jpg

 

These are valve-timing gears from the Bristol Hercules radial engine.  This engine powered a number of mid-WWII British aircraft including the Beaufighter and Stirling.

 

The Hercules used sleeve valves, which reciprocate independently of the pistons and thus require this giant mess of drive gears.  In the late 1930s there were a number of fairly convincing papers that predicted that aircraft engines would plateau in power density unless they switched to sleeve valves.  In actuality, conventional poppet valves were greatly improved and by the time aircraft sleeve valve engines were mature they had only modest power advantages over poppet-valve designs.

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1 hour ago, Collimatrix said:

DdjlPQi.jpg

 

These are valve-timing gears from the Bristol Hercules radial engine.  This engine powered a number of mid-WWII British aircraft including the Beaufighter and Stirling.

 

The Hercules used sleeve valves, which reciprocate independently of the pistons and thus require this giant mess of drive gears.  In the late 1930s there were a number of fairly convincing papers that predicted that aircraft engines would plateau in power density unless they switched to sleeve valves.  In actuality, conventional poppet valves were greatly improved and by the time aircraft sleeve valve engines were mature they had only modest power advantages over poppet-valve designs.

 

 

That's crazy complicated, the R-2800 master race!

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