Originally Posted by
mrfox
In the B-36, the jet engines are only used for the high speed dash over the target area. During cruise on piston power, nacelle doors cover the unused jet intakes. This design seems to run counter to the assumption that a blocked intake is draggier than windmilling engines.
Dave Therhino already said it, but just to be more clear: there's at least 3 configurations under the discussion:
1. Blocked/faired intake
2. Open intake with windmilling engine
3. Open intake with seized engine
And I've listed them in order of what I now think is least to most drag. (At the beginning of the thread I thought 2 and 3 were reverwed, until the few guys referenced the ETOPS data)