Metro aerodynamics

[ZugyNA]

Airplanes do?

[Silveredwings]

Originally Posted by ZugyNA

Airplanes do?

Airplanes have them only for the purpose of reducing wingtip vortices, which are side effects of producing lift. The heavier the wing loading, the higher the WTVs.

Some racing cars have winglets (short ones) because the wings have a small aspect ratio and produce heavy downforce, and so probably benefit from reducing WTVs.

If a wing was used for a modest amount of flow redirection, it should produce only a small amount of induced drag (proportional to the amount of lift produced and therefore WTVs).

[MetroMPG]

Finished cutting the front

[ZugyNA]

Originally Posted by MetroMPG

Why I'm procrastinating on this, I don't exactly know.

Probably because you just KNOW that you SHOULD be testing vortex generators?

[MetroMPG]

Have to give you points for persistence! Tell you what: before I make a fiberglass boat tail, I'll test VGs first.

[Compaq888]

Originally Posted by MetroMPG

Have to give you points for persistence! Tell you what: before I make a fiberglass boat tail, I'll test VGs first.

I wish you lived closer to me. I don't have time to do anything to my car. I haven't done any of the aero mods on my car.

[zpiloto]

Originally Posted by MetroMPG

Have to give you points for persistence! Tell you what: before I make a fiberglass boat tail, I'll test VGs first.

You'll have to test the boat tail with VG's

[MetroMPG]

I'll have to test VG's on my VG's.

---

Front portion of the undertray is in place & fastened. I got most of the center section done this evening too.

I - gasp - drilled holes in the underbody to fasten the coroplast. I think that's the real reason I've been procrastinating. I just feels so wrong to drill underneath - thinking of rust.

Once all the panels are in place, I'm going to do a B-A test, where I do some runs with the full tray, then remove it on the roadside and repeat the runs. I'm not doing A-B-A. Too complicated.

After the test, I'm going to have the car professionally undercoated and then put the panels back on.

The trickiest area left to do is the rear control arms. They hang down LOW into the flow - they're located about at the halfway point between the road and the bottom of the rear bumper. I'm thinking I may try to use the coroplast to extend them backwards in a teardrop shape. Complicated, but they're definitely a drag problem the way they are now, all blunt and exposed to the flow.

[MetroMPG]

optimistic that the tray could be significant - I'm smoothing out some serious "excrescences".

[The Toecutter]

Anyone want to make any guesses on what the tray is worth @ 55 mph? After seeing the effect of the unloaded roof racks on the top of the car, I'm cautiously optimistic that the tray could be significant - I'm smoothing out some serious "excrescences".

You mean the whole undertray itself vs. not having one?

4-7%.