Adding air to side mirrors.

[Peter7307]

Ahh , some interesting insights there.
Thanks to all posters.

Peter.

[euromodder]

Originally Posted by 3-Wheeler

The trailing edge of the housing should be closing in shape to reduce the wake behind the mirror.

That's exactly what Volvo have done on their S40/V50 range.

At least on the earliest (2004 thru 2007) and smallest versions of the mirrors, the black plastic aft part of the housing tapers in slightly.


The mirrors have since been increased in size twice, because they were rather small.

[Phantom]

I do not think that the tube would have to be very big. If a tube say the size of a garden hose or slightly larger were ran from the back of the engine bay to the side mirror and is terminated just before center with the outlet facing the front of the car (for diffusion) it could do a few things. First since there is lower pressure behind the mirror it would create a vacuum pulling air from the engine bay, along with this it could help reduce high pressure in the engine bay especially if it has a full belly pan. Once the car is warm it would work as a passive defroster. Also with the smaller tube it will not be able to move a lot of air but should have decent velocity.

[Otto]

1. Just how big does a side mirror need to be?

2. How much base or strut does it really need?

3. If the RAF Spitfire fighter plane of WWII got by with a faired ~4" round mirror on a ~4" thin stalk and flew at ~400mph (apparently with no ill effects), why do we ~70 years later need anything bigger or less streamlined?

Thoughts?


I ask because my old Porsche has "flag" mirrors of clunky angular shape, flat, fat stalks, and housings at least 25% bigger than the mirrors. My Ford van has mirrors copied from Dumbo the elephant. This from companies old enough to know better.

Seems to me a thin stalk of teardrop profile and oriented into the relative wind, blended smoothly into an elliptical shell no bigger than the mirror itself, would be much better. Wouldn't be rocket science to include the tiny remote control motor gizmo and a turn signal.

[euromodder]

Originally Posted by Otto

1. Just how big does a side mirror need to be?

I'd like to see both the ground and the vehicles aft and to the side of me.
On the earlier S40/V50 that wasn't the case: adjusted to see traffic, they're rather useless for parking, and vice-versa. So they were increased in size on later models.

3. If the RAF Spitfire fighter plane of WWII got by with a faired ~4" round mirror on a ~4" thin stalk and flew at ~400mph (apparently with no ill effects), why do we ~70 years later need anything bigger or less streamlined?

The old Spit lost a few mph in top speed because of the external mirror, despite having well over 1000 HP
Probably lost a couple mpg as well, but no-one was keeping track of that back then.

[Peter7307]

Spitfires didn't need to shuffled out of underground shopping centre car parks either!

Mirror sizes and locations are dictated by legislators and not by common sense.

Cars may be driven by the many and legislated by the few but this was NOT their finest hour.

Peter.