427 Cobra hood scoops

[cycleguy55]

I went for a brief drive today and realized shortly before hitting the highway that the hood wasn't latched. As an experiment I continued on. ~75 MPH and the hood stayed down - not even a wiggle.

If there was any pressure building up under there it would have lifted.

[strictlypersonl]

Originally Posted by cycleguy55

I went for a brief drive today and realized shortly before hitting the highway that the hood wasn't latched. As an experiment I continued on. ~75 MPH and the hood stayed down - not even a wiggle.

If there was any pressure building up under there it would have lifted.

When we raced an Austin Healey 100-4 (a similar shape to the Cobra) without a full windshield, we used loose leather belts at the rear. At speed, the rear would come up a couple of inches. The difference is that, with a windshield, high pressure extends forward enough to keep the hood down.

[cycleguy55]

Originally Posted by strictlypersonl

When we raced an Austin Healey 100-4 (a similar shape to the Cobra) without a full windshield, we used loose leather belts at the rear. At speed, the rear would come up a couple of inches. The difference is that, with a windshield, high pressure extends forward enough to keep the hood down.

I note the grille on the AH 100-4 is higher than is the opening on a Cobra. In addition the leading edge of the hood is higher and the hood itself has less front to rear slope on it than a Cobra hood. I'm not an aerodynamics expert, nor do I have access to a wind tunnel, but I believe the combined effect of these differences is quite significant.

Yes, the windshield pressure wave will affect the rear of the hood, but there are other factors at play.