Boeing 787 Dreamliner .... Engine pods
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Boeing 787 Dreamliner .... Engine pods
I'm wondering if anyone can give me a reason as to why there is a small aerofoil, on the inboared section of both engine pods..... 
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These are usually there to improve low speed characteristics of the wing.
With a high AoA, the engine will "shield" much of the leading edge, strongly disrupting the airflow over the wing. In such a situation, these "aerofoils" will create a vortex that will flow over the wing and add some energy to the boundary layer, thereby delaying the flow separation and effectively decreasing the stall speed.
On relatively small straight-pipe or low bypass jets, those were not needed (see the 707 or CV880 for example), as the engines did not disturb the airflow that much. But with the progress in engine development and the ever increasing bypass ratios, those became necessary and are commonly found on DC-10, 737 Classic, A320, 777 and also on the 787.
With a high AoA, the engine will "shield" much of the leading edge, strongly disrupting the airflow over the wing. In such a situation, these "aerofoils" will create a vortex that will flow over the wing and add some energy to the boundary layer, thereby delaying the flow separation and effectively decreasing the stall speed.
On relatively small straight-pipe or low bypass jets, those were not needed (see the 707 or CV880 for example), as the engines did not disturb the airflow that much. But with the progress in engine development and the ever increasing bypass ratios, those became necessary and are commonly found on DC-10, 737 Classic, A320, 777 and also on the 787.
Diffuser,
There was a detailed thread about this under "Fins On Engine Cowlings" some time back. In fact there have been several threads if I recall correctly.
You can find it using Pprune SEARCH.
Cheers
There was a detailed thread about this under "Fins On Engine Cowlings" some time back. In fact there have been several threads if I recall correctly.
You can find it using Pprune SEARCH.
Cheers
