Mirror Aero

[Jim Garry]

No, not for a race car. For the tow vehicle. The mirror shown is from my GMC van. At 70 mph the air hitting this flat faced mirror housing makes a lot of noise.

I'm wondering if an aero shaped "cone" mounted on the front of it would reduce the noise.

Any thoughts guys?

[SEComposites]

Worth a try. I’d try something simple first. Carve a bit of foam roughly to shape and tape it on. You’d be amazed how much wind tunnel development relies on ‘tin and tape’. You could try a vertical gurney taped on too.

[problemchild]

Any thoughts guys?

Turn up the tunes!

[fastkart]

I used to work with Toyota (and many other OEM's) on developing external mirrors. As you would expect, there are three keys: 1)Getting the air to 'split' (ie. small radius nose cone) as smoothly as possible. 2)Smoothing the air back out [ie. flat top and bottom for as long as possible]. 3)Don't 'slam' the two air fronts back together [this is rather impossible]. Toyota worked VERY hard on #1 and #2. For #3, they just decided that turbulence was inevitable, so, they directed the noise away from the driver's ear and used sound attenuating side window glass.

[Rick Kirchner]

on my motorhome the turbulence rattles the side glass so much I'm considering getting rid of the mirrors and just using cameras. If I must use mirrors I'll just use something like the old bullet mirrors on my 73 pinto

[cjsmith]

Not sure what year your truck is. One possibility could be to replace the mirror with a more conventional truck mirror that has rectangular shape that is longer in the horizontal axes. If your truck is from 2007 to 2014 you can probably find some used ones to try. The sound may be coming from the front or rear side of the mirror. Getting the mirror further from the surface of the truck could help since the boundary layer is typically thick at the A pillar as the air wraps around the edge of the windshield. If you feel like experimenting, roll up some paper into a ball and use some 100 mph tape to the front side of the mirror, tapering it to the edges to make a more circular shape on the entire front surface. Obviously not a long term solution but it would give you an idea if there is value to changing the shape of the mirror.

Let us know what you come up with to do.

[Jim Garry]

Nice idea!

It's an 06 GMC van. Low miles. I only tow with it and it's off the road Nov to April.