Armchair Aerodynamics Experts - Lift at speed

[jimbobsimmonds]

Hi all...

between p1ssing myself on the custard related thread i have been looking at the accessories offered by Volvo and noticed the 2004 S60T5 facelift spoiler "reduces lift by 20%"...

now i have taken my T5 to around Vmax and the car did feel pretty stable at those speeds but I was wondering how much lift is generated by a standard road car at say 120mph?

I would imagine it would be reasonably high as most modern cars have quite a curved upper profile and relatively flat underbodies (though i doubt enough to generate ground effect) so form a pretty usefull aerofoil profile, but then again, i am merely a person with a decent grasp of physics, not even an armchair expert

now before you all start hollering "it depends on the car" etc etc i'm looking for ballpark figures here, or actual figures for different models etc etc just to see what ranges are seen.

[MK_Bob]

For a 1980 Peugeot 305 GL (coefficient of lift 0.44) at 80 mph (36 m/s), assuming a density of air of 1.25 kg/cubic metre, and assuming a frontal area of 1.84 square metres:

655 Newtons (67 kg), theoretically.



It appears that you have to do quite a lot of work just to eliminate lift, let alone start producing downforce! The coefficient of lift of a 1994 Supertouring BMW M3 (with similar bodywork to that in the picture) still generated a small amount of lift, no downforce!



No, i have nothing better to do with my evening...

[Boosted LS1]

I should think most saloons generate lift in which case a spoiler would help as well as a frontal dam and maybe side skirts.