Quote:
Originally Posted by blownb310
That's terrific aerohead.
Thanks for taking the time to research the Sentra's body specs further. Your findings are very encouraging!
I did very little with the front of the car. It's rounded but the surfaces are basically verticle. It doesn't seem very efficient to me. Is there anything you might recommend?
Mike
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Everything I'm going to say needs to be weighed against AeroCivic and what basjoos has achieved.
90-mpg from a car which originally returned 55-mpg with the VTEC engine ( I've witnessed this first hand with John Gilkison's Civic VX) is nothing to sneeze at.
Conventional wisdom has it that once flow is attached,that any further softening of forward leading edges will result in no mpg benefit.
So the PhD is going to say to forget the front end,it's good enough,go after the rear end.
The Ford Probe-IV violates this dogma and returns Cd 0.154.With a 'conventional' cooling system that Cd might rise to 0.172 (basjoos territory!)
The Probe-IV has only 28% of a full boat tail.
There was an Italian concept car,the 'APOLLON' which achieved Cd 0.13 with very little aft-body.There is very little published for that car.
The Renault Vesta II has 28.5% of a full boat tail and achieves Cd 0.19,with a blunt nose,but 'PERFECT' windshield.If Renault were to move the Vesta's cooling system to the rear it might see sub-Cd 0.17.Don't know.
Klemperer's 'minivan' model of 1921 achieved Cd 0.16 with very little tail at all.It was a 1/10th-scale,no details,just a smooth model.It's aft-body does not exceed Mair's magic 22-degrees,although it gets there very aggressively!
My opinion is ,that since we know so little about fore-body mods/mpg,and that the 'experts' tell us to focus on the aft-body,that we SHOULD focus on the aft-body.
I tried some tricks at Bonneville and saw little from massaging the front,but when I went after the tail I got big gains for speed and mpg (I averaged 60.6 mpg from the Salt Flats to Los Angeles,and back to Texas.
I recommend you try the 'Template',push it to any length you're willing to live with.Do as much plan-taper on the sides as well.
You shouldn't see any separation at all.Empirical studies have shown that it's impossible to have separation.
From tuft testing by members,it looks like we can 'cheat; a little,but I wouldn't go too far afield.