How hard would it be to make an aero hardtop?

[Cd]

One of the reasons that a soft top would be easier to do is the fit and finish problem.
It wouldn't be that out of place ( if it was not "perfect" ) compared to some of the soft tops that I have seen on some Miatas and other convertibles.

[basslover911]

Originally Posted by Cd

LunarHighway : Wow ! I love how the curve of the window echos the curve of the scoop below it. Style !
Well done !
I'm really liking the look of that hard top !

As far as a down turned spoiler, the idea is that you want the airflow to follow the ideal shape as long as possible. By having a flat of upturned spoiler, you are kicking the airstream out of the ideal downward angle.

( But that is just my un-educated guess. )

Yea but I dont know if that window is plausible Ill have to look into it or add a little window to get that curve because the stock window is not like that...

Well the downward angle would work IF the airflow stays attatched... I dont know if the angle of the top is to steep for it to stay attatched though...

Just like in the hatchbacks that I have seen here, most spoilers they use are straight not downward...

[Bicycle Bob]

The Honda CRX was a good example of a well-angled rear window that flattened out just before the back end. Without that detail, the flat back and wake could have been a bit smaller, but it wasn't done for styling, but in order to trip the air into a single large vortex instead of many smaller, random ones.

The best angle for the back window depends on how clean the shape is ahead of it. Turbulent air will follow a more abrupt shape.

[lunarhighway]

i've recently compared some profiles in low drag cars 0.29 and lower and it seems most of these cars have a roof angle between 15 and 16 degrees

here's a drawing of the testing i did i just traced a profile drawing of the car and added some lines for measurement

[basslover911]

Hmmm so the slope of those hardtop photoshops should be alright... I also noticed how most of those have a straight edge at the end instead of continuing downward...

Should be for a reason right?!

[MazdaMatt]

my guess would be either style or stability.