>This was called turbo-compounding, a very different thing from straight
>supercharging, or straight turbocharging, the main benefit here being fuel
>efficiency...

Well, as long as we're talking Connie's (is it still Friday?), they
actually use the Wright R-3350 engine (not 3340 as reported). The power
recovery turbines are geared back to the crankshaft and may contribute
something in the vicinity of 20% of the engine's power output.

Angus (aviation police)