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Old 04-09-2008, 04:39 PM   #18 (permalink)
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ride height

I'm going to also weigh in with the "it depends" bunch.Dr. Michael Seal's Western Washington University's Viking series of 100-mpg cars used an increased ride height to channel air under their reverse airfoil bodies.Ford Motor Company used active suspension to lower their Probe series hyper-milers.Generally,my thoughts as regards to members cars would be that lowering,as mentioned,veils part of the tire/wheel from the air stream,effectively reducing frontal area,which usually reduces drag,arithmetically,as a percentage of area reduction.Also,lowering increases the fineness-ratio,something Hucho's book also addresses in the boattail modifications to the Mercedes C-111 research vehicle.Since road vehicles all suffer from the "mirroring" effect of the ground,anything which can be done to increase fineness-ratio is a shoe-in for lower drag.,and I believe there is no dispute with regards to this.Dr.Seal attempts to move up out of ground-effect into "clean" air,where fineness-ratios are doubled,Ford uses active suspension to lower cars on the highway,where ground clearance demands are lower than in an urban environment.A significant portion of Ford's low drag is attributed to "lowering".The recent article on the fuel cell Fusion also attributes "lowering" as a significant (0.08 off Cd ! ) to the cars drag reduction.With exception to W.W.University,all my accounts of drag reduction,aside from general coachwork,everyone lengthened the vehicle,lowered the vehicle,or did both.Since there are exceptions,we probably need to every vehicle on a case-specific basis.P.S.,also,in Hucho's book you'll find Dr. Morrelli's body which he developed at Pininfarina,which exhibits very low drag in "clean" air,and looks exactly like the Aptera,however suffers a drag increase as it is lowered into ground-effect.
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