Active shutters

[bandit86]

My brother came over in his F150, i noticed it had an active shutter behind the grille, but way behind more in front of the rad.

Does that still force air to go over the hood? Or is there a different purpose?

[aerohead]

Originally Posted by bandit86

My brother came over in his F150, i noticed it had an active shutter behind the grille, but way behind more in front of the rad.

Does that still force air to go over the hood? Or is there a different purpose?

The kinetic energy of the airflow can be better conserved flowing over, around, or under the outside of the body.
Air flowing 'through' the engine bay is exposed to something likened to a torture chamber, where separation is present everywhere. The turbulence produced inside there can never be converted back to useful energy. It just becomes heat. Waste ( 'entropy' associated with the 2nd-Law of Thermodynamics ).
Under low load, when there's less engine heat flux to dispose of, the radiator is essentially 'over-sized,' so by 'shuttering' a portion of the radiator area, unnecessary flow can be shunted to where it's energy can be better utilized.
It doesn't matter where the flow is arrested, as long as it's arrested.

[bandit86]

Interesting, i never thought of it that way but i suppose if the flow at the end is restricted and pressure is built in an area, then headwind would be forced over the outside, the pressurized area being the barrier.

I didnt look around to see how good everything else is sealed up

[freebeard]

The classic exampl is the P-51:


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