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With top down convertible aerodynamics improving in recent years

Mercedes Benz SLR roadster top down 0.38
2001 Mercedes Benz SL top down 0.34
2011 E Class convertible top down 0.33
2014 BMW 4 series top down 0.33
2002 Audi A4 Cabrio top down 0.33

Which on paper could compete with the Bugatti Veyron 0.41 normal ride height, 0.36 lowered stance and 0.348 Super Sport drag coefficients.

Could theoretically a top down convertible be the worlds next fastest car?

Are front engine convertibles better than mid engine ones regarding aerodynamics?

Just for fun what would happen if the driver or passenger stuck his hand out of the window or roof with the top down at 300+ mph?
Besides needing helmets for wind buffeting and racing harnesses to avoid being pulled out of the seat are there any other things to consider at that speed?

Do you think that drag coefficient is the only variable that determines vehicle performance?

In any case, there are other issues with convertibles, notably the fact that it's difficult to get good torsional stiffness out of them without adding lots of weight.

Lycoming wrote: In any case, there are other issues with convertibles, notably the fact that it's difficult to get good torsional stiffness out of them without adding lots of weight.

This is a problem of the past. At least with super-sport class cars (such as agera R). Some gain next to no additional weight (or indeed nothing) as their carbon fibre shell is easily strong enough to maintain rigidity even without roof.

As for the above mentioned cars. You'd still need lots and lots of power to surpass veyron super sport and I don't see that happening any time soon. Agera R being a roadster could probably do it without too much trouble but so far all acceleration runs have been done with roof installed.

I'm gently wondering if other aspects of the aerodynamics of the car are important at high speed, and whether a convertible is better or worse for those.

Lycoming wrote:Do you think that drag coefficient is the only variable that determines vehicle performance?

In any case, there are other issues with convertibles, notably the fact that it's difficult to get good torsional stiffness out of them without adding lots of weight.

Likely they will need both a super-sturdy transmission tunnel (for front engine cars)


AND also door X bars


Or even no doors at all!
After all its a convertible.
It could just electrically lower the windows and the convertible top when punching the alarm keyfob button.
Of course when raining or snowing you will have to either get wet seats if the convertible top drops to allow access, or get in thru the window without lowering the top (like the Dukes of Hazzard did).
Still not bad as few hypercars are actually driven in rain or snow.

Juzh wrote:

Lycoming wrote:
As for the above mentioned cars. You'd still need lots and lots of power to surpass veyron super sport and I don't see that happening any time soon. Agera R being a roadster could probably do it without too much trouble but so far all acceleration runs have been done with roof installed.

Greg Locock wrote:I'm gently wondering if other aspects of the aerodynamics of the car are important at high speed, and whether a convertible is better or worse for those.

Supposing power is NOT an issue, what about convertible aerodynamics?

g-force_addict wrote: Supposing power is NOT an issue, what about convertible aerodynamics?

If power is not an issue, then neither is the aerodynamics.

Lycoming wrote:In any case, there are other issues with convertibles, notably the fact that it's difficult to get good torsional stiffness out of them without adding lots of weight.

Possibly generally true but a recent exception would be the McLaren MP4-12C where the tub is designed with an open top from the start. This means the convertible is not much heavier and no more compliant than the coupé: