41 replies to this topic

[minimender]

The rear skirt holds you back a bit as well, fill in the gap between front of rear subframe and rear valance

[Cooperman]

The A-post seam strips are 22 sq. ins each making a further 44 sq.ins. and the rear ones are the same, although the airflow will be so disturbed by the time it gets there that it's hard to estimate the effects.

The idea of plating between the front of the rear sub-frame and the rear valence lower edge is excellent, but again hard to measure.

So to make a Mini faster and with better acceleration you could reduce the weight by fitting Perspex windows, remove a lot of the sound-proofing, remove the wheel arch extensions, fit 4.5" wide wheels with 145 section tyres. Not only will it be a lot faster, it will use less petrol as well. And that is without touching the engine at all. 

Although the ultimate dry road holding is not quite as good as with a wider tyre, the handling is much better and the road-holding and braking in the wet are also likely to be improved as well.

Then move on to improving the suspension & the engine.

[Carlos W]

Go on a diet, smaller racing battery, only fill the tank half full.

[mab01uk]

The 'average' modern car achieves a drag coefficient of between 0.30 and 0.35

Tables of many here:

http://en.wikipedia....rag_coefficient

 

Depending on model the standard classic Mini shape (without Sportpack type wheels/arches) Cd = 0.48

and I think the Clubman is about 0.53

The New MINI hatch is 0.35

I have a detailed report on some aerodynamic testing results on a Classic Mini with some diagrams from many years ago......I will try to find it and post for information.

Edited by mab01uk, 14 July 2014 - 06:36 AM.

[Alex_B]

Wow that cd figure is huge in comparison to the new much larger shape! There must be lots that can be done to tidy up the airflow. If I have time over the summer I will try and create a quick model of the mini that's accurate enough for aero testing but I don't know if I will manage it due to two projects on my to do list and the difficulties in getting it through testing, and I'm not sure I can use the mini as the basis for my final year main project as it's not current enough nor are aerodynamic mods allowed in most racing regulations that govern the mini

[The Matt]

*cough* laser scan *cough*

[Alex_B]

I don't have access to on unfortunately so I will be doing it the old fashioned way on solidworks

[The Matt]

I could possibly borrow one, I'd have to ask.

[The Matt]

I don't have access to on unfortunately so I will be doing it the old fashioned way on solidworks

 

"old fashioned way"

 

Don't let the old engineers see that statement

[Alex_B]

It was somewhat tongue in cheek, and don't laser scanners need the surface to be white or is that a different type of 3d scanner?

[The Matt]

They work off all colours, some don't perform that well with dark, glossy colours though.  Main issue is that they won't pick up the transparancies so you either have to dust them or mask them with a grid of tape or something.

[Alex_B]

Ahh that shouldn't be an issue then, one of my uni mates scanned a model of his car last year for a project and ended up painting it white to get it to scan correctly

[Dan]

  We regularly get filming locations LIDAR scanned in order that the visual effects can be modelled correctly and they don't come around and paint the building / high street / cathedral / ocean liner white first!  The scanners read off more or less anything that isn't matt black velvet.

[Mini Manannán]

The 'average' modern car achieves a drag coefficient of between 0.30 and 0.35
Tables of many here:
http://en.wikipedia....rag_coefficient
 
Depending on model the standard classic Mini shape (without Sportpack type wheels/arches) Cd = 0.48
and I think the Clubman is about 0.53
The New MINI hatch is 0.35
I have a detailed report on some aerodynamic testing results on a Classic Mini with some diagrams from many years ago......I will try to find it and post for information.

I wonder how the estate compares with that figure? Better because it's longer or worse because of the barn door rear end?

[Vinay-RS]

I don't have access to on unfortunately so I will be doing it the old fashioned way on solidworks

 

Just googled "classic mini cad model" and found this:

 

http://www.3dcadbrow...px?3dmodel=5510

 

Dunno if you can use it. Plus don't really trust the solidworks solvers. Surely it would be better to mesh the car in an actually FEM/CFD package and solve using that programs built in eulerian solvers.