Quote:
Originally Posted by scottoriou
So what if instead of an entire boat tail I created sort of a prius shape to the rear of the car. It would possibly increase the rear section area which could possibly hurt the performance but if clean separation was induced with sharp corners on all parts would it be helpful? here are some pictures of things i was thinking.
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This is kinda where Kamm and Korff were going with their recommendations.They realized that a full tail was 'impractical' with respect to driveways and parallel parking and such,and advocated that the tail be truncated at a point where the wake area equaled 50% of frontal area.
There's still 50% of the drag left on the table mind you ( good for another 25% mpg ), but your not strapped with an enormous cantilevered tail hanging way out there.
Adding only a foot to my CRX was good for Cd 0.235 and 60+ mpg @ 55 mph,52 @ 70.
I would not be concerned with 'burst'.Your Cd is fixed at about 20 mph and the separation point at the rear isn't moving around.That's straight from Hucho.
I would encourage you to do a shorter tail exactly on the 'Template' rather than a longer one which either falls above or below it.
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The Renault Vesta II is an example of a "Template" car.She's good for 138 mpg @ 100 Km/h.
The Mercedes 'Boxfish' is also a "Template" car.
Both have Cd 0.19 and are very short for their Cds.They have only about 32% of aft-body.( the New Beetle,also a 32% aft-body car suffers with Cd 0.38 due to the pseudo-Jaray 'fastback' roofline,which breaks all the rules of streamlining )
------------------------------------------------------------------------- The other thing is, that these cars are 'plug and play.' If you want more mpg at a later date,you just plug in a longer tail.Modular!