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aerohead · 08-02-2012, 06:24 PM

The 5:1 L/D ratio is for the 'apparent' ground reflection body,measured at the ground plane.Along with it's sister image below the ground it forms the 2.5:1 streamline body.
A car and it's reflection below the ground is the premise for evaluating it's aerodynamics.
The concept was first realized and introduced by Paul Jaray and gained traction after Ludwig Prandtl's and Edmund Rumpler's wind tunnel work.
The original 'Template'-C illustrates this concept.
Paraphrasing Hucho:" the low drag body is represented by the streamline body and it's reflection below the road surface."
I have cut away the ground clearance of the body based upon SAE 'approach,ramp,and breakover clearance angles.
If you extrapolate the aft-body out and down to the ground plane,it creates the aft-body of the 2.5:1 streamline body,never exceeding Mair's 22-degree angle.
I've essentially ignored the forebody,as mentioned in the 'Template' thread,as Hucho recommends we concentrate on the back of the vehicle for streamlining purposes.

08-02-2012, 06:24 PM	#469 (permalink)
aerohead Master EcoModder Join Date: Jan 2008 Location: Sanger,Texas,U.S.A. Posts: 16,272 Thanks: 24,394 Thanked 7,365 Times in 4,764 Posts	5:1 The 5:1 L/D ratio is for the 'apparent' ground reflection body,measured at the ground plane.Along with it's sister image below the ground it forms the 2.5:1 streamline body. A car and it's reflection below the ground is the premise for evaluating it's aerodynamics. The concept was first realized and introduced by Paul Jaray and gained traction after Ludwig Prandtl's and Edmund Rumpler's wind tunnel work. The original 'Template'-C illustrates this concept. Paraphrasing Hucho:" the low drag body is represented by the streamline body and it's reflection below the road surface." I have cut away the ground clearance of the body based upon SAE 'approach,ramp,and breakover clearance angles. If you extrapolate the aft-body out and down to the ground plane,it creates the aft-body of the 2.5:1 streamline body,never exceeding Mair's 22-degree angle. I've essentially ignored the forebody,as mentioned in the 'Template' thread,as Hucho recommends we concentrate on the back of the vehicle for streamlining purposes.