Quote:
Originally Posted by winkosmosis
Are you saying that the purpose of the design is to blow air into the low pressure area at the rear of the vehicle to increase pressure from the normal vacuum? That's fine with me.
But that isn't shown in any of the posts so far... the concept seems to rely on the shape of the tailcone
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Yes, the goal is to prevent the typical low pressure separation bubble behind the vehicle. I added a 'before & after' graphic at the bottom of page 2 that shows a sedan with no suction that suffers drag from this bubble and the same geometry with suction that eliminates the bubble & over half of the momentum deficit.
You're right, the shape of the tailcone is very important. Just like lift from a wing depends on camber, the thrust created by this concave tailcone depends on the nature of that concave curve. In the image on page 2, the suction would have created more thrust if the concave curve was sharper. In that case the total Cd would be lower than what is shown.
-Dave B