[hat_man]

Hello again everyone.

Yep, it's the guy with the silly questions and crazy ideas again. I feel like the underachieving student with the brain trust here at EM, but asking silly questions is just a part of my learning process. This again is something I would never do to a vehicle, but I sometimes wonder how changes affect the aero penalty of a vehicle. Most of the changes we make to our vehicles don't completely negate an aero penalty but lessen it so that the net result is a smaller penalty (positive gain?). This is just another one of those silly ideas that popped into my head while leafing through Aerodynamics of Road Vehicles again.

I know there is a high pressure area in the front of a vehicle as it moves down the road, and a lower pressure area in the rear. I believe the idea of "air curtains" is to help remove some of that high pressure in the front and move it to the sides of the vehicle so it can flow with the attached air on the sides. To me this makes a positive gain because it lowers the difference (delta ▲?) between the two pressure areas.

So the first question I had was..... what if you could move some of the high pressure from the front of the vehicle and use it to fill the low pressure void in the rear? Imagine a 6" tube from the grille running through the vehicle that exits above the bumper into the low pressure void. I'm assuming that this would create a smaller difference between the front and rear and be a theoretical benefit?

Then, while watching a NASCAR race I saw the NACA (?) ducts that move air to help keep the drivers somewhat cool. They openings must not have much aero penalty or they wouldn't use them like that. So the next crazy question was.....what if you cut two NACA ducts into a trunk (top or sides I'm not sure) or the outsides of a truck bed and tubed that air out the back above the bumper or out the tailgate (with some sort of bed cover not an open bed)?

Neither idea is practical because of having to open a trunk repeatedly for storage and losing the carrying capacity of a truck bed and I get that. But in my mind, it's a "what if....." or "wouldn't it be neat if....." kind of idea. Definitely not practical, but a way to try and better learn a concept.

Thanks for the thoughts on this and for always being willing to help me work out my crazy way of learning.