Aerodynamics of MCI buses

[Dreadnought]

I found a paper of testing done in conjunction with MCI and Purdue university. Paper number 801404. The drag coefficient of the vintage MCI buses is far better than I had imagined. The MC7 Is better aerodynamically than the MC8 (and by inference the MC9 Im sure). I'm not just talking about the frontal area but the drag coefficient too.
All manner of mods were tried and the aerodynamics were improved- but it was harder to apply to the MC8. The biggest source of drag on the front of the MC7 is what they call 'the vista cruiser' hump on the roof and the sharp edges around the windscreen and 'visor' above the windscreen. All their testing in the wind tunnel was corroborated with real world measurements and testing was also done at various yaw angles, just as we did at Navistar on the Prostar and lonestar.

By inference the MC5 will be better aerodynamically than the MC7- as it doesn't have the 'vista cruiser hump' and has an even lower frontal area.

At zero degree yaw angle the MC7 baseline was measured at 0.554. I would estimate the MC5 at better than 0.54. The MC8 is around 0.65. This would explain why I achieve such good mpg numbers along with the manual box and tall gearing. The heavier Mc7s often had 3.73 and even 4.11 rear ends.
The mods they did to the MC7 made them look kind of goofy.