Alpha Computer Systems wrote:

Paul,
What's the story on the moveable teardrop in the airflow exit area?
Does it reduce drag by streamlining outflow?  Inquiring minds
(non-engineering types) want to know! ;-)

Jim Brewer
Albemarle, NC

When you don't need all the cooling capacity the plug moves backwards and 
partially closes off the exit air. This causes the intake air flow to go
around the outside of the duct in what is known as external diffusion
thereby reducing the drag. It also speeds up what hot air is left
to provide a bit of thrust that overcomes some of the basic drag
of the cowling. Same idea with cowl flaps.

Paul Lamar
 
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