[lenswerks]

If your interested in reducing drag the pop-up roof spoiler as you know if not designed for that. Back in 2003 there was much written about at autobahn speeds the rear would lift.

The idea of this spoiler is to disrupt the flow over the roofline which keeps the rear from getting lite.

Reference this - Beetle Aerodynamics / Roofspoiler

Are you asking because you are interested in improving fuel economy? For that you would have to extend the rear.

 

[lenswerks]

I'm intrigued by your question! Where did you find air flow diagrams or wind tunnel test videos of the NB to know how the air flows over and around the body. Or even a simulated air flow test with a scale model in a chamber. This is a very exacting science.


M.

Click on this - NB information is towards the bottom - Wool Testing