non-moving aero grill blocks?
 

...just got my 1987 edition of HUCHO and while skimming through it, I thought about the patent(s) that Ford had on their new "belt" grills.

...has anybody studied the aero relationships between "sieve" and "shutter" effects of screen-mesh and flat-belt/bar grills?

• At what speed does a mesh-type grill (like the new Cadillac STS, etc.) switch over from acting like a sieve and begins to act like a shutter?

•Same question for the Ford bar grills?

...anybody know what the "describing" empirical equations might be for these two approaches to non-moving aero grill blocks?

There was a thread about that, sometime last year iirc. I'll try to find it.

EDIT: Here we are:
Solid state drag reducing vehicle grille
Adding grill mesh
grill "shield" rather than block?

Old Tele man -

I remember that thread too. Pretty sure I posted this on that thread :

http://ecomodder.com/forum/member-cf...esta-grill.jpg

CarloSW2

...that's the one, but what's the "cross-over" speed where the air transitions from 'passage' to 'blockage'?

...any rule-of-thumb equation given? I didn't find one on the Ford Patent.

1976
 

In 1976,Ford of Cologne,Germany released info on their 'Lamellar' grille which was passive,allowing full airflow at low velocities,the choking the flow down with internal stalling around the grille elements.They claimed a 12% drag reduction,which is the 'typical' drag of the entire cooling system.

speed
 

I don't recall that they actually ever said.Drat!