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aerohead · 11-30-2009, 07:20 PM

Darin,the tuft images look great.They may be a little "nervous" in places,but they're mostly pointed "back" which means attached flow and no circulation.
That's about all one could hope for,and the base pressure in the wake should really be coming up closer to your forward stagnation pressure now.
Will be anxious to see your mpg although it's a rough time for testing,weatherwise now.
As to the maximum angle,it would appear that 22-degrees is the maximum for passive aerodynamics.Anything steeper and you'll need suction-slots.
Mair's boat tail R&D arrived at 22-degrees.The SAE paper on the Dodge Daytona reveals that Chrysler Aerospace arrived at 22-degrees.Many of the concept cars have "apparent" angles which are pretty steep until you figure what happens with their active suspensions,with dropped noses kicking their hineys up to a "shallower" angle.If I take a protractor to the back of the aerodynamic template it comes in at 22-degrees.
The trick is to maintain the progressively-increasing curvature,building up to the maximum that we see with the ubiquitous teardrop.

11-30-2009, 07:20 PM	#159 (permalink)
aerohead Master EcoModder Join Date: Jan 2008 Location: Sanger,Texas,U.S.A. Posts: 16,279 Thanks: 24,401 Thanked 7,367 Times in 4,766 Posts	tail Darin,the tuft images look great.They may be a little "nervous" in places,but they're mostly pointed "back" which means attached flow and no circulation. That's about all one could hope for,and the base pressure in the wake should really be coming up closer to your forward stagnation pressure now. Will be anxious to see your mpg although it's a rough time for testing,weatherwise now. As to the maximum angle,it would appear that 22-degrees is the maximum for passive aerodynamics.Anything steeper and you'll need suction-slots. Mair's boat tail R&D arrived at 22-degrees.The SAE paper on the Dodge Daytona reveals that Chrysler Aerospace arrived at 22-degrees.Many of the concept cars have "apparent" angles which are pretty steep until you figure what happens with their active suspensions,with dropped noses kicking their hineys up to a "shallower" angle.If I take a protractor to the back of the aerodynamic template it comes in at 22-degrees. The trick is to maintain the progressively-increasing curvature,building up to the maximum that we see with the ubiquitous teardrop.