Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - example of STAR CCM+, @ Chalmers University

From the above link.

Quote:

Additionally, a major downforce was noted on the rear axle
compared to the front when the air brake was engaged.

Yep, downforce would be disproportionate.

1955 Mercedes-Benz 300SLR air brakes.
https://4.bp.blogspot.com/-LXBtGfR4q...h+airbrake.jpg

https://4.bp.blogspot.com/-oPieq78wp...5+airbreak.jpg

I wonder why they didn't go the more tried and true perforated flaps of US Navy dive bombers in WW2.

https://www.quora.com/In-WW2-why-wer...nes-perforated
https://qph.cf2.quoracdn.net/main-qi...b72fc92ad-pjlq

https://aerofred.com/details.php?image_id=80812
https://aerofred.com/data/extra_imag..._Dauntless.jpg

Quote:

..............the split flaps where the flaps work independently are together i.e. the flaps can act as a "normal flap" in that the bottom half drops in the top does not deploy. In a dive bombing situation extend i.e. the top flap goes up the bottom flap goes down and back to his air brakes so that when the airplane is in a vertical dive it doesn't exceed maximum airspeed for the pullout.