Windshield wiper cover prototype. Tried this out past couple of days. It sure make it quieter and it looks cleaner. The A pillar now seems a bit louder b/c now the wiper noise is stifled. I may do this in stainless.
One thing extra this covers, besides the wiper, is where the cowl and the A pillar meet low down. I noticed that the flow streaks from my long road trip crossed the A pillar right where there was a big step between the window and the A pillar. It's now flush.
I have been reading the R.H. Bernard book: Road Vehicle Aerodynamic Design.
A couple of things have stuck with me. One is that surface friction drag is up to 30% of modern car's total drag. More than I thought. The second thing is that a turbulent boundary layer has three times the drag of a laminar boundary layer so keeping that laminar flow really pays off. I've been inspired to do a bunch of what I thought previously to be seemingly insignificant tweaks. I sealed most of my door gaps. Usually you see the front gaps done but the Prius door gaps were simple to seal with weather stripping foam tape. I still have some more to do but I need to pick up some thicker foam for some areas. It's pretty darn weather proof.
Until I do the belly pan though, I don't expect these mods to really show up on the MPG numbers. Even then they are probably not measureable.
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Vortex generators are old tech. My new and improved vortex alternators are unstoppable.
"It’s easy to explain how rockets work but explaining the aerodynamics of a wing takes a rocket scientist.